Merge pull request #9981 from bragaigor/DDR_issue_9971

Update DDR code to comply with arrays not having NULL pointers

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/j9/gc/GCArrayObjectModel.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2019 IBM Corp. and others
+ * Copyright (c) 1991, 2020 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -45,8 +45,11 @@ public static GCArrayObjectModel from() throws CorruptDataException
 		AlgorithmVersion version = AlgorithmVersion.getVersionOf(AlgorithmVersion.GC_ARRAYLET_OBJECT_MODEL_VERSION);
 		switch (version.getAlgorithmVersion()) {
 			// Add case statements to handle new algorithm versions
-			default:
+			case 0:
+			case 1:
 				return new GCArrayletObjectModel_V1();
+			default:
+				return new GCArrayletObjectModel_V2();
 		}
 	}
 

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/j9/gc/GCArrayletObjectModelBase_V1.java → debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/j9/gc/GCArrayletObjectModelBase.java

@@ -44,7 +44,7 @@
 import com.ibm.j9ddr.vm29.types.U32;
 import com.ibm.j9ddr.vm29.types.UDATA;
 
-public abstract class GCArrayletObjectModelBase_V1 extends GCArrayObjectModel 
+public abstract class GCArrayletObjectModelBase extends GCArrayObjectModel 
 {
 	protected GC_ArrayletObjectModelPointer arrayletObjectModel;
 	protected VoidPointer arrayletRangeBase;
@@ -54,7 +54,7 @@ public abstract class GCArrayletObjectModelBase_V1 extends GCArrayObjectModel
 	protected UDATA arrayletLeafLogSize;
 	protected UDATA arrayletLeafSizeMask;
 
-	public GCArrayletObjectModelBase_V1() throws CorruptDataException 
+	public GCArrayletObjectModelBase() throws CorruptDataException 
 	{
 		arrayletObjectModel = GC_ArrayletObjectModelPointer.cast(GCBase.getExtensions().indexableObjectModel());
 		arrayletRangeBase = arrayletObjectModel._arrayletRangeBase();

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/j9/gc/GCArrayletObjectModel_V1.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2018 IBM Corp. and others
+ * Copyright (c) 1991, 2020 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -28,7 +28,7 @@
 import com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer;
 import com.ibm.j9ddr.vm29.types.UDATA;
 
-class GCArrayletObjectModel_V1 extends GCArrayletObjectModelBase_V1 
+class GCArrayletObjectModel_V1 extends GCArrayletObjectModelBase
 {
 
 	public GCArrayletObjectModel_V1() throws CorruptDataException 

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/j9/gc/GCArrayletObjectModel_V2.java

@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * Copyright (c) 1991, 2020 IBM Corp. and others
+ *
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which accompanies this
+ * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
+ * or the Apache License, Version 2.0 which accompanies this distribution and
+ * is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * This Source Code may also be made available under the following
+ * Secondary Licenses when the conditions for such availability set
+ * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
+ * General Public License, version 2 with the GNU Classpath
+ * Exception [1] and GNU General Public License, version 2 with the
+ * OpenJDK Assembly Exception [2].
+ *
+ * [1] https://www.gnu.org/software/classpath/license.html
+ * [2] http://openjdk.java.net/legal/assembly-exception.html
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
+ *******************************************************************************/
+package com.ibm.j9ddr.vm29.j9.gc;
+
+import com.ibm.j9ddr.CorruptDataException;
+import com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer;
+import com.ibm.j9ddr.vm29.types.UDATA;
+
+class GCArrayletObjectModel_V2 extends GCArrayletObjectModelBase
+{
+
+	public GCArrayletObjectModel_V2() throws CorruptDataException 
+	{		
+	}
+
+	@Override
+	public UDATA getSizeInBytesWithHeader(J9IndexableObjectPointer array) throws CorruptDataException
+	{
+		return super.getSpineSize(array);
+	}
+
+	/**
+	 * Return the total number of arraylets for an indexable object with a size of dataInSizeByte, including a (possibly empty) leaf in the spine.
+	 * @param dataSizeInBytes size of an array in bytes (not elements)
+	 * @return the number of arraylets used for an array of dataSizeInBytes bytes
+	 */
+	@Override
+	protected UDATA numArraylets(UDATA dataSizeInBytes) throws CorruptDataException
+	{
+		UDATA numberOfArraylets = new UDATA(1);
+		if (!UDATA.MAX.eq(arrayletLeafSize)) {
+			/* CMVC 135307 : following logic for calculating the leaf count would not overflow dataSizeInBytes.
+			 * the assumption is leaf size is order of 2. It's identical to:
+			 * if (dataSizeInBytes % leafSize) is 0
+			 * 	leaf count = dataSizeInBytes >> leafLogSize
+			 * else
+			 * 	leaf count = (dataSizeInBytes >> leafLogSize) + 1
+			 */
+			numberOfArraylets = dataSizeInBytes.rightShift(arrayletLeafLogSize).add(dataSizeInBytes.bitAnd(arrayletLeafSizeMask).add(arrayletLeafSizeMask).rightShift(arrayletLeafLogSize));
+		}
+		return numberOfArraylets;
+	}
+
+	@Override
+	public UDATA getTotalFootprintInBytesWithHeader(J9IndexableObjectPointer arrayPtr) throws CorruptDataException {
+		UDATA spineSize = getSizeInBytesWithHeader(arrayPtr);
+		UDATA externalArrayletSize = externalArrayletsSize(arrayPtr);
+		UDATA totalFootprint = spineSize.add(externalArrayletSize);
+		return totalFootprint;
+	}
+}

runtime/ddr/algorithm_versions.c

@@ -30,7 +30,7 @@
 #define VM_LINE_NUMBER_TABLE_VERSION 1
 #define VM_LOCAL_VARIABLE_TABLE_VERSION 1
 #define VM_CAN_ACCESS_LOCALS_VERSION 1
-#define ALG_GC_ARRAYLET_OBJECT_MODEL_VERSION 1
+#define ALG_GC_ARRAYLET_OBJECT_MODEL_VERSION 2
 #define VM_HASHTABLE_VERSION 1
 #define ALG_VM_J9CLASS_VERSION 1
 #define ALG_GC_OBJECT_HEAP_ITERATOR_SEGREGATED_ORDERED_LIST_VERSION 1