X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=c%CE%BBash%2FCLasH%2FNormalize.hs;h=b2b4bd86f0080693d29f70183ef469083b15bdfc;hb=e17057696a5f74170dad6167867ee24d64d0854b;hp=a7b197d07536c541e0786ab667956cf6a3eaf9be;hpb=63eb4d0050f202ee022c2d89c46a33f47c646d79;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git diff --git "a/c\316\273ash/CLasH/Normalize.hs" "b/c\316\273ash/CLasH/Normalize.hs" index a7b197d..b2b4bd8 100644 --- "a/c\316\273ash/CLasH/Normalize.hs" +++ "b/c\316\273ash/CLasH/Normalize.hs" @@ -4,7 +4,7 @@ -- top level function "normalize", and defines the actual transformation passes that -- are performed. -- -module CLasH.Normalize (normalizeModule) where +module CLasH.Normalize (getNormalized, normalizeExpr) where -- Standard modules import Debug.Trace @@ -34,9 +34,12 @@ import Outputable ( showSDoc, ppr, nest ) -- Local imports import CLasH.Normalize.NormalizeTypes +import CLasH.Translator.TranslatorTypes import CLasH.Normalize.NormalizeTools import CLasH.VHDL.VHDLTypes +import qualified CLasH.Utils as Utils import CLasH.Utils.Core.CoreTools +import CLasH.Utils.Core.BinderTools import CLasH.Utils.Pretty -------------------------------- @@ -49,7 +52,7 @@ import CLasH.Utils.Pretty eta, etatop :: Transform eta expr | is_fun expr && not (is_lam expr) = do let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr - id <- mkInternalVar "param" arg_ty + id <- Trans.lift $ mkInternalVar "param" arg_ty change (Lam id (App expr (Var id))) -- Leave all other expressions unchanged eta e = return e @@ -110,7 +113,7 @@ letsimpl expr@(Let (Rec binds) res) = do then do -- If the result is not a local var already (to prevent loops with -- ourselves), extract it. - id <- mkInternalVar "foo" (CoreUtils.exprType res) + id <- Trans.lift $ mkInternalVar "foo" (CoreUtils.exprType res) let bind = (id, res) change $ Let (Rec (bind:binds)) (Var id) else @@ -154,6 +157,24 @@ letflattop = everywhere ("letflat", letflat) letremovetop :: Transform letremovetop = everywhere ("letremove", inlinebind (\(b, e) -> Trans.lift $ is_local_var e)) +-------------------------------- +-- Unused let binding removal +-------------------------------- +letremoveunused, letremoveunusedtop :: Transform +letremoveunused expr@(Let (Rec binds) res) = do + -- Filter out all unused binds. + let binds' = filter dobind binds + -- Only set the changed flag if binds got removed + changeif (length binds' /= length binds) (Let (Rec binds') res) + where + bound_exprs = map snd binds + -- For each bind check if the bind is used by res or any of the bound + -- expressions + dobind (bndr, _) = not $ any (expr_uses_binders [bndr]) (res:bound_exprs) +-- Leave all other expressions unchanged +letremoveunused expr = return expr +letremoveunusedtop = everywhere ("letremoveunused", letremoveunused) + -------------------------------- -- Function inlining -------------------------------- @@ -186,7 +207,7 @@ scrutsimpl expr@(Case scrut b ty alts) = do repr <- isRepr scrut if repr then do - id <- mkInternalVar "scrut" (CoreUtils.exprType scrut) + id <- Trans.lift $ mkInternalVar "scrut" (CoreUtils.exprType scrut) change $ Let (Rec [(id, scrut)]) (Case (Var id) b ty alts) else return expr @@ -198,13 +219,18 @@ scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl) -------------------------------- -- Case binder wildening -------------------------------- -casewild, casewildtop :: Transform --- Make sure that all case alternatives have only wild binders, except for --- simple selector cases (e.g., case x of (a, ) -> a). This is done by --- creating a new let binding for each non-wild binder, which is bound to a --- new simple selector case statement. We do this only for binders with a --- representable type, to prevent loops with inlinenonrep. -casewild expr@(Case scrut b ty alts) = do +casesimpl, casesimpltop :: Transform +-- This is already a selector case (or, if x does not appear in bndrs, a very +-- simple case statement that will be removed by caseremove below). Just leave +-- it be. +casesimpl expr@(Case scrut b ty [(con, bndrs, Var x)]) = return expr +-- Make sure that all case alternatives have only wild binders and simple +-- expressions. +-- This is done by creating a new let binding for each non-wild binder, which +-- is bound to a new simple selector case statement and for each complex +-- expression. We do this only for representable types, to prevent loops with +-- inlinenonrep. +casesimpl expr@(Case scrut b ty alts) = do (bindingss, alts') <- (Monad.liftM unzip) $ mapM doalt alts let bindings = concat bindingss -- Replace the case with a let with bindings and a case @@ -213,7 +239,7 @@ casewild expr@(Case scrut b ty alts) = do -- selector (i.e., a single alt with exactly one binding), already a simple -- selector altan no bindings (i.e., no wild binders in the original case), -- don't change anything, otherwise, replace the case. - if null bindings || length alts == 1 && length bindings == 1 then return expr else change newlet + if null bindings then return expr else change newlet where -- Generate a single wild binder, since they are all the same wild = MkCore.mkWildBinder @@ -221,84 +247,71 @@ casewild expr@(Case scrut b ty alts) = do -- sideeffect. doalt :: CoreAlt -> TransformMonad ([(CoreBndr, CoreExpr)], CoreAlt) doalt (con, bndrs, expr) = do - bindings_maybe <- Monad.zipWithM mkextracts bndrs [0..] - let bindings = Maybe.catMaybes bindings_maybe - -- We replace the binders with wild binders only. We can leave expr - -- unchanged, since the new bindings bind the same vars as the original - -- did. - let newalt = (con, wildbndrs, expr) + -- Make each binder wild, if possible + bndrs_res <- Monad.zipWithM dobndr bndrs [0..] + let (newbndrs, bindings_maybe) = unzip bndrs_res + -- Extract a complex expression, if possible. For this we check if any of + -- the new list of bndrs are used by expr. We can't use free_vars here, + -- since that looks at the old bndrs. + let uses_bndrs = not $ VarSet.isEmptyVarSet $ CoreFVs.exprSomeFreeVars (`elem` newbndrs) $ expr + (exprbinding_maybe, expr') <- doexpr expr uses_bndrs + -- Create a new alternative + let newalt = (con, newbndrs, expr') + let bindings = Maybe.catMaybes (exprbinding_maybe : bindings_maybe) return (bindings, newalt) where - -- Make all binders wild + -- Make wild alternatives for each binder wildbndrs = map (\bndr -> MkCore.mkWildBinder (Id.idType bndr)) bndrs -- A set of all the binders that are used by the expression free_vars = CoreFVs.exprSomeFreeVars (`elem` bndrs) expr - -- Creates a case statement to retrieve the ith element from the scrutinee - -- and binds that to b. - mkextracts :: CoreBndr -> Int -> TransformMonad (Maybe (CoreBndr, CoreExpr)) - mkextracts b i = do + -- Look at the ith binder in the case alternative. Return a new binder + -- for it (either the same one, or a wild one) and optionally a let + -- binding containing a case expression. + dobndr :: CoreBndr -> Int -> TransformMonad (CoreBndr, Maybe (CoreBndr, CoreExpr)) + dobndr b i = do repr <- isRepr (Var b) -- Is b wild (e.g., not a free var of expr. Since b is only in scope -- in expr, this means that b is unused if expr does not use it.) let wild = not (VarSet.elemVarSet b free_vars) -- Create a new binding for any representable binder that is not - -- already wild. + -- already wild and is representable (to prevent loops with + -- inlinenonrep). if (not wild) && repr then do -- Create on new binder that will actually capture a value in this -- case statement, and return it. let bty = (Id.idType b) - id <- mkInternalVar "sel" bty + id <- Trans.lift $ mkInternalVar "sel" bty let binders = take i wildbndrs ++ [id] ++ drop (i+1) wildbndrs - return $ Just (b, Case scrut b bty [(con, binders, Var id)]) + let caseexpr = Case scrut b bty [(con, binders, Var id)] + return (wildbndrs!!i, Just (b, caseexpr)) else - return Nothing --- Leave all other expressions unchanged -casewild expr = return expr --- Perform this transform everywhere -casewildtop = everywhere ("casewild", casewild) - --------------------------------- --- Case value simplification --------------------------------- -casevalsimpl, casevalsimpltop :: Transform -casevalsimpl expr@(Case scrut b ty alts) = do - -- Try to simplify each alternative, resulting in an optional binding and a - -- new alternative. - (bindings_maybe, alts') <- (Monad.liftM unzip) $ mapM doalt alts - let bindings = Maybe.catMaybes bindings_maybe - -- Create a new let around the case, that binds of the cases values. - let newlet = Let (Rec bindings) (Case scrut b ty alts') - -- If there were no values that needed and allowed simplification, don't - -- change the case. - if null bindings then return expr else change newlet - where - doalt :: CoreAlt -> TransformMonad (Maybe (CoreBndr, CoreExpr), CoreAlt) - -- Don't simplify values that are already simple - doalt alt@(con, bndrs, Var _) = return (Nothing, alt) - -- Simplify each alt by creating a new id, binding the case value to it and - -- replacing the case value with that id. Only do this when the case value - -- does not use any of the binders bound by this alternative, for that would - -- cause those binders to become unbound when moving the value outside of - -- the case statement. Also, don't create a binding for non-representable - -- expressions, to prevent loops with inlinenonrep. - doalt alt@(con, bndrs, expr) = do - repr <- isRepr expr - -- Find if any of the binders are used by expr - let usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` bndrs))) expr - if (not usesvars && repr) - then do - id <- mkInternalVar "caseval" (CoreUtils.exprType expr) - -- We don't flag a change here, since casevalsimpl will do that above - -- based on Just we return here. - return $ (Just (id, expr), (con, bndrs, Var id)) - else - -- Don't simplify anything else - return (Nothing, alt) + -- Just leave the original binder in place, and don't generate an + -- extra selector case. + return (b, Nothing) + -- Process the expression of a case alternative. Accepts an expression + -- and whether this expression uses any of the binders in the + -- alternative. Returns an optional new binding and a new expression. + doexpr :: CoreExpr -> Bool -> TransformMonad (Maybe (CoreBndr, CoreExpr), CoreExpr) + doexpr expr uses_bndrs = do + local_var <- Trans.lift $ is_local_var expr + repr <- isRepr expr + -- Extract any expressions that do not use any binders from this + -- alternative, is not a local var already and is representable (to + -- prevent loops with inlinenonrep). + if (not uses_bndrs) && (not local_var) && repr + then do + id <- Trans.lift $ mkInternalVar "caseval" (CoreUtils.exprType expr) + -- We don't flag a change here, since casevalsimpl will do that above + -- based on Just we return here. + return $ (Just (id, expr), Var id) + else + -- Don't simplify anything else + return (Nothing, expr) -- Leave all other expressions unchanged -casevalsimpl expr = return expr +casesimpl expr = return expr -- Perform this transform everywhere -casevalsimpltop = everywhere ("casevalsimpl", casevalsimpl) +casesimpltop = everywhere ("casesimpl", casesimpl) -------------------------------- -- Case removal @@ -328,7 +341,7 @@ appsimpl expr@(App f arg) = do local_var <- Trans.lift $ is_local_var arg if repr && not local_var then do -- Extract representable arguments - id <- mkInternalVar "arg" (CoreUtils.exprType arg) + id <- Trans.lift $ mkInternalVar "arg" (CoreUtils.exprType arg) change $ Let (Rec [(id, arg)]) (App f (Var id)) else -- Leave non-representable arguments unchanged return expr @@ -364,7 +377,7 @@ argprop expr@(App _ _) | is_var fexpr = do -- the old body applied to some arguments. let newbody = MkCore.mkCoreLams newparams (MkCore.mkCoreApps body oldargs) -- Create a new function with the same name but a new body - newf <- mkFunction f newbody + newf <- Trans.lift $ mkFunction f newbody -- Replace the original application with one of the new function to the -- new arguments. change $ MkCore.mkCoreApps (Var newf) newargs @@ -410,7 +423,7 @@ argprop expr@(App _ _) | is_var fexpr = do -- Representable types will not be propagated, and arguments with free -- type variables will be propagated later. -- TODO: preserve original naming? - id <- mkBinderFor arg "param" + id <- Trans.lift $ mkBinderFor arg "param" -- Just pass the original argument to the new function, which binds it -- to a new id and just pass that new id to the old function body. return ([arg], [id], mkReferenceTo id) @@ -457,7 +470,7 @@ funextract expr@(App _ _) | is_var fexpr = do -- by the argument expression. let free_vars = VarSet.varSetElems $ CoreFVs.exprFreeVars arg let body = MkCore.mkCoreLams free_vars arg - id <- mkBinderFor body "fun" + id <- Trans.lift $ mkBinderFor body "fun" Trans.lift $ addGlobalBind id body -- Replace the argument with a reference to the new function, applied to -- all vars it uses. @@ -478,80 +491,47 @@ funextracttop = everywhere ("funextract", funextract) -- What transforms to run? -transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovetop, letrectop, letsimpltop, letflattop, casewildtop, scrutsimpltop, casevalsimpltop, caseremovetop, inlinenonreptop, appsimpltop] - --- Turns the given bind into VHDL -normalizeModule :: - HscTypes.HscEnv - -> UniqSupply.UniqSupply -- ^ A UniqSupply we can use - -> [(CoreBndr, CoreExpr)] -- ^ All bindings we know (i.e., in the current module) - -> [CoreExpr] - -> [CoreBndr] -- ^ The bindings to generate VHDL for (i.e., the top level bindings) - -> [Bool] -- ^ For each of the bindings to generate VHDL for, if it is stateful - -> ([(CoreBndr, CoreExpr)], [(CoreBndr, CoreExpr)], TypeState) -- ^ The resulting VHDL - -normalizeModule env uniqsupply bindings testexprs generate_for statefuls = runTransformSession env uniqsupply $ do - testbinds <- mapM (\x -> do { v <- mkBinderFor' x "test" ; return (v,x) } ) testexprs - let testbinders = (map fst testbinds) - -- Put all the bindings in this module in the tsBindings map - putA tsBindings (Map.fromList (bindings ++ testbinds)) - -- (Recursively) normalize each of the requested bindings - mapM normalizeBind (generate_for ++ testbinders) - -- Get all initial bindings and the ones we produced - bindings_map <- getA tsBindings - let bindings = Map.assocs bindings_map - normalized_binders' <- getA tsNormalized - let normalized_binders = VarSet.delVarSetList normalized_binders' testbinders - let ret_testbinds = zip testbinders (Maybe.catMaybes $ map (\x -> lookup x bindings) testbinders) - let ret_binds = filter ((`VarSet.elemVarSet` normalized_binders) . fst) bindings - typestate <- getA tsType - -- But return only the normalized bindings - return $ (ret_binds, ret_testbinds, typestate) - -normalizeBind :: CoreBndr -> TransformSession () -normalizeBind bndr = - -- Don't normalize global variables, these should be either builtin - -- functions or data constructors. - Monad.when (Var.isLocalId bndr) $ do - -- Skip binders that have a polymorphic type, since it's impossible to - -- create polymorphic hardware. - if is_poly (Var bndr) - then - -- This should really only happen at the top level... TODO: Give - -- a different error if this happens down in the recursion. - error $ "\nNormalize.normalizeBind: Function " ++ show bndr ++ " is polymorphic, can't normalize" - else do - normalized_funcs <- getA tsNormalized - -- See if this function was normalized already - if VarSet.elemVarSet bndr normalized_funcs - then - -- Yup, don't do it again - return () - else do - -- Nope, note that it has been and do it. - modA tsNormalized (flip VarSet.extendVarSet bndr) - expr_maybe <- getGlobalBind bndr - case expr_maybe of - Just expr -> do - -- Introduce an empty Let at the top level, so there will always be - -- a let in the expression (none of the transformations will remove - -- the last let). - let expr' = Let (Rec []) expr - -- Normalize this expression - trace ("Transforming " ++ (show bndr) ++ "\nBefore:\n\n" ++ showSDoc ( ppr expr' ) ++ "\n") $ return () - expr' <- dotransforms transforms expr' - trace ("\nAfter:\n\n" ++ showSDoc ( ppr expr')) $ return () - -- And store the normalized version in the session - modA tsBindings (Map.insert bndr expr') - -- Find all vars used with a function type. All of these should be global - -- binders (i.e., functions used), since any local binders with a function - -- type should have been inlined already. - bndrs <- getGlobalBinders - let used_funcs_set = CoreFVs.exprSomeFreeVars (\v -> not (Id.isDictId v) && v `elem` bndrs) expr' - let used_funcs = VarSet.varSetElems used_funcs_set - -- Process each of the used functions recursively - mapM normalizeBind used_funcs - return () - -- We don't have a value for this binder. This really shouldn't - -- happen for local id's... - Nothing -> error $ "\nNormalize.normalizeBind: No value found for binder " ++ pprString bndr ++ "? This should not happen!" +transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovetop, letrectop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop] + +-- | Returns the normalized version of the given function. +getNormalized :: + CoreBndr -- ^ The function to get + -> TranslatorSession CoreExpr -- The normalized function body + +getNormalized bndr = Utils.makeCached bndr tsNormalized $ do + if is_poly (Var bndr) + then + -- This should really only happen at the top level... TODO: Give + -- a different error if this happens down in the recursion. + error $ "\nNormalize.normalizeBind: Function " ++ show bndr ++ " is polymorphic, can't normalize" + else do + expr <- getBinding bndr + normalizeExpr (show bndr) expr + +-- | Normalize an expression +normalizeExpr :: + String -- ^ What are we normalizing? For debug output only. + -> CoreSyn.CoreExpr -- ^ The expression to normalize + -> TranslatorSession CoreSyn.CoreExpr -- ^ The normalized expression + +normalizeExpr what expr = do + -- Introduce an empty Let at the top level, so there will always be + -- a let in the expression (none of the transformations will remove + -- the last let). + let expr' = Let (Rec []) expr + -- Normalize this expression + trace ("Transforming " ++ what ++ "\nBefore:\n\n" ++ showSDoc ( ppr expr' ) ++ "\n") $ return () + expr'' <- dotransforms transforms expr' + trace ("\nAfter:\n\n" ++ showSDoc ( ppr expr'')) $ return () + return expr'' + +-- | Get the value that is bound to the given binder at top level. Fails when +-- there is no such binding. +getBinding :: + CoreBndr -- ^ The binder to get the expression for + -> TranslatorSession CoreExpr -- ^ The value bound to the binder + +getBinding bndr = Utils.makeCached bndr tsBindings $ do + -- If the binding isn't in the "cache" (bindings map), then we can't create + -- it out of thin air, so return an error. + error $ "Normalize.getBinding: Unknown function requested: " ++ show bndr