Re: Problem with location lists and variables on stack

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Oct 06, 2003 at 08:40:16AM +0200, Josef Zlomek wrote:
> > > No, but DW_AT_frame_base should be a location list describing the
> > > changes in the frame base.
> > 
> > How can we just describe "please use the CFA" and avoid duplicating
> > this part of the unwind info?

Yea, I'd like that too.  We can't right now, but it seems reasonable,
so I'll propose it on the DWARF-2 list.  Until then it's just a space
cost.

> Daniel Berlin has already written support for GCC to generate location
> list for DW_AT_frame_base.
> DW_AT_frame_base is a location list as any other (actually only the
> offsets relatively to original stack pointer at function start are needed).
> GDB then uses this location list to adjust offsets of other variables
> addressed using stack pointer.
> With Daniel Jacobowitz's fix for GDB it works :-)
> i.e. you can see correct values for variables located on stack
> even when stack pointer changes because of push, pop, etc.
> 
> Current GCC patch can be downloaded from:
> http://artax.karlin.mff.cuni.cz/~zlomj9am/download/vt-main.patch
> 
> (because currently GCC is in stage 2 it has to wait until GCC is in stage 1)

I suppose this is true, but it's really unfortunate.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer