binutils-gdb/ld
H.J. Lu caa65211bb Add "-z call-nop=PADDING" option to ld
The ld linker can transform indirect call to a locally defined function,
foo, via its GOT slot, to either "NOP call foo" or "call foo NOP" where
NOP is a 1-byte NOP padding.  This patch adds a "-z call-nop=PADDING"
option to x86 ld to control 1-byte NOP padding for x86 call instruction.
PADDING is one of prefix-addr, prefix-nop, suffix-nop, prefix-NUMBER or
suffix-NUMBER.

bfd/

	* elf32-i386.c (elf_i386_convert_load): Use call_nop_byte and
	check call_nop_as_suffix for 1-byte NOP padding to pad call.
	* elf64-x86-64.c (elf_x86_64_convert_load): Likewise.

include/

	* bfdlink.h (bfd_link_info): Add call_nop_as_suffix and
	call_nop_byte.

ld/

	* ld/ld.texinfo: Document "-z call-nop=PADDING" option.
	* emulparams/call_nop.sh: New file.
	* emulparams/elf_i386_be.sh: Source
	${srcdir}/emulparams/call_nop.sh.
	* emulparams/elf_i386_chaos.sh: Likewise.
	* emulparams/elf_i386_ldso.sh: Likewise.
	* emulparams/elf_i386_vxworks.sh: Likewise.
	* emulparams/elf_iamcu.sh: Likewise.
	* emulparams/elf_k1om.sh: Likewise.
	* emulparams/elf_l1om.sh: Likewise.
	* emulparams/elf_x86_64.sh: Likewise.
	* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set
	link_info.call_nop_byte if $CALL_NOP_BYTE isn't empty.

ld/testsuite/

	* ld-i386/call3.s: New file.
	* ld-i386/call3a.d: Likewise.
	* ld-i386/call3b.d: Likewise.
	* ld-i386/call3c.d: Likewise.
	* ld-i386/call3d.d: Likewise.
	* ld-i386/call3e.d: Likewise.
	* ld-i386/call3f.d: Likewise.
	* ld-i386/call3g.d: Likewise.
	* ld-i386/call3h.d: Likewise.
	* ld-i386/load1-nacl.d: Likewise.
	* ld-x86-64/call1.s: Likewise.
	* ld-x86-64/call1a.d: Likewise.
	* ld-x86-64/call1b.d: Likewise.
	* ld-x86-64/call1c.d: Likewise.
	* ld-x86-64/call1d.d: Likewise.
	* ld-x86-64/call1e.d: Likewise.
	* ld-x86-64/call1f.d: Likewise.
	* ld-x86-64/call1g.d: Likewise.
	* ld-x86-64/call1h.d: Likewise.
	* ld-x86-64/call1i.d: Likewise.
	* ld-x86-64/load1a-nacl.d: Likewise.
	* ld-x86-64/load1b-nacl.d: Likewise.
	* ld-x86-64/load1c-nacl.d: Likewise.
	* ld-x86-64/load1d-nacl.d: Likewise.
2015-10-22 04:56:39 -07:00
..
emulparams Add "-z call-nop=PADDING" option to ld 2015-10-22 04:56:39 -07:00
emultempl Add "-z call-nop=PADDING" option to ld 2015-10-22 04:56:39 -07:00
po Updated Chinese translation for the linker (again!) 2015-10-14 09:55:30 +01:00
scripttempl New ARC implementation. 2015-10-07 14:20:19 +01:00
testsuite Add "-z call-nop=PADDING" option to ld 2015-10-22 04:56:39 -07:00
.gitignore
aclocal.m4
ChangeLog Add "-z call-nop=PADDING" option to ld 2015-10-22 04:56:39 -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-9197
ChangeLog-9899
config.in Reset x86 Linux targets to not compressing debug sections by default. Enable compression of debug sections by default in the linker, if so configured. 2015-10-21 13:15:39 +01:00
configure Extend description of the --enable-compressed-debug-sections configure option in gas and ld. 2015-10-21 14:57:28 +01:00
configure.ac Extend description of the --enable-compressed-debug-sections configure option in gas and ld. 2015-10-21 14:57:28 +01:00
configure.host
configure.tgt New ARC implementation. 2015-10-07 14:20:19 +01:00
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi
genscrba.sh
genscripts.sh
h8-doc.texi
ld.h ld: Extend options for altering orphan handling behaviour. 2015-09-04 22:30:55 +01:00
ld.texinfo Add "-z call-nop=PADDING" option to ld 2015-10-22 04:56:39 -07:00
ldbuildid.c
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldemul.c ld: Extend options for altering orphan handling behaviour. 2015-09-04 22:30:55 +01:00
ldemul.h
ldexp.c When evaluating a ternary operator in a linker script, copy the symbol flags. 2015-10-15 13:28:27 +01:00
ldexp.h Delay converting linker script defined symbols from absolute 2015-09-18 12:39:16 +09:30
ldfile.c
ldfile.h
ldgram.y
ldint.texinfo
ldlang.c Delay converting linker script defined symbols from absolute 2015-09-18 12:39:16 +09:30
ldlang.h
ldlex-wrapper.c
ldlex.h Add --no-dynamic-linker option to ld, for static PIE use 2015-09-20 15:52:27 +09:30
ldlex.l
ldmain.c Reset x86 Linux targets to not compressing debug sections by default. Enable compression of debug sections by default in the linker, if so configured. 2015-10-21 13:15:39 +01:00
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c Reset x86 Linux targets to not compressing debug sections by default. Enable compression of debug sections by default in the linker, if so configured. 2015-10-21 13:15:39 +01:00
MAINTAINERS
Makefile.am New ARC implementation. 2015-10-07 14:20:19 +01:00
Makefile.in New ARC implementation. 2015-10-07 14:20:19 +01:00
mri.c
mri.h
NEWS Reset x86 Linux targets to not compressing debug sections by default. Enable compression of debug sections by default in the linker, if so configured. 2015-10-21 13:15:39 +01:00
pe-dll.c
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c Remove link_info.pic 2015-08-19 12:53:54 +09:30
plugin.h
README
stamp-h.in
sysdep.h
testplug2.c
testplug3.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.

Copyright (C) 2012-2015 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.