Copy initial state when specializing functions.

[matthijs/master-project/cλash.git] / cλash / CLasH / Normalize.hs

diff --git a/cλash/CLasH/Normalize.hs b/cλash/CLasH/Normalize.hs
index 17143ffb6d857d555f2f52a30d9d99ab7eb4752b..538b60d85c9cd53fc2dd67606c8b4aafc61572e5 100644 (file)
--- a/cλash/CLasH/Normalize.hs
+++ b/cλash/CLasH/Normalize.hs
@@ -13,7 +13,9 @@ import qualified List
 import qualified "transformers" Control.Monad.Trans as Trans
 import qualified Control.Monad as Monad
 import qualified Control.Monad.Trans.Writer as Writer
 import qualified "transformers" Control.Monad.Trans as Trans
 import qualified Control.Monad as Monad
 import qualified Control.Monad.Trans.Writer as Writer

+import qualified Data.Accessor.Monad.Trans.State as MonadState

 import qualified Data.Monoid as Monoid
 import qualified Data.Monoid as Monoid

+import qualified Data.Map as Map

 
 -- GHC API
 import CoreSyn
 
 -- GHC API
 import CoreSyn


@@ -389,6 +391,31 @@ scrutsimpl expr = return expr
 -- Perform this transform everywhere
 scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
 
 -- Perform this transform everywhere
 scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
 

+--------------------------------
+-- Scrutinee binder removal
+--------------------------------
+-- A case expression can have an extra binder, to which the scrutinee is bound
+-- after bringing it to WHNF. This is used for forcing evaluation of strict
+-- arguments. Since strictness does not matter for us (rather, everything is
+-- sort of strict), this binder is ignored when generating VHDL, and must thus
+-- be wild in the normal form.
+scrutbndrremove, scrutbndrremovetop :: Transform
+-- If the scrutinee is already simple, and the bndr is not wild yet, replace
+-- all occurences of the binder with the scrutinee variable.
+scrutbndrremove (Case (Var scrut) bndr ty alts) | bndr_used = do
+    alts' <- mapM subs_bndr alts
+    change $ Case (Var scrut) wild ty alts'
+  where
+    is_used (_, _, expr) = expr_uses_binders [bndr] expr
+    bndr_used = or $ map is_used alts
+    subs_bndr (con, bndrs, expr) = do
+      expr' <- substitute bndr (Var scrut) expr
+      return (con, bndrs, expr')
+    wild = MkCore.mkWildBinder (Id.idType bndr)
+-- Leave all other expressions unchanged
+scrutbndrremove expr = return expr
+scrutbndrremovetop = everywhere ("scrutbndrremove", scrutbndrremove)
+

 --------------------------------
 -- Case binder wildening
 --------------------------------
 --------------------------------
 -- Case binder wildening
 --------------------------------


@@ -551,6 +578,12 @@ argprop expr@(App _ _) | is_var fexpr = do
           let newbody = MkCore.mkCoreLams newparams (MkCore.mkCoreApps body oldargs)
           -- Create a new function with the same name but a new body
           newf <- Trans.lift $ mkFunction f newbody
           let newbody = MkCore.mkCoreLams newparams (MkCore.mkCoreApps body oldargs)
           -- Create a new function with the same name but a new body
           newf <- Trans.lift $ mkFunction f newbody

+
+          Trans.lift $ MonadState.modify tsInitStates (\ismap ->
+            let init_state_maybe = Map.lookup f ismap in
+            case init_state_maybe of
+              Nothing -> ismap
+              Just init_state -> Map.insert newf init_state ismap)

           -- Replace the original application with one of the new function to the
           -- new arguments.
           change $ MkCore.mkCoreApps (Var newf) newargs
           -- Replace the original application with one of the new function to the
           -- new arguments.
           change $ MkCore.mkCoreApps (Var newf) newargs


@@ -591,10 +624,18 @@ argprop expr@(App _ _) | is_var fexpr = do
           let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting arg
           -- Mark the current expression as changed
           setChanged
           let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting arg
           -- Mark the current expression as changed
           setChanged

+          -- TODO: Clone the free_vars (and update references in arg), since
+          -- this might cause conflicts if two arguments that are propagated
+          -- share a free variable. Also, we are now introducing new variables
+          -- into a function that are not fresh, which violates the binder
+          -- uniqueness invariant.

           return (map Var free_vars, free_vars, arg)
         else do
           -- Representable types will not be propagated, and arguments with free
           -- type variables will be propagated later.
           return (map Var free_vars, free_vars, arg)
         else do
           -- Representable types will not be propagated, and arguments with free
           -- type variables will be propagated later.

+          -- Note that we implicitly remove any type variables in the type of
+          -- the original argument by using the type of the actual argument
+          -- for the new formal parameter.

           -- TODO: preserve original naming?
           id <- Trans.lift $ mkBinderFor arg "param"
           -- Just pass the original argument to the new function, which binds it
           -- TODO: preserve original naming?
           id <- Trans.lift $ mkBinderFor arg "param"
           -- Just pass the original argument to the new function, which binds it


@@ -683,7 +724,7 @@ simplrestop expr = do
 
 
 -- What transforms to run?
 
 
 -- What transforms to run?

-transforms = [inlinetopleveltop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]
+transforms = [inlinetopleveltop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, scrutbndrremovetop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]

 
 -- | Returns the normalized version of the given function.
 getNormalized ::
 
 -- | Returns the normalized version of the given function.
 getNormalized ::