[ABI PATCH] static anonymous unions of function scope

[ABI PATCH] static anonymous unions of function scope

https://gcc.gnu.org/ml/gcc-patches/2018-10/msg02076.html
	* cp-tree.h (struct lang_function): Delete x_local_names field.
	(struct lang_decl_base): Rename u2sel to spare.
	(struct lang_decl_min): Remove lang_decl_u2 union.  Keep access
	field.
	(LANG_DECL_U2_CHECK): Delete.
	(DECL_DISCRIMINATOR_P): Require function scope.
	(DECL_DISCRIMINATOR): Adjust.
	(DECL_DISCRIMINATOR_SET_P): Delete.
	(DECL_CAPTURED_VARIABLE, DECL_ACCESS, THUnK_VIRTUAL_OFFSET): Adjust.
	(local_classes): Don't declare.
	(determine_local_discriminator): Declare.
	* decl.c (push_local_name): Delete.
	(local_entities, determina_local_discrminator): New.
	(duplicate_decls): Copy DECL_ACCESS. Fix formatting.
	(cp_finish_decl): Use determine_local_discriminator.
	(save_function_data): Drop x_local_names.
	(finish_function): Drop local_names.
	* decl2.c (finish_anon_union): Use determine_local_disciminator.
	* mangle.c (write_unnamed_type_name): Use
	discriminator_for_local_entity.
	(local_class_index): Delete.
	(discriminator_for_local_entity): Reimplement.
	(write_local_name): Adjust discriminator code.
	* name-lookup.c (do_pushtag): Call determine_local_discrimiator.
	* semantics.c (finish_omp_threadprivate): Drop DECL_DISCRIMINATOR
	handling.
	* class.c (local_classes): Delete.
	(init_class_processing): Don't init it.

	* g++.dg/abi/anon5.C: New.

From-SVN: r265714