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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. |
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bfd | ||
binutils | ||
config | ||
cpu | ||
elfcpp | ||
etc | ||
gas | ||
gdb | ||
gold | ||
gprof | ||
include | ||
intl | ||
ld | ||
libdecnumber | ||
libiberty | ||
opcodes | ||
readline | ||
sim | ||
texinfo | ||
zlib | ||
.cvsignore | ||
.gitattributes | ||
.gitignore | ||
ChangeLog | ||
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 | ||
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.