https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78747
--- Comment #2 from Priyanka Sabharwal <priyanka.sabharwal at clearswift dot
com> ---
(In reply to Jan Engelhardt from comment #0)
> The following testcase produces a crashing program.
> The gist seems to be that main.o and lib1.o each get a copy of the
> std::basic_string<T>::Rep::_M_dispose function, and along with it, the
> _ZNSbIDsSt11char_traitsIDsESaIDsEE4_Rep20_S_empty_rep_storageE symbol. They
> get marked hidden by the used symbol visiblity file (see below), which means
> that they will not be combined by the runtime linker, and each _M_dispose
> tests for its own empty_rep only, leading to Undesired Behavior when one
> _M_dispose gets the other _S_empty_rep_storage.
>
> void
> _M_dispose(const _Alloc& __a) _GLIBCXX_NOEXCEPT
> {
> #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
> if (__builtin_expect(this != &_S_empty_rep(), false))
> #endif
>
> In other words, a situation arises which is loosely described in the gcc
> manpage: "-fvisibility-inlines-hidden This switch declares that the user
> does not attempt to compare pointers to inline functions or methods", but
> here, we have a third case, a static object.
>
> So, are version-scripts with local:* basically incompatible with C++? Trying
> to figure out whether this is just a documentation RFE, or whether there is
> something that could be done to libstdc++ to improve the situation
> (abandoning pointerish comparisons?) Maybe bug #54173 is related too.
>
> ---main.cpp--
> #include <string>
> __attribute__((visibility("default"))) void l1_func(std::u16string &);
> int main(void)
> {
> std::u16string a;
> a.append(a);
> l1_func(a);
> return 0;
> }
> ---lib1.cpp---
> #include <string>
> __attribute__((visibility("default"))) void l1_func(std::u16string &);
> void l1_func(std::u16string &a) {
> static const char16_t t[] = {41, 42};
> a.append(t, 2);
> }
> ---lib.sym---
> ABC { global: *l1_func*; local: *; };
> ---makeit.sh---
> g++ -std=gnu++11 lib1.cpp -shared -fPIC -o lib1.so
> -Wl,--version-script=lib.sym
> g++ -std=gnu++11 ldr.cpp ./lib1.so
>
> --- Observed behavior ---
> 11:13 zap:/dev/shm/t > ./mk
> 11:13 zap:/dev/shm/t > ./a.out
> *** Error in `./a.out': free(): invalid pointer: 0x00000000006020a0 ***
> ======= Backtrace: =========
> /lib64/libc.so.6(+0x721af)[0x7f794e17c1af]
> /lib64/libc.so.6(+0x779d6)[0x7f794e1819d6]
> /lib64/libc.so.6(+0x78723)[0x7f794e182723]
> ./lib1.so(+0x149a)[0x7f794ed4b49a]
> ./lib1.so(+0x140d)[0x7f794ed4b40d]
> ./lib1.so(+0x11d0)[0x7f794ed4b1d0]
> ./lib1.so(+0xf19)[0x7f794ed4af19]
> ./lib1.so(+0xbd8)[0x7f794ed4abd8]
> ./lib1.so(_Z7l1_funcRSbIDsSt11char_traitsIDsESaIDsEE+0x24)[0x7f794ed4aaaa]
> ./a.out[0x4009de]
> /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f794e12a6e5]
> ./a.out[0x400839]
>
> Using built-in specs.
> COLLECT_GCC=g++-6
> COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/6/lto-wrapper
> Target: x86_64-suse-linux
> Configured with: ../configure --prefix=/usr --infodir=/usr/share/info
> --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64
> --enable-languages=c,c++,objc,fortran,obj-c++,java,ada,go
> --enable-offload-targets=hsa --enable-checking=release
> --with-gxx-include-dir=/usr/include/c++/6 --enable-ssp --disable-libssp
> --disable-libvtv --disable-libcc1 --disable-plugin
> --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux'
> --disable-libgcj --with-slibdir=/lib64 --with-system-zlib
> --enable-__cxa_atexit --enable-libstdcxx-allocator=new
> --disable-libstdcxx-pch --with-default-libstdcxx-abi=gcc4-compatible
> --enable-version-specific-runtime-libs --enable-linker-build-id
> --enable-linux-futex --enable-gnu-indirect-function --program-suffix=-6
> --without-system-libunwind --enable-multilib --with-arch-32=x86-64
> --with-tune=generic --build=x86_64-suse-linux --host=x86_64-suse-linux
> Thread model: posix
> gcc version 6.2.1 20161121 [gcc-6-branch revision 242657] (SUSE Linux)
Try using this (add *char* under global section)
{ global: *l1_func*; *char*; local: *; };
