Re: Variable Length Arrays (VLA) proposal

[Chris January <chris.january@allinea.com>]

On Sun, 2013-06-30 at 18:54 -0700, Joel Brobecker wrote:
> > Just to add another possibility, we implemented VLA for Fortran by
> > wrapping read_var_value and then adding a call to f_fixup_value which
> > 'fixed up' the type of the variable (filled in the array bounds, etc.)
> > by modifying the original type. (It also auto-dereferences pointers).
> 
> One of the questions that need to be asked is whether it's OK to modify
> the type in place like that. For Ada, we create new types with the
> bounds fixed-up. I think you might run into problems with cached
> values, such as the values accessible from the history (Eg: "print $2").

Do you mean in this scenario (excuse the mixed Fortran / GDB commands)?

ALLOCATE(array(10, 10))
(gdb) print array
$1 = (...)
DEALLOCATE(array)
ALLOCATE(array(20,20))
(gdb) print $1

Then no, modifying the original type does not work in that case (it
breaks $1 as you say).

Chris