2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section{Tidying up Core}
12 #include "HsVersions.h"
14 import CmdLineOpts ( opt_D_dump_simpl, opt_D_verbose_core2core, opt_UsageSPOn )
16 import CoreUnfold ( noUnfolding )
17 import CoreLint ( beginPass, endPass )
18 import Rules ( ProtoCoreRule(..), RuleBase )
19 import UsageSPInf ( doUsageSPInf )
22 import Var ( Id, Var )
23 import Id ( idType, idInfo, idName, idSpecialisation,
24 mkVanillaId, mkId, exportWithOrigOccName,
25 idStrictness, setIdStrictness,
26 idDemandInfo, setIdDemandInfo,
28 import IdInfo ( specInfo, setSpecInfo,
29 setUnfoldingInfo, setDemandInfo,
30 workerInfo, setWorkerInfo, WorkerInfo(..)
32 import Demand ( wwLazy )
33 import Name ( getOccName, tidyTopName, mkLocalName, isLocallyDefined )
34 import OccName ( initTidyOccEnv, tidyOccName )
35 import Type ( tidyTopType, tidyType, tidyTypes, tidyTyVar, tidyTyVars )
36 import Module ( Module )
37 import UniqSupply ( UniqSupply )
38 import Unique ( Uniquable(..) )
39 import SrcLoc ( noSrcLoc )
40 import Util ( mapAccumL )
45 %************************************************************************
47 \subsection{Tidying core}
49 %************************************************************************
51 Several tasks are done by @tidyCorePgm@
53 1. If @opt_UsageSPOn@ then compute usage information (which is
54 needed by Core2Stg). ** NOTE _scc_ HERE **
55 Do this first, because it may introduce new binders.
57 2. Make certain top-level bindings into Globals. The point is that
58 Global things get externally-visible labels at code generation
62 3. Give all binders a nice print-name. Their uniques aren't changed;
63 rather we give them lexically unique occ-names, so that we can
64 safely print the OccNae only in the interface file. [Bad idea to
65 change the uniques, because the code generator makes global labels
66 from the uniques for local thunks etc.]
69 tidyCorePgm :: UniqSupply -> Module -> [CoreBind] -> RuleBase
70 -> IO ([CoreBind], [ProtoCoreRule])
71 tidyCorePgm us module_name binds_in rulebase_in
75 (binds_in1,mrulebase_in1) <- if opt_UsageSPOn
76 then _scc_ "CoreUsageSPInf"
77 doUsageSPInf us binds_in rulebase_in
78 else return (binds_in,Nothing)
80 let rulebase_in1 = maybe rulebase_in id mrulebase_in1
82 (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
83 init_tidy_env binds_in1
84 rules_out = tidyProtoRules tidy_env1 (mk_local_protos rulebase_in1)
86 endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out
87 return (binds_out, rules_out)
89 -- We also make sure to avoid any exported binders. Consider
90 -- f{-u1-} = 1 -- Local decl
92 -- f{-u2-} = 2 -- Exported decl
94 -- The second exported decl must 'get' the name 'f', so we
95 -- have to put 'f' in the avoids list before we get to the first
96 -- decl. tidyTopId then does a no-op on exported binders.
97 init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
98 avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
99 exportWithOrigOccName bndr]
101 mk_local_protos :: RuleBase -> [ProtoCoreRule]
102 mk_local_protos (rule_ids, _)
103 = [ProtoCoreRule True id rule | id <- varSetElems rule_ids,
104 rule <- rulesRules (idSpecialisation id)]
106 tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
109 -> (TidyEnv, CoreBind)
110 tidyBind maybe_mod env (NonRec bndr rhs)
112 (env', bndr') = tidy_bndr maybe_mod env' env bndr
113 rhs' = tidyExpr env' rhs
114 -- We use env' when tidying the RHS even though it's not
115 -- strictly necessary; it makes the code pretty hard to read
118 (env', NonRec bndr' rhs')
120 tidyBind maybe_mod env (Rec pairs)
122 -- We use env' when tidying the rhss
123 -- When tidying the binder itself we may tidy it's
124 -- specialisations; if any of these mention other binders
125 -- in the group we should really feed env' to them too;
126 -- but that seems (a) unlikely and (b) a bit tiresome.
127 -- So I left it out for now
129 (bndrs, rhss) = unzip pairs
130 (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs
131 rhss' = map (tidyExpr env') rhss
133 (env', Rec (zip bndrs' rhss'))
135 tidyExpr env (Type ty) = Type (tidyType env ty)
136 tidyExpr env (Lit lit) = Lit lit
137 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
138 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
140 tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
142 (env', b') = tidyBind Nothing env b
144 tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
146 (env', b') = tidyBndr env b
148 tidyExpr env (Var v) = Var (tidyVarOcc env v)
150 tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
152 (env', b') = tidyBndr env b
154 tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
156 (env', vs') = tidyBndrs env vs
158 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
160 tidyNote env note = note
162 tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
168 tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
169 tidy_bndr Nothing env_idinfo env var = tidyBndr env var
174 %************************************************************************
176 \subsection{Tidying up a binder}
178 %************************************************************************
181 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
182 tidyBndr env var | isTyVar var = tidyTyVar env var
183 | otherwise = tidyId env var
185 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
186 tidyBndrs env vars = mapAccumL tidyBndr env vars
188 tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
189 tidyId env@(tidy_env, var_env) id
190 = -- Non-top-level variables
192 -- Give the Id a fresh print-name, *and* rename its type
193 -- The SrcLoc isn't important now, though we could extract it from the Id
194 name' = mkLocalName (getUnique id) occ' noSrcLoc
195 (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
196 ty' = tidyType env (idType id)
197 id' = mkVanillaId name' ty'
198 `setIdStrictness` idStrictness id
199 `setIdDemandInfo` idDemandInfo id
200 -- NB: This throws away the IdInfo of the Id, which we
201 -- no longer need. That means we don't need to
202 -- run over it with env, nor renumber it.
204 -- The exception is strictness and demand info, which
205 -- is used to decide whether to use let or case for
206 -- function arguments and let bindings
208 var_env' = extendVarEnv var_env id id'
210 ((tidy_env', var_env'), id')
212 tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
213 -- The second env is the one to use for the IdInfo
214 -- It's necessary because when we are dealing with a recursive
215 -- group, a variable late in the group might be mentioned
216 -- in the IdInfo of one early in the group
217 tidyTopId mod env@(tidy_env, var_env) env_idinfo id
218 = -- Top level variables
220 (tidy_env', name') | exportWithOrigOccName id = (tidy_env, idName id)
221 | otherwise = tidyTopName mod tidy_env (idName id)
222 ty' = tidyTopType (idType id)
223 idinfo' = tidyIdInfo env_idinfo (idInfo id)
224 id' = mkId name' ty' idinfo'
225 var_env' = extendVarEnv var_env id id'
227 ((tidy_env', var_env'), id')
231 -- tidyIdInfo does these things:
232 -- a) tidy the specialisation info and worker info (if any)
233 -- b) zap the unfolding and demand info
234 -- The latter two are to avoid space leaks
239 rules = specInfo info
241 info2 | isEmptyCoreRules rules = info
242 | otherwise = info `setSpecInfo` tidyRules env rules
244 info3 = info2 `setUnfoldingInfo` noUnfolding
245 info4 = info3 `setDemandInfo` wwLazy -- I don't understand why...
247 info5 = case workerInfo info of
249 HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
251 tidyProtoRules :: TidyEnv -> [ProtoCoreRule] -> [ProtoCoreRule]
252 tidyProtoRules env rules
253 = [ ProtoCoreRule is_local (tidyVarOcc env fn) (tidyRule env rule)
254 | ProtoCoreRule is_local fn rule <- rules
257 tidyRules :: TidyEnv -> CoreRules -> CoreRules
258 tidyRules env (Rules rules fvs)
259 = Rules (map (tidyRule env) rules)
260 (foldVarSet tidy_set_elem emptyVarSet fvs)
262 tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
264 tidyRule :: TidyEnv -> CoreRule -> CoreRule
265 tidyRule env rule@(BuiltinRule _) = rule
266 tidyRule env (Rule name vars tpl_args rhs)
267 = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
269 (env', vars') = tidyBndrs env vars