* layout.cc (Layout::make_output_section): Call target hook to make
ordinary output section.
(Layout::finalize): Adjust parameter list of call the
Target::may_relax().
* layout.h (class Layout::section_list): New method.
* merge.h (Output_merge_base::entsize): Change visibility to public.
(Output_merge_base::is_string, Output_merge_base::do_is_string):
New methods.
(Output_merge_string::do_is_string): New method.
* object.cc (Sized_relobj::do_setup): renamed from
Sized_relobj::set_up.
* object.h (Sized_relobj::adjust_shndx,
Sized_relobj::initializ_input_to_output_maps,
Sized_relobj::free_input_to_output_maps): Change visibilities to
protected.
(Sized_relobj::setup): Virtualize.
(Sized_relobj::do_setup): New method declaration.
(Sized_relobj::invalidate_section_offset,
Sized_relobj::do_invalidate_section_offset): New method decfinitions.
(Sized_relobj::elf_file, Sized_relobj::local_values): New methods.
* options.cc (parse_int): New function.
* options.h (parse_int): New declaration.
(DEFINE_int): New macro.
(stub_group_size): New option.
* output.cc (Output_section::Output_section): Initialize memebers
merge_section_map_, merge_section_by_properties_map_,
relaxed_input_section_map_, is_relaxed_input_section_map_valid_.
(Output_section::add_input_section): Handled deferred code-fill
generation and remove an old comment.
(Output_section::add_relaxed_input_section): New method definition.
(Output_section::add_merge_input_section): Use merge section by
properties map to speed to search. Update merge section maps
as appropriate.
(Output_section::build_relaxation_map): New method definition.
(Output_section::convert_input_sections_in_list_to_relaxed_sections):
Same.
(Output_section::relax_input_section): Renamed to
Output_section::convert_input_sections_to_relaxed_sections and change
interface to take a vector of pointers to relaxed sections.
(Output_section::find_merge_section,
Output_section::find_relaxed_input_section): New method definitions.
(Output_section::is_input_address_mapped,
Output_section::output_offset, Output_section::output_address):
Use output section data maps to speed up searching.
(Output_section::find_starting_output_address): Add comments.
(Output_section::do_write,
Output_section::write_to_postprocessing_buffer): Do code-fill
generation as appropriate.
(Output_section::get_input_sections): Invalidate relaxed input section
map.
(Output_section::restore_states): Adjust type of checkpoint .
Invalidate relaxed input section map.
* output.h (Output_merge_base): New class declaration.
(Input_section_specifier): New class defintion.
(class Output_relaxed_input_section) Change base class to
Output_section_data_build.
(Output_relaxed_input_section::Output_relaxed_input_section): Adjust
base class initializer.
(Output_section::add_relaxed_input_section): New method declaration.
(Output_section::Input_section): Change visibility to protected.
(Output_section::Input_section::relobj,
Output_section::Input_section::shndx): Handle relaxed input sections.
Output_section::input_sections) Change visibility to protected. Also
define overload to return a non-const pointer.
(Output_section::Merge_section_properties): New class defintion.
(Output_section::Merge_section_by_properties_map,
Output_section::Output_section_data_by_input_section_map,
Output_section::Relaxation_map): New types.
(Output_section::relax_input_section): Rename method to
Output_section::convert_input_sections_to_relaxed_sections and change
interface to take a vector of relaxed section pointers.
(Output_section::find_merge_section,
Output_section::find_relaxed_input_section,
Output_section::build_relaxation_map,
Output_section::convert_input_sections_in_list_to_relaxed_sections):
New method declarations.
(Output_section::merge_section_map_
Output_section::merge_section_by_properties_map_,
Output_section::relaxed_input_section_map_,
Output_section::is_relaxed_input_section_map_valid_,
Output_section::generate_code_fills_at_write_): New data members.
* script-sections.cc
(Output_section_element_input::set_section_addresses): Call
current_data_size and addralign methods of relaxed input sections.
(Orphan_output_section::set_section_addresses): Call current_data_size
and addralign methods of relaxed input sections.
* symtab.cc (Symbol_table::compute_final_value): Extract template
from the body of Symbol_table::sized_finalize_symbol.
(Symbol_table::sized_finalized_symbol): Call
Symbol_table::compute_final_value.
* symtab.h (Symbol_table::Compute_final_value_status): New enum type.
(Symbol_table::compute_final_value): New templated method declaration.
* target.cc (Target::do_make_output_section): New method defintion.
* target.h (Target::make_output_section): New method declaration.
(Target::relax): Add more parameters for input objects, symbol table
and layout. Adjust call to do_relax.
(Target::do_make_output_section): New method declaration.
(Target::do_relax): Add parameters for input objects, symbol table
and layout.
gold is an ELF linker. It is intended to have complete support for
ELF and to run as fast as possible on modern systems. For normal use
it is a drop-in replacement for the older GNU linker.
gold is part of the GNU binutils. See ../binutils/README for more
general notes, including where to send bug reports.
gold was originally developed at Google, and was contributed to the
Free Software Foundation in March 2008. At Google it was designed by
Ian Lance Taylor, with major contributions by Cary Coutant, Craig
Silverstein, and Andrew Chatham.
The existing GNU linker manual is intended to be accurate
documentation for features which gold supports. gold supports most of
the features of the GNU linker for ELF targets. Notable
omissions--features of the GNU linker not currently supported in
gold--are:
* MEMORY regions in linker scripts
* MRI compatible linker scripts
* cross-reference reports (--cref)
* position independent executables (-pie)
* various other minor options
Notes on the code
=================
These are some notes which may be helpful to people working on the
source code of gold itself.
gold is written in C++. It is a GNU program, and therefore follows
the GNU formatting standards as modified for C++. Source documents in
order of decreasing precedence:
http://www.gnu.org/prep/standards/
http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/C++STYLE
http://www.zembu.com/eng/procs/c++style.html
The linker is intended to have complete support for cross-compilation,
while still supporting the normal case of native linking as fast as
possible. In order to do this, many classes are actually templates
whose parameter is the ELF file class (e.g., 32 bits or 64 bits). The
C++ code is the same, but we don't pay the execution time cost of
always using 64-bit integers if the target is 32 bits. Many of these
class templates also have an endianness parameter: true for
big-endian, false for little-endian.
The linker is multi-threaded. The Task class represents a single unit
of work. Task objects are stored on a single Workqueue object. Tasks
communicate via Task_token objects. Task_token objects are only
manipulated while holding the master Workqueue lock. Relatively few
mutexes are used.
Build requirements
==================
The gold source code uses templates heavily. Building it requires a
recent version of g++. g++ 4.0.3 is known to work. g++ 3.2 and g++
3.4.3 are known to fail.
The linker script parser uses features which are only in newer
versions of bison. bison 2.3 is known to work. bison 1.26 is known
to fail. If you are building gold from an official binutils release,
the bison output should already be included.
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