RE: Variable Length Arrays (VLA) proposal

Agovic, Sanimir
2013-07-04T08:18:07Z

Hello Chris,

I tried gdb_dtd with gfortran to debug a vla sample, without success:

$ 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

gdb-72-ddt4.0-31457 / gfortran (4.7.2 20121109) / fedora 18

$ gdb_dtd vla -q -batch -ex "b 4" -ex run -ex "p vla" -ex "pt vla" -ex next -ex "p vla" -ex "adv 6" -ex "p str" -ex "p str(0)"
Breakpoint 1 at 0x40095e: file vla.f90, line 4.

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)
5 ALLOCATE(character(len=2) :: str)
$2 = (( ( 0, 0) ( 0, 0) ) ( ( 0, 0) ( 0, 0) ) )
test () at vla.f90:6
6 vla(:,:,:) = 42
Cannot access memory at address 0x6060c0
warning: array or string index out of range
valarith.c:63: internal-error: find_size_for_pointer_math: Assertion `TYPE_CODE (ptr_type) == TYPE_CODE_PTR' failed.
[core dump]

Upper/lower bounds are always 0:1, allocated character seem not work, character subscripts lead to core dump.

-Sanimir

> -----Original Message-----
> From: gdb-owner@sourceware.org [mailto:gdb-owner@sourceware.org] On Behalf Of Chris
> January
> Sent: Friday, June 28, 2013 05:41 PM
> To: gdb@sourceware.org
> Subject: Re: Variable Length Arrays (VLA) proposal
>
> Hello Sanimir,
>
> On Fri, 2013-06-28 at 13:01 +0000, Agovic, Sanimir wrote:
> > (1)
> > Resolving check_typedef:
>
> > (2)
> > Type normalization:
>
> > (3)
> > Split struct type:
>
> 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).
>
> Regards,
> Chris January - VP Engineering - Allinea Software Ltd.
>

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