gold: Add sparc IFUNC support to Gold.

gold: Add sparc IFUNC support to Gold.

elfcpp/

	* sparc.h (R_SPARC_JMP_IREL): New relocation.

gold/

	* sparc.cc (class Target_sparc): Add rela_ifunc_.
	(Target_sparc::Target_sparc): Initialize new field.
	(Target_sparc::do_plt_section_for_global): New function.
	(Target_sparc::do_plt_section_for_local): New function.
	(Target_sparc::reloc_needs_plt_for_ifunc): New function.
	(Target_sparc::make_plt_section): New function, broken out of
	make_plt_entry.  Use ORDER_NON_RELRO_FIRST for ".plt".
	(Target_sparc::make_plt_entry): Call make_plt_section.
	(Target_sparc::make_local_ifunc_plt_entry): New function.
	(Target_sparc::rela_ifunc_section): New function.
	(Target_sparc::plt_section): Remove const.
	(Output_data_plt_sparc): Update declarations.  Define Global_ifunc
	and Local_ifunc types.  Add global_ifuncs_, local_ifuncs_, ifunc_rel_,
	and ifunc_count_ fields.
	(Output_data_plt_sparc::Output_data_plt_sparc): Initialize new fields.
	(Output_data_plt_sparc::add_entry): Handle IFUNC symbols.
	(Output_data_plt_sparc::add_local_ifunc_entry): New function.
	(Output_data_plt_sparc::rela_ifunc): New function.
	(Output_data_plt_sparc::emit_pending_ifunc_relocs): New function.
	(Output_data_plt_sparc::has_ifunc_section): New function.
	(Output_data_plt_sparc::entry_count): Include ifunc_count_.
	(Output_data_plt_sparc::address_for_global): New function.
	(Output_data_plt_sparc::address_for_local): New function.
	(Output_data_plt_sparc::plt_index_to_offset): New function.
	(Output_data_plt_sparc::set_final_data_size): Use plt_index_to_offset
	and entry_count.
	(Output_data_plt_sparc::do_write): Use first_plt_entry_offset and
	entry_count.
	(Target_sparc::Scan::get_reference_flags): Add R_SPARC_IRELATIVE and
	R_SPARC_JMP_IREL to switch.
	(Target_sparc::Scan::check_non_pic): Likewise.
	(Target_sparc::Scan::local): Handle IFUNC symbols.
	(Target_sparc::Scan::local): Likewise.
	(Target_sparc::Relocate::relocate): Likewise, use plt_address_for_global
	and plt_address_for_local.
	(Target_sparc::do_finalize_sections): Call emit_pending_ifunc_relocs.
	Define __rel_iplt_start and __rel_iplt_end if doing a static link.