Thanks for your help. Replying inline On Sun, Dec 5, 2010 at 1:28 PM, Henning Thielemann wrote:

On Sun, 5 Dec 2010, Lally Singh wrote:

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Hey all, I'm trying to get started generating LLVM code, but I'm getting a rather cryptic error.

Btw. there is haskell-llvm@projects.haskell.org

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buildReaderFun :: String -> CodeGenModule (Function (IO ())) buildReaderFun nm = do  puts <- newNamedFunction ExternalLinkage "puts" :: TFunction (Ptr Word8 -> IO Word32)  greetz <- createStringNul nm  func <- createFunction ExternalLinkage $ do   tmp <- getElementPtr0 greetz (0 :: Word32, ())

You have to add a type annotation to greetz like   (greetz :: Array D42 Word8)  which limits your string to a length of 42 bytes.

If you do not know the length, better use withStringNul. I implemented the current behavior, because the former implementation was unsafe.

I'm sorry, the type signature for withStringNul is over my head. withStringNul :: String -> (forall n. (Nat n) => Global (Array n Word8) -> CodeGenModule a) -> CodeGenModule a On the LLVM side, I'm looking to simply create a string constant I can pass in, such as ConstantArray::get(..). I *think* withStringNul will generate code to build a runtime-length determined string? Sorry, I'm a little thick.

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  call puts  tmp -- Throw away return value.   ret ()  return func

My attempts at figuring out what type-level has to do with this, and how to satisfy it have so far proven unsuccessful.

type-level provides type level integers, and thus allows for static checking of sizes, such as the number of bits of an integer type.

Thanks -- sorry -- I'm guessing it's to make sure we're generating valid code? Cheers, -Lally

On Sun, Dec 5, 2010 at 12:45 PM, Lally Singh wrote:

Is that how it's intended?

I think that's correct, (it at least fits the pattern for 'with' functions in Haskell). They're idiomatically used with syntax like this:

buildReaderFun :: String -> CodeGenModule (Function (IO ())) buildReaderFun nm = do  puts <- newNamedFunction ExternalLinkage "puts" :: TFunction (Ptr Word8 -> IO Word32)  withStringNul nm $ \greetz -> createFunction ExternalLinkage $ do          tmp <- getElementPtr greetz (0 :: Word32,(0 :: Word32, ()))          call puts  tmp -- Throw away return value.          ret ()