From 18c4b939a6ba1099cd7296b839428f829533f3c8 Mon Sep 17 00:00:00 2001
From: Luke Lau <luke_lau@icloud.com>
Date: Sun, 2 Jun 2019 17:39:47 +0100
Subject: [PATCH] Detect and remove __anon_exprs in repl

You might have noticed that when entering in top-level expressions you
end up getting duplicate __anon_expr.1, __anon_expr.2s etc. Since we
don't want these anonymous functions to stick around, in this commit
we're detecting them and then removing them once we're done.

We also only want to run the JIT whenever the user has entered a
top-level expression, so we've also sketched that out.
---
 Main.hs  | 50 ++++++++++++++++++++++++++++++++++++++++----------
 Utils.hs |  8 ++++++++
 2 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/Main.hs b/Main.hs
index c3f9292..bc7c307 100644
--- a/Main.hs
+++ b/Main.hs
@@ -2,6 +2,7 @@
 
 import AST as K -- K for Kaleidoscope
 import Utils
+import Control.Monad
 import Control.Monad.Trans.Class
 import Control.Monad.Trans.Reader
 import Control.Monad.IO.Class
@@ -17,6 +18,8 @@ import LLVM.AST.Type as Type
 import LLVM.Context
 import LLVM.IRBuilder
 import LLVM.Module
+import LLVM.OrcJIT
+import LLVM.OrcJIT.CompileLayer
 import LLVM.PassManager
 import LLVM.Pretty
 import LLVM.Target
@@ -24,13 +27,29 @@ import System.IO
 import System.IO.Error
 import Text.Read (readMaybe)
 
+data JITEnv = JITEnv
+  { jitEnvContext :: Context
+  , jitEnvCompileLayer :: IRCompileLayer ObjectLinkingLayer
+  , jitEnvModuleKey :: ModuleKey
+  }
+
 main :: IO ()
-main = do
-  withContext $ \ctx -> withHostTargetMachineDefault $ \tm -> do
-    ast <- runReaderT (buildModuleT "main" repl) ctx
+main =
+  withContext $ \ctx -> withHostTargetMachineDefault $ \tm ->
+    withExecutionSession $ \exSession ->
+      withSymbolResolver exSession (SymbolResolver symResolver) $ \symResolverPtr ->
+        withObjectLinkingLayer exSession (const $ pure symResolverPtr) $ \linkingLayer ->
+          withIRCompileLayer linkingLayer tm $ \compLayer ->
+            withModuleKey exSession $ \mdlKey -> do
+              let env = JITEnv ctx compLayer mdlKey
+              _ast <- runReaderT (buildModuleT "main" repl) env
               return ()
 
-repl :: ModuleBuilderT (ReaderT Context IO) ()
+-- This can eventually be used to resolve external functions, e.g. a stdlib call
+symResolver :: MangledSymbol -> IO (Either JITSymbolError JITSymbol)
+symResolver sym = undefined
+
+repl :: ModuleBuilderT (ReaderT JITEnv IO) ()
 repl = do
   liftIO $ hPutStr stderr "ready> "
   mline <- liftIO $ catchIOError (Just <$> getLine) eofHandler
@@ -40,21 +59,32 @@ repl = do
       case readMaybe l of
         Nothing ->  liftIO $ hPutStrLn stderr "Couldn't parse"
         Just ast -> do
-          hoist $ buildAST ast
-          mostRecentDef >>= liftIO . Text.hPutStrLn stderr . ppll
+          anon <- isAnonExpr <$> hoist (buildAST ast)
+          def <- mostRecentDef
           
-          ast <- moduleSoFar "main"
-          ctx <- lift ask
-          liftIO $ withModuleFromAST ctx ast $ \mdl -> do
+          llvmAst <- moduleSoFar "main"
+          ctx <- lift $ asks jitEnvContext
+          env <- lift ask
+          liftIO $ withModuleFromAST ctx llvmAst $ \mdl -> do
+            Text.hPutStrLn stderr $ ppll def
             let spec = defaultCuratedPassSetSpec { optLevel = Just 3 }
             -- this returns true if the module was modified
             withPassManager spec $ flip runPassManager mdl
-            Text.hPutStrLn stderr . ("\n" <>) . ppllvm =<< moduleAST mdl
+            when anon (jit env mdl >>= hPrint stderr)
+
+          when anon (removeDef def)
       repl
   where
     eofHandler e
       | isEOFError e = return Nothing
       | otherwise = ioError e
+    isAnonExpr (ConstantOperand (GlobalReference _ "__anon_expr")) = True
+    isAnonExpr _ = False
+
+jit :: JITEnv -> Module -> IO Double
+jit JITEnv{jitEnvCompileLayer=compLayer, jitEnvModuleKey=mdlKey} mdl =
+  withModule compLayer mdlKey mdl $
+    return 0
 
 type Binds = Map.Map String Operand
 
diff --git a/Utils.hs b/Utils.hs
index 3bd3b37..cd325a4 100644
--- a/Utils.hs
+++ b/Utils.hs
@@ -6,6 +6,7 @@ module Utils where
 import Control.Monad.Trans.State
 import Data.ByteString.Short (ShortByteString)
 import Data.Functor.Identity
+import Data.List
 import LLVM.AST
 import LLVM.IRBuilder.Module
 import LLVM.IRBuilder.Internal.SnocList
@@ -16,6 +17,13 @@ moduleSoFar nm = do
   let ds = getSnocList (builderDefs s)
   return $ defaultModule { moduleName = nm, moduleDefinitions = ds }
 
+removeDef :: MonadModuleBuilder m => Definition -> m ()
+removeDef def = liftModuleState (modify update)
+  where
+    update (ModuleBuilderState defs typeDefs) =
+      let newDefs = SnocList (delete def (getSnocList defs))
+      in ModuleBuilderState newDefs typeDefs
+
 mostRecentDef :: Monad m => ModuleBuilderT m Definition
 mostRecentDef = last . getSnocList . builderDefs <$> liftModuleState get
 
-- 
2.30.2