Get current filename in Babel Plugin?

I'm attempting to write a plugin for babel, and am needing the filename of the current file that is being parsed. I know the lines of the code are passed in, but I haven't managed to find a reference to the filename. Any help??

For instance given this code what could I do

export default function({ types: t }) {
  return {
    visitor: {
      Identifier(path) {
       // something here??
      }
    }
  };
}