# HG changeset patch
# User Stefan Anzinger <stefan.anzinger@oracle.com>
# Date 1430839847 -7200
# Node ID 39ee26e852562e2a5928f42960f70599771cf96c
# Parent  e11eb6ec180e7b68c657b6ba68f8157e38ec75a0
Use boxed cache in HotSpotConstantpool instead of synchronization

diff -r e11eb6ec180e -r 39ee26e85256 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotConstantPool.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotConstantPool.java	Mon May 04 23:15:42 2015 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotConstantPool.java	Tue May 05 17:30:47 2015 +0200
@@ -115,13 +115,23 @@
         }
     }
 
+    private static class LookupTypeCacheElement {
+        int lastCpi = Integer.MIN_VALUE;
+        JavaType javaType;
+
+        public LookupTypeCacheElement(int lastCpi, JavaType javaType) {
+            super();
+            this.lastCpi = lastCpi;
+            this.javaType = javaType;
+        }
+    }
+
     /**
      * Reference to the C++ ConstantPool object.
      */
     private final long metaspaceConstantPool;
     private final Object[] cache;
-    private ResolvedJavaType lastType;
-    private int lastTypeCpi = Integer.MIN_VALUE;
+    private volatile LookupTypeCacheElement lastLookupType;
 
     public HotSpotConstantPool(long metaspaceConstantPool) {
         this.metaspaceConstantPool = metaspaceConstantPool;
@@ -489,22 +499,15 @@
 
     @Override
     public JavaType lookupType(int cpi, int opcode) {
-        if (cpi == this.lastTypeCpi) {
-            synchronized (this) {
-                if (cpi == this.lastTypeCpi) {
-                    return this.lastType;
-                }
-            }
+        final LookupTypeCacheElement elem = this.lastLookupType;
+        if (elem != null && elem.lastCpi == cpi) {
+            return elem.javaType;
+        } else {
+            final long metaspacePointer = runtime().getCompilerToVM().lookupKlassInPool(metaspaceConstantPool, cpi);
+            JavaType result = getJavaType(metaspacePointer);
+            this.lastLookupType = new LookupTypeCacheElement(cpi, result);
+            return result;
         }
-        final long metaspacePointer = runtime().getCompilerToVM().lookupKlassInPool(metaspaceConstantPool, cpi);
-        JavaType result = getJavaType(metaspacePointer);
-        if (result instanceof ResolvedJavaType) {
-            synchronized (this) {
-                this.lastType = (ResolvedJavaType) result;
-                this.lastTypeCpi = cpi;
-            }
-        }
-        return result;
     }
 
     @Override