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Cary Coutant cea6ffbd06 Fix treatment of symbol versions with unused as-needed libraries.
When we have a weak reference to a symbol defined in an
as-needed library, and that library ends up not-needed, gold
simply clears the version information in the symbol table, even
if the symbol could have been resolved by a needed library later
in the link order. This results in a loss of version information,
which can cause the program to bind to the wrong version at run
time.

This patch lets a dynamic definition override an earlier one if
the earlier one is from a not-needed library, so that we can
retain the version information from the binding to the needed
library. In order to do that, the tracking of needed/not-needed
had to be moved up to symbol resolution time, instead of during
Symbol_table::set_dynsym_indexes().

In cases where we still end up discarding version information,
I've added a warning.

For the original problem report and discussion, see:

https://stackoverflow.com/questions/50751421/undefined-behavior-in-shared-lib-using-libpthread-but-not-having-it-in-elf-as-d

gold/
	* resolve.cc (Symbol_table::resolve): Rename tobinding to
	orig_tobinding.  Call set_is_needed() for objects that resolve
	non-weak references.
	(Symbol_table::should_override): Allow a dynamic definition to
	override an earlier one in a not-needed library.
	* symtab.cc (Symbol_table::set_dynsym_indexes): Remove separate
	processing for as-needed symbols.  Add warning when discarding
	version informatin.
	* testsuite/Makefile.am (weak_as_needed): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/weak_as_needed.sh: New test script.
	* testsuite/weak_as_needed_a.c: New source file.
	* testsuite/weak_as_needed_b.c: New source file.
	* testsuite/weak_as_needed_b.script: New version script.
	* testsuite/weak_as_needed_c.c: New source file.
	* testsuite/weak_as_needed_c.script: New version script.
2018-06-21 13:54:16 -07:00
bfd MIPS/BFD: Correct formatting of compact EH backend methods 2018-06-21 21:40:57 +01:00
binutils Regen doc/Makefile.in 2018-06-21 23:00:05 +09:30
config Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
cpu PR22069, Several instances of register accidentally spelled as regsiter 2018-05-09 15:55:28 +09:30
elfcpp PowerPC inline PLT call support 2018-04-09 17:25:20 +09:30
etc Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
gas Regen doc/Makefile.in 2018-06-21 23:00:05 +09:30
gdb Use thread_info and inferior pointers more throughout 2018-06-21 17:09:31 +01:00
gold Fix treatment of symbol versions with unused as-needed libraries. 2018-06-21 13:54:16 -07:00
gprof Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
include Use offsets instead of addresses in ELF_SECTION_IN_SEGMENT for non SHT_NOBITS 2018-06-21 09:37:58 +01:00
intl Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ld [BFD][AARCH64]Properly truncate no overflow checking relocation value for load/store immediate. 2018-06-20 14:47:37 +01:00
libdecnumber Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
libiberty Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
opcodes RISC-V: Accept constant operands in la and lla 2018-06-20 07:24:25 +02:00
readline Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
sim Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
texinfo
zlib Regen doc/Makefile.in 2018-06-21 23:00:05 +09:30
.cvsignore
.gitattributes
.gitignore
ar-lib Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ChangeLog Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
compile
config-ml.in Update top level configure files by synchronizing them with gcc. 2018-01-10 15:29:21 +00:00
config.guess Bring in support for the NFP target in the config.sub file. 2018-05-01 16:35:04 +01:00
config.rpath
config.sub Bring in support for the NFP target in the config.sub file. 2018-05-01 16:35:04 +01:00
configure Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
configure.ac Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4 Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def This was already applied on the GCC side. 2018-06-19 00:05:40 +02:00
Makefile.in This was already applied on the GCC side. 2018-06-19 00:05:40 +02:00
Makefile.tpl This was already applied on the GCC side. 2018-06-19 00:05:40 +02:00
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
setup.com
src-release.sh Improve junk file removal in source tarball creation script. 2018-01-30 17:48:24 +00:00
symlink-tree
test-driver Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ylwrap

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.