[cfe-dev] Latest clang from source breaks clang on Windows targeting gcc linking

[Edward Diener]

Some change in the latest source has completely broken linking for clang 
on Windows targeting gcc.

// ex_aclass.hpp

#ifndef EX_ACLASS_HPP
#define EX_ACLASS_HPP
#if defined(BLD_EX_EXAMPLE)
         #define EX_DECL __attribute__((__dllexport__))
#else
	#define EX_DECL __attribute__((__dllimport__))
#endif
class EX_DECL ex_aclass
{
public:
     int a_function(long);
};
#endif // EX_ACLASS_HPP

// ex_aclass.cpp

#define BLD_EX_EXAMPLE
#include "ex_aclass.hpp"
int ex_aclass::a_function(long amt)
	{
	return(amt > 1000000 ? 10 : 20);
	}

// Compile ex_aclass.cpp

clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS -O0 -g -fno-inline 
-Wall -g -march=i686 -m32 -o "ex_aclass.obj" "ex_aclass.cpp"

// Link into ex_ac.dll

clang++.exe" -o "ex_ac.dll" -Wl,-soname -Wl,ex_ac.dll -shared 
-Wl,--start-group "ex_aclass.obj" -Wl,-Bstatic -Wl,-Bdynamic 
-Wl,--end-group -g -march=i686 -m32

libmingw32.a(lib32_libmingw32_a-pseudo-reloc.o):pseudo-reloc.c:(.text+0x1d6): 
undefined reference to `__chkstk_ms'
clang++.exe: error: linker command failed with exit code 1 (use -v to 
see invocation)

Nor does it matter what source file is used in general, whenever the 
link is done for anything the "undefined reference to `__chkstk_ms'" occurs.

Can some one of the clang developers please look at this ?

I am using clang on Windows with the 32-bit version of mingw-64/gcc-5.1 
as i686-5.1.0-posix-dwarf-rt_v4-rev0.

I realize the current problems for clang on Windows targeting gcc may 
have occurred trying to fix a more specific problem I reported in two 
other threads about linkage failure using dllexport and dllimport 
attributes on Windows, but going from a situation where a specific 
problem broke the linking to all situations are broken when attempting 
to link is not good.

I tried looking at the clang unit tests and how they can be run on 
Windows but found very little information about both. I wouldn't mind 
contributing some basic unit tests, even though I am not a clang 
developer, just to make sure that clang on Windows targeting gcc will 
work when compiling/linking dlls and using those dlls from another 
module, if I could understand what to do. That way such a snafu as this 
latest breakage would not occur so easily as whatever broke in the 
change should have been caught by some unit tests.