If China and other countries were to outlaw cheap labor, What effects would it have around the world?

Oh, none. None at all. No-one would notice. It just wouldn't be a very important thing at all. Hope this helped.

Prices would rise, China would not be as competitive and manufacturing would return to more local markets or diversify to countries that did not outlaw cheap labour. There could be a boom in some developing countries. But don't expect it to happen while the west still wants shiny blocks of glass and plastic in order to share pictures of their breakfasts.

The fact that something gets outlawed doesn't mean that it will disappear.

But whatever you do to labour laws - unilaterally or internationally - it's a logical certainty that some market somewhere on Earth will offer the cheapest labour. It's pretty certain that somewhere else will want to compete...

Oh, and how exactly do you define "Cheap" here?