[Bug c++/55958] New: vtable hidden when compiling with -fvisibility-ms-compat

[gnu at gonsoe dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55958



             Bug #: 55958

           Summary: vtable hidden when compiling with

                    -fvisibility-ms-compat

    Classification: Unclassified

           Product: gcc

           Version: 4.7.2

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: g...@gonsoe.com





Created attachment 29153

  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29153

so1.h, so1.cxx, main.cxx, Makefile + compiler --save-temp files.  Build with

'make main'



% gcc -v

Using built-in specs.

COLLECT_GCC=gcc

COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.7/lto-wrapper

Target: i686-linux-gnu

Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro

4.7.2-2ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs

--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr

--program-suffix=-4.7 --enable-shared --enable-linker-build-id

--with-system-zlib --libexecdir=/usr/lib --without-included-gettext

--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7

--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu

--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object

--enable-plugin --enable-objc-gc --enable-targets=all --disable-werror

--with-arch-32=i686 --with-tune=generic --enable-checking=release

--build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu

Thread model: posix

gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1) 





The vtable for a class with a virtual member function is HIDDEN when source

file is compiled with -fvisibility-ms-compat. If a shared library is created

from the object file, then clients of the shared library cannot construct

objects of the class without getting an undefined symbol for the vtable. 



% cat so1.h

#ifdef SO1_SOURCE

# define EXPORT __attribute ((visibility("default")))

#else

# define EXPORT

#endif



class SO1

{

 public:

  EXPORT virtual void foo();

};



% cat so1.cxx

#define SO1_SOURCE

#include "so1.h"

void SO1::foo() {}



% g++ -c so1.cxx -fvisibility-ms-compat

% eu-readelf -s so1.o | c++filt|grep SO1

   14: 00000000      5 FUNC    GLOBAL DEFAULT        4 SO1::foo()

   15: 00000000     12 OBJECT  WEAK   HIDDEN         7 vtable for SO1

   16: 00000000      8 OBJECT  WEAK   DEFAULT        9 typeinfo for SO1

   18: 00000000      5 OBJECT  WEAK   DEFAULT       11 typeinfo name for SO1



% g++ -shared -o libso1.so so1.o



% cat main.cxx

#include "so1.h"

int main()

{

  SO1 so1;

  return 0;

}



% g++ main.cxx -L. -lso1

/tmp/ccLfT7tK.o: In function `SO1::SO1()':

main.cxx:(.text._ZN3SO1C2Ev[_ZN3SO1C5Ev]+0x8): undefined reference to `vtable

for SO1'

collect2: error: ld returned 1 exit status