binutils-gdb/ld
Tamar Christina 652afeef24 AArch64: Fix LD crash on weak and undefined TLS symbols. (PR/24602).
This patch fixes a few linker crashes due to TLS code reaching an assert when it
shouldn't.

The first scenario is with weak TLS symbols that remain weak during linking.  In
this case the mid-end would not have seen a TLS symbol and so wouldn't have
allocated the TLS section.  We currently assert here and the linker crashes with
a not very useful message.

This patch changes this to return the value 0 for the TLS symbol in question
emulating what lld and gold and other BFD targets do.  However because weak TLS
is implementation defined and we don't define any behavior for it I also emit a
warning to the user to inform them of such.

Secondly when a strong TLS reference is undefined. The linker crashes even after
it correctly reported that there is an undefined reference.  This changes it so
that it gracefully exits and reports a useful error.

bfd/ChangeLog:

	PR ld/24601
	* elfnn-aarch64.c (aarch64_relocate): Handle weak TLS and undefined TLS.
	Also Pass input_bfd to _bfd_aarch64_elf_resolve_relocation.
	* elfxx-aarch64.c (_bfd_aarch64_elf_resolve_relocation): Use it.
	* elfxx-aarch64.h (_bfd_aarch64_elf_resolve_relocation): Emit warning
	for weak TLS.

ld/ChangeLog:

	PR ld/24601
	* testsuite/ld-aarch64/aarch64-elf.exp (undef-tls, weak-tls): New.
	* testsuite/ld-aarch64/undef-tls.d: New test.
	* testsuite/ld-aarch64/undef-tls.s: New test.
	* testsuite/ld-aarch64/weak-tls.d: New test.
	* testsuite/ld-aarch64/weak-tls.s: New test.
2019-08-22 11:43:15 +01:00
..
emulparams [ld] [arm] Add support for noinit section 2019-08-16 08:28:52 +00:00
emultempl PowerPC gcc bootstrap fail with bss-plt 2019-08-16 13:38:11 +09:30
po Regen POTFILES for bpf 2019-05-24 23:15:07 +09:30
scripttempl ld: use a specific linker script in BPF targets 2019-08-07 13:57:30 +02:00
testsuite AArch64: Fix LD crash on weak and undefined TLS symbols. (PR/24602). 2019-08-22 11:43:15 +01:00
.gitignore
aclocal.m4
ChangeLog AArch64: Fix LD crash on weak and undefined TLS symbols. (PR/24602). 2019-08-22 11:43:15 +01:00
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
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ChangeLog-2018
ChangeLog-9197
ChangeLog-9899
config.in
configure Regenerate with approved autotools version 2019-06-14 10:30:35 +09:30
configure.ac
configure.host
configure.tgt ld: add support for eBPF 2019-05-23 19:34:15 +02:00
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi
genscrba.sh
genscripts.sh Fix automatic makefile dependencies for generated ld/e*.c 2019-04-23 17:02:44 +09:30
h8-doc.texi
ld.h
ld.texi LD/doc: Clarify `-rpath' option's semantics WRT link-time dependencies 2019-06-07 19:25:21 +01:00
ldbuildid.c Fix compile time warning when building the linker in a MinGw32 environment using gcc 8. 2019-05-08 16:54:16 +01:00
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldemul.c
ldemul.h
ldexp.c stat_alloc casts 2019-08-10 17:16:16 +09:30
ldexp.h
ldfile.c Re: Have the linker report an error if the same script is used twice 2019-05-23 10:38:45 +09:30
ldfile.h Have the linker report an error if the same script is used twice. 2019-05-22 15:58:57 +01:00
ldgram.y
ldint.texi
ldlang.c stat_alloc casts 2019-08-10 17:16:16 +09:30
ldlang.h Sort statement_enum and lang_statement_union 2019-08-10 17:16:16 +09:30
ldlex-wrapper.c
ldlex.h
ldlex.l PR24827, Linker loops forever if unterminated multi-line comment in script 2019-07-20 10:55:16 +09:30
ldmain.c lang_input_statement_type next pointers 2019-08-10 17:16:16 +09:30
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c stat_alloc casts 2019-08-10 17:16:16 +09:30
MAINTAINERS
Makefile.am ld: add support for eBPF 2019-05-23 19:34:15 +02:00
Makefile.in Regenerate with approved autotools version 2019-06-14 10:30:35 +09:30
mri.c
mri.h
NEWS [LD, AArch64] Move ELF options behind -z 2019-06-06 12:21:14 +01:00
pe-dll.c
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c ld/plugins: avoid shadowing a C library symbol 2019-06-25 12:02:23 +02:00
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.texi), as well as the
  beginnings of an internals manual (ldint.texi).

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.texi 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) 2012-2019 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.