This is an updated version of the earlier patch. The main addition is
a second testcase that checks the errors emitted by the CFI API
functions.

It should be noted that there is some strangeness in the test for
CFI_select_part errors. The order of the tests matters. If they are
inverted from the order in the patch, the test fails for -O2 and
greater. Testing with the order inverted outside of the test harness
gave all manner of random errors and occasional success. I haven't
understood what is going on. That said, deliberately triggering a
sequence of deliberate errors like this is highly artificial since I
suppose that they would normally individually lead to termination of
execution.

Bootstrapped and regtested on FC28/x86_64 - OK for trunk?

Paul

2019-01-07  Paul Thomas  <pault@gcc.gnu.org>

    * trans-array.c (gfc_conv_descriptor_attribute): New function.
    (gfc_get_dataptr_offset): Remove static function attribute.
    * trans-array.h : Add prototypes for above functions.
    * trans-decl.c : Add declarations for the library functions
    cfi_desc_to_gfc_desc and gfc_desc_to_cfi_desc.
    * trans-expr.c (gfc_conv_gfc_desc_to_cfi_desc): New function.
    (gfc_conv_procedure_call): Call it for scalar and array actual
    arguments, when the formal arguments are bind_c with assumed
    shape or assumed rank.
    * trans.h : External declarations for gfor_fndecl_cfi_to_gfc
    and gfor_fndecl_gfc_to_cfi.

2019-01-07  Paul Thomas  <pault@gcc.gnu.org>

    * gfortran.dg/ISO_Fortran_binding_1.f90 : New test.
    * gfortran.dg/ISO_Fortran_binding_1.c : Auxilliary file for test.
    * gfortran.dg/ISO_Fortran_binding_2.f90 : New test.
    * gfortran.dg/ISO_Fortran_binding_2.c : Auxilliary file for test.
    * gfortran.dg/ISO_Fortran_binding.h : Auxilliary file for test.
    * gfortran.dg/bind_c_array_params_2.f90 : Change search string
    for dump tree scan.

2019-01-07  Paul Thomas  <pault@gcc.gnu.org>

    * ISO_Fortran_binding.h : New file.
    * Makefile.am : Include ISO_Fortran_binding.c in the list of
    files to compile.
    * Makefile.in : Regenerated.
    * gfortran.map : Add _gfortran_cfi_desc_to_gfc_desc,
    _gfortran_gfc_desc_to_cfi_desc and the CFI API functions.
    * runtime/ISO_Fortran_binding.c : New file containing the new
    functions added to the map.