Re: Can one debug 32-bit x86 images with an x86_64 gdb?

[Andrew Cagney <ac131313@xxxxxxxxxx>]

[switched mailing list as this is redhat specific]

John Yates wrote:
> We are starting to port our 32 bit product to an x86_64
> platform (RH 4.0 beta2).  Once we have it running as a
> 32 bit image (still compiled with gcc 2.96) we will start
> the slog to gcc 3.x and a full 64 bit port.
>
> Except for the 32 bit gcc which we have had to migrated
> -- our code currently includes numerous anachronisms no
> longer accepted by the 3.x compilers -- we have been able
> to coax the native system tools (bison, ar, ld, etc) into
> compliance with our 32 bit build procedure.
>
> Debugging is a different story.  The install gdb image
> describes itself as:
>
>   6.1post-1.20040607.46rh
>   x86_64-redhat-linux-gnu
>
> It does not decline to debug our 32 bit images yet it
> produces total garbage.  Is there a flag or environment
> variable that I may have overlooked?  Or is a single gdb
> image not intended to fulfill both roles?

I'd first confirm that the Red Hat [vendor] supplied compiler can 
build/debug a 32-bit application (gcc -m32).

Assuming that's the case (I expect it to since I test it and the results 
match 32-bit on 32-bit :-) I'd then start looking for other querks in 
your non-standard 32-bit build environment.  Off the top of my head: was 
that 32-bit environment built 32-bit; does it work on 32-bit systems; is 
the debug info being corrupted (stabs vs dwarf-2).

Andrew