Re: Lifetime of local variables

[Daniel Jacobowitz <drow@mvista.com>]

On Fri, Apr 12, 2002 at 10:19:50PM +0200, Martin Baulig wrote:
> Hi,
> 
> I was recently working a bit on debugging support for C# (using Mono)
> and I need a way to tell GDB about the lifetime of local variables. In
> C#, the JIT engine may decide to store two different variables at the
> same stack offset if they aren't used throughout the whole function.
> 
> Now I was wondering how to do this - DWARF 2 already has a
> `DW_AT_begin_scope' but unfortunately no `DW_AT_end_scope' - can we
> add this or something similar as a GNU extension ?

No.  I'd strongly object to adding any DWARF-2 tags without at least
discussing them with the DWARF committee (which is quite responsive, I
believe).

Also, I believe that this should be entirely subsumed by .debug_loc. 
The first variable's value may no longer be available, but it has not
actually gone out of scope, has it?  We should list it but claim that
its value is unavailable.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer