set tls_segment_ or relro_segment_.
(Layout::make_output_segment): Set tls_segment_ and relro_segment_
when appropriate.
* output.h (Output_section::clear_is_relro): New function.
* output.cc (Output_segment::add_output_section): Handle SHF_TLS
sections specially even when output_data_ is empty.
(Output_segment::maximum_alignment): When first section is relro,
only force alignment for PT_LOAD segments.
* script.cc (script_data_segment_align): New function.
(script_data_segment_relro_end): New function.
* script-c.h (script_data_segment_align): Declare.
(script_data_segment_relro_end): Declare.
* script-sections.h (class Script_sections): Declare
data_segment_align and data_segment_relro_end. Add fields
segment_align_index_ and saw_relro_end_.
* script-sections.cc (class Sections_element): Add set_is_relro
virtual function. Add new bool* parameter to place_orphan_here.
Add get_output_section virtual function.
(class Output_section_definition): Add set_is_relro. Add new
bool* parameter to place_orphan_here. Add get_output_section.
Add is_relro_ field.
(Output_section_definition::Output_section_definition): Initialize
evaluated_address_, evaluated_load_address, evaluated_addralign_,
and is_relro_ fields.
(Output_section_definition::place_orphan_here): Add is_relro
parameter.
(Output_section_definition::set_section_addresses): Set relro for
output section.
(Output_section_definition::alternate_constraint): Likewise.
(class Orphan_output_section): Add new bool* parameter to
place_orphan_here. Add get_output_section.
(Orphan_output_section::place_orphan_here): Add is_relro
parameter.
(Script_sections::Script_sections): Initialize
data_segment_align_index_ and saw_relro_end_.
(Script_sections::data_segment_align): New function.
(Script_sections::data_segment_relro_end): New function.
(Script_sections::place_orphan): Set or clear is_relro.
(Script_sections::set_section_addresses): Force alignment of first
TLS section.
* yyscript.y (exp): Call script_data_segment_align and
script_data_segment_relro_end.
* testsuite/relro_script_test.t: New file.
* testsuite/relro_test.cc (using_script): Declare.
(t1, t2): Test using_script.
* testsuite/Makefile.am (check_PROGRAMS): Add relro_script_test.
(relro_script_test_SOURCES): Define.
(relro_script_test_DEPENDENCIES): Define.
(relro_script_test_LDFLAGS): Define.
(relro_script_test_LDADD): Define.
(relro_script_test.so): New target.
* 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:
* MEMORY regions in linker scripts
* MRI compatible linker scripts
* linker map files (-M, -Map)
* cross-reference reports (--cref)
* linker garbage collection (--gc-sections)
* 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.