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From: Daniel Jacobowitz <drow@false.org>
To: Stefan Bylund <steby@enea.se>
Cc: gdb@sourceware.org
Subject: Re: Does GDB 6.7.1 for PowerPC require the framepointer register 	for backtracing?
Date: Mon, 11 Feb 2008 17:33:00 -0000	[thread overview]
Message-ID: <20080211173303.GA19507@caradoc.them.org> (raw)
In-Reply-To: <47B085BF.7090909@enea.se>

On Mon, Feb 11, 2008 at 06:28:31PM +0100, Stefan Bylund wrote:
> Hi Daniel,
>
> Thanks for your information. We use GCC 3.4.4, and when debugging we use  
> the compiler options -g -O0. I tried to add the compiler option  
> -fomit-frame-pointer (which seems to be included by -O1 and higher but  
> not by -O0) and then it works!!! So, my conclusion is that GDB 6.7.1 for  
> PowerPC tries to take advantage of frame pointer information in the  
> DWARF-2 debug information while GDB 6.3 does not. Is that correct? Is it  
> always safe to use -fomit-frame-pointer on PowerPC, i.e. will it not make 
> some type of C/C++ code undebuggable?

GDB 6.7 does use DWARF.  GDB 6.3 did not.

It sounds to me like you have a bug in the debug information generated
by your compiler.  I've seen some other bugs in the unwind tables
generated by GCC 3.4.x that were fixed in GCC 4.x.

-fomit-frame-pointer should not cause a problem for GDB as long as you
have valid DWARF information.

-- 
Daniel Jacobowitz
CodeSourcery


  reply	other threads:[~2008-02-11 17:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-11 11:03 Stefan Bylund
2008-02-11 13:08 ` Daniel Jacobowitz
2008-02-11 17:29   ` Stefan Bylund
2008-02-11 17:33     ` Daniel Jacobowitz [this message]
2008-02-12 10:24       ` Stefan Bylund
2008-02-12 13:31         ` Daniel Jacobowitz
2008-02-12 15:21           ` Stefan Bylund

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