\section[CoreRules]{Transformation rules}
\begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
-- | Functions for collecting together and applying rewrite rules to a module.
-- The 'CoreRule' datatype itself is declared elsewhere.
module Rules (
import CoreUtils ( tcEqExprX, exprType )
import PprCore ( pprRules )
import Type ( Type, TvSubstEnv )
-import Coercion ( coercionKind )
import TcType ( tcSplitTyConApp_maybe )
import CoreTidy ( tidyRules )
import Id
roughTopName (Type ty) = case tcSplitTyConApp_maybe ty of
Just (tc,_) -> Just (getName tc)
Nothing -> Nothing
-roughTopName (App f a) = roughTopName f
+roughTopName (App f _) = roughTopName f
roughTopName (Var f) | isGlobalId f = Just (idName f)
| otherwise = Nothing
-roughTopName other = Nothing
+roughTopName _ = Nothing
ruleCantMatch :: [Maybe Name] -> [Maybe Name] -> Bool
-- ^ @ruleCantMatch tpl actual@ returns True only if @actual@
-- Reason: a local variable @v@ in the actuals might [_$_]
ruleCantMatch (Just n1 : ts) (Just n2 : as) = n1 /= n2 || ruleCantMatch ts as
-ruleCantMatch (t : ts) (a : as) = ruleCantMatch ts as
-ruleCantMatch ts as = False
+ruleCantMatch (_ : ts) (_ : as) = ruleCantMatch ts as
+ruleCantMatch _ _ = False
\end{code}
\begin{code}
-- The rules are are unordered;
-- we sort out any overlaps on lookup
+emptyRuleBase :: RuleBase
emptyRuleBase = emptyNameEnv
mkRuleBase :: [CoreRule] -> RuleBase
-- Return the pair the the most specific rule
-- The (fn,args) is just for overlap reporting
-findBest target (rule,ans) [] = (rule,ans)
+findBest _ (rule,ans) [] = (rule,ans)
findBest target (rule1,ans1) ((rule2,ans2):prs)
| rule1 `isMoreSpecific` rule2 = findBest target (rule1,ans1) prs
| rule2 `isMoreSpecific` rule1 = findBest target (rule2,ans2) prs
(fn,args) = target
isMoreSpecific :: CoreRule -> CoreRule -> Bool
-isMoreSpecific (BuiltinRule {}) r2 = True
-isMoreSpecific r1 (BuiltinRule {}) = False
+isMoreSpecific (BuiltinRule {}) _ = True
+isMoreSpecific _ (BuiltinRule {}) = False
isMoreSpecific (Rule { ru_bndrs = bndrs1, ru_args = args1 })
(Rule { ru_bndrs = bndrs2, ru_args = args2 })
= isJust (matchN in_scope bndrs2 args2 args1)
-- of rule1's args, but I can't be bothered
noBlackList :: Activation -> Bool
-noBlackList act = False -- Nothing is black listed
+noBlackList _ = False -- Nothing is black listed
matchRule :: (Activation -> Bool) -> InScopeSet
-> [CoreExpr] -> [Maybe Name]
-- Any 'surplus' arguments in the input are simply put on the end
-- of the output.
-matchRule is_active in_scope args rough_args
- (BuiltinRule { ru_name = name, ru_try = match_fn })
+matchRule _is_active _in_scope args _rough_args
+ (BuiltinRule { ru_try = match_fn })
= case match_fn args of
Just expr -> Just expr
Nothing -> Nothing
matchRule is_active in_scope args rough_args
- (Rule { ru_name = rn, ru_act = act, ru_rough = tpl_tops,
+ (Rule { ru_act = act, ru_rough = tpl_tops,
ru_bndrs = tpl_vars, ru_args = tpl_args,
ru_rhs = rhs })
| not (is_active act) = Nothing
init_menv = ME { me_tmpls = mkVarSet tmpl_vars', me_env = init_rn_env }
- go menv subst [] es = Just subst
- go menv subst ts [] = Nothing -- Fail if too few actual args
+ go _ subst [] _ = Just subst
+ go _ _ _ [] = Nothing -- Fail if too few actual args
go menv subst (t:ts) (e:es) = do { subst1 <- match menv subst t e
; go menv subst1 ts es }
Nothing -> unbound tmpl_var'
| otherwise = case lookupVarEnv id_subst tmpl_var' of
Just e -> e
- other -> unbound tmpl_var'
+ _ -> unbound tmpl_var'
unbound var = pprPanic "Template variable unbound in rewrite rule"
(ppr var $$ ppr tmpl_vars $$ ppr tmpl_vars' $$ ppr tmpl_es $$ ppr target_es)
| Just subst <- match_var menv subst v1 e2
= Just subst
-match menv subst e1 (Note n e2)
+match menv subst e1 (Note _ e2)
= match menv subst e1 e2
-- Note [Notes in RULE matching]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I'm removing the cloning because that makes the above case
fail, because the inner let looks as if it has locally-bound vars -}
-match menv subst@(tv_subst, id_subst, binds) e1 (Let bind e2)
+match menv (tv_subst, id_subst, binds) e1 (Let bind e2)
| all freshly_bound bndrs,
not (any locally_bound bind_fvs)
= match (menv { me_env = rn_env' })
Rec {} -> Rec (bndrs' `zip` map (substExpr subst) rhss)
-}
-match menv subst (Lit lit1) (Lit lit2)
+match _ subst (Lit lit1) (Lit lit2)
| lit1 == lit2
= Just subst
-}
-- Everything else fails
-match menv subst e1 e2 = -- pprTrace "Failing at" ((text "e1:" <+> ppr e1) $$ (text "e2:" <+> ppr e2)) $
+match _ _ _e1 _e2 = -- pprTrace "Failing at" ((text "e1:" <+> ppr e1) $$ (text "e2:" <+> ppr e2)) $
Nothing
------------------------------------------
| otherwise -- v1 is not a template variable; check for an exact match with e2
= case e2 of
Var v2 | v1' == rnOccR rn_env v2 -> Just subst
- other -> Nothing
+ _ -> Nothing
where
rn_env = me_env menv
-> [CoreAlt] -- Template
-> [CoreAlt] -- Target
-> Maybe SubstEnv
-match_alts menv subst [] []
+match_alts _ subst [] []
= return subst
match_alts menv subst ((c1,vs1,r1):alts1) ((c2,vs2,r2):alts2)
| c1 == c2
menv' :: MatchEnv
menv' = menv { me_env = rnBndrs2 (me_env menv) vs1 vs2 }
-match_alts menv subst alts1 alts2
+match_alts _ _ _ _
= Nothing
\end{code}
ruleCheckBind :: RuleCheckEnv -> CoreBind -> Bag SDoc
-- The Bag returned has one SDoc for each call site found
-ruleCheckBind env (NonRec b r) = ruleCheck env r
-ruleCheckBind env (Rec prs) = unionManyBags [ruleCheck env r | (b,r) <- prs]
+ruleCheckBind env (NonRec _ r) = ruleCheck env r
+ruleCheckBind env (Rec prs) = unionManyBags [ruleCheck env r | (_,r) <- prs]
ruleCheck :: RuleCheckEnv -> CoreExpr -> Bag SDoc
-ruleCheck env (Var v) = emptyBag
-ruleCheck env (Lit l) = emptyBag
-ruleCheck env (Type ty) = emptyBag
+ruleCheck _ (Var _) = emptyBag
+ruleCheck _ (Lit _) = emptyBag
+ruleCheck _ (Type _) = emptyBag
ruleCheck env (App f a) = ruleCheckApp env (App f a) []
-ruleCheck env (Note n e) = ruleCheck env e
-ruleCheck env (Cast e co) = ruleCheck env e
+ruleCheck env (Note _ e) = ruleCheck env e
+ruleCheck env (Cast e _) = ruleCheck env e
ruleCheck env (Let bd e) = ruleCheckBind env bd `unionBags` ruleCheck env e
-ruleCheck env (Lam b e) = ruleCheck env e
+ruleCheck env (Lam _ e) = ruleCheck env e
ruleCheck env (Case e _ _ as) = ruleCheck env e `unionBags`
unionManyBags [ruleCheck env r | (_,_,r) <- as]
+ruleCheckApp :: RuleCheckEnv -> Expr CoreBndr -> [Arg CoreBndr] -> Bag SDoc
ruleCheckApp env (App f a) as = ruleCheck env a `unionBags` ruleCheckApp env f (a:as)
ruleCheckApp env (Var f) as = ruleCheckFun env f as
-ruleCheckApp env other as = ruleCheck env other
+ruleCheckApp env other _ = ruleCheck env other
\end{code}
\begin{code}
rule_info (BuiltinRule {}) = text "does not match"
- rule_info (Rule { ru_name = name, ru_act = act,
+ rule_info (Rule { ru_act = act,
ru_bndrs = rule_bndrs, ru_args = rule_args})
| not (is_active act) = text "active only in later phase"
| n_args < n_rule_args = text "too few arguments"
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