Am 06.04.2009 14:24, Peter Dimov schrieb:
Carsten Raas:
Finally, I tried to compile my demo program with the "-H" flag. Then I grep'ed all included header files for "sync_fetch". The only file with "sync_fetch" in it is atomicity.h and it appears three times, cf. the dependency tree: /opt/boost/1.38/intel/include/boost/date_time/date_generators.hpp /usr/include/c++/4.2.1/stdexcept /usr/include/c++/4.2.1/string /usr/include/c++/4.2.1/bits/basic_string.h /usr/include/c++/4.2.1/ext/atomicity.h /usr/include/c++/4.2.1/sstream /usr/include/c++/4.2.1/istream /usr/include/c++/4.2.1/ios /usr/include/c++/4.2.1/bits/ios_base.h /usr/include/c++/4.2.1/ext/atomicity.h /usr/include/c++/4.2.1/bits/locale_classes.h /usr/include/c++/4.2.1/ext/atomicity.h
So, it is what I thought; <string> and <istream> use __sync_fetch_and_add, not Boost.
Yes, these headers include atomicity.h. But they don't trigger the problem directly: #include <iostream> #include <string> #include <istream> int main() { std::string s="test"; std::cout << s << std::endl; } Works fine, if compiled with Intel icpc. # icpc string_istream.cpp ------------------------------------------------------------------------ Linking with shared libboost_date_time fails: # icpc -L /opt/boost/1.38/intel/lib string_istream.cpp \ -lboost_date_time-il /opt/boost/1.38/intel/lib/libboost_date_time-il.so: undefined reference to `__sync_fetch_and_add_4' So, using libstdc++ headers itself does not trigger the problem. In some sense the boost library build manages to "break" it. And only for the shared library. Very strange. ------------------------------------------------------------------------ The block #ifdef _GLIBCXX_ATOMIC_BUILTINS static inline _Atomic_word __exchange_and_add(volatile _Atomic_word* __mem, int __val) { return __sync_fetch_and_add(__mem, __val); } static inline void __atomic_add(volatile _Atomic_word* __mem, int __val) { __sync_fetch_and_add(__mem, __val); } #else in atomicity.h might be the bad part. So I disabled this block and only activate the #else part: #else _Atomic_word __attribute__ ((__unused__)) __exchange_and_add(volatile _Atomic_word*, int); void __attribute__ ((__unused__)) __atomic_add(volatile _Atomic_word*, int); #endif NOW it works. ------------------------------------------------------------------------ I wanted to use the bjam flags <compileflags>-U _GLIBCXX_ATOMIC_BUILTINS <compileflags>-u _GLIBCXX_ATOMIC_BUILTINS first, but this didnt' work out. So I provide different bits/c++config.h (where _GLIBCXX_ATOMIC_BUILTINS is defined) to build a clean (linkable) Boost library: /* Predefined symbols and macros: wrapper for Intel compilers and Boost */ /* original c++config, i.e. /usr/include/c++/4.2.1/x86_64-suse-linux/bits/c++config.h */ #include <bits/c++config.gcc.h> /* Define if builtin atomic operations are supported on this host. */ #if defined(__INTEL_COMPILER) #undef _GLIBCXX_ATOMIC_BUILTINS #endif ------------------------------------------------------------------------ I don't think this is a good solution. But I cannot figure out where is the source of the problem: libstdc++42 <-> boost <-> icpc As the static libraries worked, one could guess it's a compiler bug. But then nobody would have been able to build shared boost with the Intel compiler suite (version 10 and 11)!? -Carsten