private Dop[] makeOpcodesArray() {
    int size = insns.size();
    Dop[] result = new Dop[size];

    for (int i = 0; i < size; i++) {
      DalvInsn insn = insns.get(i);
      result[i] = insn.getOpcode();
    }

    return result;
  }
Helper for {@link #finishProcessingAndGetList}, which extracts the opcode out of each
instruction into a separate array, to be further manipulated as things progress.

@return {@code non-null;} the array of opcodes
android/android_framework/dex-maker/src/main/java/com/android/dx/dex/code/OutputFinisher.java