[SPARK-9815] Rename PlatformDependent.UNSAFE -> Platform.

PlatformDependent.UNSAFE is way too verbose.

Author: Reynold Xin <rxin@databricks.com>

Closes #8094 from rxin/SPARK-9815 and squashes the following commits:

229b603 [Reynold Xin] [SPARK-9815] Rename PlatformDependent.UNSAFE -> Platform.

13 files changed, 105 insertions, 142 deletions

diff --git a/core/src/main/java/org/apache/spark/serializer/DummySerializerInstance.java b/core/src/main/java/org/apache/spark/serializer/DummySerializerInstance.java
index 0399abc63c..0e58bb4f71 100644
--- a/core/src/main/java/org/apache/spark/serializer/DummySerializerInstance.java
+++ b/core/src/main/java/org/apache/spark/serializer/DummySerializerInstance.java
@@ -25,7 +25,7 @@ import java.nio.ByteBuffer;
 import scala.reflect.ClassTag;
 
 import org.apache.spark.annotation.Private;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 
 /**
  * Unfortunately, we need a serializer instance in order to construct a DiskBlockObjectWriter.
@@ -49,7 +49,7 @@ public final class DummySerializerInstance extends SerializerInstance {
         try {
           s.flush();
         } catch (IOException e) {
-          PlatformDependent.throwException(e);
+          Platform.throwException(e);
         }
       }
 
@@ -64,7 +64,7 @@ public final class DummySerializerInstance extends SerializerInstance {
         try {
           s.close();
         } catch (IOException e) {
-          PlatformDependent.throwException(e);
+          Platform.throwException(e);
         }
       }
     };
diff --git a/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleExternalSorter.java b/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleExternalSorter.java
index 925b60a145..3d1ef0c48a 100644
--- a/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleExternalSorter.java
+++ b/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleExternalSorter.java
@@ -37,7 +37,7 @@ import org.apache.spark.shuffle.ShuffleMemoryManager;
 import org.apache.spark.storage.BlockManager;
 import org.apache.spark.storage.DiskBlockObjectWriter;
 import org.apache.spark.storage.TempShuffleBlockId;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.array.ByteArrayMethods;
 import org.apache.spark.unsafe.memory.MemoryBlock;
 import org.apache.spark.unsafe.memory.TaskMemoryManager;
@@ -211,16 +211,12 @@ final class UnsafeShuffleExternalSorter {
       final long recordPointer = sortedRecords.packedRecordPointer.getRecordPointer();
       final Object recordPage = taskMemoryManager.getPage(recordPointer);
       final long recordOffsetInPage = taskMemoryManager.getOffsetInPage(recordPointer);
-      int dataRemaining = PlatformDependent.UNSAFE.getInt(recordPage, recordOffsetInPage);
+      int dataRemaining = Platform.getInt(recordPage, recordOffsetInPage);
       long recordReadPosition = recordOffsetInPage + 4; // skip over record length
       while (dataRemaining > 0) {
         final int toTransfer = Math.min(DISK_WRITE_BUFFER_SIZE, dataRemaining);
-        PlatformDependent.copyMemory(
-          recordPage,
-          recordReadPosition,
-          writeBuffer,
-          PlatformDependent.BYTE_ARRAY_OFFSET,
-          toTransfer);
+        Platform.copyMemory(
+          recordPage, recordReadPosition, writeBuffer, Platform.BYTE_ARRAY_OFFSET, toTransfer);
         writer.write(writeBuffer, 0, toTransfer);
         recordReadPosition += toTransfer;
         dataRemaining -= toTransfer;
@@ -447,14 +443,10 @@ final class UnsafeShuffleExternalSorter {
 
     final long recordAddress =
       taskMemoryManager.encodePageNumberAndOffset(dataPage, dataPagePosition);
-    PlatformDependent.UNSAFE.putInt(dataPageBaseObject, dataPagePosition, lengthInBytes);
+    Platform.putInt(dataPageBaseObject, dataPagePosition, lengthInBytes);
     dataPagePosition += 4;
-    PlatformDependent.copyMemory(
-      recordBaseObject,
-      recordBaseOffset,
-      dataPageBaseObject,
-      dataPagePosition,
-      lengthInBytes);
+    Platform.copyMemory(
+      recordBaseObject, recordBaseOffset, dataPageBaseObject, dataPagePosition, lengthInBytes);
     assert(inMemSorter != null);
     inMemSorter.insertRecord(recordAddress, partitionId);
   }
diff --git a/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriter.java b/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriter.java
index 02084f9122..2389c28b28 100644
--- a/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriter.java
+++ b/core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriter.java
@@ -53,7 +53,7 @@ import org.apache.spark.shuffle.ShuffleMemoryManager;
 import org.apache.spark.shuffle.ShuffleWriter;
 import org.apache.spark.storage.BlockManager;
 import org.apache.spark.storage.TimeTrackingOutputStream;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.memory.TaskMemoryManager;
 
 @Private
@@ -244,7 +244,7 @@ public class UnsafeShuffleWriter<K, V> extends ShuffleWriter<K, V> {
     assert (serializedRecordSize > 0);
 
     sorter.insertRecord(
-      serBuffer.getBuf(), PlatformDependent.BYTE_ARRAY_OFFSET, serializedRecordSize, partitionId);
+      serBuffer.getBuf(), Platform.BYTE_ARRAY_OFFSET, serializedRecordSize, partitionId);
   }
 
   @VisibleForTesting
diff --git a/core/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java b/core/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java
index 7f79cd13aa..85b46ec8bf 100644
--- a/core/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java
+++ b/core/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java
@@ -270,10 +270,10 @@ public final class BytesToBytesMap {
 
     @Override
     public Location next() {
-      int totalLength = PlatformDependent.UNSAFE.getInt(pageBaseObject, offsetInPage);
+      int totalLength = Platform.getInt(pageBaseObject, offsetInPage);
       if (totalLength == END_OF_PAGE_MARKER) {
         advanceToNextPage();
-        totalLength = PlatformDependent.UNSAFE.getInt(pageBaseObject, offsetInPage);
+        totalLength = Platform.getInt(pageBaseObject, offsetInPage);
       }
       loc.with(currentPage, offsetInPage);
       offsetInPage += 4 + totalLength;
@@ -402,9 +402,9 @@ public final class BytesToBytesMap {
 
     private void updateAddressesAndSizes(final Object page, final long offsetInPage) {
       long position = offsetInPage;
-      final int totalLength = PlatformDependent.UNSAFE.getInt(page, position);
+      final int totalLength = Platform.getInt(page, position);
       position += 4;
-      keyLength = PlatformDependent.UNSAFE.getInt(page, position);
+      keyLength = Platform.getInt(page, position);
       position += 4;
       valueLength = totalLength - keyLength - 4;
 
@@ -572,7 +572,7 @@ public final class BytesToBytesMap {
           // There wasn't enough space in the current page, so write an end-of-page marker:
           final Object pageBaseObject = currentDataPage.getBaseObject();
           final long lengthOffsetInPage = currentDataPage.getBaseOffset() + pageCursor;
-          PlatformDependent.UNSAFE.putInt(pageBaseObject, lengthOffsetInPage, END_OF_PAGE_MARKER);
+          Platform.putInt(pageBaseObject, lengthOffsetInPage, END_OF_PAGE_MARKER);
         }
         final long memoryGranted = shuffleMemoryManager.tryToAcquire(pageSizeBytes);
         if (memoryGranted != pageSizeBytes) {
@@ -608,21 +608,21 @@ public final class BytesToBytesMap {
       final long valueDataOffsetInPage = insertCursor;
       insertCursor += valueLengthBytes; // word used to store the value size
 
-      PlatformDependent.UNSAFE.putInt(dataPageBaseObject, recordOffset,
+      Platform.putInt(dataPageBaseObject, recordOffset,
         keyLengthBytes + valueLengthBytes + 4);
-      PlatformDependent.UNSAFE.putInt(dataPageBaseObject, keyLengthOffset, keyLengthBytes);
+      Platform.putInt(dataPageBaseObject, keyLengthOffset, keyLengthBytes);
       // Copy the key
-      PlatformDependent.copyMemory(
+      Platform.copyMemory(
         keyBaseObject, keyBaseOffset, dataPageBaseObject, keyDataOffsetInPage, keyLengthBytes);
       // Copy the value
-      PlatformDependent.copyMemory(valueBaseObject, valueBaseOffset, dataPageBaseObject,
+      Platform.copyMemory(valueBaseObject, valueBaseOffset, dataPageBaseObject,
         valueDataOffsetInPage, valueLengthBytes);
 
       // --- Update bookeeping data structures -----------------------------------------------------
 
       if (useOverflowPage) {
         // Store the end-of-page marker at the end of the data page
-        PlatformDependent.UNSAFE.putInt(dataPageBaseObject, insertCursor, END_OF_PAGE_MARKER);
+        Platform.putInt(dataPageBaseObject, insertCursor, END_OF_PAGE_MARKER);
       } else {
         pageCursor += requiredSize;
       }
diff --git a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
index 5e002ae1b7..71b76d5ddf 100644
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
@@ -20,10 +20,9 @@ package org.apache.spark.util.collection.unsafe.sort;
 import com.google.common.primitives.UnsignedLongs;
 
 import org.apache.spark.annotation.Private;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.types.UTF8String;
 import org.apache.spark.util.Utils;
-import static org.apache.spark.unsafe.PlatformDependent.BYTE_ARRAY_OFFSET;
 
 @Private
 public class PrefixComparators {
@@ -73,7 +72,7 @@ public class PrefixComparators {
         final int minLen = Math.min(bytes.length, 8);
         long p = 0;
         for (int i = 0; i < minLen; ++i) {
-          p |= (128L + PlatformDependent.UNSAFE.getByte(bytes, BYTE_ARRAY_OFFSET + i))
+          p |= (128L + Platform.getByte(bytes, Platform.BYTE_ARRAY_OFFSET + i))
               << (56 - 8 * i);
         }
         return p;
diff --git a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
index 5ebbf9b068..9601aafe55 100644
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java
@@ -35,7 +35,7 @@ import org.apache.spark.executor.ShuffleWriteMetrics;
 import org.apache.spark.shuffle.ShuffleMemoryManager;
 import org.apache.spark.storage.BlockManager;
 import org.apache.spark.unsafe.array.ByteArrayMethods;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.memory.MemoryBlock;
 import org.apache.spark.unsafe.memory.TaskMemoryManager;
 import org.apache.spark.util.Utils;
@@ -427,14 +427,10 @@ public final class UnsafeExternalSorter {
 
     final long recordAddress =
       taskMemoryManager.encodePageNumberAndOffset(dataPage, dataPagePosition);
-    PlatformDependent.UNSAFE.putInt(dataPageBaseObject, dataPagePosition, lengthInBytes);
+    Platform.putInt(dataPageBaseObject, dataPagePosition, lengthInBytes);
     dataPagePosition += 4;
-    PlatformDependent.copyMemory(
-      recordBaseObject,
-      recordBaseOffset,
-      dataPageBaseObject,
-      dataPagePosition,
-      lengthInBytes);
+    Platform.copyMemory(
+      recordBaseObject, recordBaseOffset, dataPageBaseObject, dataPagePosition, lengthInBytes);
     assert(inMemSorter != null);
     inMemSorter.insertRecord(recordAddress, prefix);
   }
@@ -493,18 +489,16 @@ public final class UnsafeExternalSorter {
 
     final long recordAddress =
       taskMemoryManager.encodePageNumberAndOffset(dataPage, dataPagePosition);
-    PlatformDependent.UNSAFE.putInt(dataPageBaseObject, dataPagePosition, keyLen + valueLen + 4);
+    Platform.putInt(dataPageBaseObject, dataPagePosition, keyLen + valueLen + 4);
     dataPagePosition += 4;
 
-    PlatformDependent.UNSAFE.putInt(dataPageBaseObject, dataPagePosition, keyLen);
+    Platform.putInt(dataPageBaseObject, dataPagePosition, keyLen);
     dataPagePosition += 4;
 
-    PlatformDependent.copyMemory(
-      keyBaseObj, keyOffset, dataPageBaseObject, dataPagePosition, keyLen);
+    Platform.copyMemory(keyBaseObj, keyOffset, dataPageBaseObject, dataPagePosition, keyLen);
     dataPagePosition += keyLen;
 
-    PlatformDependent.copyMemory(
-      valueBaseObj, valueOffset, dataPageBaseObject, dataPagePosition, valueLen);
+    Platform.copyMemory(valueBaseObj, valueOffset, dataPageBaseObject, dataPagePosition, valueLen);
 
     assert(inMemSorter != null);
     inMemSorter.insertRecord(recordAddress, prefix);
diff --git a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorter.java b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorter.java
index 1e4b8a116e..f7787e1019 100644
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorter.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorter.java
@@ -19,7 +19,7 @@ package org.apache.spark.util.collection.unsafe.sort;
 
 import java.util.Comparator;
 
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.util.collection.Sorter;
 import org.apache.spark.unsafe.memory.TaskMemoryManager;
 
@@ -164,7 +164,7 @@ public final class UnsafeInMemorySorter {
       final long recordPointer = sortBuffer[position];
       baseObject = memoryManager.getPage(recordPointer);
       baseOffset = memoryManager.getOffsetInPage(recordPointer) + 4;  // Skip over record length
-      recordLength = PlatformDependent.UNSAFE.getInt(baseObject, baseOffset - 4);
+      recordLength = Platform.getInt(baseObject, baseOffset - 4);
       keyPrefix = sortBuffer[position + 1];
       position += 2;
     }
diff --git a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillReader.java b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillReader.java
index ca1ccedc93..4989b05d63 100644
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillReader.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillReader.java
@@ -23,7 +23,7 @@ import com.google.common.io.ByteStreams;
 
 import org.apache.spark.storage.BlockId;
 import org.apache.spark.storage.BlockManager;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 
 /**
  * Reads spill files written by {@link UnsafeSorterSpillWriter} (see that class for a description
@@ -42,7 +42,7 @@ final class UnsafeSorterSpillReader extends UnsafeSorterIterator {
 
   private byte[] arr = new byte[1024 * 1024];
   private Object baseObject = arr;
-  private final long baseOffset = PlatformDependent.BYTE_ARRAY_OFFSET;
+  private final long baseOffset = Platform.BYTE_ARRAY_OFFSET;
 
   public UnsafeSorterSpillReader(
       BlockManager blockManager,
diff --git a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillWriter.java b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillWriter.java
index 44cf6c756d..e59a84ff8d 100644
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillWriter.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillWriter.java
@@ -28,7 +28,7 @@ import org.apache.spark.storage.BlockId;
 import org.apache.spark.storage.BlockManager;
 import org.apache.spark.storage.DiskBlockObjectWriter;
 import org.apache.spark.storage.TempLocalBlockId;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 
 /**
  * Spills a list of sorted records to disk. Spill files have the following format:
@@ -117,11 +117,11 @@ final class UnsafeSorterSpillWriter {
     long recordReadPosition = baseOffset;
     while (dataRemaining > 0) {
       final int toTransfer = Math.min(freeSpaceInWriteBuffer, dataRemaining);
-      PlatformDependent.copyMemory(
+      Platform.copyMemory(
         baseObject,
         recordReadPosition,
         writeBuffer,
-        PlatformDependent.BYTE_ARRAY_OFFSET + (DISK_WRITE_BUFFER_SIZE - freeSpaceInWriteBuffer),
+        Platform.BYTE_ARRAY_OFFSET + (DISK_WRITE_BUFFER_SIZE - freeSpaceInWriteBuffer),
         toTransfer);
       writer.write(writeBuffer, 0, (DISK_WRITE_BUFFER_SIZE - freeSpaceInWriteBuffer) + toTransfer);
       recordReadPosition += toTransfer;
diff --git a/core/src/test/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleInMemorySorterSuite.java b/core/src/test/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleInMemorySorterSuite.java
index 8fa72597db..40fefe2c9d 100644
--- a/core/src/test/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleInMemorySorterSuite.java
+++ b/core/src/test/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleInMemorySorterSuite.java
@@ -24,7 +24,7 @@ import org.junit.Assert;
 import org.junit.Test;
 
 import org.apache.spark.HashPartitioner;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.memory.ExecutorMemoryManager;
 import org.apache.spark.unsafe.memory.MemoryAllocator;
 import org.apache.spark.unsafe.memory.MemoryBlock;
@@ -34,11 +34,7 @@ public class UnsafeShuffleInMemorySorterSuite {
 
   private static String getStringFromDataPage(Object baseObject, long baseOffset, int strLength) {
     final byte[] strBytes = new byte[strLength];
-    PlatformDependent.copyMemory(
-      baseObject,
-      baseOffset,
-      strBytes,
-      PlatformDependent.BYTE_ARRAY_OFFSET, strLength);
+    Platform.copyMemory(baseObject, baseOffset, strBytes, Platform.BYTE_ARRAY_OFFSET, strLength);
     return new String(strBytes);
   }
 
@@ -74,14 +70,10 @@ public class UnsafeShuffleInMemorySorterSuite {
     for (String str : dataToSort) {
       final long recordAddress = memoryManager.encodePageNumberAndOffset(dataPage, position);
       final byte[] strBytes = str.getBytes("utf-8");
-      PlatformDependent.UNSAFE.putInt(baseObject, position, strBytes.length);
+      Platform.putInt(baseObject, position, strBytes.length);
       position += 4;
-      PlatformDependent.copyMemory(
-        strBytes,
-        PlatformDependent.BYTE_ARRAY_OFFSET,
-        baseObject,
-        position,
-        strBytes.length);
+      Platform.copyMemory(
+        strBytes, Platform.BYTE_ARRAY_OFFSET, baseObject, position, strBytes.length);
       position += strBytes.length;
       sorter.insertRecord(recordAddress, hashPartitioner.getPartition(str));
     }
@@ -98,7 +90,7 @@ public class UnsafeShuffleInMemorySorterSuite {
       Assert.assertTrue("Partition id " + partitionId + " should be >= prev id " + prevPartitionId,
         partitionId >= prevPartitionId);
       final long recordAddress = iter.packedRecordPointer.getRecordPointer();
-      final int recordLength = PlatformDependent.UNSAFE.getInt(
+      final int recordLength = Platform.getInt(
         memoryManager.getPage(recordAddress), memoryManager.getOffsetInPage(recordAddress));
       final String str = getStringFromDataPage(
         memoryManager.getPage(recordAddress),
diff --git a/core/src/test/java/org/apache/spark/unsafe/map/AbstractBytesToBytesMapSuite.java b/core/src/test/java/org/apache/spark/unsafe/map/AbstractBytesToBytesMapSuite.java
index e56a3f0b6d..1a79c20c35 100644
--- a/core/src/test/java/org/apache/spark/unsafe/map/AbstractBytesToBytesMapSuite.java
+++ b/core/src/test/java/org/apache/spark/unsafe/map/AbstractBytesToBytesMapSuite.java
@@ -32,9 +32,7 @@ import static org.mockito.Mockito.*;
 import org.apache.spark.shuffle.ShuffleMemoryManager;
 import org.apache.spark.unsafe.array.ByteArrayMethods;
 import org.apache.spark.unsafe.memory.*;
-import org.apache.spark.unsafe.PlatformDependent;
-import static org.apache.spark.unsafe.PlatformDependent.BYTE_ARRAY_OFFSET;
-import static org.apache.spark.unsafe.PlatformDependent.LONG_ARRAY_OFFSET;
+import org.apache.spark.unsafe.Platform;
 
 
 public abstract class AbstractBytesToBytesMapSuite {
@@ -80,13 +78,8 @@ public abstract class AbstractBytesToBytesMapSuite {
 
   private static byte[] getByteArray(MemoryLocation loc, int size) {
     final byte[] arr = new byte[size];
-    PlatformDependent.copyMemory(
-      loc.getBaseObject(),
-      loc.getBaseOffset(),
-      arr,
-      BYTE_ARRAY_OFFSET,
-      size
-    );
+    Platform.copyMemory(
+      loc.getBaseObject(), loc.getBaseOffset(), arr, Platform.BYTE_ARRAY_OFFSET, size);
     return arr;
   }
 
@@ -108,7 +101,7 @@ public abstract class AbstractBytesToBytesMapSuite {
       long actualLengthBytes) {
     return (actualLengthBytes == expected.length) && ByteArrayMethods.arrayEquals(
       expected,
-      BYTE_ARRAY_OFFSET,
+      Platform.BYTE_ARRAY_OFFSET,
       actualAddr.getBaseObject(),
       actualAddr.getBaseOffset(),
       expected.length
@@ -124,7 +117,7 @@ public abstract class AbstractBytesToBytesMapSuite {
       final int keyLengthInWords = 10;
       final int keyLengthInBytes = keyLengthInWords * 8;
       final byte[] key = getRandomByteArray(keyLengthInWords);
-      Assert.assertFalse(map.lookup(key, BYTE_ARRAY_OFFSET, keyLengthInBytes).isDefined());
+      Assert.assertFalse(map.lookup(key, Platform.BYTE_ARRAY_OFFSET, keyLengthInBytes).isDefined());
       Assert.assertFalse(map.iterator().hasNext());
     } finally {
       map.free();
@@ -141,14 +134,14 @@ public abstract class AbstractBytesToBytesMapSuite {
     final byte[] valueData = getRandomByteArray(recordLengthWords);
     try {
       final BytesToBytesMap.Location loc =
-        map.lookup(keyData, BYTE_ARRAY_OFFSET, recordLengthBytes);
+        map.lookup(keyData, Platform.BYTE_ARRAY_OFFSET, recordLengthBytes);
       Assert.assertFalse(loc.isDefined());
       Assert.assertTrue(loc.putNewKey(
         keyData,
-        BYTE_ARRAY_OFFSET,
+        Platform.BYTE_ARRAY_OFFSET,
         recordLengthBytes,
         valueData,
-        BYTE_ARRAY_OFFSET,
+        Platform.BYTE_ARRAY_OFFSET,
         recordLengthBytes
       ));
       // After storing the key and value, the other location methods should return results that
@@ -159,7 +152,8 @@ public abstract class AbstractBytesToBytesMapSuite {
       Assert.assertArrayEquals(valueData, getByteArray(loc.getValueAddress(), recordLengthBytes));
 
       // After calling lookup() the location should still point to the correct data.
-      Assert.assertTrue(map.lookup(keyData, BYTE_ARRAY_OFFSET, recordLengthBytes).isDefined());
+      Assert.assertTrue(
+        map.lookup(keyData, Platform.BYTE_ARRAY_OFFSET, recordLengthBytes).isDefined());
       Assert.assertEquals(recordLengthBytes, loc.getKeyLength());
       Assert.assertEquals(recordLengthBytes, loc.getValueLength());
       Assert.assertArrayEquals(keyData, getByteArray(loc.getKeyAddress(), recordLengthBytes));
@@ -168,10 +162,10 @@ public abstract class AbstractBytesToBytesMapSuite {
       try {
         Assert.assertTrue(loc.putNewKey(
           keyData,
-          BYTE_ARRAY_OFFSET,
+          Platform.BYTE_ARRAY_OFFSET,
           recordLengthBytes,
           valueData,
-          BYTE_ARRAY_OFFSET,
+          Platform.BYTE_ARRAY_OFFSET,
           recordLengthBytes
         ));
         Assert.fail("Should not be able to set a new value for a key");
@@ -191,25 +185,25 @@ public abstract class AbstractBytesToBytesMapSuite {
       for (long i = 0; i < size; i++) {
         final long[] value = new long[] { i };
         final BytesToBytesMap.Location loc =
-          map.lookup(value, PlatformDependent.LONG_ARRAY_OFFSET, 8);
+          map.lookup(value, Platform.LONG_ARRAY_OFFSET, 8);
         Assert.assertFalse(loc.isDefined());
         // Ensure that we store some zero-length keys
         if (i % 5 == 0) {
           Assert.assertTrue(loc.putNewKey(
             null,
-            PlatformDependent.LONG_ARRAY_OFFSET,
+            Platform.LONG_ARRAY_OFFSET,
             0,
             value,
-            PlatformDependent.LONG_ARRAY_OFFSET,
+            Platform.LONG_ARRAY_OFFSET,
             8
           ));
         } else {
           Assert.assertTrue(loc.putNewKey(
             value,
-            PlatformDependent.LONG_ARRAY_OFFSET,
+            Platform.LONG_ARRAY_OFFSET,
             8,
             value,
-            PlatformDependent.LONG_ARRAY_OFFSET,
+            Platform.LONG_ARRAY_OFFSET,
             8
           ));
         }
@@ -228,14 +222,13 @@ public abstract class AbstractBytesToBytesMapSuite {
         Assert.assertTrue(loc.isDefined());
         final MemoryLocation keyAddress = loc.getKeyAddress();
         final MemoryLocation valueAddress = loc.getValueAddress();
-        final long value = PlatformDependent.UNSAFE.getLong(
+        final long value = Platform.getLong(
           valueAddress.getBaseObject(), valueAddress.getBaseOffset());
         final long keyLength = loc.getKeyLength();
         if (keyLength == 0) {
           Assert.assertTrue("value " + value + " was not divisible by 5", value % 5 == 0);
         } else {
-          final long key = PlatformDependent.UNSAFE.getLong(
-            keyAddress.getBaseObject(), keyAddress.getBaseOffset());
+          final long key = Platform.getLong(keyAddress.getBaseObject(), keyAddress.getBaseOffset());
           Assert.assertEquals(value, key);
         }
         valuesSeen.set((int) value);
@@ -284,16 +277,16 @@ public abstract class AbstractBytesToBytesMapSuite {
         final long[] value = new long[] { i, i, i, i, i }; // 5 * 8 = 40 bytes
         final BytesToBytesMap.Location loc = map.lookup(
           key,
-          LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           KEY_LENGTH
         );
         Assert.assertFalse(loc.isDefined());
         Assert.assertTrue(loc.putNewKey(
           key,
-          LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           KEY_LENGTH,
           value,
-          LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           VALUE_LENGTH
         ));
       }
@@ -308,18 +301,18 @@ public abstract class AbstractBytesToBytesMapSuite {
         Assert.assertTrue(loc.isDefined());
         Assert.assertEquals(KEY_LENGTH, loc.getKeyLength());
         Assert.assertEquals(VALUE_LENGTH, loc.getValueLength());
-        PlatformDependent.copyMemory(
+        Platform.copyMemory(
           loc.getKeyAddress().getBaseObject(),
           loc.getKeyAddress().getBaseOffset(),
           key,
-          LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           KEY_LENGTH
         );
-        PlatformDependent.copyMemory(
+        Platform.copyMemory(
           loc.getValueAddress().getBaseObject(),
           loc.getValueAddress().getBaseOffset(),
           value,
-          LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           VALUE_LENGTH
         );
         for (long j : key) {
@@ -354,16 +347,16 @@ public abstract class AbstractBytesToBytesMapSuite {
           expected.put(ByteBuffer.wrap(key), value);
           final BytesToBytesMap.Location loc = map.lookup(
             key,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             key.length
           );
           Assert.assertFalse(loc.isDefined());
           Assert.assertTrue(loc.putNewKey(
             key,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             key.length,
             value,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             value.length
           ));
           // After calling putNewKey, the following should be true, even before calling
@@ -379,7 +372,8 @@ public abstract class AbstractBytesToBytesMapSuite {
       for (Map.Entry<ByteBuffer, byte[]> entry : expected.entrySet()) {
         final byte[] key = entry.getKey().array();
         final byte[] value = entry.getValue();
-        final BytesToBytesMap.Location loc = map.lookup(key, BYTE_ARRAY_OFFSET, key.length);
+        final BytesToBytesMap.Location loc =
+          map.lookup(key, Platform.BYTE_ARRAY_OFFSET, key.length);
         Assert.assertTrue(loc.isDefined());
         Assert.assertTrue(arrayEquals(key, loc.getKeyAddress(), loc.getKeyLength()));
         Assert.assertTrue(arrayEquals(value, loc.getValueAddress(), loc.getValueLength()));
@@ -405,16 +399,16 @@ public abstract class AbstractBytesToBytesMapSuite {
           expected.put(ByteBuffer.wrap(key), value);
           final BytesToBytesMap.Location loc = map.lookup(
             key,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             key.length
           );
           Assert.assertFalse(loc.isDefined());
           Assert.assertTrue(loc.putNewKey(
             key,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             key.length,
             value,
-            BYTE_ARRAY_OFFSET,
+            Platform.BYTE_ARRAY_OFFSET,
             value.length
           ));
           // After calling putNewKey, the following should be true, even before calling
@@ -429,7 +423,8 @@ public abstract class AbstractBytesToBytesMapSuite {
       for (Map.Entry<ByteBuffer, byte[]> entry : expected.entrySet()) {
         final byte[] key = entry.getKey().array();
         final byte[] value = entry.getValue();
-        final BytesToBytesMap.Location loc = map.lookup(key, BYTE_ARRAY_OFFSET, key.length);
+        final BytesToBytesMap.Location loc =
+          map.lookup(key, Platform.BYTE_ARRAY_OFFSET, key.length);
         Assert.assertTrue(loc.isDefined());
         Assert.assertTrue(arrayEquals(key, loc.getKeyAddress(), loc.getKeyLength()));
         Assert.assertTrue(arrayEquals(value, loc.getValueAddress(), loc.getValueLength()));
@@ -447,12 +442,10 @@ public abstract class AbstractBytesToBytesMapSuite {
     try {
       final long[] emptyArray = new long[0];
       final BytesToBytesMap.Location loc =
-        map.lookup(emptyArray, PlatformDependent.LONG_ARRAY_OFFSET, 0);
+        map.lookup(emptyArray, Platform.LONG_ARRAY_OFFSET, 0);
       Assert.assertFalse(loc.isDefined());
       Assert.assertFalse(loc.putNewKey(
-        emptyArray, LONG_ARRAY_OFFSET, 0,
-        emptyArray, LONG_ARRAY_OFFSET, 0
-      ));
+        emptyArray, Platform.LONG_ARRAY_OFFSET, 0, emptyArray, Platform.LONG_ARRAY_OFFSET, 0));
     } finally {
       map.free();
     }
@@ -468,8 +461,9 @@ public abstract class AbstractBytesToBytesMapSuite {
       int i;
       for (i = 0; i < 1024; i++) {
         final long[] arr = new long[]{i};
-        final BytesToBytesMap.Location loc = map.lookup(arr, PlatformDependent.LONG_ARRAY_OFFSET, 8);
-        success = loc.putNewKey(arr, LONG_ARRAY_OFFSET, 8, arr, LONG_ARRAY_OFFSET, 8);
+        final BytesToBytesMap.Location loc = map.lookup(arr, Platform.LONG_ARRAY_OFFSET, 8);
+        success =
+          loc.putNewKey(arr, Platform.LONG_ARRAY_OFFSET, 8, arr, Platform.LONG_ARRAY_OFFSET, 8);
         if (!success) {
           break;
         }
@@ -541,12 +535,12 @@ public abstract class AbstractBytesToBytesMapSuite {
     try {
       for (long i = 0; i < numRecordsPerPage * 10; i++) {
         final long[] value = new long[]{i};
-        map.lookup(value, PlatformDependent.LONG_ARRAY_OFFSET, 8).putNewKey(
+        map.lookup(value, Platform.LONG_ARRAY_OFFSET, 8).putNewKey(
           value,
-          PlatformDependent.LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           8,
           value,
-          PlatformDependent.LONG_ARRAY_OFFSET,
+          Platform.LONG_ARRAY_OFFSET,
           8);
         newPeakMemory = map.getPeakMemoryUsedBytes();
         if (i % numRecordsPerPage == 0) {
diff --git a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
index 83049b8a21..445a37b83e 100644
--- a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
+++ b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
@@ -49,7 +49,7 @@ import org.apache.spark.executor.TaskMetrics;
 import org.apache.spark.serializer.SerializerInstance;
 import org.apache.spark.shuffle.ShuffleMemoryManager;
 import org.apache.spark.storage.*;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.memory.ExecutorMemoryManager;
 import org.apache.spark.unsafe.memory.MemoryAllocator;
 import org.apache.spark.unsafe.memory.TaskMemoryManager;
@@ -166,14 +166,14 @@ public class UnsafeExternalSorterSuite {
 
   private static void insertNumber(UnsafeExternalSorter sorter, int value) throws Exception {
     final int[] arr = new int[]{ value };
-    sorter.insertRecord(arr, PlatformDependent.INT_ARRAY_OFFSET, 4, value);
+    sorter.insertRecord(arr, Platform.INT_ARRAY_OFFSET, 4, value);
   }
 
   private static void insertRecord(
       UnsafeExternalSorter sorter,
       int[] record,
       long prefix) throws IOException {
-    sorter.insertRecord(record, PlatformDependent.INT_ARRAY_OFFSET, record.length * 4, prefix);
+    sorter.insertRecord(record, Platform.INT_ARRAY_OFFSET, record.length * 4, prefix);
   }
 
   private UnsafeExternalSorter newSorter() throws IOException {
@@ -205,7 +205,7 @@ public class UnsafeExternalSorterSuite {
       iter.loadNext();
       assertEquals(i, iter.getKeyPrefix());
       assertEquals(4, iter.getRecordLength());
-      assertEquals(i, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+      assertEquals(i, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
     }
 
     sorter.cleanupResources();
@@ -253,7 +253,7 @@ public class UnsafeExternalSorterSuite {
       iter.loadNext();
       assertEquals(i, iter.getKeyPrefix());
       assertEquals(4, iter.getRecordLength());
-      assertEquals(i, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+      assertEquals(i, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
       i++;
     }
     sorter.cleanupResources();
@@ -265,7 +265,7 @@ public class UnsafeExternalSorterSuite {
     final UnsafeExternalSorter sorter = newSorter();
     byte[] record = new byte[16];
     while (sorter.getNumberOfAllocatedPages() < 2) {
-      sorter.insertRecord(record, PlatformDependent.BYTE_ARRAY_OFFSET, record.length, 0);
+      sorter.insertRecord(record, Platform.BYTE_ARRAY_OFFSET, record.length, 0);
     }
     sorter.cleanupResources();
     assertSpillFilesWereCleanedUp();
@@ -292,25 +292,25 @@ public class UnsafeExternalSorterSuite {
     iter.loadNext();
     assertEquals(123, iter.getKeyPrefix());
     assertEquals(smallRecord.length * 4, iter.getRecordLength());
-    assertEquals(123, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+    assertEquals(123, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
     // Small record
     assertTrue(iter.hasNext());
     iter.loadNext();
     assertEquals(123, iter.getKeyPrefix());
     assertEquals(smallRecord.length * 4, iter.getRecordLength());
-    assertEquals(123, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+    assertEquals(123, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
     // Large record
     assertTrue(iter.hasNext());
     iter.loadNext();
     assertEquals(456, iter.getKeyPrefix());
     assertEquals(largeRecord.length * 4, iter.getRecordLength());
-    assertEquals(456, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+    assertEquals(456, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
     // Large record
     assertTrue(iter.hasNext());
     iter.loadNext();
     assertEquals(456, iter.getKeyPrefix());
     assertEquals(largeRecord.length * 4, iter.getRecordLength());
-    assertEquals(456, PlatformDependent.UNSAFE.getInt(iter.getBaseObject(), iter.getBaseOffset()));
+    assertEquals(456, Platform.getInt(iter.getBaseObject(), iter.getBaseOffset()));
 
     assertFalse(iter.hasNext());
     sorter.cleanupResources();
diff --git a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
index 9095009305..778e813df6 100644
--- a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
+++ b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
@@ -26,7 +26,7 @@ import static org.junit.Assert.*;
 import static org.mockito.Mockito.mock;
 
 import org.apache.spark.HashPartitioner;
-import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.memory.ExecutorMemoryManager;
 import org.apache.spark.unsafe.memory.MemoryAllocator;
 import org.apache.spark.unsafe.memory.MemoryBlock;
@@ -36,11 +36,7 @@ public class UnsafeInMemorySorterSuite {
 
   private static String getStringFromDataPage(Object baseObject, long baseOffset, int length) {
     final byte[] strBytes = new byte[length];
-    PlatformDependent.copyMemory(
-      baseObject,
-      baseOffset,
-      strBytes,
-      PlatformDependent.BYTE_ARRAY_OFFSET, length);
+    Platform.copyMemory(baseObject, baseOffset, strBytes, Platform.BYTE_ARRAY_OFFSET, length);
     return new String(strBytes);
   }
 
@@ -76,14 +72,10 @@ public class UnsafeInMemorySorterSuite {
     long position = dataPage.getBaseOffset();
     for (String str : dataToSort) {
       final byte[] strBytes = str.getBytes("utf-8");
-      PlatformDependent.UNSAFE.putInt(baseObject, position, strBytes.length);
+      Platform.putInt(baseObject, position, strBytes.length);
       position += 4;
-      PlatformDependent.copyMemory(
-        strBytes,
-        PlatformDependent.BYTE_ARRAY_OFFSET,
-        baseObject,
-        position,
-        strBytes.length);
+      Platform.copyMemory(
+        strBytes, Platform.BYTE_ARRAY_OFFSET, baseObject, position, strBytes.length);
       position += strBytes.length;
     }
     // Since the key fits within the 8-byte prefix, we don't need to do any record comparison, so
@@ -113,7 +105,7 @@ public class UnsafeInMemorySorterSuite {
     position = dataPage.getBaseOffset();
     for (int i = 0; i < dataToSort.length; i++) {
       // position now points to the start of a record (which holds its length).
-      final int recordLength = PlatformDependent.UNSAFE.getInt(baseObject, position);
+      final int recordLength = Platform.getInt(baseObject, position);
       final long address = memoryManager.encodePageNumberAndOffset(dataPage, position);
       final String str = getStringFromDataPage(baseObject, position + 4, recordLength);
       final int partitionId = hashPartitioner.getPartition(str);