Re: [PATCH v3 10/11] c: Turn -Wincompatible-pointer-types into a permerror

[Richard Earnshaw <Richard.Earnshaw@foss.arm.com>]

On 05/12/2023 09:46, Florian Weimer wrote:
> * Richard Earnshaw:
> 
>> (I think it's this patch, not one of the others in the series).
>>
>> This breaks building libgfortran with newlib on arm and aarch64:
>>
>>
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2208:46:
>> error: pointer type mismatch in conditional expression
>> [-Wincompatible-pointer-types]
>>   2208 |                           dtp->common.iostat : &noiostat;
>>        |                                              ^
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2208:27:
>> note: first expression has type ‘GFC_INTEGER_4 *’ {aka ‘long int *’}
>>   2208 |                           dtp->common.iostat : &noiostat;
>>        |                           ^~~~~~~~~~~~~~~~~~
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2208:48:
>> note: second expression has type ‘int *’
>>   2208 |                           dtp->common.iostat : &noiostat;
>>        |                                                ^~~~~~~~~
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2224:34:
>> error: passing argument 2 of ‘dtp->u.p.fdtio_ptr’ from incompatible
>> pointer type [-Wincompatible-pointer-types]
>>   2224 |           dtp->u.p.fdtio_ptr (p, &unit, iotype, &vlist,
>>        |                                  ^~~~~
>>        |                                  |
>>        |                                  int *
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2224:34:
>> note: expected ‘GFC_INTEGER_4 *’ {aka ‘long int *’} but argument is of
>> type ‘int *’
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2225:31:
>> error: passing argument 5 of ‘dtp->u.p.fdtio_ptr’ from incompatible
>> pointer type [-Wincompatible-pointer-types]
>>   2225 |                               child_iostat, child_iomsg,
>>        |                               ^~~~~~~~~~~~
>>        |                               |
>>        |                               int *
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/list_read.c:2225:31:
>> note: expected ‘GFC_INTEGER_4 *’ {aka ‘long int *’} but argument is of
>> type ‘int *’
> 
> Presumably the fixes will look like this?
> 
> diff --git a/libgfortran/io/list_read.c b/libgfortran/io/list_read.c
> index db3330060ce..4fcc77dbf83 100644
> --- a/libgfortran/io/list_read.c
> +++ b/libgfortran/io/list_read.c
> @@ -2987,13 +2987,13 @@ nml_read_obj (st_parameter_dt *dtp, namelist_info *nl, index_type offset,
>   	    /* If this object has a User Defined procedure, call it.  */
>   	    if (nl->dtio_sub != NULL)
>   	      {
> -		int unit = dtp->u.p.current_unit->unit_number;
> +		GFC_INTEGER_4 unit = dtp->u.p.current_unit->unit_number;
>   		char iotype[] = "NAMELIST";
>   		gfc_charlen_type iotype_len = 8;
>   		char tmp_iomsg[IOMSG_LEN] = "";
>   		char *child_iomsg;
>   		gfc_charlen_type child_iomsg_len;
> -		int noiostat;
> +		GFC_INTEGER_4 noiostat;
>   		int *child_iostat = NULL;
>   		gfc_full_array_i4 vlist;
>   		formatted_dtio dtio_ptr = (formatted_dtio)nl->dtio_sub;
> 
> 
> Apparently the targets I built define GFC_INTEGER_4 as int, so this
> didn't show up.

It looks reasonable to me, but I'm not a real user of libgfortran, so 
there's possibly something more subtle that I've missed (I can't even 
guarantee I copied all of the errors from the build log).

I've copied Tobias as a fortran maintainer, but I don't know if this is 
his forte either, though perhaps he might know who's it is.

R.

> 
> Thanks,
> Florian
>