public void assignIndices(DalvCode.AssignIndicesCallback callback) {
    for (DalvInsn insn : insns) {
      if (insn instanceof CstInsn) {
        assignIndices((CstInsn) insn, callback);
      } else if (insn instanceof MultiCstInsn) {
        assignIndices((MultiCstInsn) insn, callback);
      }
    }
  }
Assigns indices in all instructions that need them, using the given callback to perform
lookups. This should be called before calling {@link #finishProcessingAndGetList}.

@param callback {@code non-null;} callback object
android/android_framework/dex-maker/src/main/java/com/android/dx/dex/code/OutputFinisher.java