private Insn makeInvokePolymorphicInsn(
      Rop rop, SourcePosition pos, RegisterSpecList sources, TypeList catches, Constant cst) {
    CstMethodRef cstMethodRef = (CstMethodRef) cst;
    return new InvokePolymorphicInsn(rop, pos, sources, catches, cstMethodRef);
  }
Gets the register opcode for the given Java opcode.

@param jop {@code jop >= 0;} the Java opcode
@param cst {@code null-ok;} the constant argument, if any
@return {@code >= 0;} the corresponding register opcode
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/code/RopperMachine.java