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My 2017-01-24 patch (commit f0158f44) wrongly applied an optimization of GOT entries for the __tls_get_addr_opt stub, to shared libraries. When the TLS segment layout is known, as it is for the executable and shared libraries loaded at initial program start, powerpc supports a __tls_get_addr optimization. On the first call to __tls_get_addr for a given __tls_index GOT entry, the DTPMOD word is set to zero and the DTPREL word to the thread pointer offset to the thread variable. This allows the __tls_get_addr_opt stub to return that value immediately without making a call into glibc for any subsequent __tls_get_addr calls using that __tls_index GOT entry. That's all fine, but I thought I'd be clever and when the thread variable is local, set up the GOT entry as if __tls_get_addr had already been called. Which is good only for the executable, since ld cannot know the TLS layout for shared libraries. Of course, if this only applies to executables there isn't much point to the optimization. Normally, GD and LD code in an executable will be converted to IE or LE, losing the __tls_get_addr call. So the only time it will trigger is with --no-tls-optimize. Thus, revert all support. * elf64-ppc.c (ppc64_elf_relocate_section): Don't optimize __tls_index GOT entries when using __tls_get_addr_opt stub. * elf32-ppc.c (ppc_elf_relocate_section): Likewise.
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.