make ObjC do LTO.

make ObjC do LTO.

gcc/
	PR objc/44140
	* config/darwin.c (output_objc_section_asm_op): Save and restore
	section when outputting ObjC section list.

testsuite/

	PR objc/44140
	* objc.dg/lto/trivial-1_0.m: New.
	* objc.dg/lto/lto.exp: New.
	* obj-c++.dg/lto/trivial-1_0.mm: New.
	* obj-c++.dg/lto/lto.exp: New.
	* objc.dg/symtab-1.m: Adjust sizes.
	* objc.dg/image-info.m: Do not run for gnu-runtime.

gcc/objc/

	PR objc/44140
	* objc-act.c: build_objc_string_decl() remove declaration.
	(finish_var_decl): Remove forcing of var output and marking
	as "Used".
	(init_def_list): Use integer_zero_node.
	(init_objc_symtab): Use integer_zero_node, make the short
	integer type specific on relevant nodes.
	(generate_objc_symtab_decl): Remove call to
	forward_declare_categories().  Use null_pointer_node where
	appropriate.
	(build_module_descriptor): Comment and mark this item as
	DECL_PRESERVE_P.
	(generate_static_references): Use gcc_unreachable instead of
	abort ().
	(diagnose_missing_method): New.
	(build_next_selector_translation_table): New.
	(build_gnu_selector_translation_table): New.
	(add_objc_string): Merge code from build_objc_string_decl...
	... and delete build_objc_string_decl().
	(generate_dispatch_table): Make integer types explicit.
	(generate_category): Pass implent and arrange for the data
	to be extracted within the routine.  Do not start new vars,
	but finish the ones collcted during parsing.
	(generate_shared_structures): Likewise.
	(finish_objc):  Reorder code so that we finish variables before
	referencing them.  Save the global data before calling meta-data
	creation routines, and pass the current reference to the two
	main routines.  Only call generate_objc_image_info () for the
	NeXT runtime.
	(generate_classref_translation_entry): Comment on and make this
	item DECL_PRESERVE_P.
	(handle_class_ref): Use varpool interfaces, comment on and make
	this item DECL_PRESERVE_P.
	(handle_impent): Likewise.
	(generate_objc_image_info): Only generate when the content is
	non-zero.  Make integer types explict.

From-SVN: r162030