private void addPutstatic0(CtClass target, String classname,
                               String fieldName, String desc) {
        add(PUTSTATIC);
        // target is null if it represents THIS.
        int ci = classname == null ? constPool.addClassInfo(target)
                                : constPool.addClassInfo(classname);
        addIndex(constPool.addFieldrefInfo(ci, fieldName, desc));
        growStack(-Descriptor.dataSize(desc));
    }