GHC haskell has precise ghc via the llvm and native code backends both. That said, it doesn't (i think) use any of the llvm hooks. Instead the gc machinery is

GHC haskell has precise ghc via the llvm and native code backends both. That said, it doesn't (i think) use any of the llvm hooks. Instead the gc machinery is baked into the relevant primops. The hand written primops can be found here https://github.com/ghc/ghc/blob/master/rts/PrimOps.cmm#L51 https://github.com/ghc/ghc/blob/master/rts/PrimOps.cmm#L51 (the low level primops that aren't compiler generated are written in cmm, a ghc specific dialect of c minus minus. )