From 3120362ee3a1be4915ff6c2802b4dea597ea9cfb Mon Sep 17 00:00:00 2001
From: Sven Keidel <svenkeidel@gmail.com>
Date: Thu, 24 Jan 2019 16:02:13 +0100
Subject: [PATCH] Add tracing to fixpoint algorithm

---
 .../Arrow/Transformer/Abstract/Fixpoint.hs    | 44 ++++++++++++++++++-
 lib/src/Data/Abstract/Terminating.hs          |  2 +-
 stratego/test/SortSemanticsSpec.hs            |  2 +-
 3 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/lib/src/Control/Arrow/Transformer/Abstract/Fixpoint.hs b/lib/src/Control/Arrow/Transformer/Abstract/Fixpoint.hs
index c5f381f5..d003c88e 100644
--- a/lib/src/Control/Arrow/Transformer/Abstract/Fixpoint.hs
+++ b/lib/src/Control/Arrow/Transformer/Abstract/Fixpoint.hs
@@ -10,6 +10,7 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE CPP #-}
 module Control.Arrow.Transformer.Abstract.Fixpoint(Fix,FixT,runFixT,runFixT',runFixT'',liftFixT) where
 
 import           Prelude hiding (id,(.),lookup)
@@ -35,6 +36,13 @@ import qualified Data.Abstract.Widening as W
 import           Data.Abstract.StackWidening (StackWidening)
 import qualified Data.Abstract.StackWidening as SW
 
+#define TRACE
+
+#ifdef TRACE
+import           Debug.Trace
+import           Text.Printf
+#endif
+
 -- | Fixpoint algorithm that computes the least fixpoint of an arrow computation.
 -- This fixpoint caching algorithm is due to /Abstract Definitional
 -- Interpreters, David Darais et. al., ICFP' 17/.  We made some
@@ -75,6 +83,8 @@ runFixT'' sw w (FixT f) = (\x -> (((mempty,M.empty),M.empty),x)) ^>> f (sw,w)
 liftFixT :: Arrow c => c x y -> FixT s a b c x y
 liftFixT f = FixT $ \_ -> ((\((_,o),x) -> (o,x)) ^>> second (f >>^ Terminating))
 
+
+#ifndef TRACE
 instance (Identifiable x, PreOrd y, ArrowChoice c) => ArrowFix x y (FixT s x y c) where
   fix f = proc x -> do
     old <- getOutCache -< ()
@@ -113,7 +123,39 @@ memoize (FixT f) = FixT $ \(stackWidening,widening) -> proc (((stack,inCache), o
           outCache' = M.insert x yOld outCache
           (x',stack') = runState (stackWidening x) stack 
       (outCache'',y) <- f (stackWidening,widening) -< (((stack',inCache), outCache'),x')
-      returnA -< (M.unsafeInsertWith (flip (T.widening widening)) x y outCache'',y)
+      let outCache''' = M.unsafeInsertWith (flip (T.widening widening)) x' y outCache''
+      let y' = outCache''' M.! x'
+      returnA -< (outCache''',y')
+
+#else
+              
+instance (Show x, Show y, Identifiable x, PreOrd y, ArrowChoice c) => ArrowFix x y (FixT s x y c) where
+  fix f =  proc x -> do
+    old <- getOutCache -< ()
+    setOutCache -< bottom
+    y <- localInCache (F.fix (memoize . f)) -< trace "----- ITERATION -----" $ (old,x)
+    new <- getOutCache -< ()
+    if (new ⊑ old)
+    then returnA -< y
+    else fix f -< x
+
+memoize :: (Show x, Show y, Identifiable x, PreOrd y, ArrowChoice c) => FixT s x y c x y -> FixT s x y c x y
+memoize (FixT f) = FixT $ \(stackWidening,widening) -> proc (((stack,inCache), outCache),x) -> do
+  case M.unsafeLookup x outCache of
+    Just y -> returnA -< trace (printf "HIT:  %s -> %s" (show x) (show y))
+              (outCache,y)
+    Nothing -> do
+      let yOld = fromMaybe bottom (M.unsafeLookup x inCache)
+          outCache' = M.insert x yOld outCache
+          (x',stack') = runState (stackWidening x) stack 
+      (outCache'',y) <- f (stackWidening,widening) -< trace (printf "CALL: %s" (show x')) (((stack',inCache), outCache'),x')
+      let outCache''' = M.unsafeInsertWith (flip (T.widening widening)) x' y outCache''
+          y' = fromMaybe (error "x not in cache") (M.unsafeLookup x outCache''')
+      returnA -< trace (printf "CACHE: %s := (%s -> %s)\n" (show x) (show y) (show y') ++
+                        printf "RET:  %s -> %s" (show x') (show y'))
+                  (M.unsafeInsertWith (flip (T.widening widening)) x y outCache'',y')
+              
+#endif
 
 getOutCache :: Arrow c => FixT s x y c () (Map x (Terminating y))
 getOutCache = FixT $ \_ -> arr $ \((_,o),()) -> (o,return o)
diff --git a/lib/src/Data/Abstract/Terminating.hs b/lib/src/Data/Abstract/Terminating.hs
index 2cec4e9b..5785d840 100644
--- a/lib/src/Data/Abstract/Terminating.hs
+++ b/lib/src/Data/Abstract/Terminating.hs
@@ -24,7 +24,7 @@ toEither (Terminating a) = Right a
 toEither NonTerminating = Left ()
 
 instance Show a => Show (Terminating a) where
-  show NonTerminating = "⊥"
+  show NonTerminating = "NonTerminating"
   show (Terminating a) = show a
 
 instance Applicative Terminating where
diff --git a/stratego/test/SortSemanticsSpec.hs b/stratego/test/SortSemanticsSpec.hs
index 3622c4f7..c8301d19 100644
--- a/stratego/test/SortSemanticsSpec.hs
+++ b/stratego/test/SortSemanticsSpec.hs
@@ -248,7 +248,7 @@ spec = do
       let ?ctx = Ctx.empty in
       let t = term "Exp"
           tenv = termEnv [("x",t)]
-      in seval 2 (Let [("swap", swap)] (Match "x" `Seq` Call "swap" [] [])) t `shouldBe` success (tenv, t)
+      in seval 2 (Let [("swap", swap)] (Match "x" `Seq` Call "swap" [] ["x"])) t `shouldBe` success (tenv, t)
 
     it "should support recursion" $
       let ?ctx = Ctx.empty in
-- 
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