X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreTidy.lhs;h=acc2c77cf08bf1b8a1f9646de301b81cb09b171f;hb=7d841483081735f5f906a6bb5e80249d97f3226b;hp=3f5626ddb0f290d7fe41047749f80740d3f2ff52;hpb=111cee3f1ad93816cb828e38b38521d85c3bcebb;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreTidy.lhs b/ghc/compiler/coreSyn/CoreTidy.lhs index 3f5626d..acc2c77 100644 --- a/ghc/compiler/coreSyn/CoreTidy.lhs +++ b/ghc/compiler/coreSyn/CoreTidy.lhs @@ -5,85 +5,143 @@ \begin{code} module CoreTidy ( - tidyCorePgm, tidyExpr, + tidyCorePgm, tidyExpr, tidyCoreExpr, tidyIdRules, tidyBndr, tidyBndrs ) where #include "HsVersions.h" -import CmdLineOpts ( opt_D_dump_simpl, opt_D_verbose_core2core, opt_UsageSPOn ) +import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas ) import CoreSyn -import CoreUnfold ( noUnfolding ) -import CoreLint ( beginPass, endPass ) -import Rules ( ProtoCoreRule(..) ) -import UsageSPInf ( doUsageSPInf ) +import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile ) +import CoreFVs ( ruleLhsFreeIds, ruleRhsFreeVars, exprSomeFreeVars ) +import PprCore ( pprIdRules ) +import CoreLint ( showPass, endPass ) +import CoreUtils ( exprArity ) import VarEnv import VarSet import Var ( Id, Var ) -import Id ( idType, idInfo, idName, - mkVanillaId, mkId, exportWithOrigOccName, - idStrictness, setIdStrictness, - idDemandInfo, setIdDemandInfo, +import Id ( idType, idInfo, idName, idCoreRules, + isExportedId, idUnique, mkVanillaGlobal, isLocalId, + isImplicitId, mkUserLocal, setIdInfo ) -import IdInfo ( specInfo, setSpecInfo, - inlinePragInfo, setInlinePragInfo, InlinePragInfo(..), - setUnfoldingInfo, setDemandInfo, - workerInfo, setWorkerInfo, WorkerInfo(..) +import IdInfo {- loads of stuff -} +import NewDemand ( isBottomingSig, topSig ) +import BasicTypes ( isNeverActive ) +import Name ( getOccName, nameOccName, mkInternalName, mkExternalName, + localiseName, isExternalName, nameSrcLoc ) -import Demand ( wwLazy ) -import Name ( getOccName, tidyTopName, mkLocalName, isLocallyDefined ) -import OccName ( initTidyOccEnv, tidyOccName ) -import Type ( tidyTopType, tidyType, tidyTypes, tidyTyVar, tidyTyVars ) -import Module ( Module ) -import UniqSupply ( UniqSupply ) -import Unique ( Uniquable(..) ) +import NameEnv ( filterNameEnv ) +import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName ) +import Type ( tidyTopType, tidyType, tidyTyVarBndr ) +import Module ( Module, moduleName ) +import HscTypes ( PersistentCompilerState( pcs_PRS ), + PersistentRenamerState( prsOrig ), + NameSupply( nsNames, nsUniqs ), + TypeEnv, extendTypeEnvList, typeEnvIds, + ModDetails(..), TyThing(..) + ) +import FiniteMap ( lookupFM, addToFM ) +import Maybes ( orElse ) +import ErrUtils ( showPass, dumpIfSet_core ) import SrcLoc ( noSrcLoc ) +import UniqFM ( mapUFM ) +import UniqSupply ( splitUniqSupply, uniqFromSupply ) +import List ( partition ) import Util ( mapAccumL ) +import Maybe ( isJust ) import Outputable \end{code} %************************************************************************ -%* * -\subsection{Tidying core} -%* * +%* * +\subsection{What goes on} +%* * %************************************************************************ -Several tasks are done by @tidyCorePgm@ - -1. Make certain top-level bindings into Globals. The point is that - Global things get externally-visible labels at code generation - time - - -2. 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.] - +[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 + + 1. Make it into a GlobalId + + 2. Give it a system-wide Unique. + [Even non-exported things need system-wide Uniques because the + byte-code generator builds a single Name->BCO symbol table.] + + We use the NameSupply kept in the PersistentRenamerState as the + source of such system-wide uniques. + + For external Ids, use the original-name cache in the NameSupply + to ensure that the unique assigned is the same as the Id had + in any previous compilation run. + + 3. If it's an external Id, make it have a global Name, otherwise + make it have a local Name. + This is used by the code generator to decide whether + to make the label externally visible + + 4. 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). + + 5. Give it 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 -3. If @opt_UsageSPOn@ then compute usage information (which is - needed by Core2Stg). ** NOTE _scc_ HERE ** + +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 :: UniqSupply -> Module -> [CoreBind] -> [ProtoCoreRule] - -> IO ([CoreBind], [ProtoCoreRule]) -tidyCorePgm us module_name binds_in rules - = do - beginPass "Tidy Core" - - let (tidy_env1, binds_tidy) = mapAccumL (tidyBind (Just module_name)) init_tidy_env binds_in - rules_out = tidyProtoRules tidy_env1 rules - - binds_out <- if opt_UsageSPOn - then _scc_ "CoreUsageSPInf" doUsageSPInf us binds_tidy - else return binds_tidy +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 + -- findExternalRules filters ext_rules to avoid binders that + -- aren't externally visible; but the externally-visible binders + -- are computed (by findExternalSet) assuming that all orphan + -- rules are exported. So in fact we may export more than we + -- need. (It's a sort of mutual recursion.) - endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out - return (binds_out, rules_out) - where -- We also make sure to avoid any exported binders. Consider -- f{-u1-} = 1 -- Local decl -- ... @@ -92,172 +150,562 @@ tidyCorePgm us module_name binds_in rules -- 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] + ; let prs = pcs_PRS pcs + orig_ns = prsOrig prs + + init_tidy_env = (orig_ns, initTidyOccEnv avoids, emptyVarEnv) + avoids = [getOccName name | bndr <- typeEnvIds env_tc, + let name = idName bndr, + isExternalName name] + -- In computing our "avoids" list, we must include + -- all implicit Ids + -- all things with global names (assigned once and for + -- all by the renamer) + -- since their names are "taken". + -- The type environment is a convenient source of such things. + + ; let ((orig_ns', occ_env, subst_env), tidy_binds) + = mapAccumL (tidyTopBind mod ext_ids cg_info_env) + init_tidy_env binds_in + + ; let tidy_rules = tidyIdCoreRules (occ_env,subst_env) ext_rules + + ; let prs' = prs { prsOrig = orig_ns' } + pcs' = pcs { pcs_PRS = prs' } + + ; let final_ids = [ id + | bind <- tidy_binds + , id <- bindersOf bind + , isExternalName (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 + ; dumpIfSet_core dflags Opt_D_dump_simpl + "Tidy Core Rules" + (pprIdRules tidy_rules) + + ; return (pcs', tidy_details) + } + +tidyCoreExpr :: CoreExpr -> IO CoreExpr +tidyCoreExpr expr = return (tidyExpr emptyTidyEnv expr) +\end{code} -tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested - -> 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! - 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 -tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2) +%************************************************************************ +%* * +\subsection{Write a new interface file} +%* * +%************************************************************************ -tidyNote env note = note +\begin{code} +mkFinalTypeEnv :: TypeEnv -- From typechecker + -> [Id] -- Final Ids + -> TypeEnv -tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of - Just v' -> v' - Nothing -> v +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 implicit Ids, because they won't appear + -- in the bindings from which final_ids are derived! + keep_it (AnId id) = isImplicitId id -- Remove all Ids except implicit ones + keep_it other = True -- Keep all TyCons and Classes \end{code} \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 +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 + = filter needed_rule (orphan_rules ++ local_rules) + where + local_rules = [ rule + | id <- bindersOfBinds binds, + id `elemVarEnv` ext_ids, + rule <- idCoreRules id + ] + needed_rule (id, rule) + = 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 + + && not (any internal_id (varSetElems (ruleLhsFreeIds rule))) + -- Don't export a rule whose LHS mentions an Id that + -- is completely internal (i.e. not visible to an + -- importing module) + + internal_id id = isLocalId id && not (id `elemVarEnv` ext_ids) \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 [ ruleRhsFreeVars 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 = isNeverActive (inlinePragInfo idinfo) + loop_breaker = isLoopBreaker (occInfo idinfo) + bottoming_fn = isBottomingSig (newStrictnessInfo idinfo `orElse` topSig) + 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{Tidying up a binder} +\subsection{Step 2: top-level tidying} %* * %************************************************************************ + \begin{code} +type TopTidyEnv = (NameSupply, TidyOccEnv, VarEnv Var) + +-- TopTidyEnv: when tidying we need to know +-- * ns: The NameSupply, containing a unique supply and 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 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 rhs' top_tidy_env bndr + + rhs' = tidyExpr rec_tidy_env rhs + +tidyTopBinder :: Module -> IdEnv Bool -> CgInfoEnv + -> TidyEnv -- The TidyEnv is used to tidy the IdInfo + -> CoreExpr -- RHS *before* tidying + -> CoreExpr -- RHS *after* tidying + -- The TidyEnv and the after-tidying RHS are + -- 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 rec_tidy_env rhs tidy_rhs + env@(ns2, occ_env2, subst_env2) id + -- This function is the heart of Step 2 + -- The rec_tidy_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 ns2 occ_env2 + is_external + (idName id) + ty' = tidyTopType (idType id) + idinfo = tidyTopIdInfo rec_tidy_env is_external + (idInfo id) unfold_info arity + (lookupCgInfo cg_info_env name') + + id' = mkVanillaGlobal name' ty' idinfo + + subst_env' = extendVarEnv subst_env2 id id' + + maybe_external = lookupVarEnv ext_ids id + is_external = isJust maybe_external + + -- Expose an unfolding if ext_ids tells us to + -- Remember that ext_ids maps an Id to a Bool: + -- True to show the unfolding, False to hide it + show_unfold = maybe_external `orElse` False + unfold_info | show_unfold = mkTopUnfolding tidy_rhs + | otherwise = noUnfolding + + -- Usually the Id will have an accurate arity on it, because + -- the simplifier has just run, but not always. + -- One case I found was when the last thing the simplifier + -- did was to let-bind a non-atomic argument and then float + -- it to the top level. So it seems more robust just to + -- fix it here. + arity = exprArity rhs + + + +-- tidyTopIdInfo creates the final IdInfo for top-level +-- binders. There are two delicate pieces: +-- +-- * Arity. After CoreTidy, this arity must not change any more. +-- Indeed, CorePrep must eta expand where necessary to make +-- the manifest arity equal to the claimed arity. +-- +-- * CAF info, which comes from the CoreToStg pass via a knot. +-- The CAF info will not be looked at by the downstream stuff: +-- it *generates* it, and knot-ties it back. It will only be +-- looked at by (a) MkIface when generating an interface file +-- (b) In GHCi, importing modules +-- Nevertheless, we add the info here so that it propagates to all +-- occurrences of the binders in RHSs, and hence to occurrences in +-- unfoldings, which are inside Ids imported by GHCi. Ditto RULES. +-- +-- An alterative would be to do a second pass over the unfoldings +-- of Ids, and rules, right at the top, but that would be a pain. + +tidyTopIdInfo tidy_env is_external idinfo unfold_info arity cg_info + | opt_OmitInterfacePragmas || not is_external + -- Only basic info if the Id isn't external, or if we don't have -O + = basic_info + + | otherwise -- Add extra optimisation info + = basic_info + `setInlinePragInfo` inlinePragInfo idinfo + `setUnfoldingInfo` unfold_info + `setWorkerInfo` tidyWorker tidy_env (workerInfo idinfo) + -- NB: we throw away the Rules + -- They have already been extracted by findExternalRules + + where + -- baasic_info is attached to every top-level binder + basic_info = vanillaIdInfo + `setCgInfo` cg_info + `setArityInfo` arity + `setAllStrictnessInfo` newStrictnessInfo idinfo + +-- 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 externalise it. +tidyTopName mod ns occ_env external name + | global && internal = (ns, occ_env, localiseName name) + + | global && external = (ns, occ_env, name) + -- Global names are assumed to have been allocated by the renamer, + -- so they already have the "right" unique + -- And it's a system-wide unique too + + | local && internal = (ns_w_local, occ_env', new_local_name) + -- Even local, internal names must get a unique occurrence, because + -- if we do -split-objs we externalise the name later, in the code generator + -- + -- Similarly, we must make sure it has a system-wide Unique, because + -- the byte-code generator builds a system-wide Name->BCO symbol table + + | local && external = case lookupFM ns_names key of + Just orig -> (ns, occ_env', orig) + Nothing -> (ns_w_global, occ_env', new_external_name) + -- If we want to externalise a currently-local name, check + -- whether we have already assigned a unique for it. + -- If so, use it; if not, extend the table (ns_w_global). + -- This is needed when *re*-compiling a module in GHCi; we want to + -- use the same name for externally-visible things as we did before. + + where + global = isExternalName name + local = not global + internal = not external + + (occ_env', occ') = tidyOccName occ_env (nameOccName name) + key = (moduleName mod, occ') + ns_names = nsNames ns + ns_uniqs = nsUniqs ns + (us1, us2) = splitUniqSupply ns_uniqs + uniq = uniqFromSupply us1 + loc = nameSrcLoc name + + new_local_name = mkInternalName uniq occ' loc + new_external_name = mkExternalName uniq mod occ' loc + + ns_w_local = ns { nsUniqs = us2 } + ns_w_global = ns { nsUniqs = us2, nsNames = addToFM ns_names key new_external_name } + + +------------ Worker -------------- +tidyWorker tidy_env (HasWorker work_id wrap_arity) + = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity +tidyWorker tidy_env other + = NoWorker + +------------ Rules -------------- +tidyIdRules :: Id -> [IdCoreRule] +tidyIdRules id = tidyIdCoreRules emptyTidyEnv (idCoreRules id) + +tidyIdCoreRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule] +tidyIdCoreRules env [] = [] +tidyIdCoreRules env ((fn,rule) : rules) + = tidyRule env rule =: \ rule -> + tidyIdCoreRules env rules =: \ rules -> + ((tidyVarOcc env fn, rule) : rules) + +tidyRule :: TidyEnv -> CoreRule -> CoreRule +tidyRule env rule@(BuiltinRule _ _) = rule +tidyRule env (Rule name act vars tpl_args rhs) + = tidyBndrs env vars =: \ (env', vars) -> + map (tidyExpr env') tpl_args =: \ tpl_args -> + (Rule name act vars tpl_args (tidyExpr env' rhs)) +\end{code} + +%************************************************************************ +%* * +\subsection{Step 2: inner tidying +%* * +%************************************************************************ + +\begin{code} +tidyBind :: TidyEnv + -> CoreBind + -> (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')) + + +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 alts) + = tidyBndr env b =: \ (env', b) -> + Case (tidyExpr env e) b (map (tidyAlt env') alts) + +tidyExpr env (Lam b e) + = tidyBndr env b =: \ (env', b) -> + Lam b (tidyExpr env' e) + + +tidyAlt env (con, vs, rhs) + = tidyBndrs env vs =: \ (env', vs) -> + (con, vs, tidyExpr env' rhs) + +tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2) +tidyNote env note = note +\end{code} + + +%************************************************************************ +%* * +\subsection{Tidying up non-top-level binders} +%* * +%************************************************************************ + +\begin{code} +tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of + Just v' -> v' + Nothing -> 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 none, + -- which should save some space. 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 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 -- I don't understand why... - - info5 = case workerInfo info of - NoWorker -> info4 - HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a - -tidyProtoRules :: TidyEnv -> [ProtoCoreRule] -> [ProtoCoreRule] -tidyProtoRules env rules - = [ ProtoCoreRule is_local (tidyVarOcc env fn) (tidyRule env rule) - | ProtoCoreRule is_local 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}