Two minor comments from code review on 191bf268.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateUnsafeRowJoiner.scala

@@ -76,7 +76,7 @@ object GenerateUnsafeRowJoiner extends CodeGenerator[(StructType, StructType), U
         } else if (i - bitset1Words < bitset2Words - 1) {
           // combine next two words of bitset2
           s"($getLong(obj2, offset2 + ${(i - bitset1Words) * 8}) >>> (64 - $bitset1Remainder))" +
-            s"| ($getLong(obj2, offset2 + ${(i - bitset1Words + 1) * 8}) << $bitset1Remainder)"
+            s" | ($getLong(obj2, offset2 + ${(i - bitset1Words + 1) * 8}) << $bitset1Remainder)"
         } else {
           // last word of bitset2
           s"$getLong(obj2, offset2 + ${(i - bitset1Words) * 8}) >>> (64 - $bitset1Remainder)"

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateUnsafeRowJoinerBitsetSuite.scala

@@ -92,6 +92,8 @@ class GenerateUnsafeRowJoinerBitsetSuite extends SparkFunSuite {
   private def createUnsafeRow(numFields: Int): UnsafeRow = {
     val row = new UnsafeRow
     val sizeInBytes = numFields * 8 + ((numFields + 63) / 64) * 8
+    // Allocate a larger buffer than needed and point the UnsafeRow to somewhere in the middle.
+    // This way we can test the joiner when the input UnsafeRows are not the entire arrays.
     val offset = numFields * 8
     val buf = new Array[Byte](sizeInBytes + offset)
     row.pointTo(buf, PlatformDependent.BYTE_ARRAY_OFFSET + offset, numFields, sizeInBytes)