* target.h (Target::plt_address_for_global): New function.
(Target::plt_address_for_local): New function.
(Target::plt_section_for_global): Remove.
(Target::plt_section_for_local): Remove.
(Target::do_plt_address_for_global): New virtual function.
(Target::do_plt_address_for_local): New virtual function.
(Target::do_plt_section_for_global): Remove.
(Target::do_plt_section_for_local): Remove.
(Target::register_global_plt_entry): Add Symbol_table and Layout
parameters.
* output.cc (Output_data_got::Got_entry::write): Use
plt_address_for_global and plt_address_for_local.
* layout.cc (Layout::add_target_dynamic_tags): Use size and
address of output section.
* i386.cc (class Output_data_plt_i386): Add irelative_rel_,
got_irelative_, and irelative_count_ fields. Update
declarations.
(Output_data_plt_i386::has_irelative_section): New function.
(Output_data_plt_i386::entry_count): Add irelative_count_.
(Output_data_plt_i386::set_final_data_size): Likewise.
(class Target_i386): Add got_irelative_ and rel_irelative_
fields. Update declarations.
(Target_i386::Target_i386): Initialize new fields.
(Target_i386::do_plt_address_for_global): New function replacing
do_plt_section_for_global.
(Target_i386::do_plt_address_for_local): New function replacing
do_plt_section_for_local.
(Target_i386::got_section): Create got_irelative_.
(Target_i386::rel_irelative_section): New function.
(Output_data_plt_i386::Output_data_plt_i386): Initialize new
fields. Don't define __rel_iplt_{start,end}.
(Output_data_plt_i386::add_entry): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_i386::add_local_ifunc_entry): Add symtab and
layout parameters. Change all callers. Use different PLT and
GOT.
(Output_data_plt_i386::rel_tls_desc): Fix formatting.
(Output_data_plt_i386::rel_irelative): New function.
(Output_data_plt_i386::address_for_global): New function.
(Output_data_plt_i386::address_for_local): New function.
(Output_data_plt_i386::do_write): Write out IRELATIVE area. Use
IRELATIVE GOT when changing IFUNC GOT entries.
(Target_i386::Scan::global): Use IRELATIVE GOT for IRELATIVE
reloc.
(Target_i386::do_finalize_sections): Create the __rel_iplt symbols
if we didn't create an IRELATIVE GOT.
(Target_i386::Relocate::relocate): Use plt_address_for_global and
plt_address_for_local.
(Target_i386::do_dynsym_value): Use plt_address_for_global.
* x86_64.cc (class Output_data_plt_x86_64): Add irelative_rel_,
got_irelative_, and irelative_count_ fields. Update
declarations.
(Output_data_plt_x86_64::Output_data_plt_x86_64) [both versions]:
Initialize new fields. Remove symtab parameter. Change all
callers.
(Output_data_plt_x86_64::get_tlsdesc_plt_offset): Add
irelative_count_.
(Output_data_plt_x86_64::has_irelative_section): New function.
(Output_data_plt_x86_64::entry_count): Add irelative_count_.
(class Target_x86_64): Add got_irelative_ and rel_irelative_
fields. Update declarations.
(Target_x86_64::Target_x86_64): Initialize new fields.
(Target_x86_64::do_plt_address_for_global): New function replacing
do_plt_section_for_global.
(Target_x86_64::do_plt_address_for_local): New function replacing
do_plt_section_for_local.
(Target_x86_64::got_section): Create got_irelative_.
(Target_x86_64::rela_irelative_section): New function.
(Output_data_plt_x86_64::init): Remove symtab parameter. Change
all callers. Don't create __rel_iplt_{start,end}.
(Output_data_plt_x86_64::add_entry): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_x86_64::add_local_ifunc_entry): Add symtab and
layout parameters. Change all callers. Use different PLT and
GOT.
(Output_data_plt_x86_64::add_relocation): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_x86_64::rela_tlsdesc): Fix formatting.
(Output_data_plt_x86_64::rela_irelative): New function.
(Output_data_plt_x86_64::address_for_global): New function.
(Output_data_plt_x86_64::address_for_local): New function.
(Output_data_plt_x86_64::set_final_data_size): Likewise.
(Output_data_plt_x86_64::do_write): Write out IRELATIVE area.
(Target_x86_64::init_got_plt_for_update): Create got_irelative_.
(Target_x86_64::register_global_plt_entry): Add symtab and layout
parameters.
(Target_x86_64::Scan::global): Use IRELATIVE GOT for IRELATIVE
reloc.
(Target_x86_64::do_finalize_sections): Create the __rela_iplt
symbols if we didn't create an IRELATIVE GOT.
(Target_x86_64::Relocate::relocate): Use plt_address_for_global and
plt_address_for_local.
(Target_x86_64::do_dynsym_value): Use plt_address_for_global.
* testsuite/ifuncvar1.c: New test file.
* testsuite/ifuncvar2.c: New test file.
* testsuite/ifuncvar3.c: New test file.
* testsuite/Makefile.am (check_PROGRAMS): Add ifuncvar.
(ifuncvar1_pic.o, ifuncvar2_pic.o, ifuncvar.so): New targets.
(ifuncvar_SOURCES, ifuncvar_DEPENDENCIES): New variables.
(ifuncvar_LDFLAGS, ifuncvar_LDADD): New variables.
* testsuite/Makefile.in: Rebuild.
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 and 4.1.3 are known to work. g++
3.2, 3.4.3, and 4.1.2 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.