gfortran uses internally a different array descriptor ("gfc") as
Fortran 2018 alias TS291113 defines for C interoperability via
ISO_Fortran_binding.h ("CFI").  Hence, when calling a C function
from Fortran, it has to be converted in the callee - and if a
BIND(C) procedure is written in Fortran, the CFI argument has
to be converted to gfc in order work with the rest of the FE
code and the library calls.

Before this patch, part was handled in the FE generated code and
other parts in libgfortran.  With this patch, all code is generated
and CFI is defined as proper type - visible in the debugger and to
the middle end - avoiding both alias issues and missed optimization
issues.

This patch also fixes issues like: intent(out) deallocation in
the bind(C) callee, using the CFI descriptor also for allocatable
and pointer scalars and for len=* character strings.
For 'select rank', it also optimizes the code + avoid accessing
uninitialized memory if the dummy argument is allocatable/a pointer.
It additionally rejects passing a descriptorless type(*) to an
assumed-rank dummy argument. [F2018:C711]

	PR fortran/102086
	PR fortran/92189
	PR fortran/92621
	PR fortran/101308
	PR fortran/101309
	PR fortran/101635
	PR fortran/92482

gcc/fortran/ChangeLog:

	* decl.c (gfc_verify_c_interop_param): Remove 'sorry' for
	scalar allocatable/pointer and len=*.
	* expr.c (is_CFI_desc): Return true for for those.
	* gfortran.h (CFI_type_kind_shift, CFI_type_mask,
	CFI_type_from_type_kind, CFI_VERSION, CFI_MAX_RANK,
	CFI_attribute_pointer, CFI_attribute_allocatable,
	CFI_attribute_other, CFI_type_Integer, CFI_type_Logical,
	CFI_type_Real, CFI_type_Complex, CFI_type_Character,
	CFI_type_ucs4_char, CFI_type_struct, CFI_type_cptr,
	CFI_type_cfunptr, CFI_type_other): New #define.
	* trans-array.c (CFI_FIELD_BASE_ADDR, CFI_FIELD_ELEM_LEN,
	CFI_FIELD_VERSION, CFI_FIELD_RANK, CFI_FIELD_ATTRIBUTE,
	CFI_FIELD_TYPE, CFI_FIELD_DIM, CFI_DIM_FIELD_LOWER_BOUND,
	CFI_DIM_FIELD_EXTENT, CFI_DIM_FIELD_SM,
	gfc_get_cfi_descriptor_field, gfc_get_cfi_desc_base_addr,
	gfc_get_cfi_desc_elem_len, gfc_get_cfi_desc_version,
	gfc_get_cfi_desc_rank, gfc_get_cfi_desc_type,
	gfc_get_cfi_desc_attribute, gfc_get_cfi_dim_item,
	gfc_get_cfi_dim_lbound, gfc_get_cfi_dim_extent, gfc_get_cfi_dim_sm):
	New define/functions to access the CFI array descriptor.
	(gfc_conv_descriptor_type): New function for the GFC descriptor.
	(gfc_get_array_span): Handle expr of CFI descriptors and
	assumed-type descriptors.
	(gfc_trans_array_bounds): Remove 'static'.
	(gfc_conv_expr_descriptor): For assumed type, use the dtype of
	the actual argument.
	(structure_alloc_comps): Remove ' ' inside tabs.
	* trans-array.h (gfc_trans_array_bounds, gfc_conv_descriptor_type,
	gfc_get_cfi_desc_base_addr, gfc_get_cfi_desc_elem_len,
	gfc_get_cfi_desc_version, gfc_get_cfi_desc_rank,
	gfc_get_cfi_desc_type, gfc_get_cfi_desc_attribute,
	gfc_get_cfi_dim_lbound, gfc_get_cfi_dim_extent, gfc_get_cfi_dim_sm):
	New prototypes.
	* trans-decl.c (gfor_fndecl_cfi_to_gfc, gfor_fndecl_gfc_to_cfi):
	Remove global vars.
	(gfc_build_builtin_function_decls): Remove their initialization.
	(gfc_get_symbol_decl, create_function_arglist,
	gfc_trans_deferred_vars): Update for CFI.
	(convert_CFI_desc): Remove and replace by ...
	(gfc_conv_cfi_to_gfc): ... this function
	(gfc_generate_function_code): Call it; create local GFC var for CFI.
	* trans-expr.c (gfc_maybe_dereference_var): Handle CFI.
	(gfc_conv_subref_array_arg): Handle the if-noncontigous-only copy in
	when the result should be a descriptor.
	(gfc_conv_gfc_desc_to_cfi_desc): Completely rewritten.
	(gfc_conv_procedure_call): CFI fixes.
	* trans-openmp.c (gfc_omp_is_optional_argument,
	gfc_omp_check_optional_argument): Handle optional
	CFI.
	* trans-stmt.c (gfc_trans_select_rank_cases): Cleanup, avoid invalid
	code for allocatable/pointer dummies, which cannot be assumed size.
	* trans-types.c (gfc_cfi_descriptor_base): New global var.
	(gfc_get_dtype_rank_type): Skip rank init for rank < 0.
	(gfc_sym_type): Handle CFI dummies.
	(gfc_get_function_type): Update call.
	(gfc_get_cfi_dim_type, gfc_get_cfi_type): New.
	* trans-types.h (gfc_sym_type): Update prototype.
	(gfc_get_cfi_type): New prototype.
	* trans.c (gfc_trans_runtime_check): Make conditions more consistent
	to avoid '<logical> AND_THEN <long int>' in conditions.
	* trans.h (gfor_fndecl_cfi_to_gfc, gfor_fndecl_gfc_to_cfi): Remove
	global-var declaration.

libgfortran/ChangeLog:

	* ISO_Fortran_binding.h (CFI_type_cfunptr): Make unique type again.
	* runtime/ISO_Fortran_binding.c (cfi_desc_to_gfc_desc,
	gfc_desc_to_cfi_desc): Add comment that those are no longer called
	by new code.

libgomp/ChangeLog:

	* testsuite/libgomp.fortran/optional-bind-c.f90: New test.

gcc/testsuite/ChangeLog:

	* gfortran.dg/ISO_Fortran_binding_4.f90: Extend testcase.
	* gfortran.dg/PR100914.f90: Remove xfail.
	* gfortran.dg/PR100915.c: Expect CFI_type_cfunptr.
	* gfortran.dg/PR100915.f90: Handle CFI_type_cfunptr != CFI_type_cptr.
	* gfortran.dg/PR93963.f90: Extend select-rank tests.
	* gfortran.dg/bind-c-intent-out.f90: Change to dg-do run,
	update scan-dump.
	* gfortran.dg/bind_c_array_params_2.f90: Update/extend scan-dump.
	* gfortran.dg/bind_c_char_10.f90: Update scan-dump.
	* gfortran.dg/bind_c_char_8.f90: Remove dg-error "sorry".
	* gfortran.dg/c-interop/allocatable-dummy.f90: Remove xfail.
	* gfortran.dg/c-interop/c1255-1.f90: Likewise.
	* gfortran.dg/c-interop/c407c-1.f90: Update dg-error.
	* gfortran.dg/c-interop/cf-descriptor-5.f90: Remove xfail.
	* gfortran.dg/c-interop/cf-out-descriptor-3.f90: Likewise.
	* gfortran.dg/c-interop/cf-out-descriptor-4.f90: Likewise.
	* gfortran.dg/c-interop/cf-out-descriptor-5.f90: Likewise.
	* gfortran.dg/c-interop/contiguous-2.f90: Likewise.
	* gfortran.dg/c-interop/contiguous-3.f90: Likewise.
	* gfortran.dg/c-interop/deferred-character-1.f90: Likewise.
	* gfortran.dg/c-interop/deferred-character-2.f90: Likewise.
	* gfortran.dg/c-interop/fc-descriptor-3.f90: Likewise.
	* gfortran.dg/c-interop/fc-descriptor-5.f90: Likewise.
	* gfortran.dg/c-interop/fc-descriptor-6.f90: Likewise.
	* gfortran.dg/c-interop/fc-out-descriptor-3.f90: Likewise.
	* gfortran.dg/c-interop/fc-out-descriptor-4.f90: Likewise.
	* gfortran.dg/c-interop/fc-out-descriptor-5.f90: Likewise.
	* gfortran.dg/c-interop/fc-out-descriptor-6.f90: Likewise.
	* gfortran.dg/c-interop/ff-descriptor-5.f90: Likewise.
	* gfortran.dg/c-interop/ff-descriptor-6.f90: Likewise.
	* gfortran.dg/c-interop/fc-descriptor-7.f90: Remove xfail + extend.
	* gfortran.dg/c-interop/fc-descriptor-7-c.c: Update for changes.
	* gfortran.dg/c-interop/shape.f90: Add implicit none.
	* gfortran.dg/c-interop/typecodes-array-char-c.c: Add kind=4 char.
	* gfortran.dg/c-interop/typecodes-array-char.f90: Likewise.
	* gfortran.dg/c-interop/typecodes-array-float128.f90: Remove xfail.
	* gfortran.dg/c-interop/typecodes-scalar-basic.f90: Likewise.
	* gfortran.dg/c-interop/typecodes-scalar-float128.f90: Likewise.
	* gfortran.dg/c-interop/typecodes-scalar-int128.f90: Likewise.
	* gfortran.dg/c-interop/typecodes-scalar-longdouble.f90: Likewise.
	* gfortran.dg/iso_c_binding_char_1.f90: Remove dg-error "sorry".
	* gfortran.dg/pr93792.f90: Turn XFAIL into PASS.
	* gfortran.dg/ISO_Fortran_binding_19.f90: New test.
	* gfortran.dg/assumed_type_12.f90: New test.
	* gfortran.dg/assumed_type_13.c: New test.
	* gfortran.dg/assumed_type_13.f90: New test.
	* gfortran.dg/bind-c-char-descr.f90: New test.
	* gfortran.dg/bind-c-contiguous-1.c: New test.
	* gfortran.dg/bind-c-contiguous-1.f90: New test.
	* gfortran.dg/bind-c-contiguous-2.f90: New test.
	* gfortran.dg/bind-c-contiguous-3.c: New test.
	* gfortran.dg/bind-c-contiguous-3.f90: New test.
	* gfortran.dg/bind-c-contiguous-4.c: New test.
	* gfortran.dg/bind-c-contiguous-4.f90: New test.
	* gfortran.dg/bind-c-contiguous-5.c: New test.
	* gfortran.dg/bind-c-contiguous-5.f90: New test.