Binutils with MCST patches
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Maciej W. Rozycki 80070c0d34 PR ld/21233: Avoid sweeping forced-undefined symbols in section GC
Complement commit 902e9fc76a ("PR ld/20828: Move symbol version
processing ahead of GC symbol sweep"), commit b531344c34 ("PR
ld/20828: Reorder the symbol sweep stage of section GC") and commit
81ff47b3a5 ("PR ld/20828: Fix linker script symbols wrongly forced
local with section GC"), and prevent symbols forcibly entered in the
output file with the use of the `--undefined=' or `--require-defined='
linker command line options or the EXTERN linker script command from
being swept in section garbage collection and consequently recorded in
the dynamic symbol table as local entries.  This happens in certain
circumstances, where a symbol reference also exists in one of the static
input files, however only in a section which is garbage-collected and
does not make it to the output file, and the symbol is defined in a
dynamic object present in the link.

For example with the `i386-linux' target and the `pr21233.s' and
`pr21233-l.s' sources, and the `pr21233.ld' linker script included with
this change we get:

$ as -o pr21233-l.o pr21233-l.s
$ ld -shared -T pr21233.ld -o libpr21233.so pr21233-l.o
$ as -o pr21233.o pr21233.s
$ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so
$ readelf --dyn-syms pr21233

Symbol table '.dynsym' contains 2 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000000     0 OBJECT  LOCAL  DEFAULT  UND bar
$

which makes the run-time `bar' dependency of the `pr21233' executable
different from its corresponding link-time dependency, i.e. the presence
of `libpr21233.so' and its `bar' symbol is required at the link time,
however at the run time a copy of `libpr21233.so' without `bar' will do.
Similarly with `--undefined=' and EXTERN which do not actually require
the reference to the symbol requested to be satisfied with a definition
at the link time, however once the definition has been pulled at the
link time, so it should at the dynamic load time.

Additionally with the `mips-linux' target we get:

$ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so
ld: BFD (GNU Binutils) 2.28.51.20170324 assertion fail .../bfd/elfxx-mips.c:3861
$

as the target is not prepared to handle such a local dynamic symbol.

With this change in effect we get:

$ readelf --dyn-syms pr21233

Symbol table '.dynsym' contains 2 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000000     0 OBJECT  GLOBAL DEFAULT  UND bar
$

instead, for both targets.

	ld/
	PR ld/21233
	* ldlang.c (insert_undefined): Set `mark' for ELF symbols.
	* testsuite/ld-elf/pr21233.sd: New test.
	* testsuite/ld-elf/pr21233-l.sd: New test.
	* testsuite/ld-elf/pr21233.ld: New test linker script.
	* testsuite/ld-elf/pr21233-e.ld: New test linker script.
	* testsuite/ld-elf/pr21233.s: New test source.
	* testsuite/ld-elf/pr21233-l.s: New test source.
	* testsuite/ld-elf/shared.exp: Run the new tests.
2017-04-04 23:21:44 +01:00
bfd Use symbolic constants instead of magic numbers with add_data_entry() 2017-04-04 19:12:27 +01:00
binutils Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX 2017-04-04 09:06:04 -07:00
config
cpu Update the openrisc previous program counter (ppc) when running code in the cgen based simulator. 2017-03-20 15:33:51 +00:00
elfcpp
etc
gas Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX 2017-04-04 09:06:04 -07:00
gdb Remove support for using the bsd-uthread target on FreeBSD. 2017-04-04 14:28:07 -07:00
gold Mips: Fix TLS LDM GOT entry. 2017-03-15 16:51:35 -07:00
gprof
include Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX 2017-04-04 09:06:04 -07:00
intl
ld PR ld/21233: Avoid sweeping forced-undefined symbols in section GC 2017-04-04 23:21:44 +01:00
libdecnumber
libiberty cplus_demangle_fill_component: Handle DEMANGLE_COMPONENT_RVALUE_REFERENCE 2017-03-27 14:18:41 +01:00
opcodes RISC-V: Resurrect GP-relative disassembly hints 2017-04-04 08:29:16 -07:00
readline
sim Fix bug with cmn/adds where C flag was incorrectly set. 2017-03-25 20:32:02 -07:00
texinfo
zlib
.cvsignore
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ChangeLog IA16 support 2017-04-03 09:13:19 -07:00
compile
config-ml.in
config.guess Sync top level config files with master versions in the FSF config project. 2017-03-22 14:01:03 +00:00
config.rpath
config.sub IA16 support 2017-04-03 09:13:19 -07:00
configure
configure.ac
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		   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.