[patch, Fortran] PR61933 Inquire on Internal Units

[Tobias Burnus]

Hi Jerry, hi all,

sorry for the slow patch review. I also still want to review your other 
inquire patch.

Jerry DeLisle wrote:
> The fundamental problem: if the variable containing the unit number in 
> an INQUIRE statement is of type KIND greater than 4 and the value is 
> outside the range of a KIND=4 we cannot test for it within the 
> run-time library.  Unit numbers are passed to the run-time in the 
> IOPARM structures as a KIND=4. KIND=8 are cast into the KIND=4.  The 
> test case gfortran.dg/negative_unit_int8.f illustrates a case where a 
> bogus unit number can get passed to the library.
>

> Regression tested on x86-64 and Joost's case in the PR now works as 
> expected.
> OK for trunk?

Mostly OK, however, some remarks are below.

> 2015-01-18  Jerry DeLisle <jvdelisle@gcc.gnu.org>
>
>     PR fortran/61933
>     * trans-io.c (set_parameter_value): Delete use of has_iostat.
>     Redefine to not generate any runtime error check calls.
>     (set_parameter_value_chk): Rename of the former
>     set_parameter_value with the runtimr error checks and fix
>     whitespace. (gfc_trans_io_inquire_check): New function that
>     builds a runtime conditional block to set the INQUIRE
>     common parameter block unit number to -2 when unit numbers
>     exceed positive KIND=4 limits. (set_parameter_value_inquire):
>     New function that builds the conditional expressions and calls
>     gfc_trans_io_inquire_check. (gfc_trans_open): Whitespace. For
>     unit, use the renamed set_parameter_value_chk.
>     (gfc_trans_close): Likewise use renamed function.
>     (build_filepos): Whitespace and use renamed function.
>     (gfc_trans_inquire): Whitespace and for unit use
>     set_parameter_value and set_parameter_value_inquire.
>     (gfc_trans_wait): Remove p->iostat from call to
>     set_parameter_value. Use new set_parameter_value_chk for unit.
>     (build_dt): Use the new set_parameter_value without p->iostat
>     and fix whitespace. Use set_parameter_value_chk for unit.
>
> 2015-01-18  Jerry DeLisle <jvdelisle@gcc.gnu.org>
>
>     PR libgfortran/61933
>     * io/inquire.c (inquire_via_unit): Set existing to true for
>     any negative unit that is currently connected and any positive
>     units within range of KIND=4 value.  The unit value for any out
>     of range case that may occur if the user is using a KIND=8 will
>     have been set to -2 which is reserved and can never be opened,
>     and therefore the unit does not exist.
[...]
> +  /* The unit number -2 is reserved.  No units can ever have this
> +     value.  It is used here to signal to the runtime library that the
> +     inquire unit number is outside the allowable range and so cannot
> +     exist.  It is needed when -fdefault-integer-8 is uesed.  */

I don't know where this number is used, but I really should be a 
#define; if it is shared with libgfortran, it belongs to libgfortran.h. 
You wrote that -1 is also reserved and used; is the -1 somewhere 
defined? [Disclaimer: I have only browsed the other patch and do not 
recall whether it add, handles or #defines -1 - or whether -1 is already 
defined somewhere.]

> +      /* UNIT numbers should be greater than zero.  */
> +      i = gfc_validate_kind (BT_INTEGER, 4, false);
> +      cond = build2_loc (input_location, LT_EXPR, boolean_type_node,
> +			      se.expr,
> +			      fold_convert (TREE_TYPE (se.expr),
> +			      integer_zero_node));
> +      gfc_trans_io_inquire_check (cond, var, &se.pre);
> +
> +      /* UNIT numbers should be less than the max.  */
> +      val = gfc_conv_mpz_to_tree (gfc_integer_kinds[i].huge, 4);
> +      cond = build2_loc (input_location, GT_EXPR, boolean_type_node,
> +			      se.expr,
> +			      fold_convert (TREE_TYPE (se.expr), val));
> +      gfc_trans_io_inquire_check (cond, var, &se.pre);

The conditions could be combined with a 
fold_build2_loc(...,TRUTH_AND_EXPR,...).

Thanks for the patch!

Cheers,

Tobias