binutils-gdb/ld
H.J. Lu 5c3261b0e8 ELF: Call check_relocs after opening all inputs
For all ELF targers, call check_relocs after opening all inputs and
garbage collection.  Since the symbol resolution is known, check_relocs
can be simplified.  Also garbage collection doesn't need to undo what
check_relocs has done for symbols which have been garbage collected.
Since ELF targets never see the removed sections, gc_sweep_hook can be
removed from elf_backend_data and we can avoid GOT/PLT with garbage
collection now.

Set link_info.check_relocs_after_open_input to TRUE for all linker
targets which use ELF linker and update garbage collection tests to
remove unused GOT section.

ldemul_after_check_relocs is added for powerpc to support --secure-plt,
--bss-plt and --sdata-got.

Tested natively without regressions on i686, x86-64 and x32.  Tested
cross binutils on x86-64 without regressions for aarch64-linux,
alpha-linux, arm-linux, bfin-elf, cr16-elf, cris-elf, crx-elf, frv-linux,
hppa64-linux, hppa-linux, ia64-linux, lm32-elf, m32r-elf, m68k-linux,
mcore-elf, metag-elf, microblaze-linux, mips-linux, mmix, mn10300-elf,
nds32le-linux, nios2-linux, or1k-elf, powerpc64-linux, powerpc-linux,
riscv32-linux, riscv64-linux, s390-linux, s390x-linux, score-elf,
sh3-linux, sparc64-linux, sparc-linux, tic6x-elf, tilegx-linux,
tilepro-linux, vax-linux, x86_64-mingw32 and xtensa-linux.

bfd/

	* elf-bfd.h (elf_backend_data): Remove gc_sweep_hook.
	* elf32-arm.c (elf32_arm_gc_sweep_hook): Removed.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-bfin.c (bfin_gc_sweep_hook): Likewise.
	(bfinfdpic_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-cr16.c (elf32_cr16_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-cris.c (cris_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-hppa.c (elf32_hppa_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-lm32.c (lm32_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-m32r.c (m32r_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-m68k.c (elf_m68k_got_entry): Remove elf_m68k_gc_sweep_hook
	from comments.
	(elf_m68k_remove_got_entry_type): Removed.
	(elf_m68k_find_got_entry_ptr): Likewise.
	(elf_m68k_remove_got_entry): Likewise.
	(elf_m68k_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-mcore.c (mcore_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-metag.c (elf_metag_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-microblaze.c (elf_backend_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-mips.c (elf_backend_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-nds32.c (nds32_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-nios2.c (nios2_elf32_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-or1k.c (or1k_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-ppc.c (ppc_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-s390.c (elf_s390_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-sparc.c (elf_backend_gc_sweep_hook): Likewise.
	* elf32-tic6x.c (elf32_tic6x_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-tilegx.c (elf_backend_gc_sweep_hook): Likewise.
	* elf32-tilepro.c (tilepro_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-vax.c (elf_vax_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf32-xtensa.c (elf_xtensa_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf64-alpha.c (elf64_alpha_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf64-mips.c (elf_backend_gc_sweep_hook): Likewise.
	* elf64-mmix.c (mmix_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf64-ppc.c (elf_backend_gc_sweep_hook): Likewise.
	(ppc64_elf_gc_sweep_hook): Likewise.
	* elf64-s390.c (elf_s390_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elf64-sparc.c (elf_backend_gc_sweep_hook): Likewise.
	* elf64-tilegx.c (elf_backend_gc_sweep_hook): Likewise.
	* elflink.c (elf_link_add_object_symbols): Don't call
	_bfd_elf_link_check_relocs here.
	(gc_sweep_hook_fn): Removed.
	(elf_gc_sweep): Remove gc_sweep_hook.
	* elfnn-aarch64.c (elfNN_aarch64_gc_sweep_hook): Removed.
	(elf_backend_gc_sweep_hook): Likewise.
	* elfnn-riscv.c (riscv_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elfxx-mips.c (_bfd_mips_elf_gc_sweep_hook): Likewise.
	* elfxx-mips.h (_bfd_mips_elf_gc_sweep_hook): Likewise.
	(elf_backend_gc_sweep_hook): Likewise.
	* elfxx-sparc.c (_bfd_sparc_elf_gc_sweep_hook): Likewise.
	* elfxx-sparc.h (_bfd_sparc_elf_gc_sweep_hook): Likewise.
	* elfxx-target.h (elf_backend_gc_sweep_hook): Likewise.
	(elfNN_bed): Remove elf_backend_gc_sweep_hook.
	* elfxx-tilegx.c (tilegx_elf_gc_sweep_hook): Removed.
	* elfxx-tilegx.h (tilegx_elf_gc_sweep_hook): Likewise.

ld/

	* emulparams/elf32_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Removed.
	* emulparams/elf_i386_be.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_chaos.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_ldso.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_vxworks.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_iamcu.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_k1om.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_l1om.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/i386lynx.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/i386moss.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/i386nto.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/i386nw.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shelf.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shelf32.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shelf_nto.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shelf_vxworks.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shlelf32_linux.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shlelf_linux.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/shlelf_nto.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emultempl/aarch64elf.em (gld${EMULATION_NAME}_before_parse):
	Set link_info.check_relocs_after_open_input to TRUE.
	* emultempl/armelf.em (gld${EMULATION_NAME}_before_parse):
	Likewise.
	* emultempl/scoreelf.em (gld${EMULATION_NAME}_before_parse):
	Likewise.
	* emultempl/aix.em (ld_${EMULATION_NAME}_emulation): Add
	after_parse_default.
	* emultempl/armcoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/beos.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/generic.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/gld960.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/gld960c.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/lnk960.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/m68kcoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/msp430.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/pe.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/pep.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/sunos.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/ticoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/vanilla.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Always
	set link_info.check_relocs_after_open_input to TRUE.
	(ld_${EMULATION_NAME}_emulation): Add $LDEMUL_AFTER_CHECK_RELOCS.
	* emultempl/linux.em (gld${EMULATION_NAME}_before_parse):
	Set link_info.check_relocs_after_open_input to TRUE.
	(ld_${EMULATION_NAME}_emulation): Add after_check_relocs_default.
	* emultempl/mmix-elfnmmo.em (mmix_before_parse): New function.
	(LDEMUL_BEFORE_PARSE): New.
	* emultempl/mmixelf.em (elfmmix_before_parse): Replace
	gld${EMULATION_NAME}_before_parse with mmix_before_parse.
	* emultempl/ppc32elf.em (ppc_after_open): Renamed to ...
	(ppc_after_check_relocs): This.  Call after_check_relocs_default
	instead of gld${EMULATION_NAME}_after_open.
	(LDEMUL_AFTER_OPEN): Removed.
	(LDEMUL_AFTER_CHECK_RELOCS): New.
	* ldemul.c (ldemul_after_check_relocs): New.
	(after_check_relocs_default): Likewise.
	* ldemul.h (ldemul_after_check_relocs): Likewise.
	(after_check_relocs_default): Likewise.
	(ld_emulation_xfer_struct): Add after_check_relocs.
	* ldlang.c (lang_process): Call ldemul_after_check_relocs after
	lang_check_relocs.
	* testsuite/ld-aarch64/gc-got-relocs.d: Don't expect GOT section.
	* testsuite/ld-aarch64/gc-tls-relocs.d: Likewise.
	* testsuite/ld-cris/tls-gc-68.d: Likewise.
	* testsuite/ld-cris/tls-gc-69.d: Likewise.
	* testsuite/ld-cris/tls-gc-70.d: Likewise.
	* testsuite/ld-cris/tls-gc-75.d: Likewise.
	* testsuite/ld-cris/tls-gc-79.d: Likewise.
	* testsuite/ld-mmix/bpo-10.d: Don't expect .MMIX.reg_contents
	section.
2017-10-16 03:50:13 -07:00
..
emulparams ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
emultempl ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
po ld whitespace fixes 2017-10-12 23:30:43 +10:30
scripttempl ld whitespace fixes 2017-10-12 23:30:43 +10:30
testsuite ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
.gitignore
aclocal.m4
ChangeLog ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
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 ld whitespace fixes 2017-10-12 23:30:43 +10:30
configure.ac ld whitespace fixes 2017-10-12 23:30:43 +10:30
configure.host
configure.tgt ld whitespace fixes 2017-10-12 23:30:43 +10:30
deffile.h
deffilep.y ld whitespace fixes 2017-10-12 23:30:43 +10:30
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 ld whitespace fixes 2017-10-12 23:30:43 +10:30
h8-doc.texi
ld.h Treat common symbol as undefined for --no-define-common 2017-08-06 08:19:04 -07:00
ld.texinfo ld whitespace fixes 2017-10-12 23:30:43 +10:30
ldbuildid.c
ldbuildid.h
ldcref.c ld internationalization fixes 2017-10-11 15:04:59 +10:30
ldctor.c
ldctor.h
ldemul.c ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
ldemul.h ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
ldexp.c
ldexp.h
ldfile.c
ldfile.h
ldgram.y ld whitespace fixes 2017-10-12 23:30:43 +10:30
ldint.texinfo
ldlang.c ELF: Call check_relocs after opening all inputs 2017-10-16 03:50:13 -07:00
ldlang.h LTO rescan archives 2017-09-02 17:39:04 +09:30
ldlex-wrapper.c
ldlex.h
ldlex.l ld whitespace fixes 2017-10-12 23:30:43 +10:30
ldmain.c ld internationalization fixes 2017-10-11 15:04:59 +10:30
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c ld whitespace fixes 2017-10-12 23:30:43 +10:30
MAINTAINERS
Makefile.am Correct ld/Makefile earmelfb_fuchsia dependencies 2017-10-10 14:44:58 +10:30
Makefile.in Correct ld/Makefile earmelfb_fuchsia dependencies 2017-10-10 14:44:58 +10:30
mri.c
mri.h
NEWS ld whitespace fixes 2017-10-12 23:30:43 +10:30
pe-dll.c ld whitespace fixes 2017-10-12 23:30:43 +10:30
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c ld whitespace fixes 2017-10-12 23:30:43 +10:30
plugin.h
README
stamp-h.in
sysdep.h
testplug2.c
testplug3.c
testplug4.c
testplug.c
TODO

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		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.

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Copying and distribution of this file, with or without modification,
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