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From: Ben Elliston <>
To: java <>, gcc-patches <>
Subject: PATCH, boehm-gc: silence warning
Date: Mon, 30 Nov 2009 04:28:00 -0000	[thread overview]
Message-ID: <1259555306.23081.4.camel@bapbop> (raw)

When compiling mark_rts.c, GCC warns about taking the address of a local
variable.  This is not a bug, but an explicit hack to get the
approximate address of a new stack frame, to calculate the limits of the
current frame.  There is a cleaner way to do this with GCC: use
__builtin_frame_address.  My reading of the code suggests that this will
work just as well.

Tested with a bootstrap on x86_64-linux and a full regression testsuite
run, including make check-target-boehm-gc. Okay for mainline?

2009-11-30  Ben Elliston  <>

	* mark_rts.c (GC_approx_sp): Use __builtin_frame_address when
	compiling with GCC rather than taking the address of a local

Index: mark_rts.c
--- mark_rts.c	(revision 154749)
+++ mark_rts.c	(working copy)
@@ -376,7 +376,13 @@ ptr_t GC_approx_sp()
 #   ifdef _MSC_VER
 #     pragma warning(disable:4172)
 #   endif
-    return((ptr_t)(&dummy));
+#ifdef __GNUC__
+    /* Eliminate a warning from GCC about taking the address of a
+       local variable.  */
+    return __builtin_frame_address (0);
+    return ((ptr_t)(&dummy));
+#endif /* __GNUC__ */
 #   ifdef _MSC_VER
 #     pragma warning(default:4172)
 #   endif

             reply	other threads:[~2009-11-30  4:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-30  4:28 Ben Elliston [this message]
2009-11-30 10:07 ` Andrew Haley
2012-01-10 23:40   ` Gnu Classpath on HP webOS : connexion problem between escher and X server / or loadling escher problem by Gnu classpath Yannick
2012-01-10 23:53     ` Brian Jones
2012-01-11  9:05     ` Mark Wielaard
2012-01-16 20:44       ` Yannick
2012-01-16 20:45       ` Yannick
2012-01-17 19:13         ` Yannick

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