Cary Coutant <ccoutant@google.com>
* arm.cc (Arm_exidx_merge_section::build_contents): New method.
(Arm_exidx_merge_section::section_contents_): New data member.
(Arm_input_section::Arm_input_section): Initialize original_contents_.
(Arm_input_section::~Arm_input_section): De-allocate memory.
(Arm_input_section::original_contents_): New data member.
(Arm_exidx_fixup::process_exidx_section): Pass EXIDX section contents
in parameters instead of calling Object::section_contents without
locking.
(Arm_output_section::group_section): New parameter TASK. Pass it
to callees that need locking objects.
(Arm_output_section::fix_exidx_coverage): New parameter TASK. Use it
to lock EXIDX input sections. Fix a formatting issue. Call
Arm_exidx_merged_section::build_contents to create merged section
contents.
(Arm_output_section::create_stub_group): New parameter TASK. Use it
to lock object of stub table owner.
(Arm_exidx_input_section::Arm_exidx_input_section): Add new parameter
TEXT_SIZE to initialize data member TEXT_SIZE_.
(Arm_exidx_input_section::addralign): Fix typo in comment.
(Arm_exidx_input_section::text_size): New method.
(Target_arm::do_relax): New parameter TASK. Pass it to callees
that require locking objects. Lock objects before scanning for stubs
and updating local symbols.
(Arm_input_section<big_endian>::init): Copy contents of original
input section.
(Arm_input_section<big_endian>::do_write): Use saved contents of
original input section instead of calling Object::section_contents
without locking.
(Arm_exidx_cantunwind::do_fixed_endian_write): Find out text section
size without calling Object::section_size().
(Arm_exidx_merged_section::Arm_exidx_merged_section): Add sanity check
for size. Allocate a buffer for merged EXIDX entries.
(Arm_exidx_merged_section::build_contents): New method.
(Arm_exidx_merged_section::do_write): Move merge section contents
building code to Arm_exidx_merged_section::build_contetns. Write
out contetns in buffer instead of building it on the fly.
(Arm_relobj::make_exidx_input_section): Also pass text section size
to Arm_exidx_input_section constructor.
(Arm_relobj::do_read_symbols): Fix memory leak. Fix a formatting issue.
(Arm_dynobj::do_read_symbols): Fix memory leak.
* layout.cc (Layout::finalize): Pass TASK to Target::relax().
* target.h: (class Task): Add forward declaration.
(Target::relax): Add new parameter TASK and pass it to
Target::do_relax().
(Target::do_relax):: New parameter TASK. Fix a formatting issue.
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:
* MRI compatible linker scripts
* cross-reference reports (--cref)
* 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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