X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreTidy.lhs;h=ba604667e7f22289f0e66799c48e68bcc74fe5e6;hb=28a464a75e14cece5db40f2765a29348273ff2d2;hp=7335d3aeaa807b5bfb3d749a75cf56476b04f9e6;hpb=243dedb8741d13162fe944ebf2adace921e0108d;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreTidy.lhs b/ghc/compiler/coreSyn/CoreTidy.lhs index 7335d3a..ba60466 100644 --- a/ghc/compiler/coreSyn/CoreTidy.lhs +++ b/ghc/compiler/coreSyn/CoreTidy.lhs @@ -1,266 +1,221 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 +% (c) The AQUA Project, Glasgow University, 1996-1998 % -\section{Tidying up Core} \begin{code} module CoreTidy ( - tidyCorePgm, tidyExpr, - tidyBndr, tidyBndrs + tidyExpr, tidyVarOcc, tidyRule, tidyRules ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlags, DynFlag(..), opt_UsageSPOn, dopt ) import CoreSyn -import CoreUnfold ( noUnfolding ) -import CoreLint ( beginPass, endPass ) -import UsageSPInf ( doUsageSPInf ) +import CoreUtils ( exprArity ) +import Unify ( coreRefineTys ) +import DataCon ( DataCon, isVanillaDataCon ) +import Id ( Id, mkUserLocal, idInfo, setIdInfo, idUnique, + idType, setIdType ) +import IdInfo ( setArityInfo, vanillaIdInfo, + newStrictnessInfo, setAllStrictnessInfo, + newDemandInfo, setNewDemandInfo ) +import Type ( Type, tidyType, tidyTyVarBndr, substTy, mkOpenTvSubst ) +import Var ( Var, TyVar, varName ) import VarEnv -import VarSet -import Var ( Id, Var ) -import Id ( idType, idInfo, idName, - mkVanillaId, mkId, exportWithOrigOccName, - idStrictness, setIdStrictness, - idDemandInfo, setIdDemandInfo, - ) -import IdInfo ( specInfo, setSpecInfo, - setUnfoldingInfo, setDemandInfo, - workerInfo, setWorkerInfo, WorkerInfo(..) - ) -import Demand ( wwLazy ) -import Name ( getOccName, tidyTopName, mkLocalName ) -import OccName ( initTidyOccEnv, tidyOccName ) -import Type ( tidyTopType, tidyType, tidyTyVar ) -import Module ( Module ) -import UniqSupply ( mkSplitUniqSupply ) -import Unique ( Uniquable(..) ) +import UniqFM ( lookupUFM ) +import Name ( Name, getOccName ) +import OccName ( tidyOccName ) import SrcLoc ( noSrcLoc ) +import Maybes ( orElse ) +import Outputable import Util ( mapAccumL ) \end{code} +This module contains "tidying" code for *nested* expressions, bindings, rules. +The code for *top-level* bindings is in TidyPgm. %************************************************************************ %* * -\subsection{Tidying core} +\subsection{Tidying expressions, rules} %* * %************************************************************************ -Several tasks are done by @tidyCorePgm@ - -1. If @opt_UsageSPOn@ then compute usage information (which is - needed by Core2Stg). ** NOTE _scc_ HERE ** - Do this first, because it may introduce new binders. - -2. Make certain top-level bindings into Globals. The point is that - Global things get externally-visible labels at code generation - time - - -3. Give all binders a nice print-name. Their uniques aren't changed; - rather we give them lexically unique occ-names, so that we can - safely print the OccNae only in the interface file. [Bad idea to - change the uniques, because the code generator makes global labels - from the uniques for local thunks etc.] - \begin{code} -tidyCorePgm :: DynFlags -> Module - -> [CoreBind] -> [IdCoreRule] - -> IO ([CoreBind], [IdCoreRule]) -tidyCorePgm dflags module_name binds_in orphans_in - = do - us <- mkSplitUniqSupply 'u' - - beginPass dflags "Tidy Core" - - binds_in1 <- if opt_UsageSPOn - then _scc_ "CoreUsageSPInf" - doUsageSPInf dflags us binds_in - else return binds_in - - let (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name)) - init_tidy_env binds_in1 - orphans_out = tidyIdRules tidy_env1 orphans_in - - endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags || - dopt Opt_D_verbose_core2core dflags) - binds_out - - return (binds_out, orphans_out) - where - -- We also make sure to avoid any exported binders. Consider - -- f{-u1-} = 1 -- Local decl - -- ... - -- f{-u2-} = 2 -- Exported decl - -- - -- The second exported decl must 'get' the name 'f', so we - -- have to put 'f' in the avoids list before we get to the first - -- decl. tidyTopId then does a no-op on exported binders. - init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv) - avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in, - exportWithOrigOccName bndr] - -tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested - -> TidyEnv +tidyBind :: TidyEnv -> CoreBind - -> (TidyEnv, CoreBind) -tidyBind maybe_mod env (NonRec bndr rhs) - = let - (env', bndr') = tidy_bndr maybe_mod env' env bndr - rhs' = tidyExpr env' rhs - -- We use env' when tidying the RHS even though it's not - -- strictly necessary; it makes the code pretty hard to read - -- if we don't! + -> (TidyEnv, CoreBind) + +tidyBind env (NonRec bndr rhs) + = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') -> + (env', NonRec bndr' (tidyExpr env' rhs)) + +tidyBind env (Rec prs) + = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') -> + map (tidyExpr env') (map snd prs) =: \ rhss' -> + (env', Rec (zip bndrs' rhss')) + + +------------ Expressions -------------- +tidyExpr :: TidyEnv -> CoreExpr -> CoreExpr +tidyExpr env (Var v) = Var (tidyVarOcc env v) +tidyExpr env (Type ty) = Type (tidyType env ty) +tidyExpr env (Lit lit) = Lit lit +tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a) +tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e) + +tidyExpr env (Let b e) + = tidyBind env b =: \ (env', b') -> + Let b' (tidyExpr env' e) + +tidyExpr env (Case e b ty alts) + = tidyBndr env b =: \ (env', b) -> + Case (tidyExpr env e) b (tidyType env ty) + (map (tidyAlt b env') alts) + +tidyExpr env (Lam b e) + = tidyBndr env b =: \ (env', b) -> + Lam b (tidyExpr env' e) + +------------ Case alternatives -------------- +tidyAlt case_bndr env (DataAlt con, vs, rhs) + | not (isVanillaDataCon con) -- GADT case + = tidyBndrs env tvs =: \ (env1, tvs') -> + let + env2 = refineTidyEnv env con tvs' scrut_ty in - (env', NonRec bndr' rhs') - -tidyBind maybe_mod env (Rec pairs) - = let - -- We use env' when tidying the rhss - -- When tidying the binder itself we may tidy it's - -- specialisations; if any of these mention other binders - -- in the group we should really feed env' to them too; - -- but that seems (a) unlikely and (b) a bit tiresome. - -- So I left it out for now - - (bndrs, rhss) = unzip pairs - (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs - rhss' = map (tidyExpr env') rhss - in - (env', Rec (zip bndrs' rhss')) - -tidyExpr env (Type ty) = Type (tidyType env ty) -tidyExpr env (Lit lit) = Lit lit -tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a) -tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e) - -tidyExpr env (Let b e) = Let b' (tidyExpr env' e) - where - (env', b') = tidyBind Nothing env b - -tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts) - where - (env', b') = tidyBndr env b - -tidyExpr env (Var v) = Var (tidyVarOcc env v) - -tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e) - where - (env', b') = tidyBndr env b - -tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs) - where - (env', vs') = tidyBndrs env vs + tidyBndrs env2 ids =: \ (env3, ids') -> + (DataAlt con, tvs' ++ ids', tidyExpr env3 rhs) + where + (tvs, ids) = span isTyVar vs + scrut_ty = idType case_bndr + +tidyAlt case_bndr env (con, vs, rhs) + = tidyBndrs env vs =: \ (env', vs) -> + (con, vs, tidyExpr env' rhs) + +refineTidyEnv :: TidyEnv -> DataCon -> [TyVar] -> Type -> TidyEnv +-- Refine the TidyEnv in the light of the type refinement from coreRefineTys +refineTidyEnv tidy_env@(occ_env, var_env) con tvs scrut_ty + = case coreRefineTys con tvs scrut_ty of + Nothing -> tidy_env + Just (tv_subst, all_bound_here) + | all_bound_here -- Local type refinement only + -> tidy_env + | otherwise -- Apply the refining subst to the tidy env + -- This ensures that occurences have the most refined type + -- And that means that exprType will work right everywhere + -> (occ_env, mapVarEnv (refine subst) var_env) + where + subst = mkOpenTvSubst tv_subst + where + refine subst var | isId var = setIdType var (substTy subst (idType var)) + | otherwise = var +------------ Notes -------------- tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2) - tidyNote env note = note -tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of - Just v' -> v' - Nothing -> v -\end{code} +------------ Rules -------------- +tidyRules :: TidyEnv -> [CoreRule] -> [CoreRule] +tidyRules env [] = [] +tidyRules env (rule : rules) + = tidyRule env rule =: \ rule -> + tidyRules env rules =: \ rules -> + (rule : rules) -\begin{code} -tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var -tidy_bndr Nothing env_idinfo env var = tidyBndr env var +tidyRule :: TidyEnv -> CoreRule -> CoreRule +tidyRule env rule@(BuiltinRule {}) = rule +tidyRule env rule@(Rule { ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs, + ru_fn = fn, ru_rough = mb_ns }) + = tidyBndrs env bndrs =: \ (env', bndrs) -> + map (tidyExpr env') args =: \ args -> + rule { ru_bndrs = bndrs, ru_args = args, + ru_rhs = tidyExpr env' rhs, + ru_fn = tidyNameOcc env fn, + ru_rough = map (fmap (tidyNameOcc env')) mb_ns } \end{code} - %************************************************************************ %* * -\subsection{Tidying up a binder} +\subsection{Tidying non-top-level binders} %* * %************************************************************************ \begin{code} +tidyNameOcc :: TidyEnv -> Name -> Name +-- In rules and instances, we have Names, and we must tidy them too +-- Fortunately, we can lookup in the VarEnv with a name +tidyNameOcc (_, var_env) n = case lookupUFM var_env n of + Nothing -> n + Just v -> varName v + +tidyVarOcc :: TidyEnv -> Var -> Var +tidyVarOcc (_, var_env) v = lookupVarEnv var_env v `orElse` v + +-- tidyBndr is used for lambda and case binders tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var) -tidyBndr env var | isTyVar var = tidyTyVar env var - | otherwise = tidyId env var +tidyBndr env var + | isTyVar var = tidyTyVarBndr env var + | otherwise = tidyIdBndr env var tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var]) tidyBndrs env vars = mapAccumL tidyBndr env vars -tidyId :: TidyEnv -> Id -> (TidyEnv, Id) -tidyId env@(tidy_env, var_env) id - = -- Non-top-level variables +tidyLetBndr :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var) +-- Used for local (non-top-level) let(rec)s +tidyLetBndr env (id,rhs) + = ((tidy_env,new_var_env), final_id) + where + ((tidy_env,var_env), new_id) = tidyIdBndr env id + + -- We need to keep around any interesting strictness and + -- demand info because later on we may need to use it when + -- converting to A-normal form. + -- eg. + -- f (g x), where f is strict in its argument, will be converted + -- into case (g x) of z -> f z by CorePrep, but only if f still + -- has its strictness info. + -- + -- Similarly for the demand info - on a let binder, this tells + -- CorePrep to turn the let into a case. + -- + -- Similarly arity info for eta expansion in CorePrep + -- + final_id = new_id `setIdInfo` new_info + idinfo = idInfo id + new_info = vanillaIdInfo + `setArityInfo` exprArity rhs + `setAllStrictnessInfo` newStrictnessInfo idinfo + `setNewDemandInfo` newDemandInfo idinfo + + -- Override the env we get back from tidyId with the new IdInfo + -- so it gets propagated to the usage sites. + new_var_env = extendVarEnv var_env id final_id + +-- Non-top-level variables +tidyIdBndr :: TidyEnv -> Id -> (TidyEnv, Id) +tidyIdBndr env@(tidy_env, var_env) id + = -- do this pattern match strictly, otherwise we end up holding on to + -- stuff in the OccName. + case tidyOccName tidy_env (getOccName id) of { (tidy_env', occ') -> let -- Give the Id a fresh print-name, *and* rename its type - -- The SrcLoc isn't important now, though we could extract it from the Id - name' = mkLocalName (getUnique id) occ' noSrcLoc - (tidy_env', occ') = tidyOccName tidy_env (getOccName id) + -- The SrcLoc isn't important now, + -- though we could extract it from the Id + -- + -- All nested Ids now have the same IdInfo, namely vanillaIdInfo, + -- which should save some space. + -- But note that tidyLetBndr puts some of it back. ty' = tidyType env (idType id) - id' = mkVanillaId name' ty' - `setIdStrictness` idStrictness id - `setIdDemandInfo` idDemandInfo id - -- NB: This throws away the IdInfo of the Id, which we - -- no longer need. That means we don't need to - -- run over it with env, nor renumber it. - -- - -- The exception is strictness and demand info, which - -- is used to decide whether to use let or case for - -- function arguments and let bindings - + id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc + `setIdInfo` vanillaIdInfo var_env' = extendVarEnv var_env id id' in - ((tidy_env', var_env'), id') - -tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id) - -- The second env is the one to use for the IdInfo - -- It's necessary because when we are dealing with a recursive - -- group, a variable late in the group might be mentioned - -- in the IdInfo of one early in the group -tidyTopId mod env@(tidy_env, var_env) env_idinfo id - = -- Top level variables - let - (tidy_env', name') | exportWithOrigOccName id = (tidy_env, idName id) - | otherwise = tidyTopName mod tidy_env (idName id) - ty' = tidyTopType (idType id) - idinfo' = tidyIdInfo env_idinfo (idInfo id) - id' = mkId name' ty' idinfo' - var_env' = extendVarEnv var_env id id' - in - ((tidy_env', var_env'), id') + ((tidy_env', var_env'), id') + } \end{code} \begin{code} --- tidyIdInfo does these things: --- a) tidy the specialisation info and worker info (if any) --- b) zap the unfolding and demand info --- The latter two are to avoid space leaks - -tidyIdInfo env info - = info5 - where - rules = specInfo info - - info2 | isEmptyCoreRules rules = info - | otherwise = info `setSpecInfo` tidyRules env rules - - info3 = info2 `setUnfoldingInfo` noUnfolding - info4 = info3 `setDemandInfo` wwLazy - - info5 = case workerInfo info of - NoWorker -> info4 - HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a - -tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule] -tidyIdRules env rules - = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ] - -tidyRules :: TidyEnv -> CoreRules -> CoreRules -tidyRules env (Rules rules fvs) - = Rules (map (tidyRule env) rules) - (foldVarSet tidy_set_elem emptyVarSet fvs) - where - tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var) - -tidyRule :: TidyEnv -> CoreRule -> CoreRule -tidyRule env rule@(BuiltinRule _) = rule -tidyRule env (Rule name vars tpl_args rhs) - = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs)) - where - (env', vars') = tidyBndrs env vars +m =: k = m `seq` k m \end{code}