Reimplement dynamic cast and catch matching.

Reimplement dynamic cast and catch matching.

	* cp-tree.h (get_dynamic_cast_base_type): Prototype new function
	* search.c (dynamic_cast_base_recurse): New function.
	(get_dynamic_cast_base_type): New function for dynamic cast.
	* rtti.c (build_dynamic_cast_1): Determine source and target
	class relationship. Call __dynamic_cast_2.
	* tinfo.h (__user_type_info::upcast): New catch dispatcher.
	(__user_type_info::dyncast): New dynamic cast dispatcher.
	(__user_type_info::sub_kind): New nested enumeration.
	(__user_type_info::contained_p): sub_kind predicate.
	(__user_type_info::contained_public_p): Likewise.
	(__user_type_info::contained_nonpublic_p): Likewise.
	(__user_type_info::contained_nonvirtual_p: Likewise.
	(__user_type_info::upcast_result): New nested struct.
	(__user_type_info::dyncast_result): New nested struct.
	(*::do_upcast): New catch function.
	(*::do_dyncast): New dynamic cast function.
	(__user_type_info::find_public_subobj): New dynamic cast
	helper dispatcher.
	(*::do_find_public_subobj): New dynamic cast helper function.
	* tinfo.cc (__user_type_info::upcast): Define catch dispatcher.
	(__user_type_info::dyncast): Define dynamic cast dispatcher.
	(*::do_upcast): Define catch function.
	(*::do_dyncast): Define dynamic cast function.
	(*::do_find_public_subobj): Define dynamic cast helper function.
	* tinfo2.cc (__throw_type_match_rtti_2): Use upcast.
	(__dynamic_cast): Backwards compatibility wrapper. Use dyncast.
	(__dynamic_cast_2): New dynamic cast runtime.

From-SVN: r29544