X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreTidy.lhs;h=ba604667e7f22289f0e66799c48e68bcc74fe5e6;hb=f5ca07d670fd2fcd196aa670890257117a015728;hp=64d7c738d6c7890c03d55a8cf29a2a6e1043e363;hpb=08002107c35bdf124b1e3814d42734d82e392d45;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreTidy.lhs b/ghc/compiler/coreSyn/CoreTidy.lhs index 64d7c73..ba60466 100644 --- a/ghc/compiler/coreSyn/CoreTidy.lhs +++ b/ghc/compiler/coreSyn/CoreTidy.lhs @@ -1,508 +1,42 @@ % -% (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, tidyCoreExpr, - tidyBndr, tidyBndrs + tidyExpr, tidyVarOcc, tidyRule, tidyRules ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas ) 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, - idSpecialisation, idUnique, - mkVanillaGlobal, isLocalId, isImplicitId, - hasNoBinding, mkUserLocal - ) -import IdInfo {- loads of stuff -} -import Name ( getOccName, nameOccName, globaliseName, setNameOcc, - localiseName, isGlobalName - ) -import NameEnv ( filterNameEnv ) -import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName ) -import Type ( tidyTopType, tidyType, tidyTyVar ) -import Module ( Module, moduleName ) -import HscTypes ( PersistentCompilerState( pcs_PRS ), - PersistentRenamerState( prsOrig ), - NameSupply( nsNames ), OrigNameCache, - TypeEnv, extendTypeEnvList, - ModDetails(..), TyThing(..) - ) -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 List ( partition ) -import Util ( mapAccumL ) +import Maybes ( orElse ) import Outputable +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 UTTERLY FINAL IdInfo; in ptic, - * Its IdDetails becomes VanillaGlobal, reflecting the fact that - from now on we regard it as a global, not local, Id - - * its unfolding, if it should have one - - * its arity, computed from the number of visible lambdas - - * its CAF info, computed from what is free in its RHS - - -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 - -> CgInfoEnv -- Information from the back end, - -- to be splatted into the IdInfo - -> ModDetails - -> IO (PersistentCompilerState, ModDetails) - -tidyCorePgm dflags mod pcs cg_info_env - (ModDetails { md_types = env_tc, md_insts = insts_tc, - md_binds = binds_in, md_rules = orphans_in }) - = do { showPass dflags "Tidy Core" - - ; let ext_ids = findExternalSet binds_in orphans_in - ; let ext_rules = findExternalRules binds_in orphans_in ext_ids - - ; let ((orig_env', occ_env, subst_env), tidy_binds) - = mapAccumL (tidyTopBind mod ext_ids cg_info_env) - init_tidy_env binds_in - - ; let tidy_rules = tidyIdRules (occ_env,subst_env) ext_rules - - ; let prs' = prs { prsOrig = orig { nsNames = orig_env' } } - pcs' = pcs { pcs_PRS = prs' } - - ; let final_ids = [ id | bind <- tidy_binds - , id <- bindersOf bind - , isGlobalName (idName id)] - - -- Dfuns are local Ids that might have - -- changed their unique during tidying - ; let lookup_dfun_id id = lookupVarEnv subst_env id `orElse` - pprPanic "lookup_dfun_id" (ppr id) - - - ; let tidy_type_env = mkFinalTypeEnv env_tc final_ids - tidy_dfun_ids = map lookup_dfun_id insts_tc - - ; let tidy_details = ModDetails { md_types = tidy_type_env, - md_rules = tidy_rules, - md_insts = tidy_dfun_ids, - md_binds = tidy_binds } - - ; endPass dflags "Tidy Core" Opt_D_dump_simpl tidy_binds - - ; return (pcs', tidy_details) - } - 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 = nsNames orig - - init_tidy_env = (orig_env, initTidyOccEnv avoids, emptyVarEnv) - avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in, - isGlobalName (idName bndr)] - -tidyCoreExpr :: CoreExpr -> IO CoreExpr -tidyCoreExpr expr = return (tidyExpr emptyTidyEnv expr) -\end{code} - - -%************************************************************************ -%* * -\subsection{Write a new interface file} -%* * -%************************************************************************ - -\begin{code} -mkFinalTypeEnv :: TypeEnv -- From typechecker - -> [Id] -- Final Ids - -> TypeEnv - -mkFinalTypeEnv type_env final_ids - = extendTypeEnvList (filterNameEnv keep_it type_env) - (map AnId final_ids) - where - -- The competed type environment is gotten from - -- a) keeping the types and classes - -- b) removing all Ids, - -- c) adding Ids with correct IdInfo, including unfoldings, - -- gotten from the bindings - -- From (c) we keep only those Ids with Global names; - -- the CoreTidy pass makes sure these are all and only - -- the externally-accessible ones - -- This truncates the type environment to include only the - -- exported Ids and things needed from them, which saves space - -- - -- However, we do keep things like constructors, which should not appear - -- in interface files, because they are needed by importing modules when - -- using the compilation manager - - -- We keep constructor workers, because they won't appear - -- in the bindings from which final_ids are derived! - keep_it (AnId id) = hasNoBinding id -- Remove all Ids except constructor workers - keep_it other = True -- Keep all TyCons and Classes -\end{code} - -\begin{code} -findExternalRules :: [CoreBind] - -> [IdCoreRule] -- Orphan rules - -> IdEnv a -- Ids that are exported, so we need their rules - -> [IdCoreRule] - -- The complete rules are gotten by combining - -- a) the orphan rules - -- b) rules embedded in the top-level Ids -findExternalRules binds orphan_rules ext_ids - | opt_OmitInterfacePragmas = [] - | otherwise - = orphan_rules ++ local_rules - where - local_rules = [ (id, rule) - | id <- bindersOfBinds binds, - id `elemVarEnv` ext_ids, - rule <- rulesRules (idSpecialisation id), - not (isBuiltinRule rule) - -- We can't print builtin rules in interface files - -- Since they are built in, an importing module - -- will have access to them anyway - ] -\end{code} - -%************************************************************************ -%* * -\subsection{Step 1: finding externals} -%* * -%************************************************************************ - -\begin{code} -findExternalSet :: [CoreBind] -> [IdCoreRule] - -> IdEnv Bool -- In domain => external - -- Range = 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 isLocalId 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 - -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 isLocalId 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 = (OrigNameCache, 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 external - -- True <=> their unfolding is external too - -> CgInfoEnv - -> TopTidyEnv -> CoreBind - -> (TopTidyEnv, CoreBind) - -tidyTopBind mod ext_ids cg_info_env top_tidy_env (NonRec bndr rhs) - = ((orig,occ,subst) , NonRec bndr' rhs') - where - ((orig,occ,subst), bndr') - = tidyTopBinder mod ext_ids cg_info_env rec_tidy_env rhs' top_tidy_env bndr - rec_tidy_env = (occ,subst) - rhs' = tidyExpr rec_tidy_env rhs - -tidyTopBind mod ext_ids cg_info_env top_tidy_env (Rec prs) - = (final_env, Rec prs') - where - (final_env@(_,occ,subst), prs') = mapAccumL do_one top_tidy_env prs - rec_tidy_env = (occ,subst) - - do_one top_tidy_env (bndr,rhs) - = ((orig,occ,subst), (bndr',rhs')) - where - ((orig,occ,subst), bndr') - = tidyTopBinder mod ext_ids cg_info_env - rec_tidy_env rhs' top_tidy_env bndr - - rhs' = tidyExpr rec_tidy_env rhs - -tidyTopBinder :: Module -> IdEnv Bool - -> CgInfoEnv - -> TidyEnv -> CoreExpr - -- The TidyEnv is used to tidy the IdInfo - -- The expr is the already-tided RHS - -- Both are knot-tied: don't look at them! - -> TopTidyEnv -> Id -> (TopTidyEnv, Id) - -- NB: tidyTopBinder doesn't affect the unique supply - -tidyTopBinder mod ext_ids cg_info_env tidy_env rhs - env@(orig_env2, occ_env2, subst_env2) id - - | isImplicitId 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_env2 occ_env2 - is_external - (idName id) - ty' = tidyTopType (idType id) - cg_info = lookupCgInfo cg_info_env name' - idinfo' = tidyIdInfo tidy_env is_external unfold_info cg_info id - - id' = mkVanillaGlobal name' ty' idinfo' - subst_env' = extendVarEnv subst_env2 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 tidy_env is_external unfold_info cg_info id - | opt_OmitInterfacePragmas || not is_external - -- No IdInfo if the Id isn't external, or if we don't have -O - = vanillaIdInfo - `setCgInfo` cg_info - `setStrictnessInfo` strictnessInfo core_idinfo - -- Keep strictness; it's used by CorePrep - - | otherwise - = vanillaIdInfo - `setCgInfo` cg_info - `setCprInfo` cprInfo core_idinfo - `setStrictnessInfo` strictnessInfo core_idinfo - `setInlinePragInfo` inlinePragInfo core_idinfo - `setUnfoldingInfo` unfold_info - `setWorkerInfo` tidyWorker tidy_env (workerInfo core_idinfo) - -- NB: we throw away the Rules - -- They have already been extracted by findExternalRules - where - core_idinfo = idInfo id - - --- This is where we set names to local/global based on whether they really are --- externally visible (see comment at the top of this module). If the name --- was previously local, we have to give it a unique occurrence name if --- we intend to globalise it. -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') - -- Even local, internal names must get a unique occurrence, because - -- if we do -split-objs we globalise the name later, n the code generator - - | global && external = (orig_env, occ_env, name) - -- Global names are assumed to have been allocated by the renamer, - -- so they already have the "right" unique - - | local && external = case lookupFM orig_env key of - Just orig -> (orig_env, occ_env', orig) - Nothing -> (addToFM orig_env key global_name, occ_env', global_name) - -- 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 - - where - (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 - ------------- Worker -------------- -tidyWorker tidy_env (HasWorker work_id wrap_arity) - = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity -tidyWorker tidy_env other - = NoWorker - ------------- Rules -------------- -tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule] -tidyIdRules env [] = [] -tidyIdRules env ((fn,rule) : rules) - = tidyRule env rule =: \ rule -> - tidyIdRules env rules =: \ rules -> - ((tidyVarOcc env fn, rule) : rules) - -tidyRule :: TidyEnv -> CoreRule -> CoreRule -tidyRule env rule@(BuiltinRule _) = rule -tidyRule env (Rule name vars tpl_args rhs) - = tidyBndrs env vars =: \ (env', vars) -> - map (tidyExpr env') tpl_args =: \ tpl_args -> - (Rule name vars tpl_args (tidyExpr env' rhs)) -\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} %* * %************************************************************************ @@ -512,15 +46,17 @@ tidyBind :: TidyEnv -> (TidyEnv, CoreBind) tidyBind env (NonRec bndr rhs) - = tidyBndrWithRhs env (bndr,rhs) =: \ (env', bndr') -> + = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') -> (env', NonRec bndr' (tidyExpr env' rhs)) tidyBind env (Rec prs) - = mapAccumL tidyBndrWithRhs env prs =: \ (env', bndrs') -> + = 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 @@ -531,64 +67,153 @@ tidyExpr env (Let b e) = tidyBind env b =: \ (env', b') -> Let b' (tidyExpr env' e) -tidyExpr env (Case e b alts) +tidyExpr env (Case e b ty alts) = tidyBndr env b =: \ (env', b) -> - Case (tidyExpr env e) b (map (tidyAlt env') alts) + 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 env (con, vs, rhs) +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 + +------------ 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 + | isTyVar var = tidyTyVarBndr env var + | otherwise = tidyIdBndr env var tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var]) tidyBndrs env vars = mapAccumL tidyBndr env vars --- tidyBndrWithRhs is used for let binders -tidyBndrWithRhs :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var) -tidyBndrWithRhs env (id,rhs) = tidyId env id - -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 -- - -- All local Ids now have the same IdInfo, which should save some - -- space. - (tidy_env', occ') = tidyOccName tidy_env (getOccName id) - ty' = tidyType (tidy_env,var_env) (idType 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' = mkUserLocal occ' (idUnique id) ty' noSrcLoc + `setIdInfo` vanillaIdInfo var_env' = extendVarEnv var_env id id' in ((tidy_env', var_env'), id') + } \end{code} \begin{code}