fib-llvm-jit.hs

import Data.Int
import Data.Time.Clock.POSIX
import LLVM.Core
import LLVM.ExecutionEngine
import System.Environment

main :: IO ()
main = do
    as <- getArgs
    let num =
            case as of
                [] -> 20
                [x] -> read x

    initializeNativeTarget
    f <- simpleFunction fib

    b <- getPOSIXTime
    f num >>= print
    a <- getPOSIXTime
    print (a - b)

fib :: CodeGenModule (Function (Int32 -> IO Int32))
fib = do
    f <- newFunction ExternalLinkage
    defineFunction f $ \n -> do
        bottom <- newBasicBlock
        recurse <- newBasicBlock

        cmp <- icmp IntSLT n (2 :: Int32)
        condBr cmp bottom recurse

        defineBasicBlock bottom
        ret (1 :: Int32)

        defineBasicBlock recurse
        atmp <- sub n (2 :: Int32)
        btmp <- sub n (1 :: Int32)
        afib <- call f atmp
        bfib <- call f btmp
        res <- add afib bfib
        ret res

    return f