Oh, it's need to rewrite the if in naked.cpp if (global.params.targetTriple.getOS() == llvm::Triple::MinGW32) { fullMangle = "_"; } To if (global.params.targetTriple.getOS() == llvm::Triple::MinGW32 || global.params.targetTriple.getOS() == llvm::Triple::Win32) { fullMangle = "_"; }