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 ( showPass, 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 ErrUtils ( showPass )
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
70 -> [CoreBind] -> [IdCoreRule]
71 -> IO ([CoreBind], [IdCoreRule])
72 tidyCorePgm dflags module_name binds_in orphans_in
74 us <- mkSplitUniqSupply 'u'
76 showPass dflags "Tidy Core"
78 binds_in1 <- if opt_UsageSPOn
79 then _scc_ "CoreUsageSPInf"
80 doUsageSPInf dflags us binds_in
83 let (tidy_env1, binds_out) = mapAccumL (tidyBind (Just module_name))
84 init_tidy_env binds_in1
85 orphans_out = tidyIdRules tidy_env1 orphans_in
87 endPass dflags "Tidy Core" (dopt Opt_D_dump_simpl dflags ||
88 dopt Opt_D_verbose_core2core dflags)
91 return (binds_out, orphans_out)
93 -- We also make sure to avoid any exported binders. Consider
94 -- f{-u1-} = 1 -- Local decl
96 -- f{-u2-} = 2 -- Exported decl
98 -- The second exported decl must 'get' the name 'f', so we
99 -- have to put 'f' in the avoids list before we get to the first
100 -- decl. tidyTopId then does a no-op on exported binders.
101 init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
102 avoids = [getOccName bndr | bndr <- bindersOfBinds binds_in,
103 exportWithOrigOccName bndr]
105 tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
108 -> (TidyEnv, CoreBind)
109 tidyBind maybe_mod env (NonRec bndr rhs)
111 (env', bndr') = tidy_bndr maybe_mod env' env bndr
112 rhs' = tidyExpr env' rhs
113 -- We use env' when tidying the RHS even though it's not
114 -- strictly necessary; it makes the code pretty hard to read
117 (env', NonRec bndr' rhs')
119 tidyBind maybe_mod env (Rec pairs)
121 -- We use env' when tidying the rhss
122 -- When tidying the binder itself we may tidy it's
123 -- specialisations; if any of these mention other binders
124 -- in the group we should really feed env' to them too;
125 -- but that seems (a) unlikely and (b) a bit tiresome.
126 -- So I left it out for now
128 (bndrs, rhss) = unzip pairs
129 (env', bndrs') = mapAccumL (tidy_bndr maybe_mod env') env bndrs
130 rhss' = map (tidyExpr env') rhss
132 (env', Rec (zip bndrs' rhss'))
134 tidyExpr env (Type ty) = Type (tidyType env ty)
135 tidyExpr env (Lit lit) = Lit lit
136 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
137 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
139 tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
141 (env', b') = tidyBind Nothing env b
143 tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
145 (env', b') = tidyBndr env b
147 tidyExpr env (Var v) = Var (tidyVarOcc env v)
149 tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
151 (env', b') = tidyBndr env b
153 tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
155 (env', vs') = tidyBndrs env vs
157 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
159 tidyNote env note = note
161 tidyVarOcc (_, var_env) v = case lookupVarEnv var_env v of
167 tidy_bndr (Just mod) env_idinfo env var = tidyTopId mod env env_idinfo var
168 tidy_bndr Nothing env_idinfo env var = tidyBndr env var
173 %************************************************************************
175 \subsection{Tidying up a binder}
177 %************************************************************************
180 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
181 tidyBndr env var | isTyVar var = tidyTyVar env var
182 | otherwise = tidyId env var
184 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
185 tidyBndrs env vars = mapAccumL tidyBndr env vars
187 tidyId :: TidyEnv -> Id -> (TidyEnv, Id)
188 tidyId env@(tidy_env, var_env) id
189 = -- Non-top-level variables
191 -- Give the Id a fresh print-name, *and* rename its type
192 -- The SrcLoc isn't important now, though we could extract it from the Id
193 name' = mkLocalName (getUnique id) occ' noSrcLoc
194 (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
195 ty' = tidyType env (idType id)
196 id' = mkVanillaId name' ty'
197 `setIdStrictness` idStrictness id
198 `setIdDemandInfo` idDemandInfo id
199 -- NB: This throws away the IdInfo of the Id, which we
200 -- no longer need. That means we don't need to
201 -- run over it with env, nor renumber it.
203 -- The exception is strictness and demand info, which
204 -- is used to decide whether to use let or case for
205 -- function arguments and let bindings
207 var_env' = extendVarEnv var_env id id'
209 ((tidy_env', var_env'), id')
211 tidyTopId :: Module -> TidyEnv -> TidyEnv -> Id -> (TidyEnv, Id)
212 -- The second env is the one to use for the IdInfo
213 -- It's necessary because when we are dealing with a recursive
214 -- group, a variable late in the group might be mentioned
215 -- in the IdInfo of one early in the group
216 tidyTopId mod env@(tidy_env, var_env) env_idinfo id
217 = -- Top level variables
219 (tidy_env', name') = tidyTopName mod tidy_env (idName id)
220 ty' = tidyTopType (idType id)
221 idinfo' = tidyIdInfo env_idinfo (idInfo id)
222 id' = mkId name' ty' idinfo'
223 var_env' = extendVarEnv var_env id id'
225 ((tidy_env', var_env'), id')
229 -- tidyIdInfo does these things:
230 -- a) tidy the specialisation info and worker info (if any)
231 -- b) zap the unfolding and demand info
232 -- The latter two are to avoid space leaks
237 rules = specInfo info
239 info2 | isEmptyCoreRules rules = info
240 | otherwise = info `setSpecInfo` tidyRules env rules
242 info3 = info2 `setUnfoldingInfo` noUnfolding
243 info4 = info3 `setDemandInfo` wwLazy
245 info5 = case workerInfo info of
247 HasWorker w a -> info4 `setWorkerInfo` HasWorker (tidyVarOcc env w) a
249 tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
250 tidyIdRules env rules
251 = [ (tidyVarOcc env fn, tidyRule env rule) | (fn,rule) <- rules ]
253 tidyRules :: TidyEnv -> CoreRules -> CoreRules
254 tidyRules env (Rules rules fvs)
255 = Rules (map (tidyRule env) rules)
256 (foldVarSet tidy_set_elem emptyVarSet fvs)
258 tidy_set_elem var new_set = extendVarSet new_set (tidyVarOcc env var)
260 tidyRule :: TidyEnv -> CoreRule -> CoreRule
261 tidyRule env rule@(BuiltinRule _) = rule
262 tidyRule env (Rule name vars tpl_args rhs)
263 = (Rule name vars' (map (tidyExpr env') tpl_args) (tidyExpr env' rhs))
265 (env', vars') = tidyBndrs env vars