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Re: Fixing stack backtraces on 26-bit ARM
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Ben Harris <bjh21 at NetBSD dot org>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Thu, 26 Oct 2006 16:43:29 +0100
- Subject: Re: Fixing stack backtraces on 26-bit ARM
- References: <Pine.LNX.4.61.0610192020220.15551@smaug.linux.pwf.cam.ac.uk>
On Thu, 2006-10-19 at 20:46 +0100, Ben Harris wrote:
> At present, stack backtraces don't work on 26-bit ARM systems because R15
> pulled out of stack frames doesn't get its PSR bits stripped out, so PC
> ends up appearing to point somewhere insane. This is a simple patch (from
> NetBSD CVS) to apply ADDR_BITS_REMOVE to values pulled from stack frames
> to generate PC. This patch may have been approved once before, in 2001,
> but it was never applied.
>
> 2006-10-19 Ben Harris <bjh21@NetBSD.org>
>
> * arm-tdep.c (arm_unwind_pc): Use ADDR_BITS_REMOVE.
>
> --- gdb/arm-tdep.c 2 Jul 2006 21:04:40 -0000 1.3
> +++ gdb/arm-tdep.c 14 Oct 2006 10:42:53 -0000 1.4
> @@ -1056,7 +1056,7 @@ arm_unwind_pc (struct gdbarch *gdbarch,
> {
> CORE_ADDR pc;
> pc = frame_unwind_register_unsigned (this_frame, ARM_PC_REGNUM);
> - return IS_THUMB_ADDR (pc) ? UNMAKE_THUMB_ADDR (pc) : pc;
> + return ADDR_BITS_REMOVE (pc);
> }
>
> static CORE_ADDR
I think it would be better to just call arm_addr_bits_remove() directly
(more efficient within the back-end); but otherwise this is OK.
R.