Where is the ARC impl code in swift

Hello everyone! I am a student , and I currently learn about the swift source code ,
I interesting in the arc (automatic reference count), but I didnt find the source code about arc in the swift repo ( apple/swift: The Swift Programming Language (github.com)):sob:, I want know where the source code about arc , thanks very much. :heart: :heart: :heart:

Are you asking about the basic runtime routines for refcounting or about the compiler logic that automates and/or optimizes calls to them?

Both of them :heart: :heart: :heart:

RefCount.h is a good place to start for the runtime calls. Good luck with it, it's a lot to take in.