revert literal

Author: cloud-fan

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/literals.scala

@@ -220,7 +220,7 @@ object DecimalLiteral {
 /**
  * In order to do type checking, use Literal.create() instead of constructor
  */
-case class Literal (value: Any, dataType: DataType) extends LeafExpression {
+case class Literal (value: Any, dataType: DataType) extends LeafExpression with CodegenFallback {
 
   override def foldable: Boolean = true
   override def nullable: Boolean = value == null
@@ -271,28 +271,45 @@ case class Literal (value: Any, dataType: DataType) extends LeafExpression {
       ev.isNull = "true"
       ev.copy(s"final ${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};")
     } else {
-      ev.isNull = "false"
-      ev.value = dataType match {
-        case BooleanType | IntegerType | DateType => value.toString
+      dataType match {
+        case BooleanType =>
+          ev.isNull = "false"
+          ev.value = value.toString
+          ev.copy("")
         case FloatType =>
           val v = value.asInstanceOf[Float]
           if (v.isNaN || v.isInfinite) {
-            ctx.addReferenceObj(v)
+            super[CodegenFallback].doGenCode(ctx, ev)
           } else {
-            s"${value}f"
+            ev.isNull = "false"
+            ev.value = s"${value}f"
+            ev.copy("")
           }
         case DoubleType =>
           val v = value.asInstanceOf[Double]
           if (v.isNaN || v.isInfinite) {
-            ctx.addReferenceObj(v)
+            super[CodegenFallback].doGenCode(ctx, ev)
           } else {
-            s"${value}D"
+            ev.isNull = "false"
+            ev.value = s"${value}D"
+            ev.copy("")
           }
-        case ByteType | ShortType => s"(${ctx.javaType(dataType)})$value"
-        case TimestampType | LongType => s"${value}L"
-        case other => ctx.addReferenceObj("literal", value, ctx.javaType(dataType))
+        case ByteType | ShortType =>
+          ev.isNull = "false"
+          ev.value = s"(${ctx.javaType(dataType)})$value"
+          ev.copy("")
+        case IntegerType | DateType =>
+          ev.isNull = "false"
+          ev.value = value.toString
+          ev.copy("")
+        case TimestampType | LongType =>
+          ev.isNull = "false"
+          ev.value = s"${value}L"
+          ev.copy("")
+        // eval() version may be faster for non-primitive types
+        case other =>
+          super[CodegenFallback].doGenCode(ctx, ev)
       }
-      ev.copy("")
     }
   }