Haskell JIT Example
Tiny example of building a intermediate language that JIT compiles Haskell DSL into x86-64 machine code.
The factorial function can be written in assembly, taking the input value in
%rcx and computing the resulting value in
.global main main: mov rcx, 5 mov rax, 1 .factor: mul rcx loop .factor ret
In our Haskell logic we compose these operations inside of the
factorial :: Int64 -> X86 () factorial n = do mov rcx (I n) mov rax (I 1) l1 <- label mul rcx loop l1 ret
The resulting logic can be JIT compiled inside of Haskell and invoked from inside the Haskell runtime by calling out to the JIT'd memory.
main :: IO () main = do let jitsize = 256*1024 mem <- allocateMemory jitsize let jitm = assemble mem (factorial 5) case jitm of Left err -> putStrLn err Right jitst -> do let machCode = _mach jitst fn <- jit mem machCode res <- fn putStrLn $ "Result: " <> show res
The machine code is generated.
48 c7 c1 05 00 00 00 48 c7 c0 01 00 00 00 48 f7 e1 e2 fc c3
And executed to yield the result:
Released under the MIT License. Copyright (c) 2016, Stephen Diehl