$ cat x.hpp #ifndef x_hpp #define x_hpp #include <vector> struct X { void foo(); }; typedef std::vector< X > VX; VX bar() __attribute((visibility( "default" ))); #endif $ cat x.cpp #include "x.hpp" VX bar() { return VX(); } $ g++ -fvisibility=hidden -fvisibility-inlines-hidden -fPIC x.cpp -Wall -shared -o libx.so -s $ readelf -sW libx.so | grep -v UND | c++filt Symbol table '.dynsym' contains 20 entries: Num: Value Size Type Bind Vis Ndx Name 2: 00000000000007b0 0 FUNC GLOBAL DEFAULT 10 _init 3: 00000000000009f8 0 FUNC GLOBAL DEFAULT 13 _fini 6: 000000000000090c 30 FUNC GLOBAL DEFAULT 12 bar() 7: 000000000000092a 26 FUNC WEAK DEFAULT 12 std::vector<X, std::allocator<X> >::vector() 8: 000000000000092a 26 FUNC WEAK DEFAULT 12 std::vector<X, std::allocator<X> >::vector() 9: 0000000000000944 26 FUNC WEAK DEFAULT 12 std::_Vector_base<X, std::allocator<X> >::_Vector_base() 10: 000000000000095e 61 FUNC WEAK DEFAULT 12 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() 11: 000000000000095e 61 FUNC WEAK DEFAULT 12 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() 12: 000000000000099c 26 FUNC WEAK DEFAULT 12 std::allocator<X>::allocator() 13: 00000000000009b6 10 FUNC WEAK DEFAULT 12 __gnu_cxx::new_allocator<X>::new_allocator() 14: 0000000000000944 26 FUNC WEAK DEFAULT 12 std::_Vector_base<X, std::allocator<X> >::_Vector_base() 15: 000000000000099c 26 FUNC WEAK DEFAULT 12 std::allocator<X>::allocator() 16: 00000000000009b6 10 FUNC WEAK DEFAULT 12 __gnu_cxx::new_allocator<X>::new_allocator() 17: 0000000000001dc0 0 NOTYPE GLOBAL DEFAULT ABS _edata 18: 0000000000001dc0 0 NOTYPE GLOBAL DEFAULT ABS __bss_start 19: 0000000000001dd0 0 NOTYPE GLOBAL DEFAULT ABS _end imho the std::vector details shouldn't have default visiblity in this case.
I'm not an expert here, but I have an hard time believing this is a library issue. I can see that we have been doing, for a lot of time: namespace std _GLIBCXX_VISIBILITY(default) { Is this wrong?!? Jason?
Jason, could you please help me triaging this PR? Should the library do something else here? Thanks!
I did a small test removing the visibily just in stl_vector.h grep namespace /afs/cern.ch/user/i/innocent/w2/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/bits/stl_vector.h namespace std /* _GLIBCXX_VISIBILITY(default) */ and got ++ -fvisibility=hidden -fvisibility-inlines-hidden -fPIC bha.cc -Wall -shared -o libx.so [vinavx0] ~/public/ctest $ readelf -sW libx.so | grep -v UND | sed 's/.local/ .local/g' | c++filt Symbol table '.dynsym' contains 14 entries: Num: Value Size Type Bind Vis Ndx Name 2: 0000000000000540 0 FUNC GLOBAL DEFAULT 9 _init 3: 0000000000000758 0 FUNC GLOBAL DEFAULT 12 _fini 6: 000000000000066c 30 FUNC GLOBAL DEFAULT 11 bar() 7: 00000000000006fc 26 FUNC WEAK DEFAULT 11 std::allocator<X>::allocator() 8: 00000000000006fc 26 FUNC WEAK DEFAULT 11 std::allocator<X>::allocator() 9: 0000000000000716 10 FUNC WEAK DEFAULT 11 __gnu_cxx::new_allocator<X>::new_allocator() 10: 0000000000000716 10 FUNC WEAK DEFAULT 11 __gnu_cxx::new_allocator<X>::new_allocator() 11: 0000000000001ae8 0 NOTYPE GLOBAL DEFAULT ABS _edata 12: 0000000000001ae8 0 NOTYPE GLOBAL DEFAULT ABS __bss_start 13: 0000000000001af8 0 NOTYPE GLOBAL DEFAULT ABS _end Symbol table '.symtab' contains 39 entries: Num: Value Size Type Bind Vis Ndx Name 1: 00000000000005a0 0 FUNC LOCAL DEFAULT 11 call_gmon_start 2: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c 3: 0000000000001ac0 0 OBJECT LOCAL DEFAULT 19 __CTOR_LIST__ 4: 0000000000001ad0 0 OBJECT LOCAL DEFAULT 20 __DTOR_LIST__ 5: 0000000000001ae0 0 OBJECT LOCAL DEFAULT 21 __JCR_LIST__ 6: 00000000000005c0 0 FUNC LOCAL DEFAULT 11 __do_global_dtors_aux 7: 0000000000001ae8 1 OBJECT LOCAL DEFAULT 22 completed.5901 8: 0000000000001af0 8 OBJECT LOCAL DEFAULT 22 dtor_idx.5903 9: 0000000000000640 0 FUNC LOCAL DEFAULT 11 frame_dummy 10: 0000000000000000 0 FILE LOCAL DEFAULT ABS bha.cc 11: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c 12: 0000000000001ac8 0 OBJECT LOCAL DEFAULT 19 __CTOR_END__ 13: 0000000000000840 0 OBJECT LOCAL DEFAULT 13 __FRAME_END__ 14: 0000000000001ae0 0 OBJECT LOCAL DEFAULT 21 __JCR_END__ 15: 0000000000000720 0 FUNC LOCAL DEFAULT 11 __do_global_ctors_aux 16: 0000000000001ab8 0 OBJECT LOCAL HIDDEN 18 __dso_handle 17: 000000000000068a 26 FUNC LOCAL HIDDEN 11 std::vector<X, std::allocator<X> >::vector() 18: 000000000000068a 26 FUNC LOCAL HIDDEN 11 std::vector<X, std::allocator<X> >::vector() 19: 00000000000006a4 26 FUNC LOCAL HIDDEN 11 std::_Vector_base<X, std::allocator<X> >::_Vector_base() 20: 00000000000006a4 26 FUNC LOCAL HIDDEN 11 std::_Vector_base<X, std::allocator<X> >::_Vector_base() 21: 00000000000006be 61 FUNC LOCAL HIDDEN 11 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() 22: 00000000000006be 61 FUNC LOCAL HIDDEN 11 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() 23: 0000000000001ad8 0 OBJECT LOCAL HIDDEN 20 __DTOR_END__ 24: 0000000000001880 496 OBJECT LOCAL HIDDEN 15 _DYNAMIC 25: 0000000000001a88 48 OBJECT LOCAL HIDDEN 17 _GLOBAL_OFFSET_TABLE_ 27: 0000000000000540 0 FUNC GLOBAL DEFAULT 9 _init 28: 0000000000000758 0 FUNC GLOBAL DEFAULT 12 _fini 31: 000000000000066c 30 FUNC GLOBAL DEFAULT 11 bar() 32: 00000000000006fc 26 FUNC WEAK DEFAULT 11 std::allocator<X>::allocator() 33: 00000000000006fc 26 FUNC WEAK DEFAULT 11 std::allocator<X>::allocator() 34: 0000000000000716 10 FUNC WEAK DEFAULT 11 __gnu_cxx::new_allocator<X>::new_allocator() 35: 0000000000000716 10 FUNC WEAK DEFAULT 11 __gnu_cxx::new_allocator<X>::new_allocator() 36: 0000000000001ae8 0 NOTYPE GLOBAL DEFAULT ABS _edata 37: 0000000000001ae8 0 NOTYPE GLOBAL DEFAULT ABS __bss_start 38: 0000000000001af8 0 NOTYPE GLOBAL DEFAULT ABS _end if I add -flto visibility of the "local symbols is turned again to DEFAULT, not sure if relevant though g++ -fvisibility=hidden -fvisibility-inlines-hidden -fPIC bha.cc -Wall -shared -o libx.so -flto [vinavx0] ~/public/ctest $ readelf -sW libx.so | grep -v UND | sed 's/.local/ .local/g' | c++filt Symbol table '.dynsym' contains 10 entries: Num: Value Size Type Bind Vis Ndx Name 2: 0000000000000430 0 FUNC GLOBAL DEFAULT 9 _init 3: 0000000000000628 0 FUNC GLOBAL DEFAULT 12 _fini 6: 000000000000053c 30 FUNC GLOBAL DEFAULT 11 bar() 7: 00000000000019a8 0 NOTYPE GLOBAL DEFAULT ABS _edata 8: 00000000000019a8 0 NOTYPE GLOBAL DEFAULT ABS __bss_start 9: 00000000000019b8 0 NOTYPE GLOBAL DEFAULT ABS _end Symbol table '.symtab' contains 36 entries: Num: Value Size Type Bind Vis Ndx Name 1: 0000000000000470 0 FUNC LOCAL DEFAULT 11 call_gmon_start 2: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c 3: 0000000000001980 0 OBJECT LOCAL DEFAULT 19 __CTOR_LIST__ 4: 0000000000001990 0 OBJECT LOCAL DEFAULT 20 __DTOR_LIST__ 5: 00000000000019a0 0 OBJECT LOCAL DEFAULT 21 __JCR_LIST__ 6: 0000000000000490 0 FUNC LOCAL DEFAULT 11 __do_global_dtors_aux 7: 00000000000019a8 1 OBJECT LOCAL DEFAULT 22 completed.5901 8: 00000000000019b0 8 OBJECT LOCAL DEFAULT 22 dtor_idx.5903 9: 0000000000000510 0 FUNC LOCAL DEFAULT 11 frame_dummy 10: 0000000000000000 0 FILE LOCAL DEFAULT ABS ccT50cVU.ltrans0.o 11: 000000000000055a 26 FUNC LOCAL DEFAULT 11 std::vector<X, std::allocator<X> >::vector() .local.0.2256 12: 000000000000055a 26 FUNC LOCAL DEFAULT 11 std::vector<X, std::allocator<X> >::vector() .local.1.2253 13: 0000000000000574 26 FUNC LOCAL DEFAULT 11 std::_Vector_base<X, std::allocator<X> >::_Vector_base() .local.3.2259 14: 000000000000058e 61 FUNC LOCAL DEFAULT 11 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() .local.4.2265 15: 000000000000058e 61 FUNC LOCAL DEFAULT 11 std::_Vector_base<X, std::allocator<X> >::_Vector_impl::_Vector_impl() .local.5.2262 16: 00000000000005cc 26 FUNC LOCAL DEFAULT 11 std::allocator<X>::allocator() .local.7.2268 17: 00000000000005e6 10 FUNC LOCAL DEFAULT 11 __gnu_cxx::new_allocator<X>::new_allocator() .local.9.2272 18: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c 19: 0000000000001988 0 OBJECT LOCAL DEFAULT 19 __CTOR_END__ 20: 0000000000000710 0 OBJECT LOCAL DEFAULT 13 __FRAME_END__ 21: 00000000000019a0 0 OBJECT LOCAL DEFAULT 21 __JCR_END__ 22: 00000000000005f0 0 FUNC LOCAL DEFAULT 11 __do_global_ctors_aux 23: 0000000000001978 0 OBJECT LOCAL HIDDEN 18 __dso_handle 24: 0000000000001998 0 OBJECT LOCAL HIDDEN 20 __DTOR_END__ 25: 0000000000001750 496 OBJECT LOCAL HIDDEN 15 _DYNAMIC 26: 0000000000001958 32 OBJECT LOCAL HIDDEN 17 _GLOBAL_OFFSET_TABLE_ 28: 0000000000000430 0 FUNC GLOBAL DEFAULT 9 _init 29: 0000000000000628 0 FUNC GLOBAL DEFAULT 12 _fini 32: 000000000000053c 30 FUNC GLOBAL DEFAULT 11 bar() 33: 00000000000019a8 0 NOTYPE GLOBAL DEFAULT ABS _edata 34: 00000000000019a8 0 NOTYPE GLOBAL DEFAULT ABS __bss_start 35: 00000000000019b8 0 NOTYPE GLOBAL DEFAULT ABS _end I think that, unless not imposed by the standard (why??) the visibility of "namespace std" SHALL NOT BE forced to default
(In reply to comment #3) > I think that, unless not imposed by the standard (why??) the visibility of > "namespace std" SHALL NOT BE forced to default part of the std:: (exceptions typeinfo symbols) must be visible-by-default for proper throw-catch/dynamic_cast working across shared libs boundaries.
indeed and in "exception" header-file is a place where visibility is correctly handled #pragma GCC visibility push(default) extern "C++" { namespace std { } #pragma GCC visibility pop I would have preferred specific __attribute((visibility( "default" ))) on each exception class though (push and pop and error-prone)
dup of PR 36022 ?
Seems so, thanks Jon. The older one also includes some rationale from Benjamin.
I think before the default visibility was added everywhere it was pretty easy to cause segfaults by using -fvisibility=hidden
Duplicate. *** This bug has been marked as a duplicate of bug 36022 ***