Taken quite directly from the Peyton Jones/Lester paper.
\begin{code}
+{-# OPTIONS -fno-warn-incomplete-patterns #-}
+-- 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
+
module CoreFVs (
exprFreeVars, -- CoreExpr -> VarSet -- Find all locally-defined free Ids or tyvars
exprsFreeVars, -- [CoreExpr] -> VarSet
exprFreeNames, exprsFreeNames,
idRuleVars, idFreeVars, varTypeTyVars,
- ruleRhsFreeVars, rulesRhsFreeVars,
+ ruleRhsFreeVars, rulesFreeVars,
ruleLhsFreeNames, ruleLhsFreeIds,
CoreExprWithFVs, -- = AnnExpr Id VarSet
exprsFreeVars = foldr (unionVarSet . exprFreeVars) emptyVarSet
bindFreeVars :: CoreBind -> VarSet
-bindFreeVars (NonRec b r) = exprFreeVars r
+bindFreeVars (NonRec _ r) = exprFreeVars r
bindFreeVars (Rec prs) = addBndrs (map fst prs)
(foldr (union . rhs_fvs) noVars prs)
isLocalVar emptyVarSet
union fv1 fv2 fv_cand in_scope = fv1 fv_cand in_scope `unionVarSet` fv2 fv_cand in_scope
noVars :: FV
-noVars fv_cand in_scope = emptyVarSet
+noVars _ _ = emptyVarSet
-- Comment about obselete code
-- We used to gather the free variables the RULES at a variable occurrence
someVars vars fv_cand in_scope
= filterVarSet (keep_it fv_cand in_scope) vars
+keep_it :: InterestingVarFun -> VarSet -> Var -> Bool
keep_it fv_cand in_scope var
| var `elemVarSet` in_scope = False
| fv_cand var = True
expr_fvs (Type ty) = someVars (tyVarsOfType ty)
expr_fvs (Var var) = oneVar var
-expr_fvs (Lit lit) = noVars
+expr_fvs (Lit _) = noVars
expr_fvs (Note _ expr) = expr_fvs expr
expr_fvs (App fun arg) = expr_fvs fun `union` expr_fvs arg
expr_fvs (Lam bndr body) = addBndr bndr (expr_fvs body)
= expr_fvs scrut `union` someVars (tyVarsOfType ty) `union` addBndr bndr
(foldr (union . alt_fvs) noVars alts)
where
- alt_fvs (con, bndrs, rhs) = addBndrs bndrs (expr_fvs rhs)
+ alt_fvs (_, bndrs, rhs) = addBndrs bndrs (expr_fvs rhs)
expr_fvs (Let (NonRec bndr rhs) body)
= rhs_fvs (bndr, rhs) `union` addBndr bndr (expr_fvs body)
(foldr (union . rhs_fvs) (expr_fvs body) pairs)
---------
+rhs_fvs :: (Id,CoreExpr) -> FV
rhs_fvs (bndr, rhs) = expr_fvs rhs `union` someVars (idRuleVars bndr)
-- Treat any RULES as extra RHSs of the binding
---------
+exprs_fvs :: [CoreExpr] -> FV
exprs_fvs exprs = foldr (union . expr_fvs) noVars exprs
\end{code}
\begin{code}
ruleLhsFreeNames :: CoreRule -> NameSet
ruleLhsFreeNames (BuiltinRule { ru_fn = fn }) = unitNameSet fn
-ruleLhsFreeNames (Rule { ru_fn = fn, ru_bndrs = tpl_vars, ru_args = tpl_args })
+ruleLhsFreeNames (Rule { ru_fn = fn, ru_args = tpl_args })
= addOneToNameSet (exprsFreeNames tpl_args) fn
exprFreeNames :: CoreExpr -> NameSet
go (Type ty) = tyClsNamesOfType ty -- Don't need free tyvars
go (App e1 e2) = go e1 `unionNameSets` go e2
go (Lam v e) = go e `delFromNameSet` idName v
- go (Note n e) = go e
+ go (Note _ e) = go e
go (Cast e co) = go e `unionNameSets` tyClsNamesOfType co
- go (Let (NonRec b r) e) = go e `unionNameSets` go r
+ go (Let (NonRec _ r) e) = go e `unionNameSets` go r
go (Let (Rec prs) e) = exprsFreeNames (map snd prs) `unionNameSets` go e
- go (Case e b ty as) = go e `unionNameSets` tyClsNamesOfType ty
+ go (Case e _ ty as) = go e `unionNameSets` tyClsNamesOfType ty
`unionNameSets` unionManyNameSets (map go_alt as)
go_alt (_,_,r) = go r
+exprsFreeNames :: [CoreExpr] -> NameSet
exprsFreeNames es = foldr (unionNameSets . exprFreeNames) emptyNameSet es
\end{code}
ruleRhsFreeVars :: CoreRule -> VarSet
ruleRhsFreeVars (BuiltinRule {}) = noFVs
ruleRhsFreeVars (Rule { ru_fn = fn, ru_bndrs = bndrs, ru_rhs = rhs })
- = delFromUFM fvs fn
- -- Hack alert!
- -- Don't include the Id in its own rhs free-var set.
- -- Otherwise the occurrence analyser makes bindings recursive
- -- that shoudn't be. E.g.
- -- RULE: f (f x y) z ==> f x (f y z)
+ = delFromUFM fvs fn -- Note [Rule free var hack]
where
fvs = addBndrs bndrs (expr_fvs rhs) isLocalVar emptyVarSet
-rulesRhsFreeVars :: [CoreRule] -> VarSet
-rulesRhsFreeVars rules
- = foldr (unionVarSet . ruleRhsFreeVars) emptyVarSet rules
+ruleFreeVars :: CoreRule -> VarSet -- All free variables, both left and right
+ruleFreeVars (Rule { ru_fn = fn, ru_bndrs = bndrs, ru_rhs = rhs, ru_args = args })
+ = delFromUFM fvs fn -- Note [Rule free var hack]
+ where
+ fvs = addBndrs bndrs (exprs_fvs (rhs:args)) isLocalVar emptyVarSet
+
+rulesFreeVars :: [CoreRule] -> VarSet
+rulesFreeVars rules = foldr (unionVarSet . ruleFreeVars) emptyVarSet rules
ruleLhsFreeIds :: CoreRule -> VarSet
-- This finds all locally-defined free Ids on the LHS of the rule
= addBndrs bndrs (exprs_fvs args) isLocalId emptyVarSet
\end{code}
+Note [Rule free var hack]
+~~~~~~~~~~~~~~~~~~~~~~~~~
+Don't include the Id in its own rhs free-var set.
+Otherwise the occurrence analyser makes bindings recursive
+that shoudn't be. E.g.
+ RULE: f (f x y) z ==> f x (f y z)
+
+Also since rule_fn is a Name, not a Var, we have to use the grungy delUFM.
%************************************************************************
%* *
freeVarsOf :: CoreExprWithFVs -> IdSet
freeVarsOf (free_vars, _) = free_vars
+noFVs :: VarSet
noFVs = emptyVarSet
+
+aFreeVar :: Var -> VarSet
aFreeVar = unitVarSet
+
+unionFVs :: VarSet -> VarSet -> VarSet
unionFVs = unionVarSet
delBindersFV :: [Var] -> VarSet -> VarSet
projects / ghc-hetmet.git / blobdiff