X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FcoreSyn%2FCoreTidy.lhs;h=acc2c77cf08bf1b8a1f9646de301b81cb09b171f;hb=7d841483081735f5f906a6bb5e80249d97f3226b;hp=18bba01a79a5496c6894817e65d0e2dcbf365480;hpb=05c41def95ec45bbe63d3c9ab0ba9e19648717e0;p=ghc-hetmet.git diff --git a/ghc/compiler/coreSyn/CoreTidy.lhs b/ghc/compiler/coreSyn/CoreTidy.lhs index 18bba01..acc2c77 100644 --- a/ghc/compiler/coreSyn/CoreTidy.lhs +++ b/ghc/compiler/coreSyn/CoreTidy.lhs @@ -5,7 +5,7 @@ \begin{code} module CoreTidy ( - tidyCorePgm, tidyExpr, + tidyCorePgm, tidyExpr, tidyCoreExpr, tidyIdRules, tidyBndr, tidyBndrs ) where @@ -14,38 +14,43 @@ module CoreTidy ( import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas ) import CoreSyn import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile ) -import CoreUtils ( exprArity, exprIsBottom ) -import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars ) +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, isExportedId, - idCafInfo, mkId, isLocalId, omitIfaceSigForId, - idFlavour, modifyIdInfo +import Id ( idType, idInfo, idName, idCoreRules, + isExportedId, idUnique, mkVanillaGlobal, isLocalId, + isImplicitId, mkUserLocal, setIdInfo ) import IdInfo {- loads of stuff -} -import Name ( getOccName, nameOccName, globaliseName, setNameOcc, - localiseName, mkLocalName, isGlobalName +import NewDemand ( isBottomingSig, topSig ) +import BasicTypes ( isNeverActive ) +import Name ( getOccName, nameOccName, mkInternalName, mkExternalName, + localiseName, isExternalName, nameSrcLoc ) +import NameEnv ( filterNameEnv ) import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName ) -import Type ( tidyTopType, tidyType, tidyTyVar ) +import Type ( tidyTopType, tidyType, tidyTyVarBndr ) import Module ( Module, moduleName ) -import PrimOp ( PrimOp(..), setCCallUnique ) import HscTypes ( PersistentCompilerState( pcs_PRS ), PersistentRenamerState( prsOrig ), - OrigNameEnv( origNames ), OrigNameNameEnv + NameSupply( nsNames, nsUniqs ), + TypeEnv, extendTypeEnvList, typeEnvIds, + ModDetails(..), TyThing(..) ) -import UniqSupply import FiniteMap ( lookupFM, addToFM ) -import Maybes ( maybeToBool, orElse ) -import ErrUtils ( showPass ) +import Maybes ( orElse ) +import ErrUtils ( showPass, dumpIfSet_core ) import SrcLoc ( noSrcLoc ) import UniqFM ( mapUFM ) -import Outputable -import FastTypes +import UniqSupply ( splitUniqSupply, uniqFromSupply ) import List ( partition ) import Util ( mapAccumL ) +import Maybe ( isJust ) +import Outputable \end{code} @@ -76,28 +81,41 @@ IdEnv Bool Step 2: Tidy the program ~~~~~~~~~~~~~~~~~~~~~~~~ -Next we traverse the bindings top to bottom. For each top-level +Next we traverse the bindings top to bottom. For each *top-level* binder - - Make all external Ids have Global names and vice versa + 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 - - Give external ids a "tidy" occurrence name. This means + 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). - - Give external Ids the same Unique as they had before - if the name is in the renamer's name cache - - - Clone all local Ids. This means that Tidy Core has the property - that all Ids are unique, rather than the weaker guarantee of - no clashes which the simplifier provides. + 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 - - 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 + + * 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 @@ -106,30 +124,24 @@ 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 + -> 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 - - ; us <- mkSplitUniqSupply 't' -- for "tidy" + ; 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.) - ; let ((us1, orig_env', occ_env, subst_env), binds_out) - = mapAccumL (tidyTopBind mod ext_ids) - (init_tidy_env us) binds_in - - ; let (orphans_out, _) - = initUs us1 (tidyIdRules (occ_env,subst_env) orphans_in) - - ; let prs' = prs { prsOrig = orig { origNames = orig_env' } } - pcs' = pcs { pcs_PRS = prs' } - - ; endPass dflags "Tidy Core" Opt_D_dump_simpl binds_out - - ; return (pcs', binds_out, orphans_out) - } - where -- We also make sure to avoid any exported binders. Consider -- f{-u1-} = 1 -- Local decl -- ... @@ -138,31 +150,145 @@ tidyCorePgm dflags mod pcs binds_in orphans_in -- 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 + ; 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) - init_tidy_env us = (us, orig_env, initTidyOccEnv avoids, emptyVarEnv) - avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in, - isGlobalName (idName bndr)] + + ; 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} %************************************************************************ %* * +\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 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} +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 -- True <=> show unfolding + -> 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 isIdAndLocal rule + orphan_rule_ids = unionVarSets [ ruleRhsFreeVars rule | (_, rule) <- orphan_rules] init_needed :: IdEnv Bool init_needed = mapUFM (\_ -> False) orphan_rule_ids @@ -190,8 +316,6 @@ findExternalSet binds orphan_rules 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) @@ -209,9 +333,9 @@ addExternal (id,rhs) needed spec_ids idinfo = idInfo id - dont_inline = isNeverInlinePrag (inlinePragInfo idinfo) + dont_inline = isNeverActive (inlinePragInfo idinfo) loop_breaker = isLoopBreaker (occInfo idinfo) - bottoming_fn = isBottomingStrictness (strictnessInfo idinfo) + bottoming_fn = isBottomingSig (newStrictnessInfo idinfo `orElse` topSig) spec_ids = rulesRhsFreeVars (specInfo idinfo) worker_info = workerInfo idinfo @@ -231,7 +355,7 @@ addExternal (id,rhs) needed rhs_is_small && -- Small enough okToUnfoldInHiFile rhs -- No casms etc - unfold_ids | show_unfold = exprSomeFreeVars isIdAndLocal rhs + unfold_ids | show_unfold = exprSomeFreeVars isLocalId rhs | otherwise = emptyVarSet worker_ids = case worker_info of @@ -248,10 +372,11 @@ addExternal (id,rhs) needed \begin{code} -type TopTidyEnv = (UniqSupply, OrigNameNameEnv, TidyOccEnv, VarEnv Var) +type TopTidyEnv = (NameSupply, TidyOccEnv, VarEnv Var) -- TopTidyEnv: when tidying we need to know --- * orig_env: Any pre-ordained Names. These may have arisen because the +-- * 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) @@ -262,9 +387,6 @@ type TopTidyEnv = (UniqSupply, OrigNameNameEnv, TidyOccEnv, VarEnv Var) -- are 'used' -- -- * subst_env: A Var->Var mapping that substitutes the new Var for the old --- --- * uniqsuppy: so we can clone any Ids with non-preordained names. --- \end{code} @@ -272,178 +394,197 @@ type TopTidyEnv = (UniqSupply, OrigNameNameEnv, TidyOccEnv, VarEnv Var) 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 env (NonRec bndr rhs) - = ((us2,orig,occ,subst) , NonRec bndr' rhs') +tidyTopBind mod ext_ids cg_info_env top_tidy_env (NonRec bndr rhs) + = ((orig,occ,subst) , NonRec bndr' rhs') where - ((us1,orig,occ,subst), bndr') - = tidyTopBinder mod ext_ids tidy_env rhs' caf_info env bndr - tidy_env = (occ,subst) - caf_info = hasCafRefs (const True) rhs' - (rhs',us2) = initUs us1 (tidyExpr tidy_env rhs) + ((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 env (Rec prs) +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 env prs - final_tidy_env = (occ,subst) + (final_env@(_,occ,subst), prs') = mapAccumL do_one top_tidy_env prs + rec_tidy_env = (occ,subst) - do_one env (bndr,rhs) - = ((us',orig,occ,subst), (bndr',rhs')) + do_one top_tidy_env (bndr,rhs) + = ((orig,occ,subst), (bndr',rhs')) where - ((us,orig,occ,subst), bndr') - = tidyTopBinder mod ext_ids final_tidy_env rhs' caf_info env bndr - (rhs', us') = initUs us (tidyExpr final_tidy_env rhs) - - -- the CafInfo for a recursive group says whether *any* rhs in - -- the group may refer indirectly to a CAF (because then, they all do). - (bndrs, rhss) = unzip prs' - caf_info = hasCafRefss pred rhss - pred v = v `notElem` bndrs - - -tidyTopBinder :: Module -> IdEnv Bool - -> TidyEnv -> CoreExpr -> CafInfo - -- The TidyEnv is used to tidy the IdInfo - -- The expr is the already-tided RHS - -- Both are knot-tied: don't look at them! + ((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 tidy_env rhs caf_info - env@(us, orig_env2, occ_env2, subst_env2) id - - | omitIfaceSigForId id -- Don't mess with constructors, - = (env, id) -- record selectors, and the like - - | otherwise +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 second env is the one to use for the IdInfo + -- 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 - = ((us_r, orig_env', occ_env', subst_env'), id') + = ((orig_env', occ_env', subst_env'), id') where - (us_l, us_r) = splitUniqSupply us - - (orig_env', occ_env', name') = tidyTopName mod orig_env2 occ_env2 + (orig_env', occ_env', name') = tidyTopName mod ns2 occ_env2 is_external (idName id) - ty' = tidyTopType (idType id) - idinfo' = tidyIdInfo us_l tidy_env - is_external unfold_info arity_info caf_info 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 - id' = mkId name' ty' idinfo' subst_env' = extendVarEnv subst_env2 id id' maybe_external = lookupVarEnv ext_ids id - is_external = maybeToBool maybe_external + 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 rhs + unfold_info | show_unfold = mkTopUnfolding tidy_rhs | otherwise = noUnfolding - arity_info = exprArity rhs + -- 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 -tidyIdInfo us tidy_env is_external unfold_info arity_info caf_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 - `setArityInfo` ArityExactly arity_info - `setCafInfo` caf_info - -- Keep strictness, arity and CAF info; it's used by the code generator - | otherwise - = let (rules', _) = initUs us (tidyRules tidy_env (specInfo core_idinfo)) - in - 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` rules' - `setArityInfo` ArityExactly arity_info - `setCafInfo` caf_info - -- this is the final IdInfo, it must agree with the - -- code finally generated (i.e. NO more transformations - -- after this!). +-- 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 - 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 - ConstantId -> ConstantId -- e.g. Default methods - DictFunId -> DictFunId - flavour -> pprTrace "tidyIdInfo" (ppr id <+> ppFlavourInfo flavour) - flavour + -- 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 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 +-- we intend to externalise it. +tidyTopName mod ns occ_env external name + | global && internal = (ns, occ_env, localiseName name) - | global && external = (orig_env, occ_env, 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 && 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 + | 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 + -- 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 - (occ_env', occ') = tidyOccName occ_env (nameOccName name) - key = (moduleName mod, occ') - global_name = globaliseName (setNameOcc name occ') mod - global = isGlobalName name + global = isExternalName name local = not global internal = not external -tidyIdRules :: TidyEnv -> [IdCoreRule] -> UniqSM [IdCoreRule] -tidyIdRules env [] = returnUs [] -tidyIdRules env ((fn,rule) : rules) - = tidyRule env rule `thenUs` \ rule -> - tidyIdRules env rules `thenUs` \ rules -> - returnUs ((tidyVarOcc env fn, rule) : rules) + (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 NoWorker +tidyWorker tidy_env other = NoWorker -tidyRules :: TidyEnv -> CoreRules -> UniqSM CoreRules -tidyRules env (Rules rules fvs) - = mapUs (tidyRule env) rules `thenUs` \ rules -> - returnUs (Rules rules (foldVarSet tidy_set_elem emptyVarSet fvs)) - where - tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var) - -tidyRule :: TidyEnv -> CoreRule -> UniqSM CoreRule -tidyRule env rule@(BuiltinRule _) = returnUs rule -tidyRule env (Rule name vars tpl_args rhs) - = tidyBndrs env vars `thenUs` \ (env', vars) -> - mapUs (tidyExpr env') tpl_args `thenUs` \ tpl_args -> - tidyExpr env' rhs `thenUs` \ rhs -> - returnUs (Rule name vars tpl_args rhs) +------------ 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} %************************************************************************ @@ -455,54 +596,40 @@ tidyRule env (Rule name vars tpl_args rhs) \begin{code} tidyBind :: TidyEnv -> CoreBind - -> UniqSM (TidyEnv, CoreBind) + -> (TidyEnv, CoreBind) + tidyBind env (NonRec bndr rhs) - = tidyBndrWithRhs env (bndr,rhs) `thenUs` \ (env', bndr') -> - tidyExpr env' rhs `thenUs` \ rhs' -> - returnUs (env', NonRec bndr' rhs') + = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') -> + (env', NonRec bndr' (tidyExpr env' rhs)) tidyBind env (Rec prs) - = mapAccumLUs tidyBndrWithRhs env prs `thenUs` \ (env', bndrs') -> - mapUs (tidyExpr env') (map snd prs) `thenUs` \ rhss' -> - returnUs (env', Rec (zip bndrs' rhss')) - -tidyExpr env (Var v) - = fiddleCCall v `thenUs` \ v -> - returnUs (Var (tidyVarOcc env v)) - -tidyExpr env (Type ty) = returnUs (Type (tidyType env ty)) -tidyExpr env (Lit lit) = returnUs (Lit lit) + = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') -> + map (tidyExpr env') (map snd prs) =: \ rhss' -> + (env', Rec (zip bndrs' rhss')) -tidyExpr env (App f a) - = tidyExpr env f `thenUs` \ f -> - tidyExpr env a `thenUs` \ a -> - returnUs (App f a) -tidyExpr env (Note n e) - = tidyExpr env e `thenUs` \ e -> - returnUs (Note (tidyNote env n) e) +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 `thenUs` \ (env', b') -> - tidyExpr env' e `thenUs` \ e -> - returnUs (Let b' e) + = tidyBind env b =: \ (env', b') -> + Let b' (tidyExpr env' e) tidyExpr env (Case e b alts) - = tidyExpr env e `thenUs` \ e -> - tidyBndr env b `thenUs` \ (env', b) -> - mapUs (tidyAlt env') alts `thenUs` \ alts -> - returnUs (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 `thenUs` \ (env', b) -> - tidyExpr env' e `thenUs` \ e -> - returnUs (Lam b e) + = tidyBndr env b =: \ (env', b) -> + Lam b (tidyExpr env' e) tidyAlt env (con, vs, rhs) - = tidyBndrs env vs `thenUs` \ (env', vs) -> - tidyExpr env' rhs `thenUs` \ rhs -> - returnUs (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 @@ -521,114 +648,64 @@ tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of Nothing -> v -- tidyBndr is used for lambda and case binders -tidyBndr :: TidyEnv -> Var -> UniqSM (TidyEnv, Var) +tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var) tidyBndr env var - | isTyVar var = returnUs (tidyTyVar env var) - | otherwise = tidyId env var (vanillaIdInfo `setCafInfo` NoCafRefs) - -tidyBndrs :: TidyEnv -> [Var] -> UniqSM (TidyEnv, [Var]) -tidyBndrs env vars = mapAccumLUs tidyBndr env vars - --- tidyBndrWithRhs is used for let binders -tidyBndrWithRhs :: TidyEnv -> (Var, CoreExpr) -> UniqSM (TidyEnv, Var) -tidyBndrWithRhs env (id,rhs) - = tidyId env id idinfo - where - idinfo = vanillaIdInfo `setArityInfo` ArityExactly (exprArity rhs) - `setCafInfo` NoCafRefs - -- 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. - -tidyId :: TidyEnv -> Id -> IdInfo -> UniqSM (TidyEnv, Id) -tidyId env@(tidy_env, var_env) id idinfo - = -- Non-top-level variables - getUniqueUs `thenUs` \ uniq -> + | isTyVar var = tidyTyVarBndr env var + | otherwise = tidyIdBndr env var + +tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var]) +tidyBndrs env vars = mapAccumL tidyBndr env vars + +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 uniq occ' noSrcLoc - (tidy_env', occ') = tidyOccName tidy_env (getOccName id) - ty' = tidyType (tidy_env,var_env) (idType id) - id' = mkId name' ty' idinfo + -- + -- All nested Ids now have the same IdInfo, namely none, + -- which should save some space. + ty' = tidyType env (idType id) + id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc var_env' = extendVarEnv var_env id id' in - returnUs ((tidy_env', var_env'), id') - - -fiddleCCall id - = case idFlavour id of - PrimOpId (CCallOp ccall) -> - -- Make a guaranteed unique name for a dynamic ccall. - getUniqueUs `thenUs` \ uniq -> - returnUs (modifyIdInfo (`setFlavourInfo` - PrimOpId (CCallOp (setCCallUnique ccall uniq))) id) - other_flavour -> - returnUs id + ((tidy_env', var_env'), id') + } \end{code} -%************************************************************************ -%* * -\subsection{Figuring out CafInfo for an expression} -%* * -%************************************************************************ - \begin{code} -hasCafRefs :: (Id -> Bool) -> CoreExpr -> CafInfo -hasCafRefss :: (Id -> Bool) -> [CoreExpr] -> CafInfo - -- predicate returns True for a given Id if we look at this Id when - -- calculating the result. Used to *avoid* looking at the CafInfo - -- field for an Id that is part of the current recursive group. - -hasCafRefs p expr = if isCAF expr || isFastTrue (cafRefs p expr) - then MayHaveCafRefs - else NoCafRefs - -hasCafRefss p exprs = if any isCAF exprs || isFastTrue (cafRefss p exprs) - then MayHaveCafRefs - else NoCafRefs - -cafRefs p (Var id) - | p id - = case idCafInfo id of - NoCafRefs -> fastBool False - MayHaveCafRefs -> fastBool True - | otherwise - = fastBool False - -cafRefs p (Lit l) = fastBool False -cafRefs p (App f a) = cafRefs p f `fastOr` cafRefs p a -cafRefs p (Lam x e) = cafRefs p e -cafRefs p (Let b e) = cafRefss p (rhssOfBind b) `fastOr` cafRefs p e -cafRefs p (Case e bndr alts) = cafRefs p e `fastOr` cafRefss p (rhssOfAlts alts) -cafRefs p (Note n e) = cafRefs p e -cafRefs p (Type t) = fastBool False - -cafRefss p [] = fastBool False -cafRefss p (e:es) = cafRefs p e `fastOr` cafRefss p es - --- Decide whether a closure looks like a CAF or not. In an effort to --- keep the number of CAFs (and hence the size of the SRTs) down, we --- would also like to look at the expression and decide whether it --- requires a small bounded amount of heap, so we can ignore it as a CAF. --- In these cases, we need to use an additional CAF list to keep track of --- non-collectable CAFs. --- --- We mark real CAFs as `MayHaveCafRefs' because this information is used --- to decide whether a particular closure needs to be referenced in an --- SRT or not. - -isCAF :: CoreExpr -> Bool - -- special case for expressions which are always bottom, - -- such as 'error "..."'. We don't need to record it as - -- a CAF, since it can only be entered once. -isCAF e - | not_function && is_bottom = False - | not_function && updatable = True - | otherwise = False - where - not_function = exprArity e == 0 - is_bottom = exprIsBottom e - updatable = True {- ToDo: check type for onceness? -} +m =: k = m `seq` k m \end{code}