X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=Normalize.hs;h=16d7969f64bfce9450a4c34d354f9a28dd335fa5;hb=46f93616d6a7ef012c5f07698d56372881196015;hp=99f6f0c3a59bdc57b03f4beee4a42017d3ca343a;hpb=53735ca153875e04d2d2d259d3125db6a415f998;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git diff --git a/Normalize.hs b/Normalize.hs index 99f6f0c..16d7969 100644 --- a/Normalize.hs +++ b/Normalize.hs @@ -11,7 +11,9 @@ import Debug.Trace import qualified Maybe 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.Map as Map +import qualified Data.Monoid as Monoid import Data.Accessor -- GHC API @@ -19,16 +21,23 @@ import CoreSyn import qualified UniqSupply import qualified CoreUtils import qualified Type +import qualified TcType import qualified Id import qualified Var import qualified VarSet +import qualified NameSet import qualified CoreFVs +import qualified CoreUtils +import qualified MkCore +import qualified HscTypes import Outputable ( showSDoc, ppr, nest ) -- Local imports import NormalizeTypes import NormalizeTools +import VHDLTypes import CoreTools +import Pretty -------------------------------- -- Start of transformations @@ -44,7 +53,7 @@ eta expr | is_fun expr && not (is_lam expr) = do change (Lam id (App expr (Var id))) -- Leave all other expressions unchanged eta e = return e -etatop = notapplied ("eta", eta) +etatop = notappargs ("eta", eta) -------------------------------- -- β-reduction @@ -58,12 +67,26 @@ beta (App (Let binds expr) arg) = change $ Let binds (App expr arg) beta (App (Case scrut b ty alts) arg) = change $ Case scrut b ty' alts' where alts' = map (\(con, bndrs, expr) -> (con, bndrs, (App expr arg))) alts - (_, ty') = Type.splitFunTy ty + ty' = CoreUtils.applyTypeToArg ty arg -- Leave all other expressions unchanged beta expr = return expr -- Perform this transform everywhere betatop = everywhere ("beta", beta) +-------------------------------- +-- Cast propagation +-------------------------------- +-- Try to move casts as much downward as possible. +castprop, castproptop :: Transform +castprop (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty) +castprop expr@(Cast (Case scrut b _ alts) ty) = change (Case scrut b ty alts') + where + alts' = map (\(con, bndrs, expr) -> (con, bndrs, (Cast expr ty))) alts +-- Leave all other expressions unchanged +castprop expr = return expr +-- Perform this transform everywhere +castproptop = everywhere ("castprop", castprop) + -------------------------------- -- let recursification -------------------------------- @@ -78,14 +101,21 @@ letrectop = everywhere ("letrec", letrec) -- let simplification -------------------------------- letsimpl, letsimpltop :: Transform --- Don't simplifiy lets that are already simple -letsimpl expr@(Let _ (Var _)) = return expr -- Put the "in ..." value of a let in its own binding, but not when the --- expression has a function type (to prevent loops with inlinefun). -letsimpl (Let (Rec binds) expr) | not $ is_fun expr = do - id <- mkInternalVar "foo" (CoreUtils.exprType expr) - let bind = (id, expr) - change $ Let (Rec (bind:binds)) (Var id) +-- expression is applicable (to prevent loops with inlinefun). +letsimpl expr@(Let (Rec binds) res) | not $ is_applicable expr = do + local_var <- Trans.lift $ is_local_var res + if not local_var + then do + -- If the result is not a local var already (to prevent loops with + -- ourselves), extract it. + id <- mkInternalVar "foo" (CoreUtils.exprType res) + let bind = (id, res) + change $ Let (Rec (bind:binds)) (Var id) + else + -- If the result is already a local var, don't extract it. + return expr + -- Leave all other expressions unchanged letsimpl expr = return expr -- Perform this transform everywhere @@ -121,20 +151,25 @@ letflattop = everywhere ("letflat", letflat) -------------------------------- -- Remove a = b bindings from let expressions everywhere letremovetop :: Transform -letremovetop = everywhere ("letremove", inlinebind (\(b, e) -> case e of (Var v) -> True; otherwise -> False)) +letremovetop = everywhere ("letremove", inlinebind (\(b, e) -> Trans.lift $ is_local_var e)) -------------------------------- -- Function inlining -------------------------------- --- Remove a = B bindings, with B :: a -> b, from let expressions everywhere. +-- Remove a = B bindings, with B :: a -> b, or B :: forall x . T, from let +-- expressions everywhere. This means that any value that still needs to be +-- applied to something else (polymorphic values need to be applied to a +-- Type) will be inlined, and will eventually be applied to all their +-- arguments. +-- -- This is a tricky function, which is prone to create loops in the -- transformations. To fix this, we make sure that no transformation will -- create a new let binding with a function type. These other transformations -- will just not work on those function-typed values at first, but the other -- transformations (in particular β-reduction) should make sure that the type -- of those values eventually becomes primitive. -inlinefuntop :: Transform -inlinefuntop = everywhere ("inlinefun", inlinebind (Type.isFunTy . CoreUtils.exprType . snd)) +inlinenonreptop :: Transform +inlinenonreptop = everywhere ("inlinenonrep", inlinebind ((Monad.liftM not) . isRepr . snd)) -------------------------------- -- Scrutinee simplification @@ -143,10 +178,10 @@ scrutsimpl,scrutsimpltop :: Transform -- Don't touch scrutinees that are already simple scrutsimpl expr@(Case (Var _) _ _ _) = return expr -- Replace all other cases with a let that binds the scrutinee and a new --- simple scrutinee, but not when the scrutinee is a function type (to prevent --- loops with inlinefun, though I don't think a scrutinee can have a function --- type...) -scrutsimpl (Case scrut b ty alts) | not $ is_fun scrut = do +-- simple scrutinee, but not when the scrutinee is applicable (to prevent +-- loops with inlinefun, though I don't think a scrutinee can be +-- applicable...) +scrutsimpl (Case scrut b ty alts) | not $ is_applicable scrut = do id <- mkInternalVar "scrut" (CoreUtils.exprType scrut) change $ Let (Rec [(id, scrut)]) (Case (Var id) b ty alts) -- Leave all other expressions unchanged @@ -189,6 +224,7 @@ casewild expr@(Case scrut b ty alts) = do -- and binds that to b. mkextracts :: CoreBndr -> Int -> TransformMonad (Maybe (CoreBndr, CoreExpr)) mkextracts b i = + -- TODO: Use free variables instead of is_wild. is_wild is a hack. if is_wild b || Type.isFunTy (Id.idType b) -- Don't create extra bindings for binders that are already wild, or -- for binders that bind function types (to prevent loops with @@ -228,9 +264,9 @@ casevalsimpl expr@(Case scrut b ty alts) = do -- 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 function-typed + -- the case statement. Also, don't create a binding for applicable -- expressions, to prevent loops with inlinefun. - doalt (con, bndrs, expr) | (not usesvars) && (not $ is_fun expr) = do + doalt (con, bndrs, expr) | (not usesvars) && (not $ is_applicable expr) = 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. @@ -260,54 +296,159 @@ caseremove expr = return expr caseremovetop = everywhere ("caseremove", caseremove) -------------------------------- --- Application simplification +-- Argument extraction -------------------------------- --- Make sure that all arguments in an application are simple variables. +-- Make sure that all arguments of a representable type are simple variables. appsimpl, appsimpltop :: Transform --- Don't simplify arguments that are already simple -appsimpl expr@(App f (Var _)) = return expr --- Simplify all arguments that do not have a function type (to prevent loops --- with inlinefun) and is not a type argument. Do this by introducing a new --- Let that binds the argument and passing the new binder in the application. -appsimpl (App f expr) | (not $ is_fun expr) && (not $ CoreSyn.isTypeArg expr) = do - id <- mkInternalVar "arg" (CoreUtils.exprType expr) - change $ Let (Rec [(id, expr)]) (App f (Var id)) +-- Simplify all representable arguments. Do this by introducing a new Let +-- that binds the argument and passing the new binder in the application. +appsimpl expr@(App f arg) = do + -- Check runtime representability + repr <- isRepr arg + local_var <- Trans.lift $ is_local_var arg + if repr && not local_var + then do -- Extract representable arguments + id <- mkInternalVar "arg" (CoreUtils.exprType arg) + change $ Let (Rec [(id, arg)]) (App f (Var id)) + else -- Leave non-representable arguments unchanged + return expr -- Leave all other expressions unchanged appsimpl expr = return expr -- Perform this transform everywhere appsimpltop = everywhere ("appsimpl", appsimpl) - -------------------------------- --- Type argument propagation --------------------------------- --- Remove all applications to type arguments, by duplicating the function --- called with the type application in its new definition. We leave --- dictionaries that might be associated with the type untouched, the funprop --- transform should propagate these later on. -typeprop, typeproptop :: Transform --- Transform any function that is applied to a type argument. Since type --- arguments are always the first ones to apply and we'll remove all type --- arguments, we can simply do them one by one. -typeprop expr@(App (Var f) (Type ty)) = do - id <- cloneVar f - let newty = Type.applyTy (Id.idType f) ty - let newf = Var.setVarType id newty +-- Function-typed argument propagation +-------------------------------- +-- Remove all applications to function-typed arguments, by duplication the +-- function called with the function-typed parameter replaced by the free +-- variables of the argument passed in. +argprop, argproptop :: Transform +-- Transform any application of a named function (i.e., skip applications of +-- lambda's). Also skip applications that have arguments with free type +-- variables, since we can't inline those. +argprop expr@(App _ _) | is_var fexpr = do + -- Find the body of the function called body_maybe <- Trans.lift $ getGlobalBind f case body_maybe of Just body -> do - let newbody = App body (Type ty) - Trans.lift $ addGlobalBind newf newbody - change (Var newf) + -- Process each of the arguments in turn + (args', changed) <- Writer.listen $ mapM doarg args + -- See if any of the arguments changed + case Monoid.getAny changed of + True -> do + let (newargs', newparams', oldargs) = unzip3 args' + let newargs = concat newargs' + let newparams = concat newparams' + -- Create a new body that consists of a lambda for all new arguments and + -- 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 + -- Replace the original application with one of the new function to the + -- new arguments. + change $ MkCore.mkCoreApps (Var newf) newargs + False -> + -- Don't change the expression if none of the arguments changed + return expr + -- If we don't have a body for the function called, leave it unchanged (it -- should be a primitive function then). Nothing -> return expr + where + -- Find the function called and the arguments + (fexpr, args) = collectArgs expr + Var f = fexpr + + -- Process a single argument and return (args, bndrs, arg), where args are + -- the arguments to replace the given argument in the original + -- application, bndrs are the binders to include in the top-level lambda + -- in the new function body, and arg is the argument to apply to the old + -- function body. + doarg :: CoreExpr -> TransformMonad ([CoreExpr], [CoreBndr], CoreExpr) + doarg arg = do + repr <- isRepr arg + bndrs <- Trans.lift getGlobalBinders + let interesting var = Var.isLocalVar var && (not $ var `elem` bndrs) + if not repr && not (is_var arg && interesting (exprToVar arg)) && not (has_free_tyvars arg) + then do + -- Propagate all complex arguments that are not representable, but not + -- arguments with free type variables (since those would require types + -- not known yet, which will always be known eventually). + -- Find interesting free variables, each of which should be passed to + -- the new function instead of the original function argument. + -- + -- Interesting vars are those that are local, but not available from the + -- top level scope (functions from this module are defined as local, but + -- they're not local to this function, so we can freely move references + -- to them into another function). + let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting arg + -- Mark the current expression as changed + setChanged + 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. + -- TODO: preserve original naming? + id <- 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) -- Leave all other expressions unchanged -typeprop expr = return expr +argprop expr = return expr -- Perform this transform everywhere -typeproptop = everywhere ("typeprop", typeprop) +argproptop = everywhere ("argprop", argprop) --- TODO: introduce top level let if needed? +-------------------------------- +-- Function-typed argument extraction +-------------------------------- +-- This transform takes any function-typed argument that cannot be propagated +-- (because the function that is applied to it is a builtin function), and +-- puts it in a brand new top level binder. This allows us to for example +-- apply map to a lambda expression This will not conflict with inlinefun, +-- since that only inlines local let bindings, not top level bindings. +funextract, funextracttop :: Transform +funextract expr@(App _ _) | is_var fexpr = do + body_maybe <- Trans.lift $ getGlobalBind f + case body_maybe of + -- We don't have a function body for f, so we can perform this transform. + Nothing -> do + -- Find the new arguments + args' <- mapM doarg args + -- And update the arguments. We use return instead of changed, so the + -- changed flag doesn't get set if none of the args got changed. + return $ MkCore.mkCoreApps fexpr args' + -- We have a function body for f, leave this application to funprop + Just _ -> return expr + where + -- Find the function called and the arguments + (fexpr, args) = collectArgs expr + Var f = fexpr + -- Change any arguments that have a function type, but are not simple yet + -- (ie, a variable or application). This means to create a new function + -- for map (\f -> ...) b, but not for map (foo a) b. + -- + -- We could use is_applicable here instead of is_fun, but I think + -- arguments to functions could only have forall typing when existential + -- typing is enabled. Not sure, though. + doarg arg | not (is_simple arg) && is_fun arg = do + -- Create a new top level binding that binds the argument. Its body will + -- be extended with lambda expressions, to take any free variables used + -- by the argument expression. + let free_vars = VarSet.varSetElems $ CoreFVs.exprFreeVars arg + let body = MkCore.mkCoreLams free_vars arg + id <- mkBinderFor body "fun" + Trans.lift $ addGlobalBind id body + -- Replace the argument with a reference to the new function, applied to + -- all vars it uses. + change $ MkCore.mkCoreApps (Var id) (map Var free_vars) + -- Leave all other arguments untouched + doarg arg = return arg + +-- Leave all other expressions unchanged +funextract expr = return expr +-- Perform this transform everywhere +funextracttop = everywhere ("funextract", funextract) -------------------------------- -- End of transformations @@ -317,17 +458,18 @@ typeproptop = everywhere ("typeprop", typeprop) -- What transforms to run? -transforms = [typeproptop, etatop, betatop, letremovetop, letrectop, letsimpltop, letflattop, casewildtop, scrutsimpltop, casevalsimpltop, caseremovetop, inlinefuntop, appsimpltop] +transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovetop, letrectop, letsimpltop, letflattop, casewildtop, scrutsimpltop, casevalsimpltop, caseremovetop, inlinenonreptop, appsimpltop] -- Turns the given bind into VHDL -normalizeModule :: - UniqSupply.UniqSupply -- ^ A UniqSupply we can use +normalizeModule :: + HscTypes.HscEnv + -> UniqSupply.UniqSupply -- ^ A UniqSupply we can use -> [(CoreBndr, CoreExpr)] -- ^ All bindings we know (i.e., in the current module) -> [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)] -- ^ The resulting VHDL + -> ([(CoreBndr, CoreExpr)], TypeState) -- ^ The resulting VHDL -normalizeModule uniqsupply bindings generate_for statefuls = runTransformSession uniqsupply $ do +normalizeModule env uniqsupply bindings generate_for statefuls = runTransformSession env uniqsupply $ do -- Put all the bindings in this module in the tsBindings map putA tsBindings (Map.fromList bindings) -- (Recursively) normalize each of the requested bindings @@ -336,37 +478,54 @@ normalizeModule uniqsupply bindings generate_for statefuls = runTransformSession bindings_map <- getA tsBindings let bindings = Map.assocs bindings_map normalized_bindings <- getA tsNormalized + typestate <- getA tsType -- But return only the normalized bindings - return $ filter ((flip VarSet.elemVarSet normalized_bindings) . fst) bindings + return $ (filter ((flip VarSet.elemVarSet normalized_bindings) . fst) bindings, typestate) normalizeBind :: CoreBndr -> TransformSession () -normalizeBind bndr = 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 - -- Normalize this expression - expr' <- dotransforms transforms expr - let expr'' = trace ("Before:\n\n" ++ showSDoc ( ppr expr ) ++ "\n\nAfter:\n\n" ++ showSDoc ( ppr expr')) expr' - -- 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. - let used_funcs_set = CoreFVs.exprSomeFreeVars (\v -> trace (showSDoc $ ppr $ Id.idType v) ((Type.isFunTy . snd . Type.splitForAllTys . Id.idType)v)) expr'' - let used_funcs = VarSet.varSetElems used_funcs_set - -- Process each of the used functions recursively - mapM normalizeBind (trace (show used_funcs) used_funcs) - return () - -- We don't have a value for this binder, let's assume this is a builtin - -- function. This might need some extra checking and a nice error - -- message). - Nothing -> return () +normalizeBind bndr = + -- Don't normalize global variables, these should be either builtin + -- functions or data constructors. + Monad.when (Var.isLocalIdVar 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!"