How hard can this be... when you request a pickup, the self-driving car begins driving to you, and a pin is placed on the map where it *thinks* it should pick you up. You review the pin, and move it to whatever door / street corner you want. The self-driving car then re-routes to pick you up where you placed the pin.
On future visits through the same provider, it will remember where you dropped the map pin and default to picking you up there. If you choose to move the pin again (say, you're coming out of a door the other side of the building) it then obeys that, and the app prompts you to give "friendly" names to those two points. Next time you choose to be picked up from the same vicinity, you are presented with a simple dropdown that offers you three options:
"The Green Door"
"The Other Side With The Cafe"
"Choose Another Location"
Am I missing something that makes this problem unsolvable with today's tech?