address offline comments

Author: Davies Liu

sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala

@@ -131,7 +131,7 @@ trait CodegenSupport extends SparkPlan {
         }
         val evaluateInputs = evaluateVariables(outputVars)
         // generate the code to create a UnsafeRow
-        ctx.INPUT_ROW = null
+        ctx.INPUT_ROW = row
         ctx.currentVars = outputVars
         val ev = GenerateUnsafeProjection.createCode(ctx, colExprs, false)
         val code = s"""

sql/core/src/main/scala/org/apache/spark/sql/execution/aggregate/TungstenAggregate.scala

@@ -599,6 +599,7 @@ case class TungstenAggregate(
 
     // create grouping key
     ctx.currentVars = input
+    // make sure that the generated code will not be splitted as multiple functions
     ctx.INPUT_ROW = null
     val unsafeRowKeyCode = GenerateUnsafeProjection.createCode(
       ctx, groupingExpressions.map(e => BindReferences.bindReference[Expression](e, child.output)))