//
  // Emits an error and returns failure if an error is encountered during
  // conversion. Note that success return value doesn't mean successful
  // legalization.
  mlir::LogicalResult LegalizeOp();

  // Converts the given operand to expression of kind kConstant or kXlaOp.
  // Emits a remark and returns expression of kind kInvalid on failure.
  tensorflow::XlaExpression GetExprForOperand(mlir::Value operand,