In 2to3, execfile(file, globals, locals) is translated to 

exec(open(file).read(), globals, locals)

But that's not correct, as the actual file from the executed code gets
wrong with that.

The correct thing would be:

exec(compile(open(file).read(), file, 'exec'), globals, locals)

So that the name of the file remains correct in the module that's being run.