How can you check where structure can generate without a lot of lag

I am currently attempting to generate a custom structure (a sort of hobbit hole) (MC 1.12.2).

I've managed to make a stone cube generate only on world generation.

Now I want to know if there is a way to test whether a structure can generate (e.g. in the side of a cliff) so all blocks it generates in are stone apart from the front which will be air (for an entrance).

I know I can do this by testing every block it will generate in but this will take a long time during world generation and will be very difficult to code.

Please could someone help me if there is an easier way

Edited March 23, 20205 yr by Spirfire972