binutils-gdb/ld
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
..
emulparams [ARC] Add JLI support. 2017-07-19 09:56:55 +02:00
emultempl Improve MSP430 section placement. 2017-08-29 17:18:43 +01:00
po Add new Brazilian Portuguese translation for the ld subdirectory. 2017-08-17 12:13:28 +01:00
scripttempl Add support for PE startup files that want to define their own constructor and desctructor sequencing. 2017-08-10 13:17:12 +01:00
testsuite PowerPC TPREL16_HA/LO reloc optimization 2017-08-30 20:43:31 +09:30
.gitignore
aclocal.m4
ChangeLog PowerPC TPREL16_HA/LO reloc optimization 2017-08-30 20:43:31 +09:30
ChangeLog-0001
ChangeLog-0203
ChangeLog-2004
ChangeLog-2005
ChangeLog-2006
ChangeLog-2007
ChangeLog-2008
ChangeLog-2009
ChangeLog-2010
ChangeLog-2011
ChangeLog-2012
ChangeLog-2013
ChangeLog-2014
ChangeLog-2015
ChangeLog-2016
ChangeLog-9197
ChangeLog-9899
config.in Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
configure Add new Brazilian Portuguese translation for the ld subdirectory. 2017-08-17 12:13:28 +01:00
configure.ac Add new Brazilian Portuguese translation for the ld subdirectory. 2017-08-17 12:13:28 +01:00
configure.host
configure.tgt Accept more epiphany targets 2017-06-14 06:59:37 +02:00
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi S/390: Add support for pgste marker 2017-06-23 08:00:46 +02:00
genscrba.sh
genscripts.sh
h8-doc.texi
ld.h Treat common symbol as undefined for --no-define-common 2017-08-06 08:19:04 -07:00
ld.texinfo Improve MSP430 section placement. 2017-08-29 17:18:43 +01:00
ldbuildid.c
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldemul.c
ldemul.h
ldexp.c
ldexp.h
ldfile.c Treat a prefix of "$SYSROOT" in the same way as "=" when parsing linker search paths. 2017-05-18 15:07:59 +01:00
ldfile.h
ldgram.y Treat common symbol as undefined for --no-define-common 2017-08-06 08:19:04 -07:00
ldint.texinfo
ldlang.c ld: Early detection of orphans we know will be discarded 2017-08-24 12:41:34 +01:00
ldlang.h
ldlex-wrapper.c
ldlex.h ld: Allow section groups to be resolved as part of a relocatable link 2017-06-06 09:53:38 +01:00
ldlex.l ld: Allow section groups to be resolved as part of a relocatable link 2017-06-06 09:53:38 +01:00
ldmain.c Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c Add -z globalaudit linker command line option to set the DF_GLOBALAUDIT flag bit in the dynamic tags. 2017-08-11 16:36:28 +01:00
MAINTAINERS
Makefile.am Apply ld/Makefile.in patch to the correct file 2017-07-07 10:35:31 +09:30
Makefile.in S/390: Add support for pgste marker 2017-06-23 08:00:46 +02:00
mri.c
mri.h
NEWS Add -z globalaudit linker command line option to set the DF_GLOBALAUDIT flag bit in the dynamic tags. 2017-08-11 16:36:28 +01:00
pe-dll.c Support pe-bigobj-x86-64 as an output format in 64-bit PE based linkers. 2017-05-09 14:42:43 +01:00
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c Rename non_ir_ref to non_ir_ref_regular 2017-05-16 10:35:02 +09:30
plugin.h
README
stamp-h.in
sysdep.h
testplug2.c
testplug3.c
testplug4.c
testplug.c
TODO

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.

		README for LD

This is the GNU linker.  It is distributed with other "binary
utilities" which should be in ../binutils.  See ../binutils/README for
more general notes, including where to send bug reports.

There are many features of the linker:

* The linker uses a Binary File Descriptor library (../bfd)
  that it uses to read and write object files.  This helps
  insulate the linker itself from the format of object files.

* The linker supports a number of different object file
  formats.  It can even handle multiple formats at once:
  Read two input formats and write a third.

* The linker can be configured for cross-linking.

* The linker supports a control language.

* There is a user manual (ld.texinfo), as well as the
  beginnings of an internals manual (ldint.texinfo).

Installation
============

See ../binutils/README.

If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.

To build just the linker, make the target all-ld from the top level
directory (one directory above this one).

Porting to a new target
=======================

See the ldint.texinfo manual.

Reporting bugs etc
===========================

See ../binutils/README.

Known problems
==============

The Solaris linker normally exports all dynamic symbols from an
executable.  The GNU linker does not do this by default.  This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets).  This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl.  You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.

HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly.  The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages.  There are various
workarounds to this:
  * Build and install bash, and build with "make SHELL=bash".
  * Update to a version of HP/UX with a working shell (e.g., 9.05).
  * Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
    genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
    emulparams script used exports any shell variables it sets.

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.