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 UsageSPInf ( doUsageSPInf )
21 import Var ( Id, Var )
22 import Id ( idType, idInfo, idName,
23 mkVanillaId, mkId, exportWithOrigOccName,
24 idStrictness, setIdStrictness,
25 idDemandInfo, setIdDemandInfo,
27 import IdInfo ( specInfo, setSpecInfo,
28 setUnfoldingInfo, setDemandInfo,
29 workerInfo, setWorkerInfo, WorkerInfo(..)
31 import Demand ( wwLazy )
32 import Name ( getOccName, tidyTopName, mkLocalName )
33 import OccName ( initTidyOccEnv, tidyOccName )
34 import Type ( tidyTopType, tidyType, tidyTyVar )
35 import Module ( Module )
36 import UniqSupply ( mkSplitUniqSupply )
37 import Unique ( Uniquable(..) )
38 import SrcLoc ( noSrcLoc )
39 import Util ( mapAccumL )
44 %************************************************************************
46 \subsection{Tidying core}
48 %************************************************************************
50 Several tasks are done by @tidyCorePgm@
52 1. If @opt_UsageSPOn@ then compute usage information (which is
53 needed by Core2Stg). ** NOTE _scc_ HERE **
54 Do this first, because it may introduce new binders.
56 2. Make certain top-level bindings into Globals. The point is that
57 Global things get externally-visible labels at code generation
61 3. Give all binders a nice print-name. Their uniques aren't changed;
62 rather we give them lexically unique occ-names, so that we can
63 safely print the OccNae only in the interface file. [Bad idea to
64 change the uniques, because the code generator makes global labels
65 from the uniques for local thunks etc.]
68 tidyCorePgm :: DynFlags -> Module
69 -> [CoreBind] -> [IdCoreRule]
70 -> IO ([CoreBind], [IdCoreRule])
71 tidyCorePgm dflags module_name binds_in orphans_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
82 let (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
83 init_tidy_env binds_in1
84 orphans_out = tidyIdRules tidy_env1 orphans_in
86 endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
87 dopt Opt_D_verbose_core2core dflags)
90 return (binds_out, orphans_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 tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
107 -> (TidyEnv, CoreBind)
108 tidyBind maybe_mod env (NonRec bndr rhs)
110 (env', bndr') = tidy_bndr maybe_mod env' env bndr
111 rhs' = tidyExpr env' rhs
112 -- We use env' when tidying the RHS even though it's not
113 -- strictly necessary; it makes the code pretty hard to read
116 (env', NonRec bndr' rhs')
118 tidyBind maybe_mod env (Rec pairs)
120 -- We use env' when tidying the rhss
121 -- When tidying the binder itself we may tidy it's
122 -- specialisations; if any of these mention other binders
123 -- in the group we should really feed env' to them too;
124 -- but that seems (a) unlikely and (b) a bit tiresome.
125 -- So I left it out for now
127 (bndrs, rhss) = unzip pairs
128 (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs
129 rhss' = map (tidyExpr env') rhss
131 (env', Rec (zip bndrs' rhss'))
133 tidyExpr env (Type ty) = Type (tidyType env ty)
134 tidyExpr env (Lit lit) = Lit lit
135 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
136 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
138 tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
140 (env', b') = tidyBind Nothing env b
142 tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
144 (env', b') = tidyBndr env b
146 tidyExpr env (Var v) = Var (tidyVarOcc env v)
148 tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
150 (env', b') = tidyBndr env b
152 tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
154 (env', vs') = tidyBndrs env vs
156 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
158 tidyNote env note = note
160 tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
166 tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
167 tidy_bndr Nothing env_idinfo env var = tidyBndr env var
172 %************************************************************************
174 \subsection{Tidying up a binder}
176 %************************************************************************
179 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
180 tidyBndr env var | isTyVar var = tidyTyVar env var
181 | otherwise = tidyId env var
183 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
184 tidyBndrs env vars = mapAccumL tidyBndr env vars
186 tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
187 tidyId env@(tidy_env, var_env) id
188 = -- Non-top-level variables
190 -- Give the Id a fresh print-name, *and* rename its type
191 -- The SrcLoc isn't important now, though we could extract it from the Id
192 name' = mkLocalName (getUnique id) occ' noSrcLoc
193 (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
194 ty' = tidyType env (idType id)
195 id' = mkVanillaId name' ty'
196 `setIdStrictness` idStrictness id
197 `setIdDemandInfo` idDemandInfo id
198 -- NB: This throws away the IdInfo of the Id, which we
199 -- no longer need. That means we don't need to
200 -- run over it with env, nor renumber it.
202 -- The exception is strictness and demand info, which
203 -- is used to decide whether to use let or case for
204 -- function arguments and let bindings
206 var_env' = extendVarEnv var_env id id'
208 ((tidy_env', var_env'), id')
210 tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
211 -- The second env is the one to use for the IdInfo
212 -- It's necessary because when we are dealing with a recursive
213 -- group, a variable late in the group might be mentioned
214 -- in the IdInfo of one early in the group
215 tidyTopId mod env@(tidy_env, var_env) env_idinfo id
216 = -- Top level variables
218 (tidy_env', name') = tidyTopName mod tidy_env (idName id)
219 ty' = tidyTopType (idType id)
220 idinfo' = tidyIdInfo env_idinfo (idInfo id)
221 id' = mkId name' ty' idinfo'
222 var_env' = extendVarEnv var_env id id'
224 ((tidy_env', var_env'), id')
228 -- tidyIdInfo does these things:
229 -- a) tidy the specialisation info and worker info (if any)
230 -- b) zap the unfolding and demand info
231 -- The latter two are to avoid space leaks
236 rules = specInfo info
238 info2 | isEmptyCoreRules rules = info
239 | otherwise = info `setSpecInfo` tidyRules env rules
241 info3 = info2 `setUnfoldingInfo` noUnfolding
242 info4 = info3 `setDemandInfo` wwLazy
244 info5 = case workerInfo info of
246 HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
248 tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
249 tidyIdRules env rules
250 = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ]
252 tidyRules :: TidyEnv -> CoreRules -> CoreRules
253 tidyRules env (Rules rules fvs)
254 = Rules (map (tidyRule env) rules)
255 (foldVarSet tidy_set_elem emptyVarSet fvs)
257 tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
259 tidyRule :: TidyEnv -> CoreRule -> CoreRule
260 tidyRule env rule@(BuiltinRule _) = rule
261 tidyRule env (Rule name vars tpl_args rhs)
262 = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
264 (env', vars') = tidyBndrs env vars