avoid setting the special argument if we don't need it

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinFunctions.java

@@ -570,7 +570,10 @@ Object execCustomGlobalsGlobalLocals(Object source, PDict globals, @SuppressWarn
             PCode code = createAndCheckCode(source);
             Object[] args = PArguments.create();
             setCustomGlobals(globals, setBuiltins, args);
-            setCustomLocals(args, globals);
+            // here, we don't need to set any locals, since the {Write,Read,Delete}NameNodes will
+            // fall back (like their CPython counterparts) to writing to the globals. We only need
+            // to ensure that the `locals()` call still gives us the globals dict
+            PArguments.setPFrame(args, factory().createPFrame(globals));
             return indirectCallNode.call(code.getRootCallTarget(), args);
         }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/control/TopLevelExceptionHandler.java

@@ -221,7 +221,6 @@ private Object run(VirtualFrame frame) {
             PythonModule mainModule = pythonContext.getMainModule();
             PHashingCollection mainDict = mainModule.getDict();
             PArguments.setGlobals(arguments, mainModule);
-            PArguments.setSpecialArgument(arguments, mainDict);
             PArguments.setPFrame(arguments, pythonContext.getCore().factory().createPFrame(mainDict));
         }
         return innerCallTarget.call(arguments);