code: public ValueType getOperand(StackConsumer ins, ConstantPoolGen cpg, int i) throws DataflowAnalysisException {
          int numOperands = ins.consumeStack(cpg);
          if (numOperands == Const.UNPREDICTABLE) {
              throw new DataflowAnalysisException("Unpredictable stack consumption in " + ins);
          }
          return getStackValue((numOperands - 1) - i);
      }
docs: Get the <i>i</i>th operand used by given instruction.
  
  @param ins
  the instruction, which must be a StackConsumer
  @param cpg
  the ConstantPoolGen
  @param i
  index of operand to get: 0 for the first operand, etc.
  @return the <i>i</i>th operand used by the given instruction
  @throws DataflowAnalysisException