# HG changeset patch
# User Roland Schatz <roland.schatz@oracle.com>
# Date 1374487977 -7200
# Node ID 04f817fb0456d11a0443cc645ddd5b5df9c33793
# Parent  45ca31374e9fede959d104ef0c3650bcfa27b53e
Method to reconstruct array index from LocationNode.

diff -r 45ca31374e9f -r 04f817fb0456 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotRuntime.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotRuntime.java	Mon Jul 22 11:58:00 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotRuntime.java	Mon Jul 22 12:12:57 2013 +0200
@@ -66,6 +66,7 @@
 import com.oracle.graal.api.code.CompilationResult.Infopoint;
 import com.oracle.graal.api.code.CompilationResult.Mark;
 import com.oracle.graal.api.meta.*;
+import com.oracle.graal.asm.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.hotspot.*;
 import com.oracle.graal.hotspot.HotSpotForeignCallLinkage.RegisterEffect;
@@ -934,6 +935,44 @@
         return IndexedLocationNode.create(NamedLocationIdentity.getArrayLocation(elementKind), elementKind, getArrayBaseOffset(elementKind), index, graph, scale);
     }
 
+    @Override
+    public ValueNode reconstructArrayIndex(LocationNode location) {
+        Kind elementKind = location.getValueKind();
+        assert location.getLocationIdentity().equals(NamedLocationIdentity.getArrayLocation(elementKind));
+
+        long base;
+        ValueNode index;
+        int scale = getScalingFactor(elementKind);
+
+        if (location instanceof ConstantLocationNode) {
+            base = ((ConstantLocationNode) location).getDisplacement();
+            index = null;
+        } else if (location instanceof IndexedLocationNode) {
+            IndexedLocationNode indexedLocation = (IndexedLocationNode) location;
+            assert indexedLocation.getIndexScaling() == scale;
+            base = indexedLocation.getDisplacement();
+            index = indexedLocation.getIndex();
+        } else {
+            throw GraalInternalError.shouldNotReachHere();
+        }
+
+        base -= getArrayBaseOffset(elementKind);
+        assert base >= 0 && base % scale == 0;
+
+        base /= scale;
+        assert NumUtil.isInt(base);
+
+        if (index == null) {
+            return ConstantNode.forInt((int) base, location.graph());
+        } else {
+            if (base == 0) {
+                return index;
+            } else {
+                return IntegerArithmeticNode.add(ConstantNode.forInt((int) base, location.graph()), index);
+            }
+        }
+    }
+
     private static GuardingNode createBoundsCheck(AccessIndexedNode n, LoweringTool tool) {
         StructuredGraph graph = n.graph();
         ArrayLengthNode arrayLength = graph.add(new ArrayLengthNode(n.array()));
diff -r 45ca31374e9f -r 04f817fb0456 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/GraalCodeCacheProvider.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/GraalCodeCacheProvider.java	Mon Jul 22 11:58:00 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/GraalCodeCacheProvider.java	Mon Jul 22 12:12:57 2013 +0200
@@ -25,6 +25,8 @@
 import com.oracle.graal.api.code.*;
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.extended.*;
 
 /**
  * Graal-specific extensions for the code cache provider interface.
@@ -44,4 +46,13 @@
     InstalledCode addMethod(ResolvedJavaMethod method, CompilationResult compResult, Graph graph);
 
     void lower(Node n, LoweringTool tool);
+
+    /**
+     * Reconstruct the array index from a location node that was created as a lowering of an indexed
+     * access to an array.
+     * 
+     * @param location a location pointing to an element in an array
+     * @return a node that gives the index of the element
+     */
+    ValueNode reconstructArrayIndex(LocationNode location);
 }