2 % (c) The AQUA Project, Glasgow University, 1996-1998
7 tidyExpr, tidyVarOcc, tidyRule, tidyRules
10 #include "HsVersions.h"
13 import CoreUtils ( exprArity )
14 import DataCon ( DataCon )
15 import Id ( Id, mkUserLocal, idInfo, setIdInfo, idUnique,
17 import IdInfo ( setArityInfo, vanillaIdInfo,
18 newStrictnessInfo, setAllStrictnessInfo,
19 newDemandInfo, setNewDemandInfo )
20 import Type ( Type, tidyType, tidyTyVarBndr, substTy, mkOpenTvSubst )
21 import Var ( Var, TyVar, varName )
23 import UniqFM ( lookupUFM )
24 import Name ( Name, getOccName )
25 import OccName ( tidyOccName )
26 import SrcLoc ( noSrcLoc )
27 import Maybes ( orElse )
29 import Util ( mapAccumL )
33 This module contains "tidying" code for *nested* expressions, bindings, rules.
34 The code for *top-level* bindings is in TidyPgm.
36 %************************************************************************
38 \subsection{Tidying expressions, rules}
40 %************************************************************************
45 -> (TidyEnv, CoreBind)
47 tidyBind env (NonRec bndr rhs)
48 = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') ->
49 (env', NonRec bndr' (tidyExpr env' rhs))
51 tidyBind env (Rec prs)
52 = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') ->
53 map (tidyExpr env') (map snd prs) =: \ rhss' ->
54 (env', Rec (zip bndrs' rhss'))
57 ------------ Expressions --------------
58 tidyExpr :: TidyEnv -> CoreExpr -> CoreExpr
59 tidyExpr env (Var v) = Var (tidyVarOcc env v)
60 tidyExpr env (Type ty) = Type (tidyType env ty)
61 tidyExpr env (Lit lit) = Lit lit
62 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
63 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
64 tidyExpr env (Cast e co) = Cast (tidyExpr env e) (tidyType env co)
66 tidyExpr env (Let b e)
67 = tidyBind env b =: \ (env', b') ->
68 Let b' (tidyExpr env' e)
70 tidyExpr env (Case e b ty alts)
71 = tidyBndr env b =: \ (env', b) ->
72 Case (tidyExpr env e) b (tidyType env ty)
73 (map (tidyAlt b env') alts)
75 tidyExpr env (Lam b e)
76 = tidyBndr env b =: \ (env', b) ->
77 Lam b (tidyExpr env' e)
79 ------------ Case alternatives --------------
80 tidyAlt case_bndr env (con, vs, rhs)
81 = tidyBndrs env vs =: \ (env', vs) ->
82 (con, vs, tidyExpr env' rhs)
84 ------------ Notes --------------
85 tidyNote env note = note
87 ------------ Rules --------------
88 tidyRules :: TidyEnv -> [CoreRule] -> [CoreRule]
90 tidyRules env (rule : rules)
91 = tidyRule env rule =: \ rule ->
92 tidyRules env rules =: \ rules ->
95 tidyRule :: TidyEnv -> CoreRule -> CoreRule
96 tidyRule env rule@(BuiltinRule {}) = rule
97 tidyRule env rule@(Rule { ru_bndrs = bndrs, ru_args = args, ru_rhs = rhs,
98 ru_fn = fn, ru_rough = mb_ns })
99 = tidyBndrs env bndrs =: \ (env', bndrs) ->
100 map (tidyExpr env') args =: \ args ->
101 rule { ru_bndrs = bndrs, ru_args = args,
102 ru_rhs = tidyExpr env' rhs,
103 ru_fn = tidyNameOcc env fn,
104 ru_rough = map (fmap (tidyNameOcc env')) mb_ns }
108 %************************************************************************
110 \subsection{Tidying non-top-level binders}
112 %************************************************************************
115 tidyNameOcc :: TidyEnv -> Name -> Name
116 -- In rules and instances, we have Names, and we must tidy them too
117 -- Fortunately, we can lookup in the VarEnv with a name
118 tidyNameOcc (_, var_env) n = case lookupUFM var_env n of
122 tidyVarOcc :: TidyEnv -> Var -> Var
123 tidyVarOcc (_, var_env) v = lookupVarEnv var_env v `orElse` v
125 -- tidyBndr is used for lambda and case binders
126 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
128 | isTyVar var = tidyTyVarBndr env var
129 | otherwise = tidyIdBndr env var
131 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
132 tidyBndrs env vars = mapAccumL tidyBndr env vars
134 tidyLetBndr :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var)
135 -- Used for local (non-top-level) let(rec)s
136 tidyLetBndr env (id,rhs)
137 = ((tidy_env,new_var_env), final_id)
139 ((tidy_env,var_env), new_id) = tidyIdBndr env id
141 -- We need to keep around any interesting strictness and
142 -- demand info because later on we may need to use it when
143 -- converting to A-normal form.
145 -- f (g x), where f is strict in its argument, will be converted
146 -- into case (g x) of z -> f z by CorePrep, but only if f still
147 -- has its strictness info.
149 -- Similarly for the demand info - on a let binder, this tells
150 -- CorePrep to turn the let into a case.
152 -- Similarly arity info for eta expansion in CorePrep
154 final_id = new_id `setIdInfo` new_info
156 new_info = vanillaIdInfo
157 `setArityInfo` exprArity rhs
158 `setAllStrictnessInfo` newStrictnessInfo idinfo
159 `setNewDemandInfo` newDemandInfo idinfo
161 -- Override the env we get back from tidyId with the new IdInfo
162 -- so it gets propagated to the usage sites.
163 new_var_env = extendVarEnv var_env id final_id
165 -- Non-top-level variables
166 tidyIdBndr :: TidyEnv -> Id -> (TidyEnv, Id)
167 tidyIdBndr env@(tidy_env, var_env) id
168 = -- do this pattern match strictly, otherwise we end up holding on to
169 -- stuff in the OccName.
170 case tidyOccName tidy_env (getOccName id) of { (tidy_env', occ') ->
172 -- Give the Id a fresh print-name, *and* rename its type
173 -- The SrcLoc isn't important now,
174 -- though we could extract it from the Id
176 -- All nested Ids now have the same IdInfo, namely vanillaIdInfo,
177 -- which should save some space.
178 -- But note that tidyLetBndr puts some of it back.
179 ty' = tidyType env (idType id)
180 id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc
181 `setIdInfo` vanillaIdInfo
182 var_env' = extendVarEnv var_env id id'
184 ((tidy_env', var_env'), id')