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Alan Modra 0e5fabeb2c Rewrite relro adjusting code
The linker tries to put the end of the last section in the relro
segment exactly on a page boundary, because the relro segment itself
must end on a page boundary.  If for any reason this can't be done,
padding is inserted.  Since the end of the relro segment is typically
between .got and .got.plt, padding effectively increases the size of
the GOT.  This isn't nice for targets and code models with limited GOT
addressing.

The problem with the current code is that it doesn't cope very well
with aligned sections in the relro segment.  When making .got aligned
to a 256 byte boundary for PowerPC64, I found that often the initial
alignment attempt failed and the fallback attempt to be less than
adequate.  This is a particular problem for PowerPC64 since the
distance between .got and .plt affects the size of plt call stubs,
leading to "stubs don't match calculated size" errors.

So this rewrite takes a direct approach to calculating a new relro
base.  Starting from the last section in the segment, we calculate
where it must start to position its end on the boundary, or as near as
possible considering alignment requirements.  The new start then
becomes the goal for the previous section to end, and so on for all
sections.  This of course ignores the possibility that user scripts
will place . = ALIGN(xxx); in the relro segment, or provide section
address expressions.  In those cases we might fail, but the old code
probably did too, and a fallback is provided.

ld/
	* ldexp.h (struct ldexp_control): Delete dataseg.min_base.  Add
	data_seg.relro_offset.
	* ldexp.c (fold_binary <DATA_SEGMENT_ALIGN>): Don't set min_base.
	(fold_binary <DATA_SEGMENT_RELRO_END>): Do set relro_offset.
	* ldlang.c (lang_size_sections): Rewrite code adjusting relro
	segment base to line up last section on page boundary.
ld/testsuite/
	* ld-x86-64/pr18176.d: Update.
2015-04-22 23:19:59 +09:30
bfd i386: Allow copy relocs for building PIE 2015-04-22 05:30:01 -07:00
binutils Don't hardcode offset of .shstrtab section 2015-04-20 09:55:47 -07:00
config Set zlibdir/zlibinc with top_builddir/top_srcdir 2015-04-02 05:43:07 -07:00
cpu
elfcpp Add chdr_size, Chdr, Chdr_write and Chdr_data 2015-04-08 10:29:40 -07:00
etc
gas Don't hardcode offset of .shstrtab section 2015-04-20 09:55:47 -07:00
gdb Fix pascal behavior for class fields with testcase 2015-04-21 22:10:08 +02:00
gold Ensure that dynamically loaded libraries won't use separate copies of GNU_UNIQUE symbols. 2015-04-20 18:07:49 -07:00
gprof
include Merge include/partition.h from GCC. 2015-04-17 16:13:43 +01:00
intl
ld Rewrite relro adjusting code 2015-04-22 23:19:59 +09:30
libdecnumber
libiberty
opcodes Remove the unused PREFIX_UD_XXX 2015-04-15 16:00:36 -07:00
readline
sim sim: mcore: clean up printf warnings 2015-04-21 03:10:16 -04:00
texinfo
zlib
.cvsignore
.gitattributes
.gitignore
ChangeLog Fix typo in last ChangeLog. 2015-04-15 04:11:18 +02:00
compile
config-ml.in
config.guess
config.rpath
config.sub
configure
configure.ac
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 Adjust src-release.sh for sim using the gdb create-version.sh. 2015-04-15 04:08:51 +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.