binutils-gdb/gold
Alan Modra 9a23f96e91 PowerPC TPREL16_HA/LO reloc optimization
In the TLS GD/LD to LE optimization, ld replaces a sequence like

 addi 3,2,x@got@tlsgd		R_PPC64_GOT_TLSGD16	x
 bl __tls_get_addr(x@tlsgd)	R_PPC64_TLSGD		x
				R_PPC64_REL24		__tls_get_addr
 nop

with

 addis 3,13,x@tprel@ha		R_PPC64_TPREL16_HA	x
 addi 3,3,x@tprel@l		R_PPC64_TPREL16_LO	x
 nop

When the tprel offset is small, this can be further optimized to

 nop
 addi 3,13,x@tprel
 nop

bfd/
	* elf64-ppc.c (struct ppc_link_hash_table): Add do_tls_opt.
	(ppc64_elf_tls_optimize): Set it.
	(ppc64_elf_relocate_section): Nop addis on TPREL16_HA, and convert
	insn on TPREL16_LO and TPREL16_LO_DS relocs to use r13 when
	addis would add zero.
	* elf32-ppc.c (struct ppc_elf_link_hash_table): Add do_tls_opt.
	(ppc_elf_tls_optimize): Set it.
	(ppc_elf_relocate_section): Nop addis on TPREL16_HA, and convert
	insn on TPREL16_LO relocs to use r2 when addis would add zero.
gold/
	* powerpc.cc (Target_powerpc::Relocate::relocate): Nop addis on
	TPREL16_HA, and convert insn on TPREL16_LO and TPREL16_LO_DS
	relocs to use r2/r13 when addis would add zero.
ld/
	* testsuite/ld-powerpc/tls.s: Add calls with tls markers.
	* testsuite/ld-powerpc/tls32.s: Likewise.
	* testsuite/ld-powerpc/powerpc.exp: Run tls marker tests.
	* testsuite/ld-powerpc/tls.d: Adjust for TPREL16_HA/LO optimization.
	* testsuite/ld-powerpc/tlsexe.d: Likewise.
	* testsuite/ld-powerpc/tlsexetoc.d: Likewise.
	* testsuite/ld-powerpc/tlsld.d: Likewise.
	* testsuite/ld-powerpc/tlsmark.d: Likewise.
	* testsuite/ld-powerpc/tlsopt4.d: Likewise.
	* testsuite/ld-powerpc/tlstoc.d: Likewise.
2017-08-30 20:43:31 +09:30
..
po Update PO files 2017-07-12 23:08:59 +09:30
testsuite Fix bad offset calculation for R_AARCH64_TLSDESC_* relocs. 2017-08-28 08:03:00 -07:00
ChangeLog PowerPC TPREL16_HA/LO reloc optimization 2017-08-30 20:43:31 +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 2017-08-28 James Clarke <jrtc27@jrtc27.com> 2017-08-28 16:40:51 -07:00
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 Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
configure Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
configure.ac Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
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 tls_get_addr_optimize 2017-08-29 21:29:37 +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 PowerPC TPREL16_HA/LO reloc optimization 2017-08-30 20:43:31 +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 [GOLD] PowerPC tls_get_addr_optimize 2017-08-29 21:29:37 +09:30
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 [GOLD] Reduce size of class Symbol 2017-08-29 21:29:37 +09:30
symtab.h [GOLD] PowerPC tls_get_addr_optimize 2017-08-29 21:29:37 +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 [GOLD] Symbol flag for PowerPC64 localentry:0 tracking 2017-08-28 16:27:33 +09:30
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

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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.