2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section{Tidying up Core}
12 #include "HsVersions.h"
14 import CmdLineOpts ( DynFlags, DynFlag(..), opt_UsageSPOn, dopt )
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 ( mkSplitUniqSupply )
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 :: DynFlags -> Module -> [CoreBind] -> RuleBase
70 -> IO ([CoreBind], [ProtoCoreRule])
71 tidyCorePgm dflags module_name binds_in rulebase_in
73 us <- mkSplitUniqSupply 'u'
75 beginPass dflags "Tidy Core"
77 binds_in1 <- if opt_UsageSPOn
78 then _scc_ "CoreUsageSPInf"
79 doUsageSPInf dflags us binds_in rulebase_in
82 let (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_in)
86 endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
87 dopt Opt_D_verbose_core2core dflags)
90 return (binds_out, rules_out)
92 -- We also make sure to avoid any exported binders. Consider
93 -- f{-u1-} = 1 -- Local decl
95 -- f{-u2-} = 2 -- Exported decl
97 -- The second exported decl must 'get' the name 'f', so we
98 -- have to put 'f' in the avoids list before we get to the first
99 -- decl. tidyTopId then does a no-op on exported binders.
100 init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
101 avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
102 exportWithOrigOccName bndr]
104 mk_local_protos :: RuleBase -> [ProtoCoreRule]
105 mk_local_protos (rule_ids, _)
106 = [ProtoCoreRule True id rule | id <- varSetElems rule_ids,
107 rule <- rulesRules (idSpecialisation id)]
109 tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
112 -> (TidyEnv, CoreBind)
113 tidyBind maybe_mod env (NonRec bndr rhs)
115 (env', bndr') = tidy_bndr maybe_mod env' env bndr
116 rhs' = tidyExpr env' rhs
117 -- We use env' when tidying the RHS even though it's not
118 -- strictly necessary; it makes the code pretty hard to read
121 (env', NonRec bndr' rhs')
123 tidyBind maybe_mod env (Rec pairs)
125 -- We use env' when tidying the rhss
126 -- When tidying the binder itself we may tidy it's
127 -- specialisations; if any of these mention other binders
128 -- in the group we should really feed env' to them too;
129 -- but that seems (a) unlikely and (b) a bit tiresome.
130 -- So I left it out for now
132 (bndrs, rhss) = unzip pairs
133 (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs
134 rhss' = map (tidyExpr env') rhss
136 (env', Rec (zip bndrs' rhss'))
138 tidyExpr env (Type ty) = Type (tidyType env ty)
139 tidyExpr env (Lit lit) = Lit lit
140 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
141 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
143 tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
145 (env', b') = tidyBind Nothing env b
147 tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
149 (env', b') = tidyBndr env b
151 tidyExpr env (Var v) = Var (tidyVarOcc env v)
153 tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
155 (env', b') = tidyBndr env b
157 tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
159 (env', vs') = tidyBndrs env vs
161 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
163 tidyNote env note = note
165 tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
171 tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
172 tidy_bndr Nothing env_idinfo env var = tidyBndr env var
177 %************************************************************************
179 \subsection{Tidying up a binder}
181 %************************************************************************
184 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
185 tidyBndr env var | isTyVar var = tidyTyVar env var
186 | otherwise = tidyId env var
188 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
189 tidyBndrs env vars = mapAccumL tidyBndr env vars
191 tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
192 tidyId env@(tidy_env, var_env) id
193 = -- Non-top-level variables
195 -- Give the Id a fresh print-name, *and* rename its type
196 -- The SrcLoc isn't important now, though we could extract it from the Id
197 name' = mkLocalName (getUnique id) occ' noSrcLoc
198 (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
199 ty' = tidyType env (idType id)
200 id' = mkVanillaId name' ty'
201 `setIdStrictness` idStrictness id
202 `setIdDemandInfo` idDemandInfo id
203 -- NB: This throws away the IdInfo of the Id, which we
204 -- no longer need. That means we don't need to
205 -- run over it with env, nor renumber it.
207 -- The exception is strictness and demand info, which
208 -- is used to decide whether to use let or case for
209 -- function arguments and let bindings
211 var_env' = extendVarEnv var_env id id'
213 ((tidy_env', var_env'), id')
215 tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
216 -- The second env is the one to use for the IdInfo
217 -- It's necessary because when we are dealing with a recursive
218 -- group, a variable late in the group might be mentioned
219 -- in the IdInfo of one early in the group
220 tidyTopId mod env@(tidy_env, var_env) env_idinfo id
221 = -- Top level variables
223 (tidy_env', name') | exportWithOrigOccName id = (tidy_env, idName id)
224 | otherwise = tidyTopName mod tidy_env (idName id)
225 ty' = tidyTopType (idType id)
226 idinfo' = tidyIdInfo env_idinfo (idInfo id)
227 id' = mkId name' ty' idinfo'
228 var_env' = extendVarEnv var_env id id'
230 ((tidy_env', var_env'), id')
234 -- tidyIdInfo does these things:
235 -- a) tidy the specialisation info and worker info (if any)
236 -- b) zap the unfolding and demand info
237 -- The latter two are to avoid space leaks
242 rules = specInfo info
244 info2 | isEmptyCoreRules rules = info
245 | otherwise = info `setSpecInfo` tidyRules env rules
247 info3 = info2 `setUnfoldingInfo` noUnfolding
248 info4 = info3 `setDemandInfo` wwLazy -- I don't understand why...
250 info5 = case workerInfo info of
252 HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
254 tidyProtoRules :: TidyEnv -> [ProtoCoreRule] -> [ProtoCoreRule]
255 tidyProtoRules env rules
256 = [ ProtoCoreRule is_local (tidyVarOcc env fn) (tidyRule env rule)
257 | ProtoCoreRule is_local fn rule <- rules
260 tidyRules :: TidyEnv -> CoreRules -> CoreRules
261 tidyRules env (Rules rules fvs)
262 = Rules (map (tidyRule env) rules)
263 (foldVarSet tidy_set_elem emptyVarSet fvs)
265 tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
267 tidyRule :: TidyEnv -> CoreRule -> CoreRule
268 tidyRule env rule@(BuiltinRule _) = rule
269 tidyRule env (Rule name vars tpl_args rhs)
270 = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
272 (env', vars') = tidyBndrs env vars