8373202: [lworld] ObjectReference.equals should follow == semantics for value objects

src/java.se/share/data/jdwp/jdwp.spec

@@ -1801,6 +1801,33 @@ JDWP "Java(tm) Debug Wire Protocol"
             (Error VM_DEAD)
         )
     )
+    (Command IsSameObject=11
+        "Determines whether two objects refer to the same Java object."
+        (Out
+            (object object1 "The object ID")
+            (object object2 "The object ID")
+        )
+        (Reply
+            (boolean isSameObject "true if the objects refer to the same Java object; false otherwise")
+        )
+        (ErrorSet
+            (Error INVALID_OBJECT)
+            (Error VM_DEAD)
+        )
+    )
+    (Command ObjectHashCode=12
+        "Returns hash code for an object."
+        (Out
+            (object object "The object ID")
+        )
+        (Reply
+            (int hashCode "hash code value for the object")
+        )
+        (ErrorSet
+            (Error INVALID_OBJECT)
+            (Error VM_DEAD)
+        )
+    )
 )
 
 (CommandSet StringReference=10

src/jdk.jdi/share/classes/com/sun/tools/jdi/ObjectReferenceImpl.java

@@ -147,8 +147,16 @@ public boolean vmNotSuspended(VMAction action) {
 
     public boolean equals(Object obj) {
         if (obj instanceof ObjectReferenceImpl other) {
-            return (ref() == other.ref()) &&
-                    super.equals(obj);
+            if (ref() == other.ref() && super.equals(obj)) {
+                return true;
+            }
+            // We can get equal value objects with different IDs.
+            // TODO: do it only for value objects.
+            try {
+                return JDWP.ObjectReference.IsSameObject.process(vm, this, other).isSameObject;
+            } catch (JDWPException exc) {
+                throw exc.toJDIException();
+            }
         } else {
             return false;
         }

src/jdk.jdwp.agent/share/native/libjdwp/ObjectReferenceImpl.c

@@ -357,6 +357,63 @@ referringObjects(PacketInputStream *in, PacketOutputStream *out)
     return JNI_TRUE;
 }
 
+static jboolean
+isSameObjectImpl(PacketInputStream *in, PacketOutputStream *out)
+{
+    jlong id1;
+    jlong id2;
+    jobject ref1;
+    jobject ref2;
+    JNIEnv *env;
+
+    env = getEnv();
+    id1 = inStream_readObjectID(in);
+    id2 = inStream_readObjectID(in);
+    if (inStream_error(in)) {
+        return JNI_TRUE;
+    }
+
+    if (id1 == NULL_OBJECT_ID || id2 == NULL_OBJECT_ID) {
+        outStream_setError(out, JDWP_ERROR(INVALID_OBJECT));
+        return JNI_TRUE;
+    }
+
+    ref1 = commonRef_idToRef(env, id1);
+    ref2 = commonRef_idToRef(env, id2);
+    (void)outStream_writeBoolean(out, isSameObject(env, ref1, ref2));
+
+    commonRef_idToRef_delete(env, ref1);
+    commonRef_idToRef_delete(env, ref2);
+
+    return JNI_TRUE;
+}
+
+static jboolean
+objectHashCodeImpl(PacketInputStream *in, PacketOutputStream *out)
+{
+    jlong id;
+    jobject ref;
+    JNIEnv *env;
+
+    env = getEnv();
+    id = inStream_readObjectID(in);
+    if (inStream_error(in)) {
+        return JNI_TRUE;
+    }
+
+    if (id == NULL_OBJECT_ID) {
+        outStream_setError(out, JDWP_ERROR(INVALID_OBJECT));
+        return JNI_TRUE;
+    }
+
+    ref = commonRef_idToRef(env, id);
+    (void)outStream_writeInt(out, objectHashCode(ref));
+
+    commonRef_idToRef_delete(env, ref);
+
+    return JNI_TRUE;
+}
+
 Command ObjectReference_Commands[] = {
     {referenceType, "ReferenceType"},
     {getValues, "GetValues"},
@@ -367,7 +424,9 @@ Command ObjectReference_Commands[] = {
     {disableCollection, "DisableCollection"},
     {enableCollection, "EnableCollection"},
     {isCollected, "IsCollected"},
-    {referringObjects, "ReferringObjects"}
+    {referringObjects, "ReferringObjects"},
+    {isSameObjectImpl, "IsSameObject"},
+    {objectHashCodeImpl, "ObjectHashCode"}
 };
 
 DEBUG_DISPATCH_DEFINE_CMDSET(ObjectReference)