X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreTidy.lhs;h=ba604667e7f22289f0e66799c48e68bcc74fe5e6;hb=f5ca07d670fd2fcd196aa670890257117a015728;hp=a137e7a7e011c2f77d0092d781f6bc4407708f3b;hpb=e8470a28fb1d934b592341d55f69bc990fdf25c4;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreTidy.lhs b/ghc/compiler/coreSyn/CoreTidy.lhs index a137e7a..ba60466 100644 --- a/ghc/compiler/coreSyn/CoreTidy.lhs +++ b/ghc/compiler/coreSyn/CoreTidy.lhs @@ -1,502 +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_OmitInterfacePragmas, dopt ) import CoreSyn -import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile ) -import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars ) -import CoreLint ( showPass, endPass ) +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, isExportedId, - mkVanillaId, mkId, isLocalId, omitIfaceSigForId, - setIdStrictness, setIdDemandInfo, - ) -import IdInfo ( mkIdInfo, - IdFlavour(..), flavourInfo, ppFlavourInfo, - specInfo, setSpecInfo, - cprInfo, setCprInfo, - inlinePragInfo, setInlinePragInfo, isNeverInlinePrag, - strictnessInfo, setStrictnessInfo, isBottomingStrictness, - unfoldingInfo, setUnfoldingInfo, - demandInfo, - occInfo, isLoopBreaker, - workerInfo, setWorkerInfo, WorkerInfo(..) - ) -import Name ( getOccName, nameOccName, globaliseName, setNameOcc, - localiseName, mkLocalName, isGlobalName - ) -import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName ) -import Type ( tidyTopType, tidyType, tidyTyVar ) -import Module ( Module, moduleName ) -import HscTypes ( PersistentCompilerState( pcs_PRS ), PersistentRenamerState( prsOrig ), - OrigNameEnv( origNames ), OrigNameNameEnv - ) -import Unique ( Uniquable(..) ) -import FiniteMap ( lookupFM, addToFM ) -import Maybes ( maybeToBool, orElse ) -import ErrUtils ( showPass ) +import UniqFM ( lookupUFM ) +import Name ( Name, getOccName ) +import OccName ( tidyOccName ) import SrcLoc ( noSrcLoc ) -import UniqFM ( mapUFM ) +import Maybes ( orElse ) import Outputable -import List ( partition ) import Util ( mapAccumL ) \end{code} - -%************************************************************************ -%* * -\subsection{What goes on} -%* * -%************************************************************************ - -[SLPJ: 19 Nov 00] - -The plan is this. - -Step 1: Figure out external Ids -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -First we figure out which Ids are "external" Ids. An -"external" Id is one that is visible from outside the compilation -unit. These are - a) the user exported ones - b) ones mentioned in the unfoldings, workers, - or rules of externally-visible ones -This exercise takes a sweep of the bindings bottom to top. Actually, -in Step 2 we're also going to need to know which Ids should be -exported with their unfoldings, so we produce not an IdSet but an -IdEnv Bool - - - -Step 2: Tidy the program -~~~~~~~~~~~~~~~~~~~~~~~~ -Next we traverse the bindings top to bottom. For each top-level -binder - - - Make all external Ids have Global names and vice versa - This is used by the code generator to decide whether - to make the label externally visible - - - Give external ids a "tidy" occurrence name. This means - we can print them in interface files without confusing - "x" (unique 5) with "x" (unique 10). - - - Give external Ids the same Unique as they had before - if the name is in the renamer's name cache - - - Give the Id its final IdInfo; in ptic, - * Its flavour becomes ConstantId, reflecting the fact that - from now on we regard it as a constant, not local, Id - * its unfolding, if it should have one - -Finally, substitute these new top-level binders consistently -throughout, including in unfoldings. We also tidy binders in -RHSs, so that they print nicely in interfaces. - -\begin{code} -tidyCorePgm :: DynFlags -> Module - -> PersistentCompilerState - -> [CoreBind] -> [IdCoreRule] - -> IO (PersistentCompilerState, [CoreBind], [IdCoreRule]) -tidyCorePgm dflags mod pcs binds_in orphans_in - = do { showPass dflags "Tidy Core" - - ; let ext_ids = findExternalSet binds_in orphans_in - - ; let ((orig_env', occ_env, subst_env), binds_out) - = mapAccumL (tidyTopBind mod ext_ids) init_tidy_env binds_in - - ; let orphans_out = tidyIdRules (occ_env,subst_env) orphans_in - - ; let pcs' = pcs { pcs_PRS = prs { prsOrig = orig { origNames = orig_env' }}} - - ; endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags || - dopt Opt_D_verbose_core2core dflags) - binds_out - - ; return (pcs', 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. - prs = pcs_PRS pcs - orig = prsOrig prs - orig_env = origNames orig - - init_tidy_env = (orig_env, initTidyOccEnv avoids, emptyVarEnv) - avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in, - isGlobalName (idName bndr)] -\end{code} - - -%************************************************************************ -%* * -\subsection{Step 1: finding externals} -%* * -%************************************************************************ - -\begin{code} -findExternalSet :: [CoreBind] -> [IdCoreRule] - -> IdEnv Bool -- True <=> show unfolding - -- Step 1 from the notes above -findExternalSet binds orphan_rules - = foldr find init_needed binds - where - orphan_rule_ids :: IdSet - orphan_rule_ids = unionVarSets [ ruleSomeFreeVars isIdAndLocal rule - | (_, rule) <- orphan_rules] - init_needed :: IdEnv Bool - init_needed = mapUFM (\_ -> False) orphan_rule_ids - -- The mapUFM is a bit cheesy. It is a cheap way - -- to turn the set of orphan_rule_ids, which we use to initialise - -- the sweep, into a mapping saying 'don't expose unfolding' - -- (When we come to the binding site we may change our mind, of course.) - - find (NonRec id rhs) needed - | need_id needed id = addExternal (id,rhs) needed - | otherwise = needed - find (Rec prs) needed = find_prs prs needed - - -- For a recursive group we have to look for a fixed point - find_prs prs needed - | null needed_prs = needed - | otherwise = find_prs other_prs new_needed - where - (needed_prs, other_prs) = partition (need_pr needed) prs - new_needed = foldr addExternal needed needed_prs - - -- The 'needed' set contains the Ids that are needed by earlier - -- interface file emissions. If the Id isn't in this set, and isn't - -- exported, there's no need to emit anything - need_id needed_set id = id `elemVarEnv` needed_set || isExportedId id - need_pr needed_set (id,rhs) = need_id needed_set id - -isIdAndLocal id = isId id && isLocalId id - -addExternal :: (Id,CoreExpr) -> IdEnv Bool -> IdEnv Bool --- The Id is needed; extend the needed set --- with it and its dependents (free vars etc) -addExternal (id,rhs) needed - = extendVarEnv (foldVarSet add_occ needed new_needed_ids) - id show_unfold - where - add_occ id needed = extendVarEnv needed id False - -- "False" because we don't know we need the Id's unfolding - -- We'll override it later when we find the binding site - - new_needed_ids | opt_OmitInterfacePragmas = emptyVarSet - | otherwise = worker_ids `unionVarSet` - unfold_ids `unionVarSet` - spec_ids - - idinfo = idInfo id - dont_inline = isNeverInlinePrag (inlinePragInfo idinfo) - loop_breaker = isLoopBreaker (occInfo idinfo) - bottoming_fn = isBottomingStrictness (strictnessInfo idinfo) - spec_ids = rulesRhsFreeVars (specInfo idinfo) - worker_info = workerInfo idinfo - - -- Stuff to do with the Id's unfolding - -- The simplifier has put an up-to-date unfolding - -- in the IdInfo, but the RHS will do just as well - unfolding = unfoldingInfo idinfo - rhs_is_small = not (neverUnfold unfolding) - - -- We leave the unfolding there even if there is a worker - -- In GHCI the unfolding is used by importers - -- When writing an interface file, we omit the unfolding - -- if there is a worker - show_unfold = not bottoming_fn && -- Not necessary - not dont_inline && - not loop_breaker && - rhs_is_small && -- Small enough - okToUnfoldInHiFile rhs -- No casms etc - - unfold_ids | show_unfold = exprSomeFreeVars isIdAndLocal rhs - | otherwise = emptyVarSet - - worker_ids = case worker_info of - HasWorker work_id _ -> unitVarSet work_id - otherwise -> emptyVarSet -\end{code} - - -%************************************************************************ -%* * -\subsection{Step 2: top-level tidying} -%* * -%************************************************************************ - - -\begin{code} -type TopTidyEnv = (OrigNameNameEnv, TidyOccEnv, VarEnv Var) - --- TopTidyEnv: when tidying we need to know --- * orig_env: Any pre-ordained Names. These may have arisen because the --- renamer read in an interface file mentioning M.$wf, say, --- and assigned it unique r77. If, on this compilation, we've --- invented an Id whose name is $wf (but with a different unique) --- we want to rename it to have unique r77, so that we can do easy --- comparisons with stuff from the interface file - --- * occ_env: The TidyOccEnv, which tells us which local occurrences are 'used' - --- * subst_env: A Var->Var mapping that substitutes the new Var for the old -\end{code} - - -\begin{code} -tidyTopBind :: Module - -> IdEnv Bool -- Domain = Ids that should be exernal - -- True <=> their unfolding is external too - -> TopTidyEnv -> CoreBind - -> (TopTidyEnv, CoreBind) - -tidyTopBind mod ext_ids env (NonRec bndr rhs) - = (env', NonRec bndr' rhs') - where - rhs' = tidyTopRhs env rhs - (env', bndr') = tidyTopBinder mod ext_ids env rhs' env bndr - -tidyTopBind mod ext_ids env (Rec prs) - = (final_env, Rec prs') - where - (final_env, prs') = mapAccumL do_one env prs - do_one env (bndr,rhs) = (env', (bndr', rhs')) - where - rhs' = tidyTopRhs final_env rhs - (env', bndr') = tidyTopBinder mod ext_ids final_env - rhs env bndr - -tidyTopRhs :: TopTidyEnv -> CoreExpr -> CoreExpr - -- Just an impedence matcher -tidyTopRhs (_, occ_env, subst_env) rhs = tidyExpr (occ_env, subst_env) rhs - -tidyTopBinder :: Module -> IdEnv Bool - -> TopTidyEnv -> CoreExpr - -> TopTidyEnv -> Id -> (TopTidyEnv, Id) -tidyTopBinder mod ext_ids env_idinfo rhs env@(orig_env, occ_env, subst_env) id - | omitIfaceSigForId id -- Don't mess with constructors, - = (env, id) -- record selectors, and the like - - | otherwise - -- This function is the heart of Step 2 - -- 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 - - -- The rhs is already tidied - - = ((orig_env', occ_env', subst_env'), id') - where - (orig_env', occ_env', name') = tidyTopName mod orig_env occ_env - is_external - (idName id) - ty' = tidyTopType (idType id) - idinfo' = tidyIdInfo env_idinfo is_external unfold_info id - id' = mkId name' ty' idinfo' - subst_env' = extendVarEnv subst_env id id' - - maybe_external = lookupVarEnv ext_ids id - is_external = maybeToBool maybe_external - - -- Expose an unfolding if ext_ids tells us to - show_unfold = maybe_external `orElse` False - unfold_info | show_unfold = mkTopUnfolding rhs - | otherwise = noUnfolding - -tidyIdInfo (_, occ_env, subst_env) is_external unfold_info id - | opt_OmitInterfacePragmas || not is_external - -- No IdInfo if the Id isn't external, or if we don't have -O - = mkIdInfo new_flavour - `setStrictnessInfo` strictnessInfo core_idinfo - -- Keep strictness info; it's used by the code generator - - | otherwise - = mkIdInfo new_flavour - `setCprInfo` cprInfo core_idinfo - `setStrictnessInfo` strictnessInfo core_idinfo - `setInlinePragInfo` inlinePragInfo core_idinfo - `setUnfoldingInfo` unfold_info - `setWorkerInfo` tidyWorker tidy_env (workerInfo core_idinfo) - `setSpecInfo` tidyRules tidy_env (specInfo core_idinfo) - where - tidy_env = (occ_env, subst_env) - core_idinfo = idInfo id - - -- A DFunId must stay a DFunId, so that we can gather the - -- DFunIds up later. Other local things become ConstantIds. - new_flavour = case flavourInfo core_idinfo of - VanillaId -> ConstantId - ExportedId -> ConstantId - DictFunId -> DictFunId - flavour -> pprTrace "tidyIdInfo" (ppr id <+> ppFlavourInfo flavour) - flavour - -tidyTopName mod orig_env occ_env external name - | global && internal = (orig_env, occ_env, localiseName name) - | local && internal = (orig_env, occ_env', setNameOcc name occ') - | global && external = (orig_env, occ_env, name) - | local && external = globalise - where - -- If we want to globalise a currently-local name, check - -- whether we have already assigned a unique for it. - -- If so, use it; if not, extend the table - globalise = case lookupFM orig_env key of - Just orig -> (orig_env, occ_env', orig) - Nothing -> (addToFM orig_env key global_name, occ_env', global_name) - - (occ_env', occ') = tidyOccName occ_env (nameOccName name) - key = (moduleName mod, occ') - global_name = globaliseName (setNameOcc name occ') mod - global = isGlobalName name - local = not global - internal = not external - -tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule] -tidyIdRules env rules - = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ] - - -tidyWorker tidy_env (HasWorker work_id wrap_arity) - = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity -tidyWorker tidy_env NoWorker - = NoWorker - -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 -\end{code} - +This module contains "tidying" code for *nested* expressions, bindings, rules. +The code for *top-level* bindings is in TidyPgm. %************************************************************************ %* * -\subsection{Step 2: inner tidying +\subsection{Tidying expressions, rules} %* * %************************************************************************ \begin{code} tidyBind :: TidyEnv -> CoreBind - -> (TidyEnv, CoreBind) + -> (TidyEnv, CoreBind) + tidyBind env (NonRec bndr rhs) - = let - (env', bndr') = tidyBndr env bndr - rhs' = tidyExpr env' rhs - -- We use env' when tidying the RHS even though it's not - -- strictly necessary; it makes the tidied code pretty - -- hard to read if we don't! - in - (env', NonRec bndr' rhs') + = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') -> + (env', NonRec bndr' (tidyExpr env' rhs)) tidyBind env (Rec prs) - = (final_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 + 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 - (final_env, prs') = mapAccumL do_one env prs - do_one env (bndr,rhs) = (env', (bndr', rhs')) - where - (env', bndr') = tidyBndr env bndr - rhs' = tidyExpr final_env rhs - -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 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 + 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 + +------------ Rules -------------- +tidyRules :: TidyEnv -> [CoreRule] -> [CoreRule] +tidyRules env [] = [] +tidyRules env (rule : rules) + = tidyRule env rule =: \ rule -> + tidyRules env rules =: \ rules -> + (rule : rules) + +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 non-top-level binders} +\subsection{Tidying non-top-level binders} %* * %************************************************************************ \begin{code} -tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of - Just v' -> v' - Nothing -> v +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) - idinfo = idInfo id - id' = mkVanillaId name' ty' - `setIdStrictness` strictnessInfo idinfo - `setIdDemandInfo` demandInfo idinfo - -- 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') + ((tidy_env', var_env'), id') + } +\end{code} + +\begin{code} +m =: k = m `seq` k m \end{code}