"Attribute 'builtin' can only be applied to a callsite.", &F);
// Check that this function meets the restrictions on this calling convention.
+ // Sometimes varargs is used for perfectly forwarding thunks, so some of these
+ // restrictions can be lifted.
switch (F.getCallingConv()) {
default:
- break;
case CallingConv::C:
break;
case CallingConv::Fast:
case CallingConv::Cold:
- case CallingConv::X86_FastCall:
- case CallingConv::X86_ThisCall:
case CallingConv::Intel_OCL_BI:
case CallingConv::PTX_Kernel:
case CallingConv::PTX_Device:
- Assert1(!F.isVarArg(),
- "Varargs functions must have C calling conventions!", &F);
+ Assert1(!F.isVarArg(), "Calling convention does not support varargs or "
+ "perfect forwarding!", &F);
break;
}