Re: [PATCH] PR fortran/50549 - should detect different type parameters in structure constructors

[Tobias Burnus <tobias@codesourcery.com>]

Hi Harald,

On 27.03.22 21:44, Harald Anlauf via Fortran wrote:
> when assigning character pointers, we have a check for same length,
> which however does not trigger for character pointers within a
> structure constructor.
>
> The attached patch extends the character checks slightly to fix
> this loophole.  I've verified that NAG and Crayftn behave similarly,
> while Intel does not detect the length difference.
>
> Regtested on x86_64-pc-linux-gnu.
>
> OK for mainline?

Thanks for the patch! LGTM and I think GCC 12 is still okay.

However, I have a nit:

> --- a/gcc/fortran/resolve.cc
> +++ b/gcc/fortran/resolve.cc
> @@ -1375,11 +1375,22 @@ resolve_structure_cons (gfc_expr *expr, int init)
> ...
> +           long len_a, len_b;
> +           len_a = mpz_get_si (comp->ts.u.cl->length->value.integer);
> +           len_b = mpz_get_si (cons->expr->ts.u.cl->length->value.integer);
> +           gfc_error ("Unequal character lengths (%ld/%ld) for pointer "
> +                      "component %qs in constructor at %L",
> +                      len_a, len_b, comp->name, &cons->expr->where);

'long' might be int32_t instead of int64_t (e.g. on Windows, I think both
MinGW32 and MinGW64, but I am not quite sure). Thus, I wonder whether it
makes more sense to use:

   HOST_WIDE_INT, gfc_mpz_get_hwi() and '%wd'

I note that '%wd' (and '%lld') is only supported since last August
(commit https://gcc.gnu.org/r12-3044-g1b507b1e3c5 ), but now that it is,
I think we should use it at places where the value can be larger than INT_MAX.

I think at some point, we should also check the rest of the code and
change those mpz_get_si to gfc_mpz_get_hwi which can exceed INT_MAX.
Likewise, some of the %ld/%lu or %lld/%llu code should be also converted to %wd/%wu.

Tobias

PS: For using HWI with 'sprintf' instead of diagnostic's error/warning,
HOST_WIDE_INT_PRINT_DEC exists and has to be used.

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