This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: Expansion of __builtin_frame_address

From: Richard Earnshaw <rearnsha at arm dot com>
To: Paul Brook <paul at codesourcery dot com>
Cc: gcc at gcc dot gnu dot org, Mark Shinwell <shinwell at codesourcery dot com>, Mark Mitchell <mark at codesourcery dot com>, James E Wilson <wilson at specifixinc dot com>
Date: Fri, 02 Jun 2006 16:32:07 +0100
Subject: Re: Expansion of __builtin_frame_address
References: <4475C166.5090309@codesourcery.com> <448043D6.8030907@codesourcery.com> <1149260991.14209.26.camel@pc960.cambridge.arm.com> <200606021628.03919.paul@codesourcery.com>

On Fri, 2006-06-02 at 16:28, Paul Brook wrote:
> I agree that in general you need ancillary information way to get a backtrace 
> on Arm. However if you assume only Arm code code and -fno-omit-frame-pointer 
> then you can walk the frames. Given this assumption I think it make sense to 
> have _b_f_a(0) force the use of a frame pointer.
> 

No, in the general case you can't.  Because ARM and Thumb frames are
laid out differently.  In ARM code the frame pointer is in r11 (when not
eliminated); in thumb code it is in r7 (because r11 can't be used in
memory insns).

R.

Follow-Ups:
- Re: Expansion of __builtin_frame_address
  - From: Daniel Jacobowitz

References:
- Re: Expansion of __builtin_frame_address
  - From: Mark Shinwell
- Re: Expansion of __builtin_frame_address
  - From: Richard Earnshaw
- Re: Expansion of __builtin_frame_address
  - From: Paul Brook

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]