added deleteDict to PythonObjectLibrary

Author: tomasstupka

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/PythonAbstractNativeObject.java

@@ -169,6 +169,12 @@ public void setDict(PDict value) throws UnsupportedMessageException {
         throw UnsupportedMessageException.create();
     }
 
+    @ExportMessage
+    @SuppressWarnings({"static-method", "unused"})
+    public void deleteDict() throws UnsupportedMessageException {
+        throw UnsupportedMessageException.create();
+    }
+
     @ExportMessage
     public Object asIndexWithState(ThreadState threadState,
                     @CachedLibrary("this") PythonObjectLibrary plib,

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/object/PythonObject.java

@@ -184,6 +184,11 @@ public final void setDict(PDict dict,
         dylib.put(this, DICT, dict);
     }
 
+    @ExportMessage
+    public final void deleteDict(@Shared("dylib") @CachedLibrary(limit = "4") DynamicObjectLibrary dylib) {
+        dylib.put(this, DICT, null);
+    }
+
     /* needed for some guards in exported messages of subclasses */
     public static int getCallSiteInlineCacheMaxDepth() {
         return PythonOptions.getCallSiteInlineCacheMaxDepth();

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/object/PythonObjectLibrary.java

@@ -121,6 +121,14 @@ public void setDict(Object receiver, PDict dict) throws UnsupportedMessageExcept
         throw UnsupportedMessageException.create();
     }
 
+    /**
+     * Delete the {@code __dict__} attribute of the object
+     */
+    @Abstract(ifExported = "hasDict")
+    public void deleteDict(Object receiver) throws UnsupportedMessageException {
+        throw UnsupportedMessageException.create();
+    }
+
     /**
      * @return the Python type of the receiver
      */