Whenever you get smoke from your adapter, unplug it as soon as possible and try not to use that adapter again. Because if any adapter generates smokes it simply means that something inside is burning and if not then, it also can explode anytime so better to take precaution from beginning only. Replace your adapter from Apple’s service centre.
Now whenever your Macbook Charger overheating or not showing any response at all then it means that charger’s temperature sensor is triggered because of over voltage problem. So just kindly un-plug your charger for 10-15 minutes and try to plug it again afterwards and it will be working again.
If you hear any voice while charging then it may cause because of poor cabling inside the adapter for this you can contact apple for MagSafe connector and replace your adapter.
Now coming to our main MacBook Charger heating problem, first thing you need to make sure that there is earthing enabled system in your house. If not then you need to contact an electrician in order to do that. Once you’re done with earthing try charging your MacBook again and you’ll see that now adapter is not heating up so badly like before. To know if earthing is enabled or not, plug your MacBook charger and start charging, now while charging touch the backside of your Mac or touch the near by side of Apple’s Logo; if you feel any vibration like current or something then earthing is not enabled and if you don’t feel any vibration then its completely earthing enabled system.
If still your adapter is getting hot badly then stop using your Mac while charging for 5-10 minutes and it should come down to normal. And once charger is back to normal, you can start using your Mac again.