if a._type != nil && a._type.Kind_&abi.KindMask != abi.Pointer {
		return nil, plainError("args must be a pointer or nil")
	}
	argp := a.data
	var argSize uintptr
	if argp != nil {
		argSize = (*ptrtype)(unsafe.Pointer(a._type)).Elem.Size_
	}

	h := new(debugCallHandler)
	h.gp = gp
	// gp may not be running right now, but we can still get the M
	// it will run on since it's locked.
	h.mp = gp.lockedm.ptr()