Variable Length Arrays (VLA) proposal

[Chris January]

On Thu, 2013-07-04 at 08:17 +0000, Agovic, Sanimir wrote:
> $ nl vla.f90
>      1  PROGRAM test
>      2      INTEGER,           ALLOCATABLE :: vla(:, :, :)
>      3      CHARACTER(len=:),  ALLOCATABLE :: str
>      4      ALLOCATE(vla (3, 4, 5))
>      5      ALLOCATE(character(len=2) :: str)
>      6      vla(:,:,:) = 42
>      7      str = '42'
>      8      call EXIT(0)
>      9  END PROGRAM test

> Breakpoint 1, test () at vla.f90:4
> 4           ALLOCATE(vla (3, 4, 5))
> $1 = <not allocated>
> type = integer(kind=4), ALLOCATABLE (0:1,0:1,0:1)

This highlights another issues implementing VLA. When printing a type
(e.g. in f-typeprint.c) you don't have the value of the variable and
therefore you can't evaluate the DW_AT_lower_bound, DW_AT_upper_bound,
DW_AT_allocated, etc. since they usually uses DW_OP_push_object_address
and we don't have the value address in f_type_print and friends. So to
print reliably print type type of an expression GDB actually needs to
evaluate it, something it hasn't needed to do before.

Regards,
Chris