#include "HsVersions.h"
-import CmdLineOpts ( DynFlags, DynFlag(..), opt_UsageSPOn, dopt )
+import CmdLineOpts ( DynFlags, DynFlag(..), opt_OmitInterfacePragmas, dopt )
import CoreSyn
-import CoreUnfold ( noUnfolding )
+import CoreUnfold ( noUnfolding, mkTopUnfolding, okToUnfoldInHiFile )
+import CoreFVs ( ruleSomeFreeVars, exprSomeFreeVars )
import CoreLint ( showPass, endPass )
-import UsageSPInf ( doUsageSPInf )
import VarEnv
import VarSet
import Var ( Id, Var )
import Id ( idType, idInfo, idName, isExportedId,
- mkVanillaId, mkId,
- idStrictness, setIdStrictness,
- idDemandInfo, setIdDemandInfo,
+ mkVanillaId, mkId, isLocalId,
+ setIdStrictness, setIdDemandInfo,
)
-import IdInfo ( specInfo, setSpecInfo,
- setUnfoldingInfo, setDemandInfo,
+import IdInfo ( constantIdInfo,
+ specInfo, setSpecInfo,
+ cprInfo, setCprInfo,
+ inlinePragInfo, setInlinePragInfo, isNeverInlinePrag,
+ strictnessInfo, setStrictnessInfo, isBottomingStrictness,
+ unfoldingInfo, setUnfoldingInfo,
+ demandInfo,
+ occInfo, isLoopBreaker,
workerInfo, setWorkerInfo, WorkerInfo(..)
)
-import Demand ( wwLazy )
-import Name ( getOccName, tidyTopName, mkLocalName, isGlobalName )
-import OccName ( initTidyOccEnv, tidyOccName )
+import Name ( getOccName, nameOccName, globaliseName, setNameOcc,
+ localiseName, mkLocalName, isGlobalName
+ )
+import OccName ( TidyOccEnv, initTidyOccEnv, tidyOccName )
import Type ( tidyTopType, tidyType, tidyTyVar )
-import Module ( Module )
-import UniqSupply ( mkSplitUniqSupply )
+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 SrcLoc ( noSrcLoc )
+import UniqFM ( mapUFM )
+import Outputable
+import List ( partition )
import Util ( mapAccumL )
\end{code}
%************************************************************************
-%* *
-\subsection{Tidying core}
-%* *
+%* *
+\subsection{What goes on}
+%* *
%************************************************************************
-Several tasks are done by @tidyCorePgm@
-
-1. If @opt_UsageSPOn@ then compute usage information (which is
- needed by Core2Stg). ** NOTE _scc_ HERE **
- Do this first, because it may introduce new binders.
-
-2. Make certain top-level bindings into Globals. The point is that
- Global things get externally-visible labels at code generation
- time
-
-
-3. Give all binders a nice print-name. Their uniques aren't changed;
- rather we give them lexically unique occ-names, so that we can
- safely print the OccNae only in the interface file. [Bad idea to
- change the uniques, because the code generator makes global labels
- from the uniques for local thunks etc.]
+[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 ([CoreBind], [IdCoreRule])
-tidyCorePgm dflags module_name binds_in orphans_in
- = do
- us <- mkSplitUniqSupply 'u'
+ -> 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
- showPass dflags "Tidy Core"
+ ; let ((orig_env', occ_env, subst_env), binds_out)
+ = mapAccumL (tidyTopBind mod ext_ids) init_tidy_env binds_in
- binds_in1 <- if opt_UsageSPOn
- then _scc_ "CoreUsageSPInf"
- doUsageSPInf dflags us binds_in
- else return binds_in
+ ; let orphans_out = tidyIdRules (occ_env,subst_env) orphans_in
- let (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
- init_tidy_env binds_in1
- orphans_out = tidyIdRules tidy_env1 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
+ ; endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
+ dopt Opt_D_verbose_core2core dflags)
+ binds_out
- return (binds_out, orphans_out)
+ ; return (pcs', binds_out, orphans_out)
+ }
where
-- We also make sure to avoid any exported binders. Consider
-- f{-u1-} = 1 -- Local decl
-- The second exported decl must 'get' the name 'f', so we
-- have to put 'f' in the avoids list before we get to the first
-- decl. tidyTopId then does a no-op on exported binders.
- init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
+ 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
-tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
- -> TidyEnv
+-- * 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 (orig_env, occ_env, subst_env) id
+ -- 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
+ = constantIdInfo
+
+ | otherwise
+ = constantIdInfo `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
+
+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}
+
+
+%************************************************************************
+%* *
+\subsection{Step 2: inner tidying
+%* *
+%************************************************************************
+
+\begin{code}
+tidyBind :: TidyEnv
-> CoreBind
-> (TidyEnv, CoreBind)
-tidyBind maybe_mod env (NonRec bndr rhs)
+tidyBind env (NonRec bndr rhs)
= let
- (env', bndr') = tidy_bndr maybe_mod env' env bndr
+ (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 code pretty hard to read
- -- if we don't!
+ -- strictly necessary; it makes the tidied 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'))
+tidyBind 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
+ (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 (Let b e) = Let b' (tidyExpr env' e)
where
- (env', b') = tidyBind Nothing env b
+ (env', b') = tidyBind env b
tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
where
tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
tidyNote env note = note
-
-tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
- Just v' -> v'
- Nothing -> v
\end{code}
-\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
-\end{code}
-
-
%************************************************************************
%* *
-\subsection{Tidying up a binder}
+\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 :: TidyEnv -> Var -> (TidyEnv, Var)
tidyBndr env var | isTyVar var = tidyTyVar env var
| otherwise = tidyId env var
name' = mkLocalName (getUnique id) occ' noSrcLoc
(tidy_env', occ') = tidyOccName tidy_env (getOccName id)
ty' = tidyType env (idType id)
+ idinfo = idInfo id
id' = mkVanillaId name' ty'
- `setIdStrictness` idStrictness id
- `setIdDemandInfo` idDemandInfo id
+ `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.
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') = tidyTopName mod tidy_env (isExportedId id) (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')
-\end{code}
-
-\begin{code}
--- tidyIdInfo does these things:
--- a) tidy the specialisation info and worker info (if any)
--- b) zap the unfolding and demand info
--- The latter two are to avoid space leaks
-
-tidyIdInfo env info
- = info5
- where
- rules = specInfo info
-
- info2 | isEmptyCoreRules rules = info
- | otherwise = info `setSpecInfo` tidyRules env rules
-
- info3 = info2 `setUnfoldingInfo` noUnfolding
- info4 = info3 `setDemandInfo` wwLazy
-
- info5 = case workerInfo info of
- NoWorker -> info4
- HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
-
-tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
-tidyIdRules env rules
- = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ]
-
-tidyRules :: TidyEnv -> CoreRules -> CoreRules
-tidyRules env (Rules rules fvs)
- = Rules (map (tidyRule env) rules)
- (foldVarSet tidy_set_elem emptyVarSet fvs)
- where
- tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
-
-tidyRule :: TidyEnv -> CoreRule -> CoreRule
-tidyRule env rule@(BuiltinRule _) = rule
-tidyRule env (Rule name vars tpl_args rhs)
- = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
- where
- (env', vars') = tidyBndrs env vars
\end{code}