In order to handle large character lengths on (L)LP64 targets, switch
the GFortran character length from an int to a size_t.

This is an ABI change, as procedures with character arguments take
hidden arguments with the character length.

I also changed the _size member in vtables from int to size_t, as
there were some cases where character lengths and sizes were
apparently mixed up and caused regressions otherwise. Although I
haven't tested, this might enable very large derived types as well.

Also, as there are some places in the frontend were negative character
lengths are used as special flag values, in the frontend the character
length is handled as a signed variable of the same size as a size_t,
although in the runtime library it really is size_t.

I haven't changed the character length variables for the co-array
intrinsics, as this is something that may need to be synchronized with
OpenCoarrays.

This is v5 of the patch. v4 was applied but caused breakage on big
endian targets. These have been fixed and tested, thanks to access to
the GCC compile farm.

Overview of v4 of the patch: v3 was applied but had to reverted due to
breaking bootstrap. The fix is in resolve.c:resolve_charlen, where
it's necessary to check that an expression is constant before using
mpz_sgn.

Overview of v3 of the patch: All the issues pointed out by FX's review
of v2 have been fixed. In particular, there are now new functions
gfc_mpz_get_hwi and gfc_mpz_set_hwi, similar to the GMP functions
mpz_get_si and mpz_set_si, except that they get/set a HOST_WIDE_INT
instead of a long value. Similarly, gfc_get_int_expr now takes a
HOST_WIDE_INT instead of a long, gfc_extract_long is replaced by
gfc_extract_hwi. Also, the preliminary work to handle
gfc_charlen_type_node being unsigned has been removed.

Regtested on x86_64-pc-linux-gnu, i686-pc-linux-gnu and
powerpc64-unknown-linux-gnu. Also regtested all three targets by
modifying gfortran-dg.exp to also test with "-g -flto", no new
failures observed.

frontend:

2018-01-05  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/78534
	PR fortran/66310
	* array.c (got_charlen): Use gfc_charlen_int_kind.
	* class.c (gfc_find_derived_vtab): Use gfc_size_kind instead of
	hardcoded kind.
	(find_intrinsic_vtab): Likewise.
	* decl.c (match_char_length): Use gfc_charlen_int_kind.
	(add_init_expr_to_sym): Use gfc_charlen_t and gfc_charlen_int_kind.
	(gfc_match_implicit): Use gfc_charlen_int_kind.
	* dump-parse-tree.c (show_char_const): Use gfc_charlen_t and size_t.
	(show_expr): Use HOST_WIDE_INT_PRINT_DEC.
	* expr.c (gfc_get_character_expr): Length parameter of type
	gfc_charlen_t.
	(gfc_get_int_expr): Value argument of type HOST_WIDE_INT.
	(gfc_extract_hwi): New function.
	(simplify_const_ref): Make string_len of type gfc_charlen_t.
	(gfc_simplify_expr): Use HOST_WIDE_INT for substring refs.
	* frontend-passes.c (optimize_trim): Use gfc_charlen_int_kind.
	* gfortran.h (gfc_mpz_get_hwi): New prototype.
	(gfc_mpz_set_hwi): Likewise.
	(gfc_charlen_t): New typedef.
	(gfc_expr): Use gfc_charlen_t for character lengths.
	(gfc_size_kind): New extern variable.
	(gfc_extract_hwi): New prototype.
	(gfc_get_character_expr): Use gfc_charlen_t for character length.
	(gfc_get_int_expr): Use HOST_WIDE_INT type for value argument.
	* gfortran.texi: Update description of hidden string length argument.
	* iresolve.c (check_charlen_present): Use gfc_charlen_int_kind.
	(gfc_resolve_char_achar): Likewise.
	(gfc_resolve_repeat): Pass string length directly without
	temporary, use gfc_charlen_int_kind.
	(gfc_resolve_transfer): Use gfc_charlen_int_kind.
	* match.c (select_intrinsic_set_tmp): Use HOST_WIDE_INT for charlen.
	* misc.c (gfc_mpz_get_hwi): New function.
	(gfc_mpz_set_hwi): New function.
	* module.c (atom_int): Change type from int to HOST_WIDE_INT.
	(parse_integer): Don't complain about large integers.
	(write_atom): Use HOST_WIDE_INT for integers.
	(mio_integer): Handle integer type mismatch.
	(mio_hwi): New function.
	(mio_intrinsic_op): Use HOST_WIDE_INT.
	(mio_array_ref): Likewise.
	(mio_expr): Likewise.
	* primary.c (match_substring): Use gfc_charlen_int_kind.
	* resolve.c (resolve_substring_charlen): Use gfc_charlen_int_kind.
	(resolve_character_operator): Likewise.
	(resolve_assoc_var): Likewise.
	(resolve_select_type): Use HOST_WIDE_INT for charlen, use snprintf.
	(resolve_charlen): Use mpz_sgn to determine sign.
	* simplify.c (gfc_simplify_repeat): Use HOST_WIDE_INT/gfc_charlen_t
	instead of long.
	* symbol.c (generate_isocbinding_symbol): Use gfc_charlen_int_kind.
	* target-memory.c (size_character): Length argument of type
	gfc_charlen_t.
	(gfc_encode_character): Likewise.
	(gfc_interpret_character): Use gfc_charlen_t.
	* target-memory.h (gfc_encode_character): Modify prototype.
	* trans-array.c (gfc_trans_array_ctor_element): Use existing type.
	(get_array_ctor_var_strlen): Use gfc_conv_mpz_to_tree_type.
	(trans_array_constructor): Use existing type.
	(get_array_charlen): Likewise.
	* trans-const.c (gfc_conv_mpz_to_tree_type): New function.
	* trans-const.h (gfc_conv_mpz_to_tree_type): New prototype.
	* trans-decl.c (gfc_trans_deferred_vars): Use existing type.
	(add_argument_checking): Likewise.
	* trans-expr.c (gfc_class_len_or_zero_get): Build const of type
	gfc_charlen_type_node.
	(gfc_conv_intrinsic_to_class): Use gfc_charlen_int_kind instead of
	4, fold_convert to correct type.
	(gfc_conv_class_to_class): Build const of type size_type_node for
	size.
	(gfc_copy_class_to_class): Likewise.
	(gfc_conv_string_length): Use same type in expression.
	(gfc_conv_substring): Likewise, use HOST_WIDE_INT for charlen.
	(gfc_conv_string_tmp): Make sure len is of the right type.
	(gfc_conv_concat_op): Use same type in expression.
	(gfc_conv_procedure_call): Likewise.
	(fill_with_spaces): Comment out memset() block due to spurious
	-Wstringop-overflow warnings.
	(gfc_trans_string_copy): Use gfc_charlen_type_node.
	(alloc_scalar_allocatable_for_subcomponent_assignment):
	fold_convert to right type.
	(gfc_trans_subcomponent_assign): Likewise.
	(trans_class_vptr_len_assignment): Build const of correct type.
	(gfc_trans_pointer_assignment): Likewise.
	(alloc_scalar_allocatable_for_assignment): fold_convert to right
	type in expr.
	(trans_class_assignment): Build const of correct type.
	* trans-intrinsic.c (gfc_conv_associated): Likewise.
	(gfc_conv_intrinsic_repeat): Do calculation in sizetype.
	* trans-io.c (gfc_build_io_library_fndecls): Use
	gfc_charlen_type_node for character lengths.
	(set_string): Convert to right type in assignment.
	* trans-stmt.c (gfc_trans_label_assign): Build const of
	gfc_charlen_type_node.
	(trans_associate_var): Likewise.
	(gfc_trans_character_select): Likewise.
	(gfc_trans_allocate): Likewise, don't typecast strlen result.
	(gfc_trans_deallocate): Don't typecast strlen result.
	* trans-types.c (gfc_size_kind): New variable.
	(gfc_init_types): Determine gfc_charlen_int_kind and gfc_size_kind
	from size_type_node.
	* trans-types.h: Fix comment.

testsuite:

2018-01-05  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/78534
	PR fortran/66310
	* gfortran.dg/char_cast_1.f90: Update scan pattern.
	* gfortran.dg/dependency_49.f90: Likewise.
	* gfortran.dg/repeat_4.f90: Use integers of kind C_SIZE_T.
	* gfortran.dg/repeat_7.f90: New test for PR 66310.
	* gfortran.dg/scan_2.f90: Handle potential cast in assignment.
	* gfortran.dg/string_1.f90: Limit to ilp32 targets.
	* gfortran.dg/string_1_lp64.f90: New test.
	* gfortran.dg/string_3.f90: Limit to ilp32 targets.
	* gfortran.dg/string_3_lp64.f90: New test.

libgfortran:

2019-01-05  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/78534
	* intrinsics/args.c (getarg_i4): Use gfc_charlen_type.
	(get_command_argument_i4): Likewise.
	(get_command_i4): Likewise.
	* intrinsics/chmod.c (chmod_internal): Likewise.
	* intrinsics/env.c (get_environment_variable_i4): Likewise.
	* intrinsics/extends_type_of.c (struct vtype): Use size_t for size
	member.
	* intrinsics/gerror.c (gerror): Use gfc_charlen_type.
	* intrinsics/getlog.c (getlog): Likewise.
	* intrinsics/hostnm.c (hostnm_0): Likewise.
	* intrinsics/string_intrinsics_inc.c (string_len_trim): Rework to
	work if gfc_charlen_type is unsigned.
	(string_scan): Likewise.
	* io/transfer.c (transfer_character): Modify prototype.
	(transfer_character_write): Likewise.
	(transfer_character_wide): Likewise.
	(transfer_character_wide_write): Likewise.
	(transfer_array): Typecast to avoid signed-unsigned comparison.
	* io/unit.c (is_trim_ok): Use gfc_charlen_type.
	* io/write.c (namelist_write): Likewise.
	* libgfortran.h (gfc_charlen_type): Change typedef to size_t.

From-SVN: r256284