GDB that can debug Mach-Os on Linux
Go to file
Alan Modra b53dfeb26e PowerPC64 ELFv1 function symbol definition vs LTO and discarded sections
When functions are emitted in comdat groups, global symbols defined in
duplicates of the group are treated as if they were undefined.  That
prevents the symbols in the discarded sections from affecting the
linker's global symbol hash table or causing duplicate symbol errors.
Annoyingly, when gcc emits a function to a comdat group, it does not
put *all* of a function's code and data in the comdat group.
Typically, constant tables, exception handling info, and debug info
are emitted to normal sections outside of the group, which is a
perennial source of linker problems due to the special handling needed
to deal with the extra-group pieces that ought to be discarded.  In
the case of powerpc64-gcc, the OPD entry for a function is not put in
the group.  Since the function symbol is defined on the OPD entry this
means we need to handle symbols in .opd specially.

To see how this affects LTO in particular, consider the linker
testcase PR ld/12942 (1).  This testcase links an LTO object file
pr12942a.o with a normal (non-LTO) object pr12942b.o.  Both objects
contain a definition for _Z4testv in a comdat group.  On loading
pr12942a.o, the linker sees a comdat group (actually linkonce section)
for _Z4testv and a weak _Z4testv defined in the IR.  On loading
pr12942b.o, the linker sees the same comdat group, and thus discards
it.  However, _Z4testv is a weak symbol defined in .opd, not part of
the group, so this weak symbol overrides the weak IR symbol.  On
(re)loading the LTO version of pr12942a.o, the linker sees another
weak _Z4testv, but this one does not override the value we have from
pr12942b.o.  The result is a linker complaint about "`_Z4testv'
... defined in discarded section `.group' of tmpdir/pr12942b.o".

	* elf64-ppc.c (ppc64_elf_add_symbol_hook): If function code
	section for function symbols defined in .opd is discarded, let
	the symbol appear to be undefined.
	(opd_entry_value): Ensure the result section is that for the
	function code section in the same object as the OPD entry.
2014-10-18 23:07:08 +10:30
bfd PowerPC64 ELFv1 function symbol definition vs LTO and discarded sections 2014-10-18 23:07:08 +10:30
binutils Bump bfd version. 2014-10-15 10:21:25 +02:00
config
cpu
elfcpp
etc
gas Fix PR17493, attempted output of *GAS `reg' section* symbol 2014-10-18 23:07:07 +10:30
gdb New python event "clear_objfiles". 2014-10-17 11:12:17 -07:00
gold * configure.tgt (targ_extra_obj) [aarch64*-*]: Define. 2014-10-18 10:31:31 +02:00
gprof Bump bfd version. 2014-10-15 10:21:25 +02:00
include opcodes, elf: annotate instructions with HWCAP2_VIS3B. 2014-10-17 22:00:02 +02:00
intl
ld Fix ld tests with sysroot=/ and --enable-targets=all and test --print-sysroot 2014-10-17 13:11:42 +02:00
libdecnumber
libiberty Use strtod instead of strtold in libiberty/d-demangle.c 2014-10-16 14:52:17 -07:00
opcodes opcodes, elf: annotate instructions with HWCAP2_VIS3B. 2014-10-17 22:00:02 +02:00
readline
sim
texinfo
.cvsignore
.gitattributes
.gitignore
ChangeLog src-release.sh: configure using --target. 2014-10-15 09:50:53 +02:00
compile
config-ml.in
config.guess
config.rpath
config.sub
configure Add aarch64 to list of targets that support gold. 2014-10-03 14:48:14 -07:00
configure.ac Add aarch64 to list of targets that support gold. 2014-10-03 14:48:14 -07:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def
Makefile.in
Makefile.tpl
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release.sh src-release.sh: configure using --target. 2014-10-15 09:50:53 +02:00
symlink-tree
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.