# HG changeset patch
# User Christian Wimmer <christian.wimmer@oracle.com>
# Date 1367521971 25200
# Node ID ae5cd887e67c83572ebe6484d3b690682223d495
# Parent  038fa65cbd8d4f4a373e9c773d531481ad49420d
Use a LocationIdentity interface instead of just Object for the location identity of a LocationNode

diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/PushNodesThroughPiTest.java
--- a/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/PushNodesThroughPiTest.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/PushNodesThroughPiTest.java	Thu May 02 12:12:51 2013 -0700
@@ -31,8 +31,9 @@
 import com.oracle.graal.debug.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.extended.*;
-import com.oracle.graal.nodes.spi.Lowerable.*;
+import com.oracle.graal.nodes.spi.Lowerable.LoweringType;
 import com.oracle.graal.phases.common.*;
 import com.oracle.graal.phases.tiers.*;
 
@@ -66,7 +67,7 @@
                 StructuredGraph graph = compileTestSnippet(snippet);
 
                 for (ReadNode rn : graph.getNodes().filter(ReadNode.class)) {
-                    Object locId = rn.location().getLocationIdentity();
+                    LocationIdentity locId = rn.location().getLocationIdentity();
                     if (locId instanceof ResolvedJavaField) {
                         ResolvedJavaField field = (ResolvedJavaField) locId;
                         if (field.getName().equals("x")) {
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/WriteBarrierVerificationTest.java
--- a/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/WriteBarrierVerificationTest.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/WriteBarrierVerificationTest.java	Thu May 02 12:12:51 2013 -0700
@@ -31,12 +31,13 @@
 import com.oracle.graal.debug.*;
 import com.oracle.graal.hotspot.phases.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.extended.*;
-import com.oracle.graal.nodes.spi.Lowerable.*;
+import com.oracle.graal.nodes.spi.Lowerable.LoweringType;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.phases.common.*;
 import com.oracle.graal.phases.graph.*;
-import com.oracle.graal.phases.graph.ReentrantNodeIterator.*;
+import com.oracle.graal.phases.graph.ReentrantNodeIterator.NodeIteratorClosure;
 import com.oracle.graal.phases.tiers.*;
 
 /**
@@ -643,7 +644,7 @@
                     protected void processNode(FixedNode node, State currentState) {
                         if (node instanceof WriteNode) {
                             WriteNode write = (WriteNode) node;
-                            Object obj = write.getLocationIdentities()[0];
+                            LocationIdentity obj = write.getLocationIdentities()[0];
                             if (obj instanceof ResolvedJavaField) {
                                 if (((ResolvedJavaField) obj).getName().equals("barrierIndex")) {
                                     /*
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotResolvedJavaField.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotResolvedJavaField.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotResolvedJavaField.java	Thu May 02 12:12:51 2013 -0700
@@ -31,13 +31,14 @@
 
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.hotspot.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.replacements.*;
 
 /**
  * Represents a field in a HotSpot type.
  */
-public class HotSpotResolvedJavaField extends CompilerObject implements ResolvedJavaField {
+public class HotSpotResolvedJavaField extends CompilerObject implements ResolvedJavaField, LocationIdentity {
 
     // Must not conflict with any fields flags used by the VM - the assertion in the constructor
     // checks this assumption
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/BeginLockScopeNode.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/BeginLockScopeNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/BeginLockScopeNode.java	Thu May 02 12:12:51 2013 -0700
@@ -29,6 +29,7 @@
 import com.oracle.graal.hotspot.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.type.*;
 import com.oracle.graal.word.*;
 
@@ -53,8 +54,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/DirectCompareAndSwapNode.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/DirectCompareAndSwapNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/DirectCompareAndSwapNode.java	Thu May 02 12:12:51 2013 -0700
@@ -26,14 +26,16 @@
 import com.oracle.graal.compiler.target.*;
 import com.oracle.graal.hotspot.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.extended.*;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.word.*;
 
 /**
  * A special purpose store node that differs from {@link CompareAndSwapNode} in that it is not a
- * {@link StateSplit} and it {@linkplain #compareAndSwap(Object, long, Word, Word, Object)} returns
- * either the expected value or the compared against value instead of a boolean.
+ * {@link StateSplit} and it
+ * {@linkplain #compareAndSwap(Object, long, Word, Word, LocationIdentity)} returns either the
+ * expected value or the compared against value instead of a boolean.
  */
 public class DirectCompareAndSwapNode extends FixedWithNextNode implements LIRGenLowerable, MemoryCheckpoint {
 
@@ -42,9 +44,9 @@
     @Input private ValueNode expectedValue;
     @Input private ValueNode newValue;
 
-    private final Object locationIdentity;
+    private final LocationIdentity locationIdentity;
 
-    public DirectCompareAndSwapNode(ValueNode object, ValueNode offset, ValueNode expected, ValueNode newValue, Object locationIdentity) {
+    public DirectCompareAndSwapNode(ValueNode object, ValueNode offset, ValueNode expected, ValueNode newValue, LocationIdentity locationIdentity) {
         super(expected.stamp());
         this.object = object;
         this.offset = offset;
@@ -70,8 +72,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{locationIdentity};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{locationIdentity};
     }
 
     @Override
@@ -92,5 +94,5 @@
      * @return either {@code expectedValue} or the actual value
      */
     @NodeIntrinsic
-    public static native Word compareAndSwap(Object object, long offset, Word expectedValue, Word newValue, @ConstantNodeParameter Object locationIdentity);
+    public static native Word compareAndSwap(Object object, long offset, Word expectedValue, Word newValue, @ConstantNodeParameter LocationIdentity locationIdentity);
 }
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/EndLockScopeNode.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/EndLockScopeNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/EndLockScopeNode.java	Thu May 02 12:12:51 2013 -0700
@@ -26,6 +26,7 @@
 import com.oracle.graal.compiler.target.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.type.*;
 
 /**
@@ -44,8 +45,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/HotSpotInstalledCodeExecuteNode.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/HotSpotInstalledCodeExecuteNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/HotSpotInstalledCodeExecuteNode.java	Thu May 02 12:12:51 2013 -0700
@@ -30,6 +30,7 @@
 import com.oracle.graal.hotspot.replacements.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
@@ -47,8 +48,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/HotSpotReplacementsUtil.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/HotSpotReplacementsUtil.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/HotSpotReplacementsUtil.java	Thu May 02 12:12:51 2013 -0700
@@ -34,6 +34,7 @@
 import com.oracle.graal.hotspot.meta.*;
 import com.oracle.graal.hotspot.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.replacements.Snippet.Fold;
 import com.oracle.graal.replacements.nodes.*;
 import com.oracle.graal.word.*;
@@ -45,8 +46,8 @@
  */
 public class HotSpotReplacementsUtil {
 
-    public static final Object ANY_LOCATION = LocationNode.ANY_LOCATION;
-    public static final Object FINAL_LOCATION = LocationNode.FINAL_LOCATION;
+    public static final LocationIdentity ANY_LOCATION = LocationNode.ANY_LOCATION;
+    public static final LocationIdentity FINAL_LOCATION = LocationNode.FINAL_LOCATION;
 
     public static HotSpotVMConfig config() {
         return graalRuntime().getConfig();
@@ -62,7 +63,7 @@
         return config().verifyOops;
     }
 
-    public static final Object EXCEPTION_OOP_LOCATION = LocationNode.createLocation("ExceptionOop");
+    public static final LocationIdentity EXCEPTION_OOP_LOCATION = LocationNode.createLocation("ExceptionOop");
 
     /**
      * @see HotSpotVMConfig#threadExceptionOopOffset
@@ -72,35 +73,35 @@
         return config().threadExceptionOopOffset;
     }
 
-    public static final Object EXCEPTION_PC_LOCATION = LocationNode.createLocation("ExceptionPc");
+    public static final LocationIdentity EXCEPTION_PC_LOCATION = LocationNode.createLocation("ExceptionPc");
 
     @Fold
     public static int threadExceptionPcOffset() {
         return config().threadExceptionPcOffset;
     }
 
-    public static final Object TLAB_TOP_LOCATION = LocationNode.createLocation("TlabTop");
+    public static final LocationIdentity TLAB_TOP_LOCATION = LocationNode.createLocation("TlabTop");
 
     @Fold
     public static int threadTlabTopOffset() {
         return config().threadTlabTopOffset;
     }
 
-    public static final Object TLAB_END_LOCATION = LocationNode.createLocation("TlabEnd");
+    public static final LocationIdentity TLAB_END_LOCATION = LocationNode.createLocation("TlabEnd");
 
     @Fold
     private static int threadTlabEndOffset() {
         return config().threadTlabEndOffset;
     }
 
-    public static final Object TLAB_START_LOCATION = LocationNode.createLocation("TlabStart");
+    public static final LocationIdentity TLAB_START_LOCATION = LocationNode.createLocation("TlabStart");
 
     @Fold
     private static int threadTlabStartOffset() {
         return config().threadTlabStartOffset;
     }
 
-    public static final Object PENDING_EXCEPTION_LOCATION = LocationNode.createLocation("PendingException");
+    public static final LocationIdentity PENDING_EXCEPTION_LOCATION = LocationNode.createLocation("PendingException");
 
     /**
      * @see HotSpotVMConfig#pendingExceptionOffset
@@ -110,7 +111,7 @@
         return config().pendingExceptionOffset;
     }
 
-    public static final Object OBJECT_RESULT_LOCATION = LocationNode.createLocation("ObjectResult");
+    public static final LocationIdentity OBJECT_RESULT_LOCATION = LocationNode.createLocation("ObjectResult");
 
     @Fold
     private static int objectResultOffset() {
@@ -223,7 +224,7 @@
         return Unsafe.getUnsafe().pageSize();
     }
 
-    public static final Object PROTOTYPE_MARK_WORD_LOCATION = LocationNode.createLocation("PrototypeMarkWord");
+    public static final LocationIdentity PROTOTYPE_MARK_WORD_LOCATION = LocationNode.createLocation("PrototypeMarkWord");
 
     @Fold
     public static int prototypeMarkWordOffset() {
@@ -264,14 +265,14 @@
         return config().klassSuperKlassOffset;
     }
 
-    public static final Object MARK_WORD_LOCATION = LocationNode.createLocation("MarkWord");
+    public static final LocationIdentity MARK_WORD_LOCATION = LocationNode.createLocation("MarkWord");
 
     @Fold
     public static int markOffset() {
         return config().markOffset;
     }
 
-    public static final Object HUB_LOCATION = LocationNode.createLocation("Hub");
+    public static final LocationIdentity HUB_LOCATION = LocationNode.createLocation("Hub");
 
     @Fold
     private static int hubOffset() {
@@ -398,21 +399,21 @@
         return config().superCheckOffsetOffset;
     }
 
-    public static final Object SECONDARY_SUPER_CACHE_LOCATION = LocationNode.createLocation("SecondarySuperCache");
+    public static final LocationIdentity SECONDARY_SUPER_CACHE_LOCATION = LocationNode.createLocation("SecondarySuperCache");
 
     @Fold
     public static int secondarySuperCacheOffset() {
         return config().secondarySuperCacheOffset;
     }
 
-    public static final Object SECONDARY_SUPERS_LOCATION = LocationNode.createLocation("SecondarySupers");
+    public static final LocationIdentity SECONDARY_SUPERS_LOCATION = LocationNode.createLocation("SecondarySupers");
 
     @Fold
     public static int secondarySupersOffset() {
         return config().secondarySupersOffset;
     }
 
-    public static final Object DISPLACED_MARK_WORD_LOCATION = LocationNode.createLocation("DisplacedMarkWord");
+    public static final LocationIdentity DISPLACED_MARK_WORD_LOCATION = LocationNode.createLocation("DisplacedMarkWord");
 
     @Fold
     public static int lockDisplacedMarkOffset() {
@@ -491,7 +492,7 @@
         return CodeUtil.log2(wordSize());
     }
 
-    public static final Object CLASS_STATE_LOCATION = LocationNode.createLocation("ClassState");
+    public static final LocationIdentity CLASS_STATE_LOCATION = LocationNode.createLocation("ClassState");
 
     @Fold
     public static int klassStateOffset() {
@@ -523,14 +524,14 @@
         return config().klassInstanceSizeOffset;
     }
 
-    public static final Object HEAP_TOP_LOCATION = LocationNode.createLocation("HeapTop");
+    public static final LocationIdentity HEAP_TOP_LOCATION = LocationNode.createLocation("HeapTop");
 
     @Fold
     public static long heapTopAddress() {
         return config().heapTopAddress;
     }
 
-    public static final Object HEAP_END_LOCATION = LocationNode.createLocation("HeapEnd");
+    public static final LocationIdentity HEAP_END_LOCATION = LocationNode.createLocation("HeapEnd");
 
     @Fold
     public static long heapEndAddress() {
@@ -552,42 +553,42 @@
         return config().tlabAlignmentReserve;
     }
 
-    public static final Object TLAB_SIZE_LOCATION = LocationNode.createLocation("TlabSize");
+    public static final LocationIdentity TLAB_SIZE_LOCATION = LocationNode.createLocation("TlabSize");
 
     @Fold
     public static int threadTlabSizeOffset() {
         return config().threadTlabSizeOffset;
     }
 
-    public static final Object TLAB_THREAD_ALLOCATED_BYTES_LOCATION = LocationNode.createLocation("TlabThreadAllocatedBytes");
+    public static final LocationIdentity TLAB_THREAD_ALLOCATED_BYTES_LOCATION = LocationNode.createLocation("TlabThreadAllocatedBytes");
 
     @Fold
     public static int threadAllocatedBytesOffset() {
         return config().threadAllocatedBytesOffset;
     }
 
-    public static final Object TLAB_REFILL_WASTE_LIMIT_LOCATION = LocationNode.createLocation("RefillWasteLimit");
+    public static final LocationIdentity TLAB_REFILL_WASTE_LIMIT_LOCATION = LocationNode.createLocation("RefillWasteLimit");
 
     @Fold
     public static int tlabRefillWasteLimitOffset() {
         return config().tlabRefillWasteLimitOffset;
     }
 
-    public static final Object TLAB_NOF_REFILLS_LOCATION = LocationNode.createLocation("TlabNOfRefills");
+    public static final LocationIdentity TLAB_NOF_REFILLS_LOCATION = LocationNode.createLocation("TlabNOfRefills");
 
     @Fold
     public static int tlabNumberOfRefillsOffset() {
         return config().tlabNumberOfRefillsOffset;
     }
 
-    public static final Object TLAB_FAST_REFILL_WASTE_LOCATION = LocationNode.createLocation("TlabFastRefillWaste");
+    public static final LocationIdentity TLAB_FAST_REFILL_WASTE_LOCATION = LocationNode.createLocation("TlabFastRefillWaste");
 
     @Fold
     public static int tlabFastRefillWasteOffset() {
         return config().tlabFastRefillWasteOffset;
     }
 
-    public static final Object TLAB_SLOW_ALLOCATIONS_LOCATION = LocationNode.createLocation("TlabSlowAllocations");
+    public static final LocationIdentity TLAB_SLOW_ALLOCATIONS_LOCATION = LocationNode.createLocation("TlabSlowAllocations");
 
     @Fold
     public static int tlabSlowAllocationsOffset() {
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Thu May 02 12:12:51 2013 -0700
@@ -41,6 +41,7 @@
 import com.oracle.graal.hotspot.nodes.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.java.MethodCallTargetNode.InvokeKind;
 import com.oracle.graal.nodes.spi.*;
@@ -344,7 +345,7 @@
      */
     private static final boolean ENABLE_BREAKPOINT = false;
 
-    private static final Object MONITOR_COUNTER_LOCATION = LocationNode.createLocation("MonitorCounter");
+    private static final LocationIdentity MONITOR_COUNTER_LOCATION = LocationNode.createLocation("MonitorCounter");
 
     @NodeIntrinsic(BreakpointNode.class)
     static native void bkpt(Object object, Word mark, Word tmp, Word value);
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/TypeCheckSnippetUtils.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/TypeCheckSnippetUtils.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/TypeCheckSnippetUtils.java	Thu May 02 12:12:51 2013 -0700
@@ -33,6 +33,7 @@
 import com.oracle.graal.hotspot.meta.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.replacements.*;
 import com.oracle.graal.word.*;
@@ -44,7 +45,7 @@
  */
 public class TypeCheckSnippetUtils {
 
-    public static final Object TYPE_DISPLAY_LOCATION = LocationNode.createLocation("TypeDisplay");
+    public static final LocationIdentity TYPE_DISPLAY_LOCATION = LocationNode.createLocation("TypeDisplay");
 
     static boolean checkSecondarySubType(Word t, Word s) {
         // if (S.cache == T) return true
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeNode.java	Thu May 02 12:12:51 2013 -0700
@@ -27,6 +27,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.util.*;
 
@@ -88,8 +89,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeWithExceptionNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeWithExceptionNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/InvokeWithExceptionNode.java	Thu May 02 12:12:51 2013 -0700
@@ -27,6 +27,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.util.*;
@@ -151,8 +152,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     public FrameState stateDuring() {
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StartNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StartNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StartNode.java	Thu May 02 12:12:51 2013 -0700
@@ -23,6 +23,7 @@
 package com.oracle.graal.nodes;
 
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 
 /**
  * The start node of a graph.
@@ -30,7 +31,7 @@
 public class StartNode extends BeginStateSplitNode implements MemoryCheckpoint {
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 }
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/AddLocationNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/AddLocationNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/AddLocationNode.java	Thu May 02 12:12:51 2013 -0700
@@ -64,7 +64,7 @@
     }
 
     @Override
-    public Object getLocationIdentity() {
+    public LocationIdentity getLocationIdentity() {
         return getX().getLocationIdentity();
     }
 
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ConstantLocationNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ConstantLocationNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ConstantLocationNode.java	Thu May 02 12:12:51 2013 -0700
@@ -35,14 +35,14 @@
 public final class ConstantLocationNode extends LocationNode {
 
     private final Kind valueKind;
-    private final Object locationIdentity;
+    private final LocationIdentity locationIdentity;
     private final long displacement;
 
-    public static ConstantLocationNode create(Object identity, Kind kind, long displacement, Graph graph) {
+    public static ConstantLocationNode create(LocationIdentity identity, Kind kind, long displacement, Graph graph) {
         return graph.unique(new ConstantLocationNode(identity, kind, displacement));
     }
 
-    private ConstantLocationNode(Object identity, Kind kind, long displacement) {
+    private ConstantLocationNode(LocationIdentity identity, Kind kind, long displacement) {
         super(StampFactory.extension());
         assert kind != Kind.Illegal && kind != Kind.Void;
         this.valueKind = kind;
@@ -56,7 +56,7 @@
     }
 
     @Override
-    public Object getLocationIdentity() {
+    public LocationIdentity getLocationIdentity() {
         return locationIdentity;
     }
 
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/IndexedLocationNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/IndexedLocationNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/IndexedLocationNode.java	Thu May 02 12:12:51 2013 -0700
@@ -37,7 +37,7 @@
 public final class IndexedLocationNode extends LocationNode implements Canonicalizable {
 
     private final Kind valueKind;
-    private final Object locationIdentity;
+    private final LocationIdentity locationIdentity;
     private final long displacement;
     @Input private ValueNode index;
     private final int indexScaling;
@@ -60,11 +60,11 @@
         return indexScaling;
     }
 
-    public static IndexedLocationNode create(Object identity, Kind kind, long displacement, ValueNode index, Graph graph, int indexScaling) {
+    public static IndexedLocationNode create(LocationIdentity identity, Kind kind, long displacement, ValueNode index, Graph graph, int indexScaling) {
         return graph.unique(new IndexedLocationNode(identity, kind, displacement, index, indexScaling));
     }
 
-    private IndexedLocationNode(Object identity, Kind kind, long displacement, ValueNode index, int indexScaling) {
+    private IndexedLocationNode(LocationIdentity identity, Kind kind, long displacement, ValueNode index, int indexScaling) {
         super(StampFactory.extension());
         assert kind != Kind.Illegal && kind != Kind.Void;
         this.valueKind = kind;
@@ -80,7 +80,7 @@
     }
 
     @Override
-    public Object getLocationIdentity() {
+    public LocationIdentity getLocationIdentity() {
         return locationIdentity;
     }
 
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/LocationNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/LocationNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/LocationNode.java	Thu May 02 12:12:51 2013 -0700
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes.extended;
 
+import java.util.*;
+
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.Node.ValueNumberable;
 import com.oracle.graal.nodes.calc.*;
@@ -36,13 +38,33 @@
 public abstract class LocationNode extends FloatingNode implements LIRLowerable, ValueNumberable {
 
     /**
+     * Marker interface for location identities. Apart from the special values {@link #ANY_LOCATION}
+     * and {@link #FINAL_LOCATION}, a different location identity of two memory accesses guarantees
+     * that the two accesses do not interfere.
+     */
+    public interface LocationIdentity {
+    }
+
+    /**
+     * Denotes any location. A write to such a location kills all values in a memory map during an
+     * analysis of memory accesses in a graph. A read from this location cannot be moved or
+     * coalesced with other reads because its interaction with other reads is not known.
+     */
+    public static final LocationIdentity ANY_LOCATION = createLocation("ANY_LOCATION");
+
+    /**
+     * Denotes the location of a value that is guaranteed to be final.
+     */
+    public static final LocationIdentity FINAL_LOCATION = createLocation("FINAL_LOCATION");
+
+    /**
      * Creates a new unique location identity for read and write operations.
      * 
      * @param name the name of the new location identity, for debugging purposes
      * @return the new location identity
      */
-    public static Object createLocation(final String name) {
-        return new Object() {
+    public static LocationIdentity createLocation(final String name) {
+        return new LocationIdentity() {
 
             @Override
             public String toString() {
@@ -52,16 +74,23 @@
     }
 
     /**
-     * Denotes any location. A write to such a location kills all values in a memory map during an
-     * analysis of memory accesses in a graph. A read from this location cannot be moved or
-     * coalesced with other reads because its interaction with other reads is not known.
+     * Returns the location identity for an array of the given element kind. Array accesses of the
+     * same kind must have the same location identity unless an alias analysis guarantees that two
+     * distinct arrays are accessed.
      */
-    public static final Object ANY_LOCATION = createLocation("ANY_LOCATION");
+    public static LocationIdentity getArrayLocation(Kind elementKind) {
+        return ARRAY_LOCATIONS.get(elementKind);
+    }
+
+    private static final EnumMap<Kind, LocationIdentity> ARRAY_LOCATIONS = initArrayLocations();
 
-    /**
-     * Denotes the location of a value that is guaranteed to be final.
-     */
-    public static final Object FINAL_LOCATION = createLocation("FINAL_LOCATION");
+    private static EnumMap<Kind, LocationIdentity> initArrayLocations() {
+        EnumMap<Kind, LocationIdentity> result = new EnumMap<>(Kind.class);
+        for (Kind kind : Kind.values()) {
+            result.put(kind, createLocation("Array: " + kind.getJavaName()));
+        }
+        return result;
+    }
 
     /**
      * Marker interface for locations in snippets.
@@ -69,10 +98,6 @@
     public interface Location {
     }
 
-    public static Object getArrayLocation(Kind elementKind) {
-        return elementKind;
-    }
-
     protected LocationNode(Stamp stamp) {
         super(stamp);
     }
@@ -83,11 +108,9 @@
     public abstract Kind getValueKind();
 
     /**
-     * Returns the identity of the accessed memory location. Apart from the special values
-     * {@link #ANY_LOCATION} and {@link #FINAL_LOCATION}, a different location identity of two
-     * memory accesses guarantees that the two accesses do not interfere.
+     * Returns the identity of the accessed memory location.
      */
-    public abstract Object getLocationIdentity();
+    public abstract LocationIdentity getLocationIdentity();
 
     @Override
     public final void generate(LIRGeneratorTool generator) {
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MembarNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MembarNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MembarNode.java	Thu May 02 12:12:51 2013 -0700
@@ -31,6 +31,7 @@
 import com.oracle.graal.api.code.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -50,8 +51,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MemoryCheckpoint.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MemoryCheckpoint.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/MemoryCheckpoint.java	Thu May 02 12:12:51 2013 -0700
@@ -23,6 +23,7 @@
 package com.oracle.graal.nodes.extended;
 
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 
 /**
  * This interface marks is used for subclasses of {@link FixedNode} that kill a set of memory
@@ -37,6 +38,6 @@
      * 
      * @return the identities of all locations killed by this node.
      */
-    Object[] getLocationIdentities();
+    LocationIdentity[] getLocationIdentities();
 
 }
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ReadNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ReadNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ReadNode.java	Thu May 02 12:12:51 2013 -0700
@@ -27,6 +27,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -43,7 +44,7 @@
         super(object, location, stamp, dependencies);
     }
 
-    private ReadNode(ValueNode object, int displacement, Object locationIdentity, Kind kind) {
+    private ReadNode(ValueNode object, int displacement, LocationIdentity locationIdentity, Kind kind) {
         super(object, ConstantLocationNode.create(locationIdentity, kind, displacement, object.graph()), StampFactory.forKind(kind));
     }
 
@@ -101,7 +102,7 @@
 
     @Override
     public boolean push(PiNode parent) {
-        Object locId = location().getLocationIdentity();
+        LocationIdentity locId = location().getLocationIdentity();
         if (locId instanceof ResolvedJavaField) {
             ResolvedJavaType fieldType = ((ResolvedJavaField) locId).getDeclaringClass();
             ValueNode piValueStamp = parent.object();
@@ -128,5 +129,5 @@
      * @return the value read from memory
      */
     @NodeIntrinsic(setStampFromReturnType = true)
-    public static native <T> T read(Object base, @ConstantNodeParameter int displacement, @ConstantNodeParameter Object locationIdentity, @ConstantNodeParameter Kind kind);
+    public static native <T> T read(Object base, @ConstantNodeParameter int displacement, @ConstantNodeParameter LocationIdentity locationIdentity, @ConstantNodeParameter Kind kind);
 }
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/RuntimeCallNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/RuntimeCallNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/RuntimeCallNode.java	Thu May 02 12:12:51 2013 -0700
@@ -26,6 +26,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -50,8 +51,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/SnippetLocationNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/SnippetLocationNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/SnippetLocationNode.java	Thu May 02 12:12:51 2013 -0700
@@ -65,9 +65,9 @@
     }
 
     @Override
-    public Object getLocationIdentity() {
+    public LocationIdentity getLocationIdentity() {
         if (locationIdentity.isConstant()) {
-            return locationIdentity.asConstant().asObject();
+            return (LocationIdentity) locationIdentity.asConstant().asObject();
         }
         // We do not know our actual location identity yet, so be conservative.
         return LocationNode.ANY_LOCATION;
@@ -77,7 +77,7 @@
     public ValueNode canonical(CanonicalizerTool tool) {
         if (valueKind.isConstant() && locationIdentity.isConstant() && displacement.isConstant() && (indexScaling == null || indexScaling.isConstant())) {
             Kind constKind = (Kind) valueKind.asConstant().asObject();
-            Object constLocation = locationIdentity.asConstant().asObject();
+            LocationIdentity constLocation = (LocationIdentity) locationIdentity.asConstant().asObject();
             long constDisplacement = displacement.asConstant().asLong();
             int constIndexScaling = indexScaling == null ? 0 : indexScaling.asConstant().asInt();
 
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeStoreNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeStoreNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeStoreNode.java	Thu May 02 12:12:51 2013 -0700
@@ -27,6 +27,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
@@ -74,8 +75,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteMemoryCheckpointNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteMemoryCheckpointNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteMemoryCheckpointNode.java	Thu May 02 12:12:51 2013 -0700
@@ -23,6 +23,7 @@
 package com.oracle.graal.nodes.extended;
 
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -37,8 +38,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/WriteNode.java	Thu May 02 12:12:51 2013 -0700
@@ -25,6 +25,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -93,7 +94,7 @@
     public static native void writeMemory(Object object, Object value, Object location, @ConstantNodeParameter WriteBarrierType barrierType);
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{location().getLocationIdentity()};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{location().getLocationIdentity()};
     }
 }
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CompareAndSwapNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CompareAndSwapNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CompareAndSwapNode.java	Thu May 02 12:12:51 2013 -0700
@@ -28,7 +28,8 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
-import com.oracle.graal.nodes.extended.WriteNode.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
+import com.oracle.graal.nodes.extended.WriteNode.WriteBarrierType;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -95,8 +96,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/ExceptionObjectNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/ExceptionObjectNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/ExceptionObjectNode.java	Thu May 02 12:12:51 2013 -0700
@@ -25,6 +25,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -39,8 +40,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorEnterNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorEnterNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorEnterNode.java	Thu May 02 12:12:51 2013 -0700
@@ -24,6 +24,7 @@
 
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 
 /**
@@ -44,8 +45,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorExitNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorExitNode.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/MonitorExitNode.java	Thu May 02 12:12:51 2013 -0700
@@ -25,6 +25,7 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.*;
 
 /**
@@ -45,8 +46,8 @@
     }
 
     @Override
-    public Object[] getLocationIdentities() {
-        return new Object[]{LocationNode.ANY_LOCATION};
+    public LocationIdentity[] getLocationIdentities() {
+        return new LocationIdentity[]{LocationNode.ANY_LOCATION};
     }
 
     @Override
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java
--- a/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java	Thu May 02 12:12:51 2013 -0700
@@ -27,6 +27,7 @@
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.PhiNode.PhiType;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.phases.graph.*;
 import com.oracle.graal.phases.graph.ReentrantNodeIterator.LoopInfo;
@@ -36,7 +37,7 @@
 
     private static class MemoryMap {
 
-        private IdentityHashMap<Object, ValueNode> lastMemorySnapshot;
+        private IdentityHashMap<LocationIdentity, ValueNode> lastMemorySnapshot;
 
         public MemoryMap(MemoryMap memoryMap) {
             lastMemorySnapshot = new IdentityHashMap<>(memoryMap.lastMemorySnapshot);
@@ -51,7 +52,7 @@
             lastMemorySnapshot = new IdentityHashMap<>();
         }
 
-        private ValueNode getLastLocationAccess(Object locationIdentity) {
+        private ValueNode getLastLocationAccess(LocationIdentity locationIdentity) {
             ValueNode lastLocationAccess;
             if (locationIdentity == LocationNode.FINAL_LOCATION) {
                 return null;
@@ -73,50 +74,50 @@
 
     @Override
     protected void run(StructuredGraph graph) {
-        Map<LoopBeginNode, Set<Object>> modifiedInLoops = new IdentityHashMap<>();
-        ReentrantNodeIterator.apply(new CollectMemoryCheckpointsClosure(modifiedInLoops), graph.start(), new HashSet<>(), null);
+        Map<LoopBeginNode, Set<LocationIdentity>> modifiedInLoops = new IdentityHashMap<>();
+        ReentrantNodeIterator.apply(new CollectMemoryCheckpointsClosure(modifiedInLoops), graph.start(), new HashSet<LocationIdentity>(), null);
         ReentrantNodeIterator.apply(new FloatingReadClosure(modifiedInLoops), graph.start(), new MemoryMap(graph.start()), null);
     }
 
-    private static class CollectMemoryCheckpointsClosure extends NodeIteratorClosure<Set<Object>> {
+    private static class CollectMemoryCheckpointsClosure extends NodeIteratorClosure<Set<LocationIdentity>> {
 
-        private final Map<LoopBeginNode, Set<Object>> modifiedInLoops;
+        private final Map<LoopBeginNode, Set<LocationIdentity>> modifiedInLoops;
 
-        public CollectMemoryCheckpointsClosure(Map<LoopBeginNode, Set<Object>> modifiedInLoops) {
+        public CollectMemoryCheckpointsClosure(Map<LoopBeginNode, Set<LocationIdentity>> modifiedInLoops) {
             this.modifiedInLoops = modifiedInLoops;
         }
 
         @Override
-        protected void processNode(FixedNode node, Set<Object> currentState) {
+        protected void processNode(FixedNode node, Set<LocationIdentity> currentState) {
             if (node instanceof MemoryCheckpoint) {
-                for (Object identity : ((MemoryCheckpoint) node).getLocationIdentities()) {
+                for (LocationIdentity identity : ((MemoryCheckpoint) node).getLocationIdentities()) {
                     currentState.add(identity);
                 }
             }
         }
 
         @Override
-        protected Set<Object> merge(MergeNode merge, List<Set<Object>> states) {
-            Set<Object> result = new HashSet<>();
-            for (Set<Object> other : states) {
+        protected Set<LocationIdentity> merge(MergeNode merge, List<Set<LocationIdentity>> states) {
+            Set<LocationIdentity> result = new HashSet<>();
+            for (Set<LocationIdentity> other : states) {
                 result.addAll(other);
             }
             return result;
         }
 
         @Override
-        protected Set<Object> afterSplit(AbstractBeginNode node, Set<Object> oldState) {
+        protected Set<LocationIdentity> afterSplit(AbstractBeginNode node, Set<LocationIdentity> oldState) {
             return new HashSet<>(oldState);
         }
 
         @Override
-        protected Map<LoopExitNode, Set<Object>> processLoop(LoopBeginNode loop, Set<Object> initialState) {
-            LoopInfo<Set<Object>> loopInfo = ReentrantNodeIterator.processLoop(this, loop, new HashSet<>());
-            Set<Object> modifiedLocations = new HashSet<>();
-            for (Set<Object> end : loopInfo.endStates.values()) {
+        protected Map<LoopExitNode, Set<LocationIdentity>> processLoop(LoopBeginNode loop, Set<LocationIdentity> initialState) {
+            LoopInfo<Set<LocationIdentity>> loopInfo = ReentrantNodeIterator.processLoop(this, loop, new HashSet<LocationIdentity>());
+            Set<LocationIdentity> modifiedLocations = new HashSet<>();
+            for (Set<LocationIdentity> end : loopInfo.endStates.values()) {
                 modifiedLocations.addAll(end);
             }
-            for (Set<Object> exit : loopInfo.exitStates.values()) {
+            for (Set<LocationIdentity> exit : loopInfo.exitStates.values()) {
                 exit.addAll(modifiedLocations);
                 exit.addAll(initialState);
             }
@@ -129,9 +130,9 @@
 
     private static class FloatingReadClosure extends NodeIteratorClosure<MemoryMap> {
 
-        private final Map<LoopBeginNode, Set<Object>> modifiedInLoops;
+        private final Map<LoopBeginNode, Set<LocationIdentity>> modifiedInLoops;
 
-        public FloatingReadClosure(Map<LoopBeginNode, Set<Object>> modifiedInLoops) {
+        public FloatingReadClosure(Map<LoopBeginNode, Set<LocationIdentity>> modifiedInLoops) {
             this.modifiedInLoops = modifiedInLoops;
         }
 
@@ -145,7 +146,7 @@
         }
 
         private static void processCheckpoint(MemoryCheckpoint checkpoint, MemoryMap state) {
-            for (Object identity : checkpoint.getLocationIdentities()) {
+            for (LocationIdentity identity : checkpoint.getLocationIdentities()) {
                 if (identity == LocationNode.ANY_LOCATION) {
                     state.lastMemorySnapshot.clear();
                 }
@@ -156,7 +157,7 @@
         private static void processFloatable(FloatableAccessNode accessNode, MemoryMap state) {
             StructuredGraph graph = (StructuredGraph) accessNode.graph();
             assert accessNode.getNullCheck() == false;
-            Object locationIdentity = accessNode.location().getLocationIdentity();
+            LocationIdentity locationIdentity = accessNode.location().getLocationIdentity();
             if (locationIdentity != LocationNode.ANY_LOCATION) {
                 ValueNode lastLocationAccess = state.getLastLocationAccess(locationIdentity);
                 FloatingAccessNode floatingNode = accessNode.asFloatingNode(lastLocationAccess);
@@ -177,13 +178,13 @@
         protected MemoryMap merge(MergeNode merge, List<MemoryMap> states) {
             MemoryMap newState = new MemoryMap();
 
-            Set<Object> keys = new HashSet<>();
+            Set<LocationIdentity> keys = new HashSet<>();
             for (MemoryMap other : states) {
                 keys.addAll(other.lastMemorySnapshot.keySet());
             }
             assert !keys.contains(LocationNode.FINAL_LOCATION);
 
-            for (Object key : keys) {
+            for (LocationIdentity key : keys) {
                 int mergedStatesCount = 0;
                 boolean isPhi = false;
                 ValueNode merged = null;
@@ -225,7 +226,7 @@
                  * needs to choose by putting in the location identity on both successors.
                  */
                 InvokeWithExceptionNode checkpoint = (InvokeWithExceptionNode) node.predecessor();
-                for (Object identity : checkpoint.getLocationIdentities()) {
+                for (LocationIdentity identity : checkpoint.getLocationIdentities()) {
                     result.lastMemorySnapshot.put(identity, node);
                 }
             }
@@ -234,15 +235,15 @@
 
         @Override
         protected Map<LoopExitNode, MemoryMap> processLoop(LoopBeginNode loop, MemoryMap initialState) {
-            Set<Object> modifiedLocations = modifiedInLoops.get(loop);
+            Set<LocationIdentity> modifiedLocations = modifiedInLoops.get(loop);
             if (modifiedLocations.contains(LocationNode.ANY_LOCATION)) {
                 // create phis for all locations if ANY is modified in the loop
                 modifiedLocations = new HashSet<>(modifiedLocations);
                 modifiedLocations.addAll(initialState.lastMemorySnapshot.keySet());
             }
 
-            Map<Object, PhiNode> phis = new HashMap<>();
-            for (Object location : modifiedLocations) {
+            Map<LocationIdentity, PhiNode> phis = new HashMap<>();
+            for (LocationIdentity location : modifiedLocations) {
                 PhiNode phi = loop.graph().add(new PhiNode(PhiType.Memory, loop, location));
                 phi.addInput(initialState.getLastLocationAccess(location));
                 phis.put(location, phi);
@@ -253,8 +254,8 @@
 
             for (Map.Entry<LoopEndNode, MemoryMap> entry : loopInfo.endStates.entrySet()) {
                 int endIndex = loop.phiPredecessorIndex(entry.getKey());
-                for (Map.Entry<Object, PhiNode> phiEntry : phis.entrySet()) {
-                    Object key = phiEntry.getKey();
+                for (Map.Entry<LocationIdentity, PhiNode> phiEntry : phis.entrySet()) {
+                    LocationIdentity key = phiEntry.getKey();
                     PhiNode phi = phiEntry.getValue();
                     phi.initializeValueAt(endIndex, entry.getValue().getLastLocationAccess(key));
                 }
@@ -262,7 +263,7 @@
             for (Map.Entry<LoopExitNode, MemoryMap> entry : loopInfo.exitStates.entrySet()) {
                 LoopExitNode exit = entry.getKey();
                 MemoryMap state = entry.getValue();
-                for (Object location : modifiedLocations) {
+                for (LocationIdentity location : modifiedLocations) {
                     ValueNode lastAccessAtExit = state.lastMemorySnapshot.get(location);
                     if (lastAccessAtExit != null) {
                         state.lastMemorySnapshot.put(location, ProxyNode.forMemory(lastAccessAtExit, exit, location, (StructuredGraph) loop.graph()));
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java
--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java	Thu May 02 12:12:51 2013 -0700
@@ -31,6 +31,7 @@
 import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.cfg.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.virtual.*;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.phases.graph.*;
@@ -88,7 +89,7 @@
                 if (node instanceof FloatingReadNode) {
                     currentState.add((FloatingReadNode) node);
                 } else if (node instanceof MemoryCheckpoint) {
-                    for (Object identity : ((MemoryCheckpoint) node).getLocationIdentities()) {
+                    for (LocationIdentity identity : ((MemoryCheckpoint) node).getLocationIdentities()) {
                         for (Iterator<FloatingReadNode> iter = currentState.iterator(); iter.hasNext();) {
                             FloatingReadNode read = iter.next();
                             FixedNode fixed = (FixedNode) node;
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.replacements.test/src/com/oracle/graal/replacements/test/PointerTest.java
--- a/graal/com.oracle.graal.replacements.test/src/com/oracle/graal/replacements/test/PointerTest.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.replacements.test/src/com/oracle/graal/replacements/test/PointerTest.java	Thu May 02 12:12:51 2013 -0700
@@ -33,6 +33,7 @@
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.replacements.*;
 import com.oracle.graal.replacements.Snippet.*;
 import com.oracle.graal.word.*;
@@ -42,7 +43,7 @@
  */
 public class PointerTest extends GraalCompilerTest implements Snippets {
 
-    private static final Object ID = new Object();
+    private static final LocationIdentity ID = LocationNode.createLocation("ID");
     private static final Kind[] KINDS = new Kind[]{Kind.Byte, Kind.Char, Kind.Short, Kind.Int, Kind.Long, Kind.Float, Kind.Double, Kind.Object};
     private final TargetDescription target;
     private final ReplacementsImpl installer;
@@ -102,7 +103,7 @@
         }
     }
 
-    private void assertRead(StructuredGraph graph, Kind kind, boolean indexConvert, Object locationIdentity) {
+    private void assertRead(StructuredGraph graph, Kind kind, boolean indexConvert, LocationIdentity locationIdentity) {
         ReadNode read = (ReadNode) graph.start().next();
         Assert.assertEquals(kind.getStackKind(), read.kind());
 
@@ -127,7 +128,7 @@
         Assert.assertEquals(read, ret.result());
     }
 
-    private void assertWrite(StructuredGraph graph, Kind kind, boolean indexConvert, Object locationIdentity) {
+    private void assertWrite(StructuredGraph graph, Kind kind, boolean indexConvert, LocationIdentity locationIdentity) {
         WriteNode write = (WriteNode) graph.start().next();
         Assert.assertEquals(graph.getLocal(2), write.value());
         Assert.assertEquals(Kind.Void, write.kind());
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/BlockState.java
--- a/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/BlockState.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/BlockState.java	Thu May 02 12:12:51 2013 -0700
@@ -29,6 +29,7 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.spi.Virtualizable.EscapeState;
 import com.oracle.graal.nodes.virtual.*;
 
@@ -41,10 +42,10 @@
 
     static class ReadCacheEntry {
 
-        public final Object identity;
+        public final LocationIdentity identity;
         public final ValueNode object;
 
-        public ReadCacheEntry(Object identity, ValueNode object) {
+        public ReadCacheEntry(LocationIdentity identity, ValueNode object) {
             this.identity = identity;
             this.object = object;
         }
@@ -82,7 +83,7 @@
         readCache = new HashMap<>(other.readCache);
     }
 
-    public void addReadCache(ValueNode object, Object identity, ValueNode value) {
+    public void addReadCache(ValueNode object, LocationIdentity identity, ValueNode value) {
         ValueNode cacheObject;
         ObjectState obj = getObjectState(object);
         if (obj != null) {
@@ -94,7 +95,7 @@
         readCache.put(new ReadCacheEntry(identity, cacheObject), value);
     }
 
-    public ValueNode getReadCache(ValueNode object, Object identity) {
+    public ValueNode getReadCache(ValueNode object, LocationIdentity identity) {
         ValueNode cacheObject;
         ObjectState obj = getObjectState(object);
         if (obj != null) {
@@ -114,7 +115,7 @@
         return cacheValue;
     }
 
-    public void killReadCache(Object identity) {
+    public void killReadCache(LocationIdentity identity) {
         if (identity == LocationNode.ANY_LOCATION) {
             readCache.clear();
         } else {
@@ -186,7 +187,7 @@
             if (virtual instanceof VirtualInstanceNode) {
                 VirtualInstanceNode instance = (VirtualInstanceNode) virtual;
                 for (int i = 0; i < entries.length; i++) {
-                    readCache.put(new ReadCacheEntry(instance.field(i), representation), values.get(pos + i));
+                    readCache.put(new ReadCacheEntry((LocationIdentity) instance.field(i), representation), values.get(pos + i));
                 }
             }
         } else {
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/PartialEscapeClosure.java
--- a/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/PartialEscapeClosure.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/PartialEscapeClosure.java	Thu May 02 12:12:51 2013 -0700
@@ -34,6 +34,7 @@
 import com.oracle.graal.nodes.PhiNode.PhiType;
 import com.oracle.graal.nodes.VirtualState.NodeClosure;
 import com.oracle.graal.nodes.cfg.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 import com.oracle.graal.nodes.extended.*;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.spi.*;
@@ -158,18 +159,18 @@
                     if (node instanceof StoreFieldNode) {
                         METRIC_STOREFIELD_RECORDED.increment();
                         StoreFieldNode store = (StoreFieldNode) node;
-                        ValueNode cachedValue = state.getReadCache(store.object(), store.field());
-                        state.killReadCache(store.field());
+                        ValueNode cachedValue = state.getReadCache(store.object(), (LocationIdentity) store.field());
+                        state.killReadCache((LocationIdentity) store.field());
 
                         if (cachedValue == store.value()) {
                             effects.deleteFixedNode(store);
                             changed = true;
                         } else {
-                            state.addReadCache(store.object(), store.field(), store.value());
+                            state.addReadCache(store.object(), (LocationIdentity) store.field(), store.value());
                         }
                     } else if (node instanceof LoadFieldNode) {
                         LoadFieldNode load = (LoadFieldNode) node;
-                        ValueNode cachedValue = state.getReadCache(load.object(), load.field());
+                        ValueNode cachedValue = state.getReadCache(load.object(), (LocationIdentity) load.field());
                         if (cachedValue != null) {
                             METRIC_LOADFIELD_ELIMINATED.increment();
                             effects.replaceAtUsages(load, cachedValue);
@@ -177,12 +178,12 @@
                             changed = true;
                         } else {
                             METRIC_LOADFIELD_NOT_ELIMINATED.increment();
-                            state.addReadCache(load.object(), load.field(), load);
+                            state.addReadCache(load.object(), (LocationIdentity) load.field(), load);
                         }
                     } else if (node instanceof MemoryCheckpoint) {
                         METRIC_MEMORYCHECKOINT.increment();
                         MemoryCheckpoint checkpoint = (MemoryCheckpoint) node;
-                        for (Object identity : checkpoint.getLocationIdentities()) {
+                        for (LocationIdentity identity : checkpoint.getLocationIdentities()) {
                             state.killReadCache(identity);
                         }
                     }
@@ -703,7 +704,7 @@
             }
         }
 
-        private void mergeReadCachePhi(PhiNode phi, Object identity, List<BlockState> states) {
+        private void mergeReadCachePhi(PhiNode phi, LocationIdentity identity, List<BlockState> states) {
             ValueNode[] values = new ValueNode[phi.valueCount()];
             for (int i = 0; i < phi.valueCount(); i++) {
                 ValueNode value = states.get(i).getReadCache(phi.valueAt(i), identity);
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.word/src/com/oracle/graal/word/Pointer.java
--- a/graal/com.oracle.graal.word/src/com/oracle/graal/word/Pointer.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.word/src/com/oracle/graal/word/Pointer.java	Thu May 02 12:12:51 2013 -0700
@@ -23,6 +23,7 @@
 package com.oracle.graal.word;
 
 import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 
 public interface Pointer extends Unsigned {
 
@@ -47,7 +48,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    byte readByte(WordBase offset, Object locationIdentity);
+    byte readByte(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -61,7 +62,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    char readChar(WordBase offset, Object locationIdentity);
+    char readChar(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -75,7 +76,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    short readShort(WordBase offset, Object locationIdentity);
+    short readShort(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -89,7 +90,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    int readInt(WordBase offset, Object locationIdentity);
+    int readInt(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -103,7 +104,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    long readLong(WordBase offset, Object locationIdentity);
+    long readLong(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -117,7 +118,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    float readFloat(WordBase offset, Object locationIdentity);
+    float readFloat(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -131,7 +132,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    double readDouble(WordBase offset, Object locationIdentity);
+    double readDouble(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -145,7 +146,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    Word readWord(WordBase offset, Object locationIdentity);
+    Word readWord(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -159,7 +160,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    Object readObject(WordBase offset, Object locationIdentity);
+    Object readObject(WordBase offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -169,7 +170,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    byte readByte(int offset, Object locationIdentity);
+    byte readByte(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -179,7 +180,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    char readChar(int offset, Object locationIdentity);
+    char readChar(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -189,7 +190,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    short readShort(int offset, Object locationIdentity);
+    short readShort(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -199,7 +200,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    int readInt(int offset, Object locationIdentity);
+    int readInt(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -209,7 +210,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    long readLong(int offset, Object locationIdentity);
+    long readLong(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -219,7 +220,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    float readFloat(int offset, Object locationIdentity);
+    float readFloat(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -229,7 +230,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    double readDouble(int offset, Object locationIdentity);
+    double readDouble(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -239,7 +240,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    Word readWord(int offset, Object locationIdentity);
+    Word readWord(int offset, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -249,7 +250,7 @@
      * @param locationIdentity the identity of the read (see {@link LocationNode})
      * @return the result of the memory access
      */
-    Object readObject(int offset, Object locationIdentity);
+    Object readObject(int offset, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -263,7 +264,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeByte(WordBase offset, byte val, Object locationIdentity);
+    void writeByte(WordBase offset, byte val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -277,7 +278,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeChar(WordBase offset, char val, Object locationIdentity);
+    void writeChar(WordBase offset, char val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -291,7 +292,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeShort(WordBase offset, short val, Object locationIdentity);
+    void writeShort(WordBase offset, short val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -305,7 +306,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeInt(WordBase offset, int val, Object locationIdentity);
+    void writeInt(WordBase offset, int val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -319,7 +320,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeLong(WordBase offset, long val, Object locationIdentity);
+    void writeLong(WordBase offset, long val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -333,7 +334,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeFloat(WordBase offset, float val, Object locationIdentity);
+    void writeFloat(WordBase offset, float val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -347,7 +348,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeDouble(WordBase offset, double val, Object locationIdentity);
+    void writeDouble(WordBase offset, double val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -361,7 +362,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeWord(WordBase offset, WordBase val, Object locationIdentity);
+    void writeWord(WordBase offset, WordBase val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -375,7 +376,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeObject(WordBase offset, Object val, Object locationIdentity);
+    void writeObject(WordBase offset, Object val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -385,7 +386,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeByte(int offset, byte val, Object locationIdentity);
+    void writeByte(int offset, byte val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -395,7 +396,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeChar(int offset, char val, Object locationIdentity);
+    void writeChar(int offset, char val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -405,7 +406,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeShort(int offset, short val, Object locationIdentity);
+    void writeShort(int offset, short val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -415,7 +416,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeInt(int offset, int val, Object locationIdentity);
+    void writeInt(int offset, int val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -425,7 +426,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeLong(int offset, long val, Object locationIdentity);
+    void writeLong(int offset, long val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -435,7 +436,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeFloat(int offset, float val, Object locationIdentity);
+    void writeFloat(int offset, float val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -445,7 +446,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeDouble(int offset, double val, Object locationIdentity);
+    void writeDouble(int offset, double val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -455,7 +456,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeWord(int offset, WordBase val, Object locationIdentity);
+    void writeWord(int offset, WordBase val, LocationIdentity locationIdentity);
 
     /**
      * Writes the memory at address {@code (this + offset)}. Both the base address and offset are in
@@ -465,7 +466,7 @@
      * @param locationIdentity the identity of the write (see {@link LocationNode})
      * @param val the value to be written to memory
      */
-    void writeObject(int offset, Object val, Object locationIdentity);
+    void writeObject(int offset, Object val, LocationIdentity locationIdentity);
 
     /**
      * Reads the memory at address {@code (this + offset)}. Both the base address and offset are in
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.word/src/com/oracle/graal/word/Word.java
--- a/graal/com.oracle.graal.word/src/com/oracle/graal/word/Word.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.word/src/com/oracle/graal/word/Word.java	Thu May 02 12:12:51 2013 -0700
@@ -30,6 +30,7 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
 
 public abstract class Word implements Signed, Unsigned, Pointer {
 
@@ -601,215 +602,215 @@
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public byte readByte(WordBase offset, Object locationIdentity) {
+    public byte readByte(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getByte(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public char readChar(WordBase offset, Object locationIdentity) {
+    public char readChar(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getChar(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public short readShort(WordBase offset, Object locationIdentity) {
+    public short readShort(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getShort(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public int readInt(WordBase offset, Object locationIdentity) {
+    public int readInt(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getInt(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public long readLong(WordBase offset, Object locationIdentity) {
+    public long readLong(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getLong(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public float readFloat(WordBase offset, Object locationIdentity) {
+    public float readFloat(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getFloat(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public double readDouble(WordBase offset, Object locationIdentity) {
+    public double readDouble(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getDouble(add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public Word readWord(WordBase offset, Object locationIdentity) {
+    public Word readWord(WordBase offset, LocationIdentity locationIdentity) {
         return box(unsafe.getAddress(add((Word) offset).unbox()));
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public Object readObject(WordBase offset, Object locationIdentity) {
+    public Object readObject(WordBase offset, LocationIdentity locationIdentity) {
         return unsafe.getObject(null, add((Word) offset).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public byte readByte(int offset, Object locationIdentity) {
+    public byte readByte(int offset, LocationIdentity locationIdentity) {
         return readByte(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public char readChar(int offset, Object locationIdentity) {
+    public char readChar(int offset, LocationIdentity locationIdentity) {
         return readChar(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public short readShort(int offset, Object locationIdentity) {
+    public short readShort(int offset, LocationIdentity locationIdentity) {
         return readShort(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public int readInt(int offset, Object locationIdentity) {
+    public int readInt(int offset, LocationIdentity locationIdentity) {
         return readInt(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public long readLong(int offset, Object locationIdentity) {
+    public long readLong(int offset, LocationIdentity locationIdentity) {
         return readLong(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public float readFloat(int offset, Object locationIdentity) {
+    public float readFloat(int offset, LocationIdentity locationIdentity) {
         return readFloat(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public double readDouble(int offset, Object locationIdentity) {
+    public double readDouble(int offset, LocationIdentity locationIdentity) {
         return readDouble(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public Word readWord(int offset, Object locationIdentity) {
+    public Word readWord(int offset, LocationIdentity locationIdentity) {
         return readWord(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.READ)
-    public Object readObject(int offset, Object locationIdentity) {
+    public Object readObject(int offset, LocationIdentity locationIdentity) {
         return readObject(signed(offset), locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeByte(WordBase offset, byte val, Object locationIdentity) {
+    public void writeByte(WordBase offset, byte val, LocationIdentity locationIdentity) {
         unsafe.putByte(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeChar(WordBase offset, char val, Object locationIdentity) {
+    public void writeChar(WordBase offset, char val, LocationIdentity locationIdentity) {
         unsafe.putChar(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeShort(WordBase offset, short val, Object locationIdentity) {
+    public void writeShort(WordBase offset, short val, LocationIdentity locationIdentity) {
         unsafe.putShort(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeInt(WordBase offset, int val, Object locationIdentity) {
+    public void writeInt(WordBase offset, int val, LocationIdentity locationIdentity) {
         unsafe.putInt(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeLong(WordBase offset, long val, Object locationIdentity) {
+    public void writeLong(WordBase offset, long val, LocationIdentity locationIdentity) {
         unsafe.putLong(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeFloat(WordBase offset, float val, Object locationIdentity) {
+    public void writeFloat(WordBase offset, float val, LocationIdentity locationIdentity) {
         unsafe.putFloat(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeDouble(WordBase offset, double val, Object locationIdentity) {
+    public void writeDouble(WordBase offset, double val, LocationIdentity locationIdentity) {
         unsafe.putDouble(add((Word) offset).unbox(), val);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeWord(WordBase offset, WordBase val, Object locationIdentity) {
+    public void writeWord(WordBase offset, WordBase val, LocationIdentity locationIdentity) {
         unsafe.putAddress(add((Word) offset).unbox(), ((Word) val).unbox());
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public native void writeObject(WordBase offset, Object val, Object locationIdentity);
+    public native void writeObject(WordBase offset, Object val, LocationIdentity locationIdentity);
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeByte(int offset, byte val, Object locationIdentity) {
+    public void writeByte(int offset, byte val, LocationIdentity locationIdentity) {
         writeByte(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeChar(int offset, char val, Object locationIdentity) {
+    public void writeChar(int offset, char val, LocationIdentity locationIdentity) {
         writeChar(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeShort(int offset, short val, Object locationIdentity) {
+    public void writeShort(int offset, short val, LocationIdentity locationIdentity) {
         writeShort(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeInt(int offset, int val, Object locationIdentity) {
+    public void writeInt(int offset, int val, LocationIdentity locationIdentity) {
         writeInt(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeLong(int offset, long val, Object locationIdentity) {
+    public void writeLong(int offset, long val, LocationIdentity locationIdentity) {
         writeLong(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeFloat(int offset, float val, Object locationIdentity) {
+    public void writeFloat(int offset, float val, LocationIdentity locationIdentity) {
         writeFloat(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeDouble(int offset, double val, Object locationIdentity) {
+    public void writeDouble(int offset, double val, LocationIdentity locationIdentity) {
         writeDouble(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeWord(int offset, WordBase val, Object locationIdentity) {
+    public void writeWord(int offset, WordBase val, LocationIdentity locationIdentity) {
         writeWord(signed(offset), val, locationIdentity);
     }
 
     @Override
     @Operation(opcode = Opcode.WRITE)
-    public void writeObject(int offset, Object val, Object locationIdentity) {
+    public void writeObject(int offset, Object val, LocationIdentity locationIdentity) {
         writeObject(signed(offset), val, locationIdentity);
     }
 
diff -r 038fa65cbd8d -r ae5cd887e67c graal/com.oracle.graal.word/src/com/oracle/graal/word/phases/WordTypeRewriterPhase.java
--- a/graal/com.oracle.graal.word/src/com/oracle/graal/word/phases/WordTypeRewriterPhase.java	Thu May 02 10:38:48 2013 -0700
+++ b/graal/com.oracle.graal.word/src/com/oracle/graal/word/phases/WordTypeRewriterPhase.java	Thu May 02 12:12:51 2013 -0700
@@ -29,7 +29,8 @@
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.extended.*;
-import com.oracle.graal.nodes.extended.WriteNode.*;
+import com.oracle.graal.nodes.extended.LocationNode.LocationIdentity;
+import com.oracle.graal.nodes.extended.WriteNode.WriteBarrierType;
 import com.oracle.graal.nodes.java.*;
 import com.oracle.graal.nodes.type.*;
 import com.oracle.graal.nodes.util.*;
@@ -159,14 +160,14 @@
                     case READ:
                         assert arguments.size() == 2 || arguments.size() == 3;
                         Kind readKind = asKind(callTargetNode.returnType());
-                        Object readLocation = arguments.size() == 2 ? LocationNode.ANY_LOCATION : arguments.get(2).asConstant().asObject();
+                        LocationIdentity readLocation = arguments.size() == 2 ? LocationNode.ANY_LOCATION : (LocationIdentity) arguments.get(2).asConstant().asObject();
                         replace(invoke, readOp(graph, arguments.get(0), arguments.get(1), invoke, readKind, readLocation));
                         break;
 
                     case WRITE:
                         assert arguments.size() == 3 || arguments.size() == 4;
                         Kind writeKind = asKind(targetMethod.getSignature().getParameterType(1, targetMethod.getDeclaringClass()));
-                        Object writeLocation = arguments.size() == 3 ? LocationNode.ANY_LOCATION : arguments.get(3).asConstant().asObject();
+                        LocationIdentity writeLocation = arguments.size() == 3 ? LocationNode.ANY_LOCATION : (LocationIdentity) arguments.get(3).asConstant().asObject();
                         replace(invoke, writeOp(graph, arguments.get(0), arguments.get(1), arguments.get(2), invoke, writeKind, writeLocation));
                         break;
 
@@ -284,7 +285,7 @@
         return materialize;
     }
 
-    private static ValueNode readOp(StructuredGraph graph, ValueNode base, ValueNode offset, Invoke invoke, Kind readKind, Object locationIdentity) {
+    private static ValueNode readOp(StructuredGraph graph, ValueNode base, ValueNode offset, Invoke invoke, Kind readKind, LocationIdentity locationIdentity) {
         IndexedLocationNode location = IndexedLocationNode.create(locationIdentity, readKind, 0, offset, graph, 1);
         ReadNode read = graph.add(new ReadNode(base, location, invoke.asNode().stamp()));
         graph.addBeforeFixed(invoke.asNode(), read);
@@ -294,7 +295,7 @@
         return read;
     }
 
-    private static ValueNode writeOp(StructuredGraph graph, ValueNode base, ValueNode offset, ValueNode value, Invoke invoke, Kind writeKind, Object locationIdentity) {
+    private static ValueNode writeOp(StructuredGraph graph, ValueNode base, ValueNode offset, ValueNode value, Invoke invoke, Kind writeKind, LocationIdentity locationIdentity) {
         IndexedLocationNode location = IndexedLocationNode.create(locationIdentity, writeKind, 0, offset, graph, 1);
         WriteNode write = graph.add(new WriteNode(base, value, location, WriteBarrierType.NONE));
         write.setStateAfter(invoke.stateAfter());