"When GHC reaches a call to one of these primops, it automatically replaces it with the real implementation for you, which will be some assembly code, LLVM code

"When GHC reaches a call to one of these primops, it automatically replaces it with the real implementation for you, which will be some assembly code, LLVM code, or something similar." This, plus the "magic hashes" reminds me a great deal of Urbit's hinting syntax for jet propulsion (associating a body of high-level code in Hoon with an alternative (presumably low-level) implementation).