IRScript script = new IRScript("__file__", file, rootNode.getStaticScope());
IRClass rootClass = script.getRootClass();
IRMethod rootMethod = rootClass.getRootMethod();
// Debug info: record file name
rootMethod.addInstr(new FilenameInstr(file));
// add a "self" recv here
// TODO: is this right?
rootMethod.addInstr(new ReceiveSelfInstruction(getSelf(rootMethod)));