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With -pie and x86, the linker complains if it sees a PC-relative relocation to access a global as it expects a GOTPCREL relocation. This is really not necessary as the linker could use a copy relocation to get around it. This patch enables copy relocations with pie. Context: This is useful because currently the GCC compiler with option -fpie makes every extern global access go through the GOT. That is because the compiler cannot tell if a global will end up being defined in the executable or not and is conservative. This ends up hurting performance when the binary is linked as mostly static where most of the globals do end up being defined in the executable. By allowing copy relocs with fPIE, the compiler need not generate a GOTPCREL(GOT access) for any global access. It can safely assume that all globals will be defined in the executable and generate a PC-relative access instead. Gold can then create a copy reloc for only the undefined globals.
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.