Extract reusePropertyLookup() in ObsolescenceStrategy

Author: eregon

truffle/src/com.oracle.truffle.api.object.test/src/com/oracle/truffle/api/object/test/ObjectModelRegressionTest.java

@@ -142,6 +142,27 @@ public void testDefinePropertyWithFlagsChangeAndFinalInvalidation() {
         assertObjectLocation(b.getShape().getProperty("x").getLocation());
     }
 
+    @Test
+    public void testAddNewPropertyOnObsoleteShape() {
+        Shape emptyShape = newEmptyShape();
+        DynamicObject a = newInstance(emptyShape);
+        DynamicObject b = newInstance(emptyShape);
+
+        DynamicObjectLibrary library = createLibrary(DynamicObjectLibrary.class, a);
+
+        library.put(a, "x", 1);
+        library.put(b, "x", 1);
+        library.put(b, "x", "");
+        assertTrue(b.getShape().isValid()); // updated by put()
+        assertFalse(a.getShape().isValid()); // obsolete
+        library.put(a, "y", 2); // put on obsolete shape
+        assertTrue(a.getShape().isValid());
+
+        assertEquals(1, library.getOrDefault(a, "x", null));
+        assertEquals("", library.getOrDefault(b, "x", null));
+        assertEquals(2, library.getOrDefault(a, "y", null));
+    }
+
     @Test
     public void testRemovePropertyOnObsoleteShape() {
         Shape emptyShape = newEmptyShape();

truffle/src/com.oracle.truffle.api.object/src/com/oracle/truffle/api/object/ObsolescenceStrategy.java

@@ -191,16 +191,11 @@ private boolean putGenericSlowPath(DynamicObject object, Object key, Object valu
         CompilerAsserts.neverPartOfCompilation();
         updateShape(object);
         Shape oldShape;
-        Property existingProperty;
         Shape newShape;
         Property property;
         do {
             oldShape = object.getShape();
-            if (oldShape == initialShape) {
-                existingProperty = propertyOfInitialShape;
-            } else {
-                existingProperty = oldShape.getProperty(key);
-            }
+            final Property existingProperty = reusePropertyLookup(key, initialShape, propertyOfInitialShape, oldShape);
             if (existingProperty == null) {
                 if (Flags.isSetExisting(putFlags)) {
                     return false;
@@ -235,6 +230,15 @@ private boolean putGenericSlowPath(DynamicObject object, Object key, Object valu
         return true;
     }
 
+    static Property reusePropertyLookup(Object key, Shape cachedShape, Property cachedProperty, Shape updatedShape) {
+        assert cachedProperty == null || cachedProperty.getKey().equals(key);
+        if (updatedShape == cachedShape) {
+            return cachedProperty;
+        } else {
+            return updatedShape.getProperty(key);
+        }
+    }
+
     Shape defineProperty(Shape shape, Object key, Object value, int flags) {
         return defineProperty(shape, key, value, flags, Flags.DEFAULT);
     }