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 inlinePragInfo, setInlinePragInfo, InlinePragInfo(..),
30 setUnfoldingInfo, setDemandInfo,
31 workerInfo, setWorkerInfo, WorkerInfo(..)
33 import Demand ( wwLazy )
34 import Name ( getOccName, tidyTopName, mkLocalName, isLocallyDefined )
35 import OccName ( initTidyOccEnv, tidyOccName )
36 import Type ( tidyTopType, tidyType, tidyTypes, tidyTyVar, tidyTyVars )
37 import Module ( Module )
38 import UniqSupply ( UniqSupply )
39 import Unique ( Uniquable(..) )
40 import SrcLoc ( noSrcLoc )
41 import Util ( mapAccumL )
47 %************************************************************************
49 \subsection{Tidying core}
51 %************************************************************************
53 Several tasks are done by @tidyCorePgm@
55 1. If @opt_UsageSPOn@ then compute usage information (which is
56 needed by Core2Stg). ** NOTE _scc_ HERE **
57 Do this first, because it may introduce new binders.
59 2. Make certain top-level bindings into Globals. The point is that
60 Global things get externally-visible labels at code generation
64 3. Give all binders a nice print-name. Their uniques aren't changed;
65 rather we give them lexically unique occ-names, so that we can
66 safely print the OccNae only in the interface file. [Bad idea to
67 change the uniques, because the code generator makes global labels
68 from the uniques for local thunks etc.]
71 tidyCorePgm :: UniqSupply -> Module -> [CoreBind] -> RuleBase
72 -> IO ([CoreBind], [ProtoCoreRule])
73 tidyCorePgm us module_name binds_in rulebase_in
77 (binds_in1,mrulebase_in1) <- if opt_UsageSPOn
78 then _scc_ "CoreUsageSPInf"
79 doUsageSPInf us binds_in rulebase_in
80 else return (binds_in,Nothing)
82 let rulebase_in1 = maybe rulebase_in id mrulebase_in1
84 (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
85 init_tidy_env binds_in1
86 rules_out = tidyProtoRules tidy_env1 (mk_local_protos rulebase_in1)
88 endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out
89 return (binds_out, rules_out)
91 -- We also make sure to avoid any exported binders. Consider
92 -- f{-u1-} = 1 -- Local decl
94 -- f{-u2-} = 2 -- Exported decl
96 -- The second exported decl must 'get' the name 'f', so we
97 -- have to put 'f' in the avoids list before we get to the first
98 -- decl. tidyTopId then does a no-op on exported binders.
99 init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
100 avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
101 exportWithOrigOccName bndr]
103 mk_local_protos :: RuleBase -> [ProtoCoreRule]
104 mk_local_protos (rule_ids, _)
105 = [ProtoCoreRule True id rule | id <- varSetElems rule_ids,
106 rule <- rulesRules (idSpecialisation id)]
108 tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
111 -> (TidyEnv, CoreBind)
112 tidyBind maybe_mod env (NonRec bndr rhs)
114 (env', bndr') = tidy_bndr maybe_mod env' env bndr
115 rhs' = tidyExpr env' rhs
116 -- We use env' when tidying the RHS even though it's not
117 -- strictly necessary; it makes the code pretty hard to read
120 (env', NonRec bndr' rhs')
122 tidyBind maybe_mod env (Rec pairs)
124 -- We use env' when tidying the rhss
125 -- When tidying the binder itself we may tidy it's
126 -- specialisations; if any of these mention other binders
127 -- in the group we should really feed env' to them too;
128 -- but that seems (a) unlikely and (b) a bit tiresome.
129 -- So I left it out for now
131 (bndrs, rhss) = unzip pairs
132 (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs
133 rhss' = map (tidyExpr env') rhss
135 (env', Rec (zip bndrs' rhss'))
137 tidyExpr env (Type ty) = Type (tidyType env ty)
138 tidyExpr env (Lit lit) = Lit lit
139 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
140 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
142 tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
144 (env', b') = tidyBind Nothing env b
146 tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
148 (env', b') = tidyBndr env b
150 tidyExpr env (Var v) = Var (tidyVarOcc env v)
152 tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
154 (env', b') = tidyBndr env b
156 tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
158 (env', vs') = tidyBndrs env vs
160 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
162 tidyNote env note = note
164 tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
170 tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
171 tidy_bndr Nothing env_idinfo env var = tidyBndr env var
176 %************************************************************************
178 \subsection{Tidying up a binder}
180 %************************************************************************
183 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
184 tidyBndr env var | isTyVar var = tidyTyVar env var
185 | otherwise = tidyId env var
187 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
188 tidyBndrs env vars = mapAccumL tidyBndr env vars
190 tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
191 tidyId env@(tidy_env, var_env) id
192 = -- Non-top-level variables
194 -- Give the Id a fresh print-name, *and* rename its type
195 -- The SrcLoc isn't important now, though we could extract it from the Id
196 name' = mkLocalName (getUnique id) occ' noSrcLoc
197 (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
198 ty' = tidyType env (idType id)
199 id' = mkVanillaId name' ty'
200 `setIdStrictness` idStrictness id
201 `setIdDemandInfo` idDemandInfo id
202 -- NB: This throws away the IdInfo of the Id, which we
203 -- no longer need. That means we don't need to
204 -- run over it with env, nor renumber it.
206 -- The exception is strictness and demand info, which
207 -- is used to decide whether to use let or case for
208 -- function arguments and let bindings
210 var_env' = extendVarEnv var_env id id'
212 ((tidy_env', var_env'), id')
214 tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
215 -- The second env is the one to use for the IdInfo
216 -- It's necessary because when we are dealing with a recursive
217 -- group, a variable late in the group might be mentioned
218 -- in the IdInfo of one early in the group
219 tidyTopId mod env@(tidy_env, var_env) env_idinfo id
220 = -- Top level variables
222 (tidy_env', name') | exportWithOrigOccName id = (tidy_env, idName id)
223 | otherwise = tidyTopName mod tidy_env (idName id)
224 ty' = tidyTopType (idType id)
225 idinfo' = tidyIdInfo env_idinfo (idInfo id)
226 id' = mkId name' ty' idinfo'
227 var_env' = extendVarEnv var_env id id'
229 ((tidy_env', var_env'), id')
233 -- tidyIdInfo does these things:
234 -- a) tidy the specialisation info and worker info (if any)
235 -- b) zap the unfolding and demand info
236 -- The latter two are to avoid space leaks
241 rules = specInfo info
243 info2 | isEmptyCoreRules rules = info
244 | otherwise = info `setSpecInfo` tidyRules env rules
246 info3 = info2 `setUnfoldingInfo` noUnfolding
247 info4 = info3 `setDemandInfo` wwLazy -- I don't understand why...
249 info5 = case workerInfo info of
251 HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
253 tidyProtoRules :: TidyEnv -> [ProtoCoreRule] -> [ProtoCoreRule]
254 tidyProtoRules env rules
255 = [ ProtoCoreRule is_local (tidyVarOcc env fn) (tidyRule env rule)
256 | ProtoCoreRule is_local fn rule <- rules
259 tidyRules :: TidyEnv -> CoreRules -> CoreRules
260 tidyRules env (Rules rules fvs)
261 = Rules (map (tidyRule env) rules)
262 (foldVarSet tidy_set_elem emptyVarSet fvs)
264 tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
266 tidyRule :: TidyEnv -> CoreRule -> CoreRule
267 tidyRule env rule@(BuiltinRule _) = rule
268 tidyRule env (Rule name vars tpl_args rhs)
269 = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
271 (env', vars') = tidyBndrs env vars