[Bug fortran/100917] Bind(c): errors handling long double real

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100917

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Sandra Loosemore <sandra@gcc.gnu.org>:

https://gcc.gnu.org/g:93b6b2f614eb692d1d8126ec6cb946984a9d01d7

commit r12-3321-g93b6b2f614eb692d1d8126ec6cb946984a9d01d7
Author: Sandra Loosemore <sandra@codesourcery.com>
Date:   Wed Aug 18 07:22:03 2021 -0700

    libgfortran: Further fixes for GFC/CFI descriptor conversions.

    This patch is for:
    PR100907 - Bind(c): failure handling wide character
    PR100911 - Bind(c): failure handling C_PTR
    PR100914 - Bind(c): errors handling complex
    PR100915 - Bind(c): failure handling C_FUNPTR
    PR100917 - Bind(c): errors handling long double real

    All of these problems are related to the GFC descriptors constructed
    by the Fortran front end containing ambigous or incomplete
    information.  This patch does not attempt to change the GFC data
    structure or the front end, and only makes the runtime interpret it in
    more reasonable ways.  It's not a complete fix for any of the listed
    issues.

    The Fortran front end does not distinguish between C_PTR and
    C_FUNPTR, mapping both onto BT_VOID.  That is what this patch does also.

    The other bugs are related to GFC descriptors only containing elem_len
    and not kind.  For complex types, the elem_len needs to be divided by
    2 and then mapped onto a real kind.  On x86 targets, the kind
    corresponding to C long double is different than its elem_len; since
    we cannot accurately disambiguate between a 16-byte kind 10 long
    double from __float128, this patch arbitrarily prefers to interpret that as
    the standard long double type rather than the GNU extension.

    Similarly, for character types, the GFC descriptor cannot distinguish
    between character(kind=c_char, len=4) and character(kind=ucs4, len=1).
    But since the front end currently rejects anything other than len=1
    (PR92482) this patch uses the latter interpretation.

    2021-09-01  Sandra Loosemore  <sandra@codesourcery.com>
                José Rui Faustino de Sousa  <jrfsousa@gmail.com>

    gcc/testsuite/
            PR fortran/100911
            PR fortran/100915
            PR fortran/100916
            * gfortran.dg/PR100911.c: New file.
            * gfortran.dg/PR100911.f90: New file.
            * gfortran.dg/PR100914.c: New file.
            * gfortran.dg/PR100914.f90: New file.
            * gfortran.dg/PR100915.c: New file.
            * gfortran.dg/PR100915.f90: New file.

    libgfortran/
            PR fortran/100907
            PR fortran/100911
            PR fortran/100914
            PR fortran/100915
            PR fortran/100917
            * ISO_Fortran_binding-1-tmpl.h (CFI_type_cfunptr): Make equivalent
            to CFI_type_cptr.
            * runtime/ISO_Fortran_binding.c (cfi_desc_to_gfc_desc): Fix
            handling of CFI_type_cptr and CFI_type_cfunptr.  Additional error
            checking and code cleanup.
            (gfc_desc_to_cfi_desc): Likewise.  Also correct kind mapping
            for character, complex, and long double types.