This is a temporary URL until I can be bothered setting up a blog.
(This assumes you are compiling Clang 3.1 or 3.2 (trunk) with the official MinGW 4.7.0 distribution)
MinGW now distributes libstdc++ compiled with GCC 4.7 which now uses an ABI which Clang does not (yet) support. If you attempt to use this version of libstdc++ (or any GCC 4.7 library) with Clang, your program will likely crash at the first call of any standard library function.
I spent several hours tracking down the source of the issue, documented
by a single line on the
GCC 4.7 changelog
(search for "thiscall").
A quick fix that only involves recompiling a single file is to change the
default ABI ("itanium") to use the calling convention code from the
"microsoft" ABI:
If you want to retain the default Itanium calling convention (i.e. for
cross-compiling), you will have to create your own CXXABI implementation
(exercise left to reader) and specify it in clang invocations for any code
that interfaces with GCC 4.7 produced code.
Note: clang++ -Xclang -cxx-abi -Xclang microsoft won't help as the
name mangling for symbols in libstdc++-6.dll haven't changed, only the
calling convention. Even if did, there are other compatabilities
between the Microsoft and GCC ABI.
Tags: Clang, MinGW, C++, libstdc++
Author: Julian Smythe
CallingConv getDefaultMethodCallConv(bool isVariadic) const {
return CC_C;
} CallingConv getDefaultMethodCallConv(bool isVariadic) const {
if (!isVariadic && Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
return CC_X86ThisCall;
else
return CC_C;
}