duplicate symbol link error with clang-compiled DLL

[Quuxplusone]

Bugzilla Link	PR18730
Status	NEW
Importance	P normal
Reported by	Yaron Keren (yaron.keren@gmail.com)
Reported on	2014-02-04 16:22:13 -0800
Last modified on	2017-06-10 12:48:16 -0700
Version	trunk
Hardware	PC Windows NT
CC	anton@korobeynikov.info, geek4civic@gmail.com, llvm-bugs@lists.llvm.org, rafael@espindo.la
Fixed by commit(s)
Attachments	c1.bat (522 bytes, application/octet-stream) e.cpp (70 bytes, text/plain) c2.bat (721 bytes, application/octet-stream) d.cpp (69 bytes, text/plain) c.sh (277 bytes, application/octet-stream)
Blocks
Blocked by
See also

Created attachment 12008
batch file to compile

I have a problem when linking C++ DLLs compiled with MinGW 4.8.2 with clang-
produced object file. The linker complains about multiple definitions for
several typeinfos. The scenario is rather complex but I had reduced the issue
to differences between the typeinfos emitted for a simple testcase.

The same include files and libraries were used, MinGW 4.8.2 MinGW-w64 rev2 with
trivial compilation flags. Attached is a simple batch file to reproduce the
issue. Clang is svn few days old, gcc is MinGW-w64 rev2, the latest.

The source code is:

 #include <stdexcept>
 int main() { throw std::exception(); return 0; }

When compiling with clang, nm --demangle e_clang.o =
00000000 d .eh_frame
00000000 t .text
00000000 t .text
00000001 a @feat.00
         U __cxa_allocate_exception
         U __cxa_throw
         U __main
00000000 T std::exception::exception()
         U std::exception::~exception()
         U typeinfo for std::exception
         U vtable for std::exception
00000000 T main

but with gcc, nm --demangle e_gcc.o
00000000 b .bss
00000000 d .data
00000000 r .eh_frame
00000000 r .eh_frame$_ZNSt9exceptionC1Ev
00000000 r .rdata$_ZTISt9exception
00000000 r .rdata$_ZTSSt9exception
00000000 r .rdata$zzz
00000000 t .text
00000000 t .text$_ZNSt9exceptionC1Ev
         U __cxa_allocate_exception
         U __cxa_throw
         U __main
00000000 T std::exception::exception()
         U std::exception::~exception()
00000000 R typeinfo for std::exception
00000000 R typeinfo name for std::exception
         U vtable for __cxxabiv1::__class_type_info
         U vtable for std::exception
00000000 T main

there are couple of differences:

* clang producing U typeinfo for std::exception whereas gcc produces R typeinfo
for std::exception.
* The R typeinfo name for std::exception is not produced by clang.
* r .rdata$ records are also not produced by clang.

One or more of these differences causes typeinfos merging failure while linking
the above object files with C++ DLLs compiled with MinGW.
I suspect the first difference is the critical one.
In any case, clang output of typeinfos should match gcc.

[Quuxplusone]

Attached e.cpp (70 bytes, text/plain): testcase source code

[Quuxplusone]

Will you please linker output here as well?

[Quuxplusone]

Yes. Let's create a trivial DLL :

#include <stdexcept>
int ddd() { throw std::exception(); return 0; }

compiled with:

  gcc -shared d.cpp -o d.dll -lstdc++

e_gcc.o can link against it OK:

  gcc e_gcc.o -o e_gcc.exe -lstdc++ d.dll

without error, but linking the clang-compiled object against it:

  gcc e_clang.o -o e_clang.exe -lstdc++ d.dll

produces error of multiple definition of the typename exception.

d000001.o:(.idata$5+0x0): multiple definition of `_imp___ZTISt9exception'
c:/mingw-builds/i686-4.8.2-release-win32-dwarf-rt_v3-
rev2/mingw32/bin/../lib/gcc/i686-w64-
mingw32/4.8.2/libstdc++.dll.a(d003499.o):(.idata$5+0x0): first defined here
d000001.o:(.idata$6+0x0): multiple definition of `_nm___ZTISt9exception'
c:/mingw-builds/i686-4.8.2-release-win32-dwarf-rt_v3-
rev2/mingw32/bin/../lib/gcc/i686-w64-
mingw32/4.8.2/libstdc++.dll.a(d003499.o):(.idata$6+0x0): first defined here
collect2.exe: error: ld returned 1 exit status

I will attach the DLL source and updated compile script.

[Quuxplusone]

Oh, linking with the additional DLL works for both gcc and clang.

[Quuxplusone]

Oh, linking without the additional DLL works for both gcc and clang.

[Quuxplusone]

Attached c1.bat (522 bytes, application/octet-stream): batch file to compile

[Quuxplusone]

Attached d.cpp (69 bytes, text/plain): Trivial DLL source

[Quuxplusone]

Attached c2.bat (721 bytes, application/octet-stream): Updated batch file to compile and link against a trivial DLL

[Quuxplusone]

Attached c.sh (277 bytes, application/octet-stream): shell script to run example

[Quuxplusone]

still fails as of mingw 5.4 and clang r305089