hhlo-0.2.0.0: examples/12-while.hs

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Example 12: While loop — count from 0 to 5.
--
-- Build and run with:
--   LD_LIBRARY_PATH=deps/pjrt:$LD_LIBRARY_PATH cabal run example-while

module Main where

import qualified Data.Text as T
import qualified Data.Vector.Storable as V
import Foreign.C
import Foreign.Marshal.Alloc (alloca)
import Foreign.Ptr
import Foreign.Storable (peek)

import HHLO.Core.Types
import HHLO.EDSL.Ops
import HHLO.IR.AST (FuncArg(..), TensorType(..))
import HHLO.IR.Builder
import HHLO.IR.Pretty
import HHLO.Runtime.PJRT.FFI
import HHLO.Runtime.PJRT.Types
import HHLO.Runtime.PJRT.Error
import HHLO.Runtime.Compile
import HHLO.Runtime.Execute
import HHLO.Runtime.Buffer

main :: IO ()
main = do
    putStrLn "=== Example 12: While Loop ==="

    api <- withCString "deps/pjrt/libpjrt_cpu.so" $ \path -> do
        alloca $ \apiPtrPtr -> do
            checkError nullPtr $ c_pjrtLoadPlugin path apiPtrPtr
            PJRTApi <$> peek apiPtrPtr

    client <- alloca $ \clientPtrPtr -> do
        checkError (unApi api) $ c_pjrtCreateClient (unApi api) clientPtrPtr
        PJRTClient <$> peek clientPtrPtr

    let program = do
            initVal <- constant @'[] @'F32 0.0
            limit   <- constant @'[] @'F32 5.0
            one     <- constant @'[] @'F32 1.0

            result <- whileLoop initVal
                (\loopVar -> lessThan loopVar limit)
                (\loopVar -> add loopVar one)

            return result

    let modu = moduleFromBuilder @'[] @'F32 "main" [] program

    putStrLn "Generated MLIR:"
    putStrLn (T.unpack $ render modu)

    putStrLn "\nExecuting..."
    exec <- compile api client (render modu)
    [bufR] <- execute api exec []
    result <- fromDeviceF32 api bufR 1

    putStrLn $ "Result: " ++ show (V.toList result) ++ " (expected: [5.0])"

    checkError (unApi api) $ c_pjrtClientDestroy (unApi api) (unClient client)
  where
    unApi (PJRTApi p) = p
    unClient (PJRTClient p) = p