Re: [PATCH][GOLD] Add support for relaxation.

[=?big5?b?RG91ZyBLd2FuICjD9q62vHcp?= <dougkwan at google dot com>]

Hi Ian,

   Thanks for the review.  Here is an updated patch.  I made the
following changes:

-Removed all debug printing code.  It is not essential and can be
added back in another patch with your suggested change.
-Removed the RELAXATION_DEBUG #define and related code. I replaced
them with changes in debug.h.
-Change Layout::save_segments to take a pointer to Segment_states
instead of a reference.
-Removed redundant parentheses around operand of delete.
-Updated a comment in layout.cc to add the missing "first" and fixed
another typo.
-Extracted the relaxation loop into a seperate function.  I also
extracted some preparation code to another function to make
Layout::finalize look less busy.  I also added a few new data members
to Layout to avoid passing too many arguments.  I also added a
destructor to delete two allocated objects used for relaxation and
relaxation debugging.
-Reformatted Output_section::Input_section::relobj() and
Output_section::Input_section::shndx().
-Added a new union member to Output_section::Input_section::u2_ for
Output_relaxed_input_section.  Removed the static cast in
Output_section::Input_section::relaxed_input_section().
-Renamed class Output_section::Checkpoint to
Output_section::Checkpoint_output_section.

I did not change the interface or the implementation of
Output_section::relax_input_section even though we discussed it
briefly how to do it.  I already know there are a few other issues
with this change.  They will be addressed in the next patch that
contains the code that use the relaxation code to implement
stub-generation in the ARM backend.  The patch will hopefully be done
in a few days.  Unfortunately, that one is also going to be huge.

The updated patch was tested for both x86_64 and arm-eabi targets.
All tests passed.  I also force running the testsuite with the
relaxation debugging mode and they all passed on x86_64.

-Doug

2009-09-16  Doug Kwan  <dougkwan@google.com>

        * debug.h (DEBUG_RELAXATION): New constant.
        (DEBUG_ALL): Add DEBUG_RELAXATION.
        (debug_string_to_enum): Add relaxation debug option.
        * layout.cc
        (Layout::Relaxation_debug_check::check_output_data_for_reset_values,
        Layout::Relaxation_debug_check::read_sections,
        Layout::Relaxation_debug_check::read_sections): New method definitions.
        (Layout::Layout): Initialize data members
        record_output_section_data_from_scrips_,
        script_output_section_data_list_ and relaxation_debug_check_.
        (Layout::save_segments, Layout::restore_segments,
        Layout::clean_up_after_relaxation, Layout::prepare_for_relaxation,
        Layout::relaxation_loop_body): New method definitions.
        (Layout::finalize): Support relaxation.  Move section layout code to
        Layout::relaxation_loop_body.
        (Layout::set_asection_address_from_script): Move code for orphan
        section placement out.
        (Layout::place_orphan_sections_in_script): New method definition.
        * layout.h (Output_segment_headers, Output_file_header):
        New forward class declarations.
        (Layout::~Layout): Define.
        (Layout::new_output_section_data_from_script): New method definition.
        (Layout::place_orphan_sections_in_script): New method declaration.
        (Layout::Segment_states): New type declaration.
        (Layout::save_segments, Layout::restore_segments,
        Layout::clean_up_after_relaxation, Layout::prepare_for_relaxation,
        Layout::relaxation_loop_body): New method declarations.
        (Layout::Output_section_data_list): New type declaration.
        (Layout::Relaxation_debug_check): New class definition.
        (Layout::record_output_section_data_from_script_,
        Layout::script_output_section_data_list_, Layout::segment_states_,
        Layout::relaxation_debug_check_): New data members.
        * output.cc: (Output_section_headers::do_size): New method definition.
        (Output_section_headers::Output_section_headers): Move size
        computation to Output_section_headers::do_size.
        (Output_segment_headers::do_size): New method definition.
        (Output_file_header::Output_file_header): Move size computation to
        Output_file_header::do_size and call it.
        (Output_file_header::do_size): New method definition.
        (Output_data_group::Output_data_group): Adjust call to
        Output_section_data.
        (Output_data_dynamic::set_final_data_size): Add DT_NULL tag only once.
        (Output_symtab_xindex::do_write): Add array bound check.
        (Output_section::Input_section::print_to_mapfile): Handle
        RELAXED_INPUT_SECTION_CODE.
        (Output_section::Output_section): Initialize data member checkpoint_.
        (Output_section::~Output_section): Delete checkpoint object pointed
        by checkpoint_.
        (Output_section::add_input_section): Always add an Input_section if
        relaxing.
        (Output_section::add_merge_input_section): Add assert.
        (Output_section::relax_input_section): New method definition.
        (Output_section::set_final_data_size): Set load address to zero for
        an unallocated section.
        (Output_section::do_address_and_file_offset_have_reset_values):
        New method definition.
        (Output_section::Input_section_sort_enty::Input_section_sort_enty):
        Handle relaxed input section.
        (Output_section::sort_attached_input_sections): Checkpoint input
        section list lazily.
        (Output_section::get_input_sections): Change type of input_sections to
        list of Simple_input_section pointers.  Checkpoint input section list
        lazily.  Also handle relaxed input sections.
        (Output_section::add_input_section_for_script): Take a reference to
        a Simple_input_section object instead of Relobj pointer and section
        index as parameter.  Handle relaxed input sections.
        (Output_section::save_states, Output_section::restore_states): New
        method definitions.
        * output.h (Output_data::Output_data): Initialize is_data_size_fixed_.
        (Output_data::is_data_size_fixed): New method definition.
        (Output_data::reset_addresss_and_file_offset): Do not reset data size
        if it is fixed.
        (Output_data::address_and_file_offset_have_reset_values): New method
        definition.
        (Output_data::do_address_and_file_offset_have_reset_values): New method
        definition.
        (Output_data::set_data_size): Check that data size is not fixed.
        (Output_data::fix_data_size): New method definition.
        (Output_data::is_data_size_fixed_): New data member.
        (Output_section_headers::set_final_data_size): New method definition.
        (Output_section_headers::do_size): New method declaration.
        (Output_segment_headers::set_final_data_size): New method definition.
        (Output_segment_headers::do_size): New method declaration.
        (Output_file_header::set_final_data_size)::New method definition.
        (Output_file_header::do_size)::New method declaration.
        (Output_section_data::Output_section_data): Add new parameter
        is_data_size_fixed and use it to fix data size.
        (Output_data_const::Output_data_const): Adjust call to base class
        constructor and fix data size.
        (Output_data_const_buffer::Output_data_const_buffer): Adjust call to
        base class constructor and fix data size.
        (Output_data_fixed_space::Output_data_fixed_space): Adjust call to
        base class constructor and fix data size.
        (Output_data_zero_fill::Output_data_zero_fill): Adjust call to base
        class constructor and fix data size.
        (Output_data_group::set_final_data_size): New method definition.
        (Output_data_dynamic::Dynamic_entry::tag): New method definition.
        (Output_symtab_xindex::Output_symtab_xindex): Adjust call to base
        class constructor and fix data size.
        (Output_relaxed_input_section): New class definition.
        (Output_section::Simple_input_section): New class definition.
        (Output_section::get_input_sections): Adjust parameter list.
        (Output_section::add_input_section_for_script): Same.
        (Output_section::save_states, Output_section::restore_states,
        Output_section::do_address_and_file_offset_have_reset_values,
        (Output_section::Input_section::Input_section): Handle
        RELAXED_INPUT_SECTION_CODE.  Add new overload for
        Output_relaxed_input_section.
        (Output_section::Input_section::is_input_section,
        Output_section::Input_section::set_output_section): Handle relaxed
        input section.
        (Output_section::Input_section::is_relaxed_input_section,
        Output_section::Input_section::output_section_data,
        Output_section::Input_section::relaxed_input_section): New method
        definitions.
        (Output_section::Input_section::RELAXED_INPUT_SECTION_CODE): New enum
        value.
        (Output_section::Input_section::u1_): Update comments.
        (Output_section::Input_section::u2_): Add new union member poris.
        (Output_section::Checkpoint_output_section): New classs definition.
        (Output_section::relax_input_section): New method declaration.
        (Output_section::checkpoint_): New data member.
        (Output_segment): Update comments.
        (Output_segment::Output_segment): Un-privatize copy constructor.
        (Output_segment::operator=): Un-privatize.
        * script-sections.cc (Output_section_element::Input_section_list):
        Change element type to Output_section::Simple_input_section.
        (Output_section_element_dot_assignment::set_section_addresses):
        Register output section data for relaxation clean up.
        (Output_data_exression::Output_data_expression): Adjust call to base
        constructor to fix data size.
        (Output_section_element_data::set_section_addresses): Register
        Output_data_expression object for relaxation clean up.
        (struct Input_section_info): Replace Relobj pointer and section index
        pair with Output_section::Simple_input_section and Convert struct to a
        class.
        (Input_section_sorter::operator()): Adjust access to
        Input_section_info data member to use accessors.
        (Output_section_element_input::set_section_addresses): Use layout
        parameter.  Adjust code to use Output_section::Simple_input_section
        and Input_secction_info classes.  Register filler for relaxation
        clean up.
        (Orphan_output_section::set_section_addresses): Replace Relobj pointer
        and section index pair with Output_section::Simple_input_section
        class.  Adjust code accordingly.
        (Phdrs_element::release_segment): New method definition.
        (Script_sections::attach_sections_using_phdrs_clause): Do not modify
        segment list.
        (Script_sections::release_segments): New method definition.
        * gold/script-sections.h (Script_sections::release_segments): New
        method declaration.
        * gold/target.h (Target::may_relax, Target::relax,
        Target::do_may_relax, Target::do_relax): New method definitions.

Attachment: patch.txt
Description: Text document