llvm-tf-3.0.3.1: example/Varargs.hs

module Main (main) where

import LLVM.ExecutionEngine (simpleFunction)
import LLVM.Core

import Foreign.Ptr (Ptr)
import Data.Word (Word8, Word32)


bldVarargs :: CodeGenModule (Function (Word32 -> IO ()))
bldVarargs =
   withStringNul "Hello\n" (\fmt1 ->
   withStringNul "A number %d\n" (\fmt2 ->
   withStringNul "Two numbers %d %d\n" (\fmt3 -> do
      printf <- newNamedFunction ExternalLinkage "printf" :: TFunction (Ptr Word8 -> VarArgs Word32)
      func <- createFunction ExternalLinkage $ \ x -> do

        tmp1 <- getElementPtr0 fmt1 (0::Word32, ())
        let p1 = castVarArgs printf :: Function (Ptr Word8 -> IO Word32)
        _ <- call p1 tmp1

        tmp2 <- getElementPtr0 fmt2 (0::Word32, ())
        let p2 = castVarArgs printf :: Function (Ptr Word8 -> Word32 -> IO Word32)
        _ <- call p2 tmp2 x

        tmp3 <- getElementPtr0 fmt3 (0::Word32, ())
        let p3 = castVarArgs printf :: Function (Ptr Word8 -> Word32 -> Word32 -> IO Word32)
        _ <- call p3 tmp3 x x

        ret ()
      return func
   )))

main :: IO ()
main = do
    initializeNativeTarget
    varargs <- simpleFunction bldVarargs
    varargs 42
    return ()