public <D, V> void iput(
      FieldId<D, V> fieldId, Local<? extends D> instance, Local<? extends V> source) {
    addInstruction(
        new ThrowingCstInsn(
            Rops.opPutField(source.type.ropType),
            sourcePosition,
            RegisterSpecList.make(source.spec(), instance.spec()),
            catches,
            fieldId.constant));
  }
Copies the value in {@code source} to the instance field {@code fieldId} of {@code instance}.
android/android_framework/dex-maker/src/main/java/com/android/dx/Code.java