libgccjit-haskell

Example:

$ cabal run TutorialXX

{-# LANGUAGE ForeignFunctionInterface #-}
{- Ported from https://gcc.gnu.org/onlinedocs/jit/intro/tutorial01.html -}
module Main (main) where
import qualified GccJit
import GccJit.Utils (release)
import Foreign.Ptr
import Foreign.C (CString, newCString)
import System.Exit
import System.IO
type GreetFunction = CString -> IO ()
foreign import ccall "dynamic" mkFun :: FunPtr GreetFunction -> GreetFunction
unwrapOrDie :: IO (Maybe a) -> String -> IO a
unwrapOrDie x msg = do
 x' <- x
 case x' of
 Nothing -> die msg
 Just x'' -> return x''
createCode :: Ptr GccJit.Context -> IO ()
createCode ctxt = do
 {-
 Let's try to inject the equivalent of:
 void greet (const char *name)
 {
 printf ("hello %s\n", name);
 }
 -}
 voidType <- GccJit.contextGetType ctxt GccJit.Void
 constCharPtrType <- GccJit.contextGetType ctxt GccJit.ConstCharPtr
 paramName <- GccJit.contextNewParam ctxt nullPtr constCharPtrType "format"
 func <- GccJit.contextNewFunction ctxt nullPtr GccJit.FunctionExported voidType "greet" [paramName] False
 paramFormat <- GccJit.contextNewParam ctxt nullPtr constCharPtrType "format"
 intType <- GccJit.contextGetType ctxt GccJit.Int
 printFunc <- GccJit.contextNewFunction ctxt nullPtr GccJit.FunctionImported intType "printf" [paramFormat] True
 formatArg <- GccJit.contextNewStringLiteral ctxt "Hello %s!\n"
 nameArg <- GccJit.paramAsRValue paramName
 block <- unwrapOrDie (GccJit.functionNewBlock func Nothing) "NULL block"
 printCall <- GccJit.contextNewCall ctxt nullPtr printFunc [formatArg, nameArg]
 GccJit.blockAddEval block nullPtr printCall
 GccJit.blockEndWithVoidReturn block nullPtr
main :: IO ()
main = do
 -- Get a "context" object for working with the library.
 ctxt <- unwrapOrDie GccJit.contextAcquire "NULL ctxt"
 
 -- Set some options on the context.
 -- Let's see the code being generated, in assembler form.
 GccJit.setBoolOption ctxt GccJit.DumpGeneratedCode True
 -- Populate the context.
 createCode ctxt
 -- Compile the code.
 result <- unwrapOrDie (GccJit.contextCompile ctxt) "NULL result"
 -- Extract the generated code from "result".
 greet <- unwrapOrDie (GccJit.resultGetCode result "greet") "NULL greet"
 
 -- Now call the generated function:
 worldStr <- newCString "World"
 mkFun greet worldStr
 hFlush stdout
 release ctxt
 release result

License