[Haskell-cafe] LLVM, getElementPtr?
lally.singh at gmail.com
Sun Dec 5 21:45:17 CET 2010
No wait, sorry.
buildReaderFun :: String -> CodeGenModule (Function (IO ()))
buildReaderFun nm = do
puts <- newNamedFunction ExternalLinkage "puts" :: TFunction (Ptr
Word8 -> IO Word32)
let callPuts greetz = createFunction ExternalLinkage $ do
tmp <- getElementPtr greetz (0 :: Word32,(0 :: Word32, ()))
call puts tmp -- Throw away return value.
withStringNul nm callPuts
Is that how it's intended?
On Sun, Dec 5, 2010 at 3:35 PM, Lally Singh <lally.singh at gmail.com> wrote:
> Thanks for your help. Replying inline
> On Sun, Dec 5, 2010 at 1:28 PM, Henning Thielemann
> <lemming at henning-thielemann.de> wrote:
>> On Sun, 5 Dec 2010, Lally Singh wrote:
>>> Hey all, I'm trying to get started generating LLVM code, but I'm
>>> getting a rather cryptic error.
>> Btw. there is haskell-llvm at projects.haskell.org
>>> 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
> 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.
>>> 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?
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