Patch adds support to allow plugins to map selected subset of sections to unique

Patch adds support to allow plugins to map selected subset of sections to unique
segments.

2012-08-24  Sriraman Tallam  <tmsriram@google.com>

	* gold.cc (queue_middle_tasks): Call layout again when unique
	segments for sections is desired.
	* layout.cc (Layout::Layout): Initialize new members.
	(Layout::get_output_section_flags): New function.
	(Layout::choose_output_section): Call get_output_section_flags.
	(Layout::layout): Make output section for mapping to a unique segment.
	(Layout::insert_section_segment_map): New function.
	(Layout::attach_allocated_section_to_segment): Make unique segment for
	output sections marked so.
	(Layout::segment_precedes): Check for unique segments when sorting.
	* layout.h (Layout::Unique_segment_info): New struct.
	(Layout::Section_segment_map): New typedef.
	(Layout::insert_section_segment_map): New function.
	(Layout::get_output_section_flags): New function.
	(Layout::is_unique_segment_for_sections_specified): New function.
	(Layout::set_unique_segment_for_sections_specified): New function.
	(Layout::unique_segment_for_sections_specified_): New member.
	(Layout::section_segment_map_): New member.
	* object.cc (Sized_relobj_file<size, big_endian>::do_layout):
	Rename is_gc_pass_one to is_pass_one.
	Rename is_gc_pass_two to is_pass_two.
	Rename is_gc_or_icf to is_two_pass.
	Check for which pass based on whether symbols data is present.
	Make it two pass when unique segments for sections is desired.
	* output.cc (Output_section::Output_section): Initialize new
	members.
	* output.h (Output_section::is_unique_segment): New function.
	(Output_section::set_is_unique_segment): New function.
	(Output_section::is_unique_segment_): New member.
	(Output_section::extra_segment_flags): New function.
	(Output_section::set_extra_segment_flags): New function.
	(Output_section::extra_segment_flags_): New member.
	(Output_section::segment_alignment): New function.
	(Output_section::set_segment_alignment): New function.
	(Output_section::segment_alignment_): New member.
	(Output_segment::Output_segment): Initialize is_unique_segment_.
	(Output_segment::is_unique_segment): New function.
	(Output_segment::set_is_unique_segment): New function.
	(Output_segment::is_unique_segment_): New member.
	* plugin.cc (allow_unique_segment_for_sections): New function.
	(unique_segment_for_sections): New function.
	(Plugin::load): Add new functions to transfer vector.
	* Makefile.am (plugin_final_layout.readelf.stdout): Add readelf output.
	* Makefile.in: Regenerate.
	* testsuite/plugin_final_layout.sh: Check if unique segment
	functionality works.
	* testsuite/plugin_section_order.c (onload): Check if new interfaces
	are available.
	(allow_unique_segment_for_sections): New global.
	(unique_segment_for_sections): New global.
	(claim_file_hook): Call allow_unique_segment_for_sections.
	(all_symbols_read_hook): Call unique_segment_for_sections.

2012-08-24  Sriraman Tallam  <tmsriram@google.com>

	* plugin-api.h (ld_plugin_allow_unique_segment_for_sections):
	New interface.
	(ld_plugin_unique_segment_for_sections): New interface.
	(LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val.
	(LDPT_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val.
	(tv_allow_unique_segment_for_sections): New member.
	(tv_unique_segment_for_sections): New member.