Always clear the source location when moving locations.

Author: woess

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

@@ -393,10 +393,8 @@ static RemovePlan prepareRemove(Shape shapeBefore, Shape shapeAfter, Property re
         if (canMoveInPlace) {
             if (moves.isEmpty()) {
                 Location removedPropertyLoc = removedProperty.getLocation();
-                if (!removedPropertyLoc.isPrimitive()) {
-                    // Use a no-op move to clear the location of the removed property.
-                    moves.add(new Move(removedPropertyLoc, removedPropertyLoc, 0, 0));
-                }
+                // Use a no-op move to clear the location of the removed property.
+                moves.add(new Move(removedPropertyLoc, removedPropertyLoc, 0, 0));
             } else if (!isSorted(moves)) {
                 moves.sort(Move::compareTo);
             }
@@ -415,6 +413,10 @@ private static boolean isSorted(List<Move> moves) {
         return true;
     }
 
+    /**
+     * Moves the value from one location to another, and clears the from location. If both locations
+     * are the same, only clears the location.
+     */
     private static final class Move implements Comparable<Move> {
         private final Location fromLoc;
         private final Location toLoc;
@@ -432,10 +434,10 @@ private static final class Move implements Comparable<Move> {
         }
 
         void perform(DynamicObject obj) {
-            if (fromLoc == toLoc) {
-                return;
+            if (fromLoc != toLoc) {
+                performSet(obj, performGet(obj));
             }
-            performSet(obj, performGet(obj));
+            clear(obj);
         }
 
         Object performGet(DynamicObject obj) {
@@ -446,8 +448,14 @@ void performSet(DynamicObject obj, Object value) {
             toLoc.setSafe(obj, value, false, true);
         }
 
-        void clear(DynamicObject obj) {
-            // clear location to avoid memory leak
+        Object performGetAndClear(DynamicObject obj) {
+            Object value = performGet(obj);
+            clear(obj);
+            return value;
+        }
+
+        private void clear(DynamicObject obj) {
+            // clear the location to avoid memory leak AND kill the location identity
             fromLoc.clear(obj);
         }
 
@@ -498,25 +506,19 @@ void perform(DynamicObject object) {
                     moves[i].perform(object);
                 }
 
-                if (moves.length > 0) {
-                    moves[0].clear(object);
-                }
-
                 DynamicObjectSupport.trimToSize(object, shapeBefore, shapeAfter);
-                object.setShape(shapeAfter);
             } else {
                 // we cannot perform the moves in place, so stash away the values
                 Object[] tempValues = new Object[moves.length];
                 for (int i = moves.length - 1; i >= 0; i--) {
-                    tempValues[i] = moves[i].performGet(object);
-                    moves[i].clear(object);
+                    tempValues[i] = moves[i].performGetAndClear(object);
                 }
                 DynamicObjectSupport.resize(object, shapeBefore, shapeAfter);
                 for (int i = moves.length - 1; i >= 0; i--) {
                     moves[i].performSet(object, tempValues[i]);
                 }
-                object.setShape(shapeAfter);
             }
+            object.setShape(shapeAfter);
         }
 
         @TruffleBoundary