added ConstantReflectionProvider.identityHashCode

Author: dougxc

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/HotSpotConstantReflectionProvider.java

@@ -22,10 +22,6 @@
  */
 package jdk.vm.ci.hotspot;
 
-import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
-
-import java.util.Objects;
-
 import jdk.vm.ci.common.JVMCIError;
 import jdk.vm.ci.meta.Constant;
 import jdk.vm.ci.meta.ConstantReflectionProvider;
@@ -36,6 +32,10 @@
 import jdk.vm.ci.meta.ResolvedJavaField;
 import jdk.vm.ci.meta.ResolvedJavaType;
 
+import java.util.Objects;
+
+import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
+
 /**
  * HotSpot implementation of {@link ConstantReflectionProvider}.
  */
@@ -190,4 +190,16 @@ public Constant asObjectHub(ResolvedJavaType type) {
             throw JVMCIError.unimplemented();
         }
     }
+
+    @Override
+    public Integer identityHashCode(JavaConstant constant) {
+        JavaKind kind = Objects.requireNonNull(constant).getJavaKind();
+        if (kind != JavaKind.Object) {
+            throw new IllegalArgumentException("Constant has unexpected kind " + kind + ": " + constant);
+        } else if (constant.isNull()) {
+            /* System.identityHashCode is specified to return 0 when passed null. */
+            return 0;
+        }
+        return ((HotSpotObjectConstant) constant).getIdentityHashCode();
+    }
 }

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/HotSpotObjectConstantImpl.java

@@ -22,14 +22,14 @@
  */
 package jdk.vm.ci.hotspot;
 
-import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
-import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE;
-
 import jdk.vm.ci.meta.Assumptions;
 import jdk.vm.ci.meta.JavaConstant;
 import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.ResolvedJavaType;
 
+import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
+import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE;
+
 /**
  * Represents a constant non-{@code null} object reference, within the compiler and across the
  * compiler/runtime interface.
@@ -57,20 +57,11 @@ public boolean isCompressible() {
         return !compressed;
     }
 
-    @Override
-    public abstract JavaConstant compress();
-
-    @Override
-    public abstract JavaConstant uncompress();
-
     @Override
     public HotSpotResolvedObjectType getType() {
         return runtime().reflection.getType(this);
     }
 
-    @Override
-    public abstract int getIdentityHashCode();
-
     private boolean isFullyInitializedConstantCallSite() {
         if (!runtime().getConstantCallSite().isInstance(this)) {
             return false;

src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/meta/ConstantReflectionProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -71,15 +71,15 @@ public interface ConstantReflectionProvider {
     /**
      * Converts the given {@link JavaKind#isPrimitive() primitive} constant to a boxed
      * {@link JavaKind#Object object} constant, according to the Java boxing rules. Returns
-     * {@code null} if the source is is not a primitive constant, or the boxed value is not
+     * {@code null} if the source is not a primitive constant, or the boxed value is not
      * available at this point.
      */
     JavaConstant boxPrimitive(JavaConstant source);
 
     /**
      * Converts the given {@link JavaKind#Object object} constant to a {@link JavaKind#isPrimitive()
      * primitive} constant, according to the Java unboxing rules. Returns {@code null} if the source
-     * is is not an object constant that can be unboxed, or the unboxed value is not available at
+     * is not an object constant that can be unboxed, or the unboxed value is not available at
      * this point.
      */
     JavaConstant unboxPrimitive(JavaConstant source);
@@ -116,4 +116,15 @@ public interface ConstantReflectionProvider {
      * type representation which is typically stored in the object header.
      */
     Constant asObjectHub(ResolvedJavaType type);
+
+    /**
+     * Gets the identity hash code of the object value represented by {@code constant}.
+     * <p>
+     * For the {@link JavaConstant#isNull() null constant}, this method returns zero as specified by
+     * {@link System#identityHashCode(Object)}.
+     *
+     * @throws NullPointerException if {@code constant == null}
+     * @throws IllegalArgumentException if {@code constant.getJavaKind() != JavaKind.Object}
+     */
+    Integer identityHashCode(JavaConstant constant);
 }

test/hotspot/jtreg/compiler/jvmci/jdk.vm.ci.runtime.test/src/jdk/vm/ci/runtime/test/TestConstantReflectionProvider.java

@@ -41,7 +41,13 @@
 import java.lang.reflect.Array;
 import java.util.List;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
  * Tests for {@link ConstantReflectionProvider}. It assumes an implementation of the interface that
@@ -92,6 +98,31 @@ static class BoxedConstants {
         static final Boolean BOOL_CONST = true;
     }
 
+    @Test
+    public void identityHashCodeTest() {
+        try {
+            constantReflection.identityHashCode(null);
+            fail("Expected NullPointerException");
+        } catch (NullPointerException e) {
+            // Expected
+        }
+        assertEquals(Integer.valueOf(0), constantReflection.identityHashCode(JavaConstant.NULL_POINTER));
+        for (ConstantValue cv : constants()) {
+            if (cv.value.getJavaKind() != JavaKind.Object) {
+                try {
+                    constantReflection.identityHashCode(cv.value);
+                    fail("Expected IllegalArgumentException for " + cv);
+                } catch (IllegalArgumentException e) {
+                    // Expected
+                }
+            } else if (cv.boxed != cv.value) {
+                int expect = System.identityHashCode(cv.boxed);
+                int actual = constantReflection.identityHashCode(cv.value);
+                assertEquals(cv.toString(), expect, actual);
+            }
+        }
+    }
+
     @Test
     public void boxTest() {
         for (ConstantValue cv : constants()) {