-- -- Functions to bring a Core expression in normal form. This module provides a -- top level function "normalize", and defines the actual transformation passes that -- are performed. -- module CLasH.Normalize (getNormalized, normalizeExpr, splitNormalized, transforms) where -- Standard modules import Debug.Trace import qualified Maybe import qualified List import qualified Control.Monad.Trans.Class as Trans import qualified Control.Monad as Monad import qualified Control.Monad.Trans.Writer as Writer import qualified Data.Accessor.Monad.Trans.StrictState as MonadState import qualified Data.Monoid as Monoid import qualified Data.Map as Map -- GHC API import CoreSyn import qualified CoreUtils import qualified BasicTypes import qualified Type import qualified TysWiredIn import qualified Id import qualified Var import qualified Name import qualified DataCon import qualified VarSet import qualified CoreFVs import qualified Class import qualified MkCore import Outputable ( showSDoc, ppr, nest ) -- Local imports import CLasH.Normalize.NormalizeTypes import CLasH.Translator.TranslatorTypes import CLasH.Normalize.NormalizeTools import CLasH.VHDL.Constants (builtinIds) import qualified CLasH.Utils as Utils import CLasH.Utils.Core.CoreTools import CLasH.Utils.Core.BinderTools import CLasH.Utils.Pretty ---------------------------------------------------------------- -- Cleanup transformations ---------------------------------------------------------------- -------------------------------- -- β-reduction -------------------------------- beta :: Transform -- Substitute arg for x in expr. For value lambda's, also clone before -- substitution. beta c (App (Lam x expr) arg) | CoreSyn.isTyVar x = setChanged >> substitute x arg c expr | otherwise = setChanged >> substitute_clone x arg c expr -- Leave all other expressions unchanged beta c expr = return expr -------------------------------- -- Unused let binding removal -------------------------------- letremoveunused :: Transform letremoveunused c expr@(Let (NonRec b bound) res) = do let used = expr_uses_binders [b] res if used then return expr else change res letremoveunused c 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, _) = any (expr_uses_binders [bndr]) (res:bound_exprs) -- Leave all other expressions unchanged letremoveunused c expr = return expr -------------------------------- -- empty let removal -------------------------------- -- Remove empty (recursive) lets letremove :: Transform letremove c (Let (Rec []) res) = change res -- Leave all other expressions unchanged letremove c expr = return expr -------------------------------- -- Simple let binding removal -------------------------------- -- Remove a = b bindings from let expressions everywhere letremovesimple :: Transform letremovesimple = inlinebind (\(b, e) -> Trans.lift $ is_local_var e) -------------------------------- -- Cast propagation -------------------------------- -- Try to move casts as much downward as possible. castprop :: Transform castprop c (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty) castprop c 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 c expr = return expr -------------------------------- -- Cast simplification. Mostly useful for state packing and unpacking, but -- perhaps for others as well. -------------------------------- castsimpl :: Transform castsimpl c expr@(Cast val ty) = do -- Don't extract values that are already simpl local_var <- Trans.lift $ is_local_var val -- Don't extract values that are not representable, to prevent loops with -- inlinenonrep repr <- isRepr val if (not local_var) && repr then do -- Generate a binder for the expression id <- Trans.lift $ mkBinderFor val "castval" -- Extract the expression change $ Let (NonRec id val) (Cast (Var id) ty) else return expr -- Leave all other expressions unchanged castsimpl c expr = return expr -------------------------------- -- Top level function inlining -------------------------------- -- This transformation inlines simple top level bindings. Simple -- currently means that the body is only a single application (though -- the complexity of the arguments is not currently checked) or that the -- normalized form only contains a single binding. This should catch most of the -- cases where a top level function is created that simply calls a type class -- method with a type and dictionary argument, e.g. -- fromInteger = GHC.Num.fromInteger (SizedWord D8) $dNum -- which is later called using simply -- fromInteger (smallInteger 10) -- -- These useless wrappers are created by GHC automatically. If we don't -- inline them, we get loads of useless components cluttering the -- generated VHDL. -- -- Note that the inlining could also inline simple functions defined by -- the user, not just GHC generated functions. It turns out to be near -- impossible to reliably determine what functions are generated and -- what functions are user-defined. Instead of guessing (which will -- inline less than we want) we will just inline all simple functions. -- -- Only functions that are actually completely applied and bound by a -- variable in a let expression are inlined. These are the expressions -- that will eventually generate instantiations of trivial components. -- By not inlining any other reference, we also prevent looping problems -- with funextract and inlinedict. inlinetoplevel :: Transform inlinetoplevel c expr | not (null c) && is_letbinding_ctx (head c) && not (is_fun expr) = case collectArgs expr of (Var f, args) -> do body_maybe <- needsInline f case body_maybe of Just body -> do -- If we inline a top-level function which has an associated -- initial state, and if the body of of the function is an -- Application. Then we need to clone the function indicated -- by the first argument of the application, and associate the -- initial state with this clone. We also need to replace the -- original reference with a reference to this clone initSmap <- Trans.lift $ MonadState.get tsInitStates clocksMap <- Trans.lift $ MonadState.get tsClocks case (CoreSyn.collectArgs body, Map.lookup f initSmap, Map.lookup f clocksMap) of ((Var inlineF, inlineFargs), Just initState, Just clock) -> do -- Get the body belong to the applied function and clone it inlineFbody <- Trans.lift $ getGlobalBind inlineF newInlineF <- Trans.lift $ mkFunction inlineF (Maybe.fromMaybe (error $ "Normalize.inlinetoplevel: no expr found for bndr: " ++ pprString inlineF) inlineFbody) -- Associate the initial state and clock with the cloned function Trans.lift $ MonadState.modify tsInitStates (\ismap -> Map.insert (newInlineF) initState ismap) Trans.lift $ MonadState.modify tsClocks (\clocksMap -> Map.insert (newInlineF) clock clocksMap) -- Replace original reference with a reference to the cloned function let newBody = mkApps (Var newInlineF) inlineFargs newBodyUniqued <- Trans.lift $ genUniques newBody change (mkApps newBodyUniqued args) _ -> do -- Regenerate all uniques in the to-be-inlined expression body_uniqued <- Trans.lift $ genUniques body -- And replace the variable reference with the unique'd body. change (mkApps body_uniqued args) -- No need to inline Nothing -> return expr -- This is not an application of a binder, leave it unchanged. _ -> return expr -- Leave all other expressions unchanged inlinetoplevel c expr = return expr -- | Does the given binder need to be inlined? If so, return the body to -- be used for inlining. needsInline :: CoreBndr -> TransformMonad (Maybe CoreExpr) needsInline f = do body_maybe <- Trans.lift $ getGlobalBind f case body_maybe of -- No body available? Nothing -> return Nothing Just body -> case CoreSyn.collectArgs body of -- The body is some (top level) binder applied to 0 or more -- arguments. That should be simple enough to inline. (Var f, args) -> return $ Just body -- Body is more complicated, try normalizing it _ -> do norm_maybe <- Trans.lift $ getNormalized_maybe False f case norm_maybe of -- Noth normalizeable Nothing -> return Nothing Just norm -> case splitNormalizedNonRep norm of -- The function has just a single binding, so that's simple -- enough to inline. (args, [bind], Var res) -> return $ Just norm -- More complicated function, don't inline _ -> return Nothing ---------------------------------------------------------------- -- Program structure transformations ---------------------------------------------------------------- -------------------------------- -- η expansion -------------------------------- -- Make sure all parameters to the normalized functions are named by top -- level lambda expressions. For this we apply η expansion to the -- function body (possibly enclosed in some lambda abstractions) while -- it has a function type. Eventually this will result in a function -- body consisting of a bunch of nested lambdas containing a -- non-function value (e.g., a complete application). eta :: Transform eta c expr | not (null c) && is_appfirst_ctx (head c) = return expr -- Also don't apply to arguments, since this can cause loops with -- funextract. This isn't the proper solution, but due to an -- implementation bug in notappargs, this is how it used to work so far. | not (null c) && is_appsecond_ctx (head c) = return expr | is_fun expr && not (is_lam expr) = do let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr id <- Trans.lift $ mkInternalVar "param" arg_ty change (Lam id (App expr (Var id))) -- Leave all other expressions unchanged eta c e = return e -------------------------------- -- Application propagation -------------------------------- -- Move applications into let and case expressions. appprop :: Transform -- Propagate the application into the let appprop c (App (Let binds expr) arg) = change $ Let binds (App expr arg) -- Propagate the application into each of the alternatives appprop c (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' = CoreUtils.applyTypeToArg ty arg -- Leave all other expressions unchanged appprop c expr = return expr -------------------------------- -- Let recursification -------------------------------- -- Make all lets recursive, so other transformations don't need to -- handle non-recursive lets letrec :: Transform letrec c expr@(Let (NonRec bndr val) res) = change $ Let (Rec [(bndr, val)]) res -- Leave all other expressions unchanged letrec c expr = return expr -------------------------------- -- let flattening -------------------------------- -- Takes a let that binds another let, and turns that into two nested lets. -- e.g., from: -- let b = (let b' = expr' in res') in res -- to: -- let b' = expr' in (let b = res' in res) letflat :: Transform -- Turn a nonrec let that binds a let into two nested lets. letflat c (Let (NonRec b (Let binds res')) res) = change $ Let binds (Let (NonRec b res') res) letflat c (Let (Rec binds) expr) = do -- Flatten each binding. binds' <- Utils.concatM $ Monad.mapM flatbind binds -- Return the new let. We don't use change here, since possibly nothing has -- changed. If anything has changed, flatbind has already flagged that -- change. return $ Let (Rec binds') expr where -- Turns a binding of a let into a multiple bindings, or any other binding -- into a list with just that binding flatbind :: (CoreBndr, CoreExpr) -> TransformMonad [(CoreBndr, CoreExpr)] flatbind (b, Let (Rec binds) expr) = change ((b, expr):binds) flatbind (b, Let (NonRec b' expr') expr) = change [(b, expr), (b', expr')] flatbind (b, expr) = return [(b, expr)] -- Leave all other expressions unchanged letflat c expr = return expr -------------------------------- -- Return value simplification -------------------------------- -- Ensure the return value of a function follows proper normal form. eta -- expansion ensures the body starts with lambda abstractions, this -- transformation ensures that the lambda abstractions always contain a -- recursive let and that, when the return value is representable, the -- let contains a local variable reference in its body. -- Extract the return value from the body of the top level lambdas (of -- which ther could be zero), unless it is a let expression (in which -- case the next clause applies). retvalsimpl c expr | all is_lambdabody_ctx c && not (is_lam expr) && not (is_let expr) = do local_var <- Trans.lift $ is_local_var expr repr <- isRepr expr if not local_var && repr then do id <- Trans.lift $ mkBinderFor expr "res" change $ Let (Rec [(id, expr)]) (Var id) else return expr -- Extract the return value from the body of a let expression, which is -- itself the body of the top level lambdas (of which there could be -- zero). retvalsimpl c expr@(Let (Rec binds) body) | all is_lambdabody_ctx c = do -- Don't extract values that are already a local variable, to prevent -- loops with ourselves. local_var <- Trans.lift $ is_local_var body -- Don't extract values that are not representable, to prevent loops with -- inlinenonrep repr <- isRepr body if not local_var && repr then do id <- Trans.lift $ mkBinderFor body "res" change $ Let (Rec ((id, body):binds)) (Var id) else return expr -- Leave all other expressions unchanged retvalsimpl c expr = return expr -------------------------------- -- Representable arguments simplification -------------------------------- -- Make sure that all arguments of a representable type are simple variables. appsimpl :: Transform -- Simplify all representable arguments. Do this by introducing a new Let -- that binds the argument and passing the new binder in the application. appsimpl c 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 <- Trans.lift $ mkBinderFor arg "arg" change $ Let (NonRec id arg) (App f (Var id)) else -- Leave non-representable arguments unchanged return expr -- Leave all other expressions unchanged appsimpl c expr = return expr ---------------------------------------------------------------- -- Built-in function transformations ---------------------------------------------------------------- -------------------------------- -- 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 inlinenonrep, -- since that only inlines local let bindings, not top level bindings. funextract :: Transform funextract c 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 && not (has_free_tyvars 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 <- 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. change $ MkCore.mkCoreApps (Var id) (map Var free_vars) -- Leave all other arguments untouched doarg arg = return arg -- Leave all other expressions unchanged funextract c expr = return expr ---------------------------------------------------------------- -- Case normalization transformations ---------------------------------------------------------------- -------------------------------- -- Scrutinee simplification -------------------------------- -- Make sure the scrutinee of a case expression is a local variable -- reference. scrutsimpl :: Transform -- Replace a case expression with a let that binds the scrutinee and a new -- simple scrutinee, but only when the scrutinee is representable (to prevent -- loops with inlinenonrep, though I don't think a non-representable scrutinee -- will be supported anyway...) and is not a local variable already. scrutsimpl c expr@(Case scrut b ty alts) = do repr <- isRepr scrut local_var <- Trans.lift $ is_local_var scrut if repr && not local_var then do id <- Trans.lift $ mkBinderFor scrut "scrut" change $ Let (NonRec id scrut) (Case (Var id) b ty alts) else return expr -- Leave all other expressions unchanged scrutsimpl c expr = return expr -------------------------------- -- 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 :: 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 c (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) c expr return (con, bndrs, expr') wild = MkCore.mkWildBinder (Id.idType bndr) -- Leave all other expressions unchanged scrutbndrremove c expr = return expr -------------------------------- -- Case normalization -------------------------------- -- Turn a case expression with any number of alternatives with any -- number of non-wild binders into as set of case and let expressions, -- all of which are in normal form (e.g., a bunch of extractor case -- expressions to extract all fields from the scrutinee, a number of let -- bindings to bind each alternative and a single selector case to -- select the right value. casesimpl :: 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 c 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 c expr@(Case scrut bndr ty alts) | not bndr_used = do (bindingss, alts') <- (Monad.liftM unzip) $ mapM doalt alts let bindings = concat bindingss -- Replace the case with a let with bindings and a case let newlet = mkNonRecLets bindings (Case scrut bndr ty alts') -- If there are no non-wild binders, or this case is already a simple -- 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 then return expr else change newlet where -- Check if the scrutinee binder is used is_used (_, _, expr) = expr_uses_binders [bndr] expr bndr_used = or $ map is_used alts -- Generate a single wild binder, since they are all the same wild = MkCore.mkWildBinder -- Wilden the binders of one alt, producing a list of bindings as a -- sideeffect. doalt :: CoreAlt -> TransformMonad ([(CoreBndr, CoreExpr)], CoreAlt) doalt (LitAlt _, _, _) = error $ "Don't know how to handle LitAlt in case expression: " ++ pprString expr doalt alt@(DEFAULT, [], expr) = do local_var <- Trans.lift $ is_local_var expr repr <- isRepr expr -- Extract any expressions that is not a local var already and is -- representable (to prevent loops with inlinenonrep). (exprbinding_maybe, expr') <- if (not local_var) && repr then do id <- Trans.lift $ mkBinderFor expr "caseval" -- 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) let newalt = (DEFAULT, [], expr') let bindings = Maybe.catMaybes [exprbinding_maybe] return (bindings, newalt) doalt (DataAlt dc, bndrs, expr) = do -- 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 = (DataAlt dc, newbndrs, expr') let bindings = Maybe.catMaybes (bindings_maybe ++ [exprbinding_maybe]) return (bindings, newalt) where -- 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 -- 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 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 and is representable (to prevent loops with -- inlinenonrep). if (not wild) && repr then do let dc_i = datacon_index (CoreUtils.exprType scrut) dc caseexpr <- Trans.lift $ mkSelCase scrut dc_i i -- Create a new binder that will actually capture a value in this -- case statement, and return it. return (wildbndrs!!i, Just (b, caseexpr)) else -- 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 $ mkBinderFor expr "caseval" -- 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 casesimpl c expr = return expr -------------------------------- -- Case removal -------------------------------- -- Remove case statements that have only a single alternative and only wild -- binders. caseremove :: Transform -- Replace a useless case by the value of its single alternative caseremove c (Case scrut b ty [(con, bndrs, expr)]) | not usesvars = change expr -- Find if any of the binders are used by expr where usesvars = (not . VarSet.isEmptyVarSet . (CoreFVs.exprSomeFreeVars (`elem` b:bndrs))) expr -- Leave all other expressions unchanged caseremove c expr = return expr -------------------------------- -- Case of known constructor simplification -------------------------------- -- If a case expressions scrutinizes a datacon application, we can -- determine which alternative to use and remove the case alltogether. -- We replace it with a let expression the binds every binder in the -- alternative bound to the corresponding argument of the datacon. We do -- this instead of substituting the binders, to prevent duplication of -- work and preserve sharing wherever appropriate. knowncase :: Transform knowncase context expr@(Case scrut@(App _ _) bndr ty alts) | not bndr_used = do case collectArgs scrut of (Var f, args) -> case Id.isDataConId_maybe f of -- Not a dataconstructor? Don't change anything (probably a -- function, then) Nothing -> return expr Just dc -> do let (altcon, bndrs, res) = case List.find (\(altcon, bndrs, res) -> altcon == (DataAlt dc)) alts of Just alt -> alt -- Return the alternative found Nothing -> head alts -- If the datacon is not present, the first must be the default alternative -- Double check if we have either the correct alternative, or -- the default. if altcon /= (DataAlt dc) && altcon /= DEFAULT then error ("Normalize.knowncase: Invalid core, datacon not found in alternatives and DEFAULT alternative is not first? " ++ pprString expr) else return () -- Find out how many arguments to drop (type variables and -- predicates like dictionaries). let (tvs, preds, _, _) = DataCon.dataConSig dc let count = length tvs + length preds -- Create a let expression that binds each of the binders in -- this alternative to the corresponding argument of the data -- constructor. let binds = zip bndrs (drop count args) change $ Let (Rec binds) res _ -> return expr -- Scrutinee is not an application of a var where is_used (_, _, expr) = expr_uses_binders [bndr] expr bndr_used = or $ map is_used alts -- Leave all other expressions unchanged knowncase c expr = return expr ---------------------------------------------------------------- -- Unrepresentable value removal transformations ---------------------------------------------------------------- -------------------------------- -- Non-representable binding inlining -------------------------------- -- Remove a = B bindings, with B of a non-representable type, from let -- expressions everywhere. This means that any value that we can't generate a -- signal for, will be inlined and hopefully turned into something we can -- represent. -- -- 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 non-representable 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 representable. inlinenonrep :: Transform inlinenonrep = inlinebind ((Monad.liftM not) . isRepr . snd) -------------------------------- -- Function specialization -------------------------------- -- Remove all applications to non-representable arguments, by duplicating the -- function called with the non-representable parameter replaced by the free -- variables of the argument passed in. argprop :: 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 c 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 -- 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 <- Trans.lift $ mkFunction f newbody -- Copy initial statee if it has one 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) -- Copy clock if it has one Trans.lift $ MonadState.modify tsClocks (\clockMap -> let clockMaybe = Map.lookup f clockMap in case clockMaybe of Nothing -> clockMap Just clock -> Map.insert newf clock clockMap) -- 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 && (var `notElem` 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 -- 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. -- 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 -- 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 argprop c expr = return expr -------------------------------- -- Non-representable result inlining -------------------------------- -- This transformation takes a function (top level binding) that has a -- non-representable result (e.g., a tuple containing a function, or an -- Integer. The latter can occur in some cases as the result of the -- fromIntegerT function) and inlines enough of the function to make the -- result representable again. -- -- This is done by first normalizing the function and then "inlining" -- the result. Since no unrepresentable let bindings are allowed in -- normal form, we can be sure that all free variables of the result -- expression will be representable (Note that we probably can't -- guarantee that all representable parts of the expression will be free -- variables, so we might inline more than strictly needed). -- -- The new function result will be a tuple containing all free variables -- of the old result, so the old result can be rebuild at the caller. -- -- We take care not to inline dictionary id's, which are top level -- bindings with a non-representable result type as well, since those -- will never become VHDL signals directly. There is a separate -- transformation (inlinedict) that specifically inlines dictionaries -- only when it is useful. inlinenonrepresult :: Transform -- Apply to any (application of) a reference to a top level function -- that is fully applied (i.e., dos not have a function type) but is not -- representable. We apply in any context, since non-representable -- expressions are generally left alone and can occur anywhere. inlinenonrepresult context expr | not (is_applicable expr) && not (has_free_tyvars expr) = case collectArgs expr of (Var f, args) | not (Id.isDictId f) -> do repr <- isRepr expr if not repr then do body_maybe <- Trans.lift $ getNormalized_maybe True f case body_maybe of Just body -> do let (bndrs, binds, res) = splitNormalizedNonRep body if has_free_tyvars res then -- Don't touch anything with free type variables, since -- we can't return those. We'll wait until argprop -- removed those variables. return expr else do -- Get the free local variables of res global_bndrs <- Trans.lift getGlobalBinders let interesting var = Var.isLocalVar var && (var `notElem` global_bndrs) let free_vars = VarSet.varSetElems $ CoreFVs.exprSomeFreeVars interesting res let free_var_types = map Id.idType free_vars let n_free_vars = length free_vars -- Get a tuple datacon to wrap around the free variables let fvs_datacon = TysWiredIn.tupleCon BasicTypes.Boxed n_free_vars let fvs_datacon_id = DataCon.dataConWorkId fvs_datacon -- Let the function now return a tuple with references to -- all free variables of the old return value. First pass -- all the types of the variables, since tuple -- constructors are polymorphic. let newres = if (n_free_vars == 1) then res else mkApps (Var fvs_datacon_id) (map Type free_var_types ++ map Var free_vars) -- Recreate the function body with the changed return value let newbody = mkLams bndrs (Let (Rec binds) newres) -- Create the new function f' <- Trans.lift $ mkFunction f newbody -- Call the new function let newapp = mkApps (Var f') args res_bndr <- Trans.lift $ mkBinderFor newapp "res" -- Create extractor case expressions to extract each of the -- free variables from the tuple. sel_cases <- if (n_free_vars == 1) then return [(Var res_bndr)] else Trans.lift $ mapM (mkSelCase (Var res_bndr) 0) [0..n_free_vars-1] -- Bind the res_bndr to the result of the new application -- and each of the free variables to the corresponding -- selector case. Replace the let body with the original -- body of the called function (which can still access all -- of its free variables, from the let). let binds = (res_bndr, newapp):(zip free_vars sel_cases) let letexpr = Let (Rec binds) res -- Finally, regenarate all uniques in the new expression, -- since the free variables could otherwise become -- duplicated. It is not strictly necessary to regenerate -- res, since we're moving that expression, but it won't -- hurt. letexpr_uniqued <- Trans.lift $ genUniques letexpr change letexpr_uniqued Nothing -> return expr else -- Don't touch representable expressions or (applications of) -- dictionary ids. return expr -- Not a reference to or application of a top level function _ -> return expr -- Leave all other expressions unchanged inlinenonrepresult c expr = return expr ---------------------------------------------------------------- -- Type-class transformations ---------------------------------------------------------------- -------------------------------- -- ClassOp resolution -------------------------------- -- Resolves any class operation to the actual operation whenever -- possible. Class methods (as well as parent dictionary selectors) are -- special "functions" that take a type and a dictionary and evaluate to -- the corresponding method. A dictionary is nothing more than a -- special dataconstructor applied to the type the dictionary is for, -- each of the superclasses and all of the class method definitions for -- that particular type. Since dictionaries all always inlined (top -- levels dictionaries are inlined by inlinedict, local dictionaries are -- inlined by inlinenonrep), we will eventually have something like: -- -- baz -- @ CLasH.HardwareTypes.Bit -- (D:Baz @ CLasH.HardwareTypes.Bit bitbaz) -- -- Here, baz is the method selector for the baz method, while -- D:Baz is the dictionary constructor for the Baz and bitbaz is the baz -- method defined in the Baz Bit instance declaration. -- -- To resolve this, we can look at the ClassOp IdInfo from the baz Id, -- which contains the Class it is defined for. From the Class, we can -- get a list of all selectors (both parent class selectors as well as -- method selectors). Since the arguments to D:Baz (after the type -- argument) correspond exactly to this list, we then look up baz in -- that list and replace the entire expression by the corresponding -- argument to D:Baz. -- -- We don't resolve methods that have a builtin translation (such as -- ==), since the actual implementation is not always (easily) -- translateable. For example, when deriving ==, GHC generates code -- using $con2tag functions to translate a datacon to an int and compare -- that with GHC.Prim.==# . Better to avoid that for now. classopresolution :: Transform classopresolution c expr@(App (App (Var sel) ty) dict) | not is_builtin = case Id.isClassOpId_maybe sel of -- Not a class op selector Nothing -> return expr Just cls -> case collectArgs dict of (_, []) -> return expr -- Dict is not an application (e.g., not inlined yet) (Var dictdc, (ty':selectors)) | not (Maybe.isJust (Id.isDataConId_maybe dictdc)) -> return expr -- Dictionary is not a datacon yet (but e.g., a top level binder) | tyargs_neq ty ty' -> error $ "Normalize.classopresolution: Applying class selector to dictionary without matching type?\n" ++ pprString expr | otherwise -> let selector_ids = Class.classSelIds cls in -- Find the selector used in the class' list of selectors case List.elemIndex sel selector_ids of Nothing -> error $ "Normalize.classopresolution: Selector not found in class' selector list? This should not happen!\nExpression: " ++ pprString expr ++ "\nClass: " ++ show cls ++ "\nSelectors: " ++ show selector_ids -- Get the corresponding argument from the dictionary Just n -> change (selectors!!n) (_, _) -> return expr -- Not applying a variable? Don't touch where -- Compare two type arguments, returning True if they are _not_ -- equal tyargs_neq (Type ty1) (Type ty2) = not $ Type.coreEqType ty1 ty2 tyargs_neq _ _ = True -- Is this a builtin function / method? is_builtin = elem (Name.getOccString sel) builtinIds -- Leave all other expressions unchanged classopresolution c expr = return expr -------------------------------- -- Dictionary inlining -------------------------------- -- Inline all top level dictionaries, that are in a position where -- classopresolution can actually resolve them. This makes this -- transformation look similar to classoperesolution below, but we'll -- keep them separated for clarity. By not inlining other dictionaries, -- we prevent expression sizes exploding when huge type level integer -- dictionaries are inlined which can never be expanded (in casts, for -- example). inlinedict c expr@(App (App (Var sel) ty) (Var dict)) | not is_builtin && is_classop = do body_maybe <- Trans.lift $ getGlobalBind dict case body_maybe of -- No body available (no source available, or a local variable / -- argument) Nothing -> return expr Just body -> change (App (App (Var sel) ty) body) where -- Is this a builtin function / method? is_builtin = elem (Name.getOccString sel) builtinIds -- Are we dealing with a class operation selector? is_classop = Maybe.isJust (Id.isClassOpId_maybe sel) -- Leave all other expressions unchanged inlinedict c expr = return expr {- -------------------------------- -- Identical let binding merging -------------------------------- -- Merge two bindings in a let if they are identical -- TODO: We would very much like to use GHC's CSE module for this, but that -- doesn't track if something changed or not, so we can't use it properly. letmerge :: Transform letmerge c expr@(Let _ _) = do let (binds, res) = flattenLets expr binds' <- domerge binds return $ mkNonRecLets binds' res where domerge :: [(CoreBndr, CoreExpr)] -> TransformMonad [(CoreBndr, CoreExpr)] domerge [] = return [] domerge (e:es) = do es' <- mapM (mergebinds e) es es'' <- domerge es' return (e:es'') -- Uses the second bind to simplify the second bind, if applicable. mergebinds :: (CoreBndr, CoreExpr) -> (CoreBndr, CoreExpr) -> TransformMonad (CoreBndr, CoreExpr) mergebinds (b1, e1) (b2, e2) -- Identical expressions? Replace the second binding with a reference to -- the first binder. | CoreUtils.cheapEqExpr e1 e2 = change $ (b2, Var b1) -- Different expressions? Don't change | otherwise = return (b2, e2) -- Leave all other expressions unchanged letmerge c expr = return expr -} ---------------------------------------------------------------- -- Arrow transformations ---------------------------------------------------------------- extractArrowExpression :: CoreBndr -> TransformMonad CoreExpr extractArrowExpression bndr = do fExpr <- Trans.lift $ getNormalized False bndr arrowsMap <- Trans.lift $ MonadState.get tsArrows let transF = Maybe.fromMaybe (error $ "Normalize.extractArrowExpression: could not find real function of: " ++ pprString bndr) $ Map.lookup bndr arrowsMap return $ Var transF -------------------------------- -- ArrowHooks (>>>) inlining -------------------------------- -- Arrow expressions usually take on the form of: -- -- letrec d = (>>>) a b c .... -- in -- letrec -- x = d y z -- o = d p q -- ... -- -- So we want to inline the arrow hooks (>>>) hoping the arrowHooksExtract -- transformation (which mathes on the operator) will later remove it at every -- inlined location. inlineArrowHooks :: Transform inlineArrowHooks c expr@(Let (Rec [(bndr,val)]) res) | isArrowE expr = inlinebind condition c expr where condition :: ((CoreBndr, CoreExpr) -> TransformMonad Bool) condition (b, e) = do return (b == bndr) inlineArrowHooks c expr = return expr -------------------------------- -- liftS (^^^) extraction -------------------------------- -- Stateful functions are explicitly lifted to arrows by the programmer using -- the lifting (^^^) function, e.g. f ^^^ i; where f is of type: -- a -> b -> (a,c). We replace the lifting function by an application of 'f' -- to its arguments: f (x::a) (y::b). We also associate the initial state, -- 'i', to this particular instantiation of f. -- -- From: -- (^^^) (f :: s -> a -> (s,b)) i -- -- To: -- \(s::s) (i::a) -> f i arrowLiftSExtract :: Transform arrowLiftSExtract c expr@(App _ _) | isLift (appliedF, alreadyMappedArgs) || isComponent (appliedF, alreadyMappedArgs) = do -- Collect the lifted function and the initial state let (Var liftS) = appliedF let valArgs = get_val_args (Var.varType liftS) alreadyMappedArgs let [realfun, initvalue] = take 2 valArgs -- TODO: All of this looks/is hacked! Needs rethinking and rewriting (realfunBndr, realfunBody) <- case realfun of (Var realfunBndr) -> do exprMaybe <- Trans.lift $ getGlobalBind realfunBndr let body = Maybe.fromMaybe (error $ "Normalize.arrowLiftSExtract(Var): could not find lifted function: " ++ pprString realfun) exprMaybe -- Clone the lifted function realfun' <- Trans.lift $ mkFunction realfunBndr body return (realfun', Var realfun') (App _ _) -> do let (Var appliedFunBndr, appliedArgs) = collectArgs realfun exprMaybe <- Trans.lift $ getGlobalBind appliedFunBndr let body = Maybe.fromMaybe (error $ "Normalize.arrowLiftSExtract(App): could not find lifted function: " ++ pprString realfun) exprMaybe -- Clone the lifted function realfun' <- Trans.lift $ mkFunction appliedFunBndr body return (realfun', CoreSyn.mkApps (Var realfun') appliedArgs) (Lam id1 (Lam id2 (Cast (App (App appliedFun lamArg1) lamArg2) ty))) -> do let (Var appliedFunBndr, appliedArgs) = collectArgs appliedFun exprMaybe <- Trans.lift $ getGlobalBind appliedFunBndr let body = Maybe.fromMaybe (error $ "Normalize.arrowLiftSExtract(LamLamCastAppApp): could not find lifted function: " ++ pprString realfun) exprMaybe -- Clone the lifted function realfun' <- Trans.lift $ mkFunction appliedFunBndr body return (realfun', Lam id1 (Lam id2 (Cast (App (App (CoreSyn.mkApps (Var realfun') appliedArgs) lamArg1) lamArg2) ty))) otherwise -> error $ "Normalize.arrowLiftSExtract: Don't know how to lift: " ++ pprString realfun -- Create 2 new Vars that that will be applied to the lifted function let [arg1Ty,arg2Ty] = (fst . Type.splitFunTys . CoreUtils.exprType) realfun id1 <- Trans.lift $ mkInternalVar "param" arg1Ty id2 <- Trans.lift $ mkInternalVar "param" arg2Ty -- Associate initial value with the cloned function initbndr <- case initvalue of (Var initvalueBndr) -> do initBndrMaybe <- Trans.lift $ getGlobalBind initvalueBndr case initBndrMaybe of (Just a) -> return initvalueBndr -- FIXME: This is definately broken, we're making a top-level binder that -- rerefences a local variable from another function... What we should do -- is copy the value that's referenced by the local variable! Nothing -> do let body = Var initvalueBndr initId <- Trans.lift $ mkBinderFor body ("init" ++ Name.getOccString realfunBndr) Trans.lift $ addGlobalBind initId body return initId otherwise -> do -- FIXME: This is also broken! In case a local variable is referenced anywhere -- in the expression that we're making a top-level binder, we'll again be making -- a reference that the new top-level binder can not find. We should check if -- there are any references to local variables, and copy their values! initId <- Trans.lift $ mkBinderFor initvalue ("init" ++ Name.getOccString realfunBndr) Trans.lift $ addGlobalBind initId initvalue return initId Trans.lift $ MonadState.modify tsInitStates (Map.insert realfunBndr initbndr) -- Associate clock with the clone function clockEdge <- if isLift (appliedF, alreadyMappedArgs) then return (True,1) else do let clock = last valArgs case clock of (Var clockBndr) -> do exprMaybe <- Trans.lift $ getGlobalBind clockBndr let clockExpr = Maybe.fromMaybe (error $ "Normalize.arrowLiftSExtract: could not find clock for: " ++ pprString realfun) exprMaybe let (Var appliedFunBndr, [litArg]) = collectArgs clockExpr clockLit <- Trans.lift $ getIntegerLiteral litArg case (Name.getOccString appliedFunBndr) of "ClockUp" -> return (True,clockLit) "ClockDown" -> return (False,clockLit) (App _ _) -> do let (Var appliedFunBndr, [litArg]) = collectArgs clock clockLit <- Trans.lift $ getIntegerLiteral litArg case (Name.getOccString appliedFunBndr) of "ClockUp" -> return (True,clockLit) "ClockDown" -> return (False,clockLit) otherwise -> do error $ "Normalize.arrowLiftSExtract: Do now know how to handle clock:" ++ show clock Trans.lift $ MonadState.modify tsClocks (Map.insert realfunBndr clockEdge) -- Return the extracted expression change (Lam id1 (Lam id2 (App (App realfunBody (Var id1)) (Var id2)))) where (appliedF, alreadyMappedArgs) = collectArgs expr -- Leave all other expressions unchanged arrowLiftSExtract c e = return e ---------------------------------- -- implicit lift (arr) extraction ---------------------------------- -- Combinational functions are implicitly lifted to arrows by GHC using the -- the 'arr' function, e.g. arr f; where f is of type: a -> b. We replace the -- lifting function by an application of 'f' to its argument: f (x::a). -- -- From: -- arr (f :: a -> b) -- -- To: -- \() (x::a) -> ((), f x) arrowLiftExtract :: Transform arrowLiftExtract c expr@(App _ _) | isArrLift (appliedF, alreadyMappedArgs) = do -- Collect the lifted function and the initial state let (Var arr) = appliedF let [realfun] = get_val_args (Var.varType arr) alreadyMappedArgs -- Create 2 new Vars of which the 2nd is applied to the lifted function let [argTy] = (fst . Type.splitFunTys . CoreUtils.exprType) realfun id1 <- Trans.lift $ mkInternalVar "param" TysWiredIn.unitTy id2 <- Trans.lift $ mkInternalVar "param" argTy -- Return the extracted expression let realfunapp = App realfun (Var id2) let realfunpack = MkCore.mkCoreTup [MkCore.mkCoreTup [],realfunapp] change (Lam id1 (Lam id2 (realfunpack))) where (appliedF, alreadyMappedArgs) = collectArgs expr -- Leave all other expressions unchanged arrowLiftExtract c e = return e ------------------------------------- -- return value (returnA) extraction ------------------------------------- -- The returnA function normally returns the value of an Arrow, it is replaced -- by a statefull identity function -- -- From: -- (returnA :: (Arrow a) => a b b) -- -- To: -- \() (x::b) -> ((), x) arrowReturnExtract :: Transform arrowReturnExtract c expr@(Var f) | ((Name.getOccString f) == "returnA") = do -- Create 2 new Vars of which the 2nd is of the value type of the arrow let arg_ty = (head . snd . Type.splitTyConApp . CoreUtils.exprType) expr id1 <- Trans.lift $ mkInternalVar "param" TysWiredIn.unitTy id2 <- Trans.lift $ mkInternalVar "param" arg_ty -- Return the extracted expression let packinps = MkCore.mkCoreTup [MkCore.mkCoreTup [],Var id2] change (Lam id1 (Lam id2 packinps)) -- Leave all other expressions unchanged arrowReturnExtract c e = return e -------------------------------- -- arrow hooks (>>>) extraction -------------------------------- -- The (>>>) function composes 2 arrows into 1: -- -- ----- ----- -- β --> | f | --> γ >>> γ ---> | g | ---> δ -- ----- ----- -- -- It is replaced by a statefull function that evaluates the 2 lifted -- functions in a letbinding and returns the result of the 2nd function. -- -- From: -- (>>>) (f :: s1 -> β -> (s1,γ)) (g :: s2 -> γ -> (s2,δ)) -- -- To: -- \((s::(s1,s2)) (β::β) -> letrec -- s1 = case s of (s1,s2) -> s1 -- s2 = case s of (s1,s2) -> s2 -- fout = f s1 β -- s1' = case fout of (s1',γ) -> s1' -- γ = case fout of (s1',γ) -> γ -- gout = g s2 γ -- s2' = case fout of (s2',δ) -> s2' -- δ = case fout of (s2',δ) -> δ -- aout = ((s1',s2'),δ) -- in -- aout arrowHooksExtract :: Transform arrowHooksExtract c expr@(App _ _) | isArrHooks (appliedF, alreadyMappedArgs) = do -- Collect the two lifted functions let (Var hooks) = appliedF let [f,g] = get_val_args (Var.varType hooks) alreadyMappedArgs -- Collect the types and expression for f realF <- if isArrowE f -- If f is still an arrow, arrow-normalize it first then do case f of -- If it's a variable reference, make sure the referenced expression -- is normalized, and return the bndr for the normalized expression (Var bndr) -> extractArrowExpression bndr -- Otherwise, just normalize the expression otherwise -> Trans.lift $ normalizeExpr "hookleft" aTransforms f else return f -- Collect the types and expression for g realG <- if isArrowE g -- If g is still an arrow, arrow-normalize it first then do case g of -- If it's a variable reference, make sure the referenced expression -- is normalized, and return the bndr for the normalized expression (Var bndr) -> extractArrowExpression bndr -- Otherwise, just normalize the expression otherwise -> Trans.lift $ normalizeExpr "hookright" aTransforms g else return g let [([fStateTy,fInpTy], fResTy),([gStateTy,gInpTy], gResTy)] = map (Type.splitFunTys . CoreUtils.exprType) [realF,realG] -- Create the State input type of the combined functions let stateTy = MkCore.mkCoreTupTy [fStateTy,gStateTy] stateId <- Trans.lift $ mkInternalVar "inputStateHooks" stateTy inputId <- Trans.lift $ mkInternalVar "inputHooks" fInpTy -- Unpack the states of functions f and g fStateScrutId <- Trans.lift $ mkInternalVar "fStateScrutHooks" fStateTy gStateScrutId <- Trans.lift $ mkInternalVar "gStateScrutHooks" gStateTy fStateId <- Trans.lift $ mkInternalVar "fStateHooks" fStateTy gStateId <- Trans.lift $ mkInternalVar "gStateHooks" gStateTy stateSelbndr <- Trans.lift $ mkInternalVar "stateSelHooks" stateTy let unpackFState = MkCore.mkSmallTupleSelector [fStateScrutId,gStateScrutId] fStateScrutId stateSelbndr (Var stateId) let unpackGState = MkCore.mkSmallTupleSelector [fStateScrutId,gStateScrutId] gStateScrutId stateSelbndr (Var stateId) -- Unpack the updated state and output of f fResultId <- Trans.lift $ mkInternalVar "fResultHooks" fResTy fStatePrimeScrutId <- Trans.lift $ mkInternalVar "fStatePrimeScrutHooks" fStateTy gammaScrutId <- Trans.lift $ mkInternalVar "gammaScrutHooks" gInpTy fStatePrimeId <- Trans.lift $ mkInternalVar "fStatePrimeHooks" fStateTy gammaId <- Trans.lift $ mkInternalVar "gammaHooks" gInpTy fResultSelbndr <- Trans.lift $ mkInternalVar "fResultSelHooks" fResTy let unpackFStatePrime = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,gammaScrutId] fStatePrimeScrutId fResultSelbndr (Var fResultId) let unpackGamma = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,gammaScrutId] gammaScrutId fResultSelbndr (Var fResultId) -- Unpack the updated state and output of g let deltaType = (last . snd . Type.splitTyConApp) gResTy gResultId <- Trans.lift $ mkInternalVar "gResultHooks" gResTy gStatePrimeScrutId <- Trans.lift $ mkInternalVar "gStatePrimeScrutHooks" gStateTy deltaScrutId <- Trans.lift $ mkInternalVar "deltaScrutHooks" deltaType gStatePrimeId <- Trans.lift $ mkInternalVar "gStatePrimeHooks" gStateTy deltaId <- Trans.lift $ mkInternalVar "deltaHooks" deltaType gResultSelbndr <- Trans.lift $ mkInternalVar "gResultSelHooks" gResTy let unpackGStatePrime = MkCore.mkSmallTupleSelector [gStatePrimeScrutId,deltaScrutId] gStatePrimeScrutId gResultSelbndr (Var gResultId) let unpackDelta = MkCore.mkSmallTupleSelector [gStatePrimeScrutId,deltaScrutId] deltaScrutId gResultSelbndr (Var gResultId) -- Pack the update state, and pack the result of g let resPack = MkCore.mkCoreTup [MkCore.mkCoreTup [Var fStatePrimeId, Var gStatePrimeId], Var deltaId] arrowHooksOutId <- Trans.lift $ mkInternalVar "arrowHooksOut" (CoreUtils.exprType (resPack)) let letexprs = Rec [(fStateId, unpackFState) ,(gStateId, unpackGState) , (fResultId, (App (App realF (Var fStateId)) (Var inputId))) , (fStatePrimeId, unpackFStatePrime) , (gammaId, unpackGamma) , (gResultId, (App (App realG (Var gStateId)) (Var gammaId))) , (gStatePrimeScrutId, unpackGStatePrime) , (deltaId, unpackDelta) , (arrowHooksOutId, resPack) ] let letExpression = MkCore.mkCoreLets [letexprs] (Var arrowHooksOutId) change (Lam stateId (Lam inputId (letExpression))) where (appliedF, alreadyMappedArgs) = collectArgs expr -- Leave all other expressions unchanged arrowHooksExtract c e = return e -------------------------------- -- arrow first extraction -------------------------------- -- The first function encapsulates arrow in a larger arrow which has a input -- tuple and an output tuple. The inner arrow is applied to the first value -- of the tuple: -- -- ------------- -- | ----- | -- β ---|-> | f | --|--> γ -- | ----- | -- δ ---|-----------|--> δ -- ------------- -- -- It is replaced by a statefull function that evaluates the lifted -- function in a letbinding and returns the result as part of the tuple. -- -- From: -- first (f :: s -> β -> (s,γ)) -- -- To: -- \(s::s) (i::(β,δ)) -> letrec -- β = case i of (β,δ) -> β -- δ = case i of (β,δ) -> δ -- fout = f s β -- s' = case fout of (s',γ) -> s' -- γ = case fout of (s',γ) -> γ -- aout = (s',(γ,δ)) -- in -- aout arrowFirstExtract :: Transform arrowFirstExtract c expr@(App _ _) | isArrFirst (appliedF, alreadyMappedArgs) = do let (Var first) = appliedF -- Get type of delta and gamma let deltaTy = (last . snd . Type.splitTyConApp . head . snd . Type.splitTyConApp . CoreUtils.exprType) expr let gammaTy = (head . snd . Type.splitTyConApp . last . snd . Type.splitTyConApp . CoreUtils.exprType) expr -- Retreive the packed functions let [f] = get_val_args (Var.varType first) alreadyMappedArgs -- Get the State, Input and Result type of the packed function realF <- if isArrowE f -- If f is still an arrow, arrow-normalize it first then do case f of -- If it's a variable reference, make sure the referenced expression -- is normalized, and return the bndr for the normalized expression (Var bndr) -> extractArrowExpression bndr -- Otherwise, just normalize the expression otherwise -> Trans.lift $ normalizeExpr "first" aTransforms f else return f let ([fStateTy,fInpTy], fResTy) = (Type.splitFunTys . CoreUtils.exprType) realF -- Create a new input type that is a combination of the input of 'f' and delta let inputTy = MkCore.mkCoreTupTy [fInpTy,deltaTy] inputStateId <- Trans.lift $ mkInternalVar "inputStateFirst" fStateTy inputId <- Trans.lift $ mkInternalVar "inputFirst" inputTy -- Unpack input into input for function f and delta fInputScrutId <- Trans.lift $ mkInternalVar "fInputScrutFirst" fInpTy deltaScrutId <- Trans.lift $ mkInternalVar "deltaScrutFirst" deltaTy fInput <- Trans.lift $ mkInternalVar "fInputFirst" fInpTy deltaId <- Trans.lift $ mkInternalVar "deltaFirst" deltaTy let unpackFInput = MkCore.mkSmallTupleSelector [fInputScrutId,deltaScrutId] fInputScrutId (MkCore.mkWildBinder inputTy) (Var inputId) let unpackDelta = MkCore.mkSmallTupleSelector [fInputScrutId,deltaScrutId] deltaScrutId (MkCore.mkWildBinder inputTy) (Var inputId) -- Unpack the updated state of 'f' and its output fResultId <- Trans.lift $ mkInternalVar "fResultFirst" fResTy fStatePrimeScrutId <- Trans.lift $ mkInternalVar "fStatePrimeScrutFirst" fStateTy gammaScrutId <- Trans.lift $ mkInternalVar "gammaScrutFirst" gammaTy fStatePrimeId <- Trans.lift $ mkInternalVar "fStatePrimeFirst" fStateTy gammaId <- Trans.lift $ mkInternalVar "gammaFirst" gammaTy let unpackFStatePrime = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,gammaScrutId] fStatePrimeScrutId (MkCore.mkWildBinder fResTy) (Var fResultId) let unpackGamma = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,gammaScrutId] gammaScrutId (MkCore.mkWildBinder fResTy) (Var fResultId) -- Pack the update state, and pack the result of f and delta let resPack = MkCore.mkCoreTup [Var fStatePrimeId, MkCore.mkCoreTup [Var gammaId, Var deltaId]] arrowFirstOutId <- Trans.lift $ mkInternalVar "arrowFirstOut" (CoreUtils.exprType (resPack)) let letexprs = Rec [ (fInput, unpackFInput) , (deltaId, unpackDelta) , (fResultId, (App (App realF (Var inputStateId)) (Var fInput))) , (fStatePrimeId, unpackFStatePrime) , (gammaId, unpackGamma) , (arrowFirstOutId, resPack) ] let letExpression = MkCore.mkCoreLets [letexprs] (Var arrowFirstOutId) change (Lam inputStateId (Lam inputId (letExpression))) where (appliedF, alreadyMappedArgs) = collectArgs expr -- Leave all other expressions unchanged arrowFirstExtract c e = return e -------------------------------- -- arrow loop extraction -------------------------------- -- The loop function feeds back the latter part of the outputtuple of an arrow -- -- ------- -- β ---> | | ---> γ -- | f | -- ---> | | --- -- | ------- | -- ---------------- -- δ -- -- It is replaced by a statefull function that evaluates the lifted -- function in a letbinding and feeds back part of the result to itself -- -- From: -- loop (f :: s -> (β,δ) -> (s,(γ,δ)) -- -- To: -- \(s::s) (i::(β,δ)) -> letrec -- i = (β,δ) -- fout = f s i -- s' = case fout of (s',fres) -> s' -- fres = case fout of (s',fres) -> fres -- γ = case fres of (γ,δ) -> γ -- δ = case fres of (γ,δ) -> δ -- aout = (s',γ) -- in -- aout arrowLoopExtract :: Transform arrowLoopExtract c expr@(App _ _) | isArrLoop (appliedF, alreadyMappedArgs) = do let (Var loop) = appliedF let [f] = get_val_args (Var.varType loop) alreadyMappedArgs -- Get the State, Input and Result type of the packed function realF <- if isArrowE f -- If f is still an arrow, arrow-normalize it first then do case f of -- If it's a variable reference, make sure the referenced expression -- is normalized, and return the bndr for the normalized expression (Var bndr) -> extractArrowExpression bndr -- Otherwise, just normalize the expression otherwise -> Trans.lift $ normalizeExpr "arrowLoop" aTransforms f else return f let ([fStateTy,fInpTy], fResTy) = (Type.splitFunTys . CoreUtils.exprType) realF let [betaTy,deltaTy] = (snd . Type.splitTyConApp) fInpTy let fOutTy = (last . snd . Type.splitTyConApp) fResTy let gammaTy = (head . snd . Type.splitTyConApp) fOutTy betaId <- Trans.lift $ mkInternalVar "betaLoop" betaTy deltaId <- Trans.lift $ mkInternalVar "deltaLoop" deltaTy gammaId <- Trans.lift $ mkInternalVar "gammaLoop" gammaTy deltaScrutId <- Trans.lift $ mkInternalVar "deltaScrutLoop" deltaTy gammaScrutId <- Trans.lift $ mkInternalVar "gammaScrutLoop" gammaTy fInput <- Trans.lift $ mkInternalVar "fInputLoop" fInpTy inputStateId <- Trans.lift $ mkInternalVar "inputStateLoop" fStateTy let inputPack = MkCore.mkCoreTup [Var betaId, Var deltaId] fResultId <- Trans.lift $ mkInternalVar "fResultLoop" fResTy fOutId <- Trans.lift $ mkInternalVar "fOutLoop" fOutTy fOutScrutId <- Trans.lift $ mkInternalVar "fOutScrutLoop" fOutTy fStatePrimeId <- Trans.lift $ mkInternalVar "fStatePrimeLoop" fStateTy fStatePrimeScrutId <- Trans.lift $ mkInternalVar "fStatePrimeScrutLoop" fStateTy let unpackFStatePrime = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,fOutScrutId] fStatePrimeScrutId (MkCore.mkWildBinder fResTy) (Var fResultId) let unpackFOut = MkCore.mkSmallTupleSelector [fStatePrimeScrutId,fOutScrutId] fOutScrutId (MkCore.mkWildBinder fResTy) (Var fResultId) let unpackGamma = MkCore.mkSmallTupleSelector [gammaScrutId,deltaScrutId] gammaScrutId (MkCore.mkWildBinder fOutTy) (Var fOutId) let unpackDelta = MkCore.mkSmallTupleSelector [gammaScrutId,deltaScrutId] deltaScrutId (MkCore.mkWildBinder fOutTy) (Var fOutId) let resPack = MkCore.mkCoreTup [Var fStatePrimeId, Var gammaId] arrowLoopOutId <- Trans.lift $ mkInternalVar "arrowLoopOut" (CoreUtils.exprType (resPack)) let letexprs = Rec [ (fInput, inputPack) , (fResultId, (App (App realF (Var inputStateId)) (Var fInput))) , (fStatePrimeId, unpackFStatePrime) , (fOutId, unpackFOut) , (gammaId, unpackGamma) , (deltaId, unpackDelta) , (arrowLoopOutId, resPack) ] let letExpression = MkCore.mkCoreLets [letexprs] (Var arrowLoopOutId) change (Lam inputStateId (Lam betaId (letExpression))) where (appliedF, alreadyMappedArgs) = collectArgs expr -- Leave all other expressions unchanged arrowLoopExtract c e = return e -------------------------------- -- End of transformations -------------------------------- -- What transforms to run? transforms = [ ("inlinedict", inlinedict) , ("inlinetoplevel", inlinetoplevel) , ("inlinenonrepresult", inlinenonrepresult) , ("knowncase", knowncase) , ("classopresolution", classopresolution) , ("argprop", argprop) , ("funextract", funextract) , ("eta", eta) , ("beta", beta) , ("appprop", appprop) , ("castprop", castprop) , ("letremovesimple", letremovesimple) , ("letrec", letrec) , ("letremove", letremove) , ("retvalsimpl", retvalsimpl) , ("letflat", letflat) , ("scrutsimpl", scrutsimpl) , ("scrutbndrremove", scrutbndrremove) , ("casesimpl", casesimpl) , ("caseremove", caseremove) , ("inlinenonrep", inlinenonrep) , ("appsimpl", appsimpl) , ("letremoveunused", letremoveunused) , ("castsimpl", castsimpl) ] -- What transforms to apply to get rid of arrows aTransforms = [ ("inlinenonrep", inlinenonrep) , ("letrec", letrec) , ("inlineArrowHooks", inlineArrowHooks) , ("letremove", letremove) , ("beta", beta) , ("eta", eta) , ("arrowLiftSExtract", arrowLiftSExtract) , ("arrowLiftExtract", arrowLiftExtract) , ("arrowReturnExtract", arrowReturnExtract) , ("arrowHooksExtract", arrowHooksExtract) , ("arrowFirstExtract", arrowFirstExtract) , ("arrowLoopExtract", arrowLoopExtract) ] -- | Returns the normalized version of the given function, or an error -- if it is not a known global binder. getNormalized :: Bool -- ^ Allow the result to be unrepresentable? -> CoreBndr -- ^ The function to get -> TranslatorSession CoreExpr -- The normalized function body getNormalized result_nonrep bndr = do norm <- getNormalized_maybe result_nonrep bndr return $ Maybe.fromMaybe (error $ "Normalize.getNormalized: Unknown or non-representable function requested: " ++ show bndr) norm -- | Returns the normalized version of the given function, or Nothing -- when the binder is not a known global binder or is not normalizeable. getNormalized_maybe :: Bool -- ^ Allow the result to be unrepresentable? -> CoreBndr -- ^ The function to get -> TranslatorSession (Maybe CoreExpr) -- The normalized function body getNormalized_maybe result_nonrep bndr = do expr_maybe <- getGlobalBind bndr case (isArrowB bndr, expr_maybe) of -- The bndr is an Arrow (True, Just arrowf) -> do normalizedA <- Utils.makeCached bndr tsNormalized $ do { -- First apply the transformations that remove the arrows ; arrowLessExpr <- normalizeExpr (show bndr) aTransforms arrowf -- Secondly apply the standard normalization transformations ; normalizeExpr (show bndr) transforms arrowLessExpr } normalizeable <- isNormalizeableE result_nonrep normalizedA if not normalizeable then return Nothing else do realfun <- mkFunction bndr normalizedA MonadState.modify tsArrows (Map.insert bndr realfun) return (Just normalizedA) -- The expression is not an Arrow (False, Just expr) -> do normalizeable <- isNormalizeable result_nonrep bndr if not normalizeable then -- Binder not normalizeable return Nothing else do -- Binder found and is monomorphic. Normalize the expression -- and cache the result. normalized <- Utils.makeCached bndr tsNormalized $ normalizeExpr (show bndr) transforms expr return (Just normalized) -- No expression belonging to this binder found otherwise -> return Nothing where isLiftMaybe :: Maybe CoreExpr -> Bool isLiftMaybe Nothing = False isLiftMaybe (Just x) = (isLift . CoreSyn.collectArgs) x -- | Normalize an expression normalizeExpr :: String -- ^ What are we normalizing? For debug output only. -> [(String, Transform)] -- ^ What transformations we are applying -> CoreSyn.CoreExpr -- ^ The expression to normalize -> TranslatorSession CoreSyn.CoreExpr -- ^ The normalized expression normalizeExpr what normTransforms expr = do startcount <- MonadState.get tsTransformCounter expr_uniqued <- genUniques expr -- Do a debug print, if requested let expr_uniqued' = Utils.traceIf (normalize_debug >= NormDbgFinal) (what ++ " before normalization:\n\n" ++ showSDoc ( ppr expr_uniqued ) ++ "\n") expr_uniqued -- Normalize this expression expr' <- dotransforms normTransforms expr_uniqued' endcount <- MonadState.get tsTransformCounter -- Do a debug print, if requested Utils.traceIf (normalize_debug >= NormDbgFinal) (what ++ " after normalization:\n\n" ++ showSDoc ( ppr expr') ++ "\nNeeded " ++ show (endcount - startcount) ++ " transformations to normalize " ++ what) $ return expr' -- | Split a normalized expression into the argument binders, top level -- bindings and the result binder. This function returns an error if -- the type of the expression is not representable. splitNormalized :: CoreExpr -- ^ The normalized expression -> ([CoreBndr], [Binding], CoreBndr) splitNormalized expr = case splitNormalizedNonRep expr of (args, binds, Var res) -> (args, binds, res) _ -> error $ "Normalize.splitNormalized: Not in normal form: " ++ pprString expr ++ "\n" -- Split a normalized expression, whose type can be unrepresentable. splitNormalizedNonRep:: CoreExpr -- ^ The normalized expression -> ([CoreBndr], [Binding], CoreExpr) splitNormalizedNonRep expr = (args, binds, resexpr) where (args, letexpr) = CoreSyn.collectBinders expr (binds, resexpr) = flattenLets letexpr