DWARF: describe properly Ada packed arrays

DWARF: describe properly Ada packed arrays

gcc/ada/ChangeLog:

	* gcc-interface/ada-tree.h
	(TYPE_IMPLEMENTS_PACKED_ARRAY_P, TYPE_CAN_HAVE_DEBUG_TYPE_P,
	TYPE_ORIGINAL_PACKED_ARRAY, SET_TYPE_ORIGINAL_PACKED_ARRAY): New
	macros.
	* gcc-interface/decl.c (add_parallel_type_for_packed_array):
	Rename to associate_original_type_to_packed_array.  When
	-fgnat-encodings=minimal, set original packed array type as so
	instead of as a parallel type to the implementation type.  In
	this case, also rename the implementation type to the name of
	the original array type.
	(gnat_to_gnu_entity): Update invocations to
	add_parallel_type_for_packed_array.  Tag ARRAY_TYPE nodes for
	packed arrays with the TYPE_PACKED flag.
	When -fgnat-encodings=minimal:
	  - strip ___XP suffixes in packed arrays' names;
	  - set the debug type for padding records around packed arrays
	    to the packed array;
	  - do not attach ___XUP types as parallel types of constrained
	    array types.
	* gcc-interface/misc.c (gnat_print_type): Update to handle
	orignal packed arrays.
	(gnat_get_debug_type): Update to reject packed arrays
	implementation types.
	(get_array_bit_stride): New.
	(gnat_get_array_descr_info): Add packed arrays handling.
	* gcc-interface/utils.c (maybe_pad_type): When
	-fgnat-encodings=minimal, set the name of the padding type to
	the one of the original packed type, if any.  Fix TYPE_DECL
	peeling around the name of the input type.

From-SVN: r231768