Date: Sat, 31 Mar 2007 04:26:23 +0200 From: Pieter de Goeje <pieter@degoeje.nl> To: freebsd-hackers@freebsd.org Subject: Thread local storage not working with -fPIC and shared objects Message-ID: <200703310426.23953.pieter@degoeje.nl>
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Hello List, I have these files: --- loader.cpp --- #include <stdio.h> #include "tls.h" int main() { tls = 0; printf("%d\n", tls); } --- tls.cpp --- #include "tls.h" int __thread tls; --- tls.h --- extern __thread int tls; When I compile them like this: c++ -fPIC -o tls.so tls.cpp -shared c++ -fPIC -o loader loader.cpp tls.so And run the resulting program, I get: pyotr@nox:~/projects/misc/tls> ./loader /libexec/ld-elf.so.1: ./loader: Unsupported relocation type 37 in non-PLT relocations When I omit -fPIC, it runs fine. But I need fPIC for the shared object on amd64 arch. I've tried it on Linux/i386 (gcc 4.1) and it ran fine (with fPIC). Much to my surprise however, a particularly large application I'm working on did compile & run on FreeBSD/amd64 using -fpic (lowercase) and gcc 4.3. Trying -fpic on FreeBSD/i386 resulted in failure. FYI, I need tls to work because I'm using OpenMP's tls (#pragma omp threadprivate()) support in gcc 4.3. The workaround I found on FreeBSD/amd64 was linking the main executable with -fno-PIC, or building everything with -fpic. (both workarounds didn't work on FreeBSD/i386) I would be grateful if someone could shed some light on this. Regards, Pieter de Goeje
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