* gold.cc (queue_middle_tasks): Process existing GOT/PLT entries.

	* gold.cc (queue_middle_tasks): Process existing GOT/PLT entries.
	* incremental-dump.cc (dump_incremental_inputs): Mask high-order
	bit when checking got_type.
	* incremental.cc (Sized_incremental_binary::setup_readers):
	Store symbol table and string table locations; initialize bit vector
	of file status flags.
	(Sized_incremental_binary::do_reserve_layout): Set bit flag for
	unchanged files.
	(Sized_incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::get_symtab_view): Use stored locations.
	(Output_section_incremental_inputs::set_final_data_size): Record
	file index for each input file.
	(Output_section_incremental_inputs::write_got_plt): Store file index
	instead of input entry offset for each GOT entry.
	* incremental.h
	(Incremental_input_entry::Incremental_input_entry): Initialize new
	data member.
	(Incremental_input_entry::set_offset): Store file index.
	(Incremental_input_entry::get_file_index): New function.
	(Incremental_input_entry::file_index_): New data member.
	(Incremental_binary::process_got_plt): New function.
	(Incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::Sized_incremental_binary): Initialize new
	data members.
	(Sized_incremental_binary::~Sized_incremental_binary): New destructor.
	(Sized_incremental_binary::set_file_is_unchanged): New function.
	(Sized_incremental_binary::file_is_unchanged): New function.
	(Sized_incremental_binary::do_process_got_plt): New function.
	(Sized_incremental_binary::file_status_): New data member.
	(Sized_incremental_binary::main_symtab_loc_): New data member.
	(Sized_incremental_binary::main_strtab_loc_): New data member.
	* output.cc (Output_data_got::Got_entry::write): Add case
	RESERVED_CODE.
	(Output_data_got::add_global): Call add_got_entry.
	(Output_data_got::add_global_plt): Likewise.
	(Output_data_got::add_global_with_rel): Likewise.
	(Output_data_got::add_global_with_rela): Likewise.
	(Output_data_got::add_global_pair_with_rel): Call add_got_entry_pair.
	(Output_data_got::add_global_pair_with_rela): Likewise.
	(Output_data_got::add_local): Call add_got_entry.
	(Output_data_got::add_local_plt): Likewise.
	(Output_data_got::add_local_with_rel): Likewise.
	(Output_data_got::add_local_with_rela): Likewise.
	(Output_data_got::add_local_pair_with_rel): Call add_got_entry_pair.
	(Output_data_got::add_local_pair_with_rela): Likewise.
	(Output_data_got::reserve_slot): New function.
	(Output_data_got::reserve_slot_for_global): New function.
	(Output_data_got::add_got_entry): New function.
	(Output_data_got::add_got_entry_pair): New function.
	(Output_section::add_output_section_data): Edit FIXME.
	* output.h
	(Output_section_data_build::Output_section_data_build): New
	constructor with size parameter.
	(Output_data_space::Output_data_space): Likewise.
	(Output_data_got::Output_data_got): Initialize new data member; new
	constructor with size parameter.
	(Output_data_got::add_constant): Call add_got_entry.
	(Output_data_got::reserve_slot): New function.
	(Output_data_got::reserve_slot_for_global): New function.
	(class Output_data_got::Got_entry): Add RESERVED_CODE.
	(Output_data_got::add_got_entry): New function.
	(Output_data_got::add_got_entry_pair): New function.
	(Output_data_got::free_list_): New data member.
	* target.h (Sized_target::init_got_plt_for_update): New function.
	(Sized_target::register_global_plt_entry): New function.
	* x86_64.cc (Output_data_plt_x86_64::Output_data_plt_x86_64):
	Initialize new data member; call init; add constructor with PLT count.
	(Output_data_plt_x86_64::init): New function.
	(Output_data_plt_x86_64::add_relocation): New function.
	(Output_data_plt_x86_64::reserve_slot): New function.
	(Output_data_plt_x86_64::free_list_): New data member.
	(Target_x86_64::init_got_plt_for_update): New function.
	(Target_x86_64::register_global_plt_entry): New function.
	(Output_data_plt_x86_64::add_entry): Allocate from free list for
	incremental updates.
	(Output_data_plt_x86_64::add_relocation): New function.
	* testsuite/object_unittest.cc (Object_test): Set default options.