binutils-gdb/gold
Alan Modra be897fb774 [GOLD] PowerPC recreate eh_frame for stubs on each relax pass
There is a very small but non-zero probability that a stub group
contains stubs on one relax pass, but does not on the next.  In that
case we would get an FDE covering a zero length address range.
(Actually, it's even worse.  Alignment padding for stubs can mean the
address for the non-existent stubs is past the end of the original
section to which stubs are attached, and due to the way
do_plt_fde_location calculates the length we can get a negative
length.)  Fixing this properly requires removing the FDE.

Also, I have been implementing the __tls_get_addr_opt support for
gold, and that stub needs something other than the default FDE.  The
necessary FDE will depend on the offset to the __tls_get_addr_opt
stub, which of course can change during relaxation.  That means at the
very least, rewriting the FDE on each pass, possibly changing the FDE
size.  I think that is better done by completely recreating PLT
eh_frame FDEs.

	* ehframe.cc (Fde::operator==): New.
	(Cie::remove_fde, Eh_frame::remove_ehframe_for_plt): New.
	* ehframe.h (Fde::operator==): Declare.
	(Cie::remove_fde, Eh_frame::remove_ehframe_for_plt): Likewise.
	* layout.cc (Layout::remove_eh_frame_for_plt): New.
	* layout.h (Layout::remove_eh_frame_for_plt): Declare.
	* powerpc.cc (Target_powerpc::do_relax): Remove old eh_frame FDEs.
	(Stub_table::add_eh_frame): Delete eh_frame_added_ condition.
	Don't add eh_frame for empty stub section.
	(Stub_table::remove_eh_frame): New.
2017-08-01 14:08:53 +09:30
..
po Update PO files 2017-07-12 23:08:59 +09:30
testsuite Fix misplacement of a relaxed section on AArch64. 2017-05-12 15:24:32 -07:00
ChangeLog [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
ChangeLog-0815 binutils ChangeLog rotation 2016-01-01 22:59:17 +10:30
ChangeLog-2016 ChangeLog rotation 2017-01-02 13:55:05 +10:30
Makefile.am Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
Makefile.in Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
NEWS Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
README Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
TODO
aarch64-reloc-property.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
aarch64-reloc-property.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
aarch64-reloc.def Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
aarch64.cc Fix spelling typos. 2017-07-18 16:58:14 +01:00
aclocal.m4 Regenerate Makefile.in/aclocal.m4 automake 1.11.6 2016-04-15 16:20:55 -07:00
archive.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
archive.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
arm-reloc-property.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
arm-reloc-property.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
arm-reloc.def Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
arm.cc Fix spelling typos. 2017-07-18 16:58:14 +01:00
attributes.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
attributes.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
binary.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
binary.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
common.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
common.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
compressed_output.cc gold: Add put_ch_reserved to 64-bit Chdr_write 2017-07-28 13:40:01 -07:00
compressed_output.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
config.in gold: Add a linker configure option --enable-relro 2016-06-22 05:39:39 -07:00
configure Fix spelling mistakes in comments in configure scripts 2016-11-22 15:43:03 +00:00
configure.ac Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
configure.tgt Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
copy-relocs.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
copy-relocs.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
cref.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
cref.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
debug.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
defstd.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
defstd.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
descriptors.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
descriptors.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dirsearch.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dirsearch.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dwarf_reader.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dwarf_reader.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dwp.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dwp.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dynobj.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dynobj.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ehframe.cc [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
ehframe.h [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
errors.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
errors.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
expression.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ffsll.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
fileread.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
fileread.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
freebsd.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ftruncate.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gc.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gc.h Improved support for --icf=safe when used with -pie. 2017-02-15 00:37:10 -08:00
gdb-index.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gdb-index.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gold-threads.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gold-threads.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gold.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
gold.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
i386.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
icf.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
icf.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
incremental-dump.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
incremental.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
incremental.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
int_encoding.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
int_encoding.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
layout.cc [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
layout.h [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
main.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
mapfile.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
mapfile.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
merge.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
merge.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
mips.cc Gold: Fix mips.cc for GCC 4.2 2017-07-26 10:43:36 -07:00
mremap.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
nacl.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
nacl.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
object.cc Fix incorrect byte counts. 2017-01-12 11:51:40 -08:00
object.h Refactor Sized_relobj_file::do_relocate_sections. 2017-01-10 07:46:43 -08:00
options.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
options.h [GOLD] PowerPC --no-tls-optimize 2017-07-31 19:53:49 +09:30
output.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
output.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
parameters.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
parameters.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
plugin.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
plugin.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
powerpc.cc [GOLD] PowerPC recreate eh_frame for stubs on each relax pass 2017-08-01 14:08:53 +09:30
pread.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
readsyms.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
readsyms.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
reduced_debug_output.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
reduced_debug_output.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
reloc-types.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
reloc.cc Refactor Sized_relobj_file::do_relocate_sections. 2017-01-10 07:46:43 -08:00
reloc.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
resolve.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
s390.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
script-c.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
script-sections.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
script-sections.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
script.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
script.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
sparc.cc Fix assertion failure relaxing TLS for position-independent executables. 2017-05-13 08:01:15 -07:00
stringpool.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
stringpool.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
symtab.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
symtab.h [GOLD] PowerPC64 tocsave 2017-06-23 20:37:34 +09:30
system.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
target-reloc.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
target-select.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
target-select.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
target.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
target.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
tilegx.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
timer.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
timer.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
tls.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
token.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
version.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
workqueue-internal.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
workqueue-threads.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
workqueue.cc Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
workqueue.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
x86_64.cc Fix spelling typos. 2017-07-18 16:58:14 +01:00
yyscript.y Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30

README

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

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++/manual/source_code_style.html
    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.


Copyright (C) 2012-2017 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.