-- | A module concerned with finding the free variables of an expression.
module CoreFVs (
-- * Free variables of expressions and binding groups
- exprFreeVars, -- CoreExpr -> VarSet -- Find all locally-defined free Ids or tyvars
- exprFreeIds, -- CoreExpr -> IdSet -- Find all locally-defined free Ids
- exprsFreeVars, -- [CoreExpr] -> VarSet
- bindFreeVars, -- CoreBind -> VarSet
+ exprFreeVars, -- CoreExpr -> VarSet -- Find all locally-defined free Ids or tyvars
+ exprFreeIds, -- CoreExpr -> IdSet -- Find all locally-defined free Ids
+ exprsFreeVars, -- [CoreExpr] -> VarSet
+ bindFreeVars, -- CoreBind -> VarSet
-- * Selective free variables of expressions
InterestingVarFun,
- exprSomeFreeVars, exprsSomeFreeVars,
- exprFreeNames, exprsFreeNames,
+ exprSomeFreeVars, exprsSomeFreeVars,
-- * Free variables of Rules, Vars and Ids
varTypeTyVars, varTypeTcTyVars,
- idUnfoldingVars, idFreeVars, idRuleAndUnfoldingVars,
- idRuleVars, idRuleRhsVars,
- ruleRhsFreeVars, rulesFreeVars,
- ruleLhsFreeNames, ruleLhsFreeIds,
+ idUnfoldingVars, idFreeVars, idRuleAndUnfoldingVars,
+ idRuleVars, idRuleRhsVars, stableUnfoldingVars,
+ ruleRhsFreeVars, rulesFreeVars,
+ ruleLhsOrphNames, ruleLhsFreeIds,
+ vectsFreeVars,
-- * Core syntax tree annotation with free variables
- CoreExprWithFVs, -- = AnnExpr Id VarSet
- CoreBindWithFVs, -- = AnnBind Id VarSet
- freeVars, -- CoreExpr -> CoreExprWithFVs
- freeVarsOf -- CoreExprWithFVs -> IdSet
+ CoreExprWithFVs, -- = AnnExpr Id VarSet
+ CoreBindWithFVs, -- = AnnBind Id VarSet
+ freeVars, -- CoreExpr -> CoreExprWithFVs
+ freeVarsOf -- CoreExprWithFVs -> IdSet
) where
#include "HsVersions.h"
import VarSet
import Var
import TcType
+import Coercion
import Util
+import BasicTypes( Activation )
import Outputable
\end{code}
expr_fvs :: CoreExpr -> FV
expr_fvs (Type ty) = someVars (tyVarsOfType ty)
+expr_fvs (Coercion co) = someVars (tyCoVarsOfCo co)
expr_fvs (Var var) = oneVar var
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 (Cast expr co) = expr_fvs expr `union` someVars (tyVarsOfType co)
+expr_fvs (Cast expr co) = expr_fvs expr `union` someVars (tyCoVarsOfCo co)
expr_fvs (Case scrut bndr ty alts)
= expr_fvs scrut `union` someVars (tyVarsOfType ty) `union` addBndr bndr
%************************************************************************
\begin{code}
--- | Similar to 'exprFreeNames'. However, this is used when deciding whether
+-- | ruleLhsOrphNames is used when deciding whether
-- a rule is an orphan. In particular, suppose that T is defined in this
-- module; we want to avoid declaring that a rule like:
--
--
-- is an orphan. Of course it isn't, and declaring it an orphan would
-- make the whole module an orphan module, which is bad.
-ruleLhsFreeNames :: CoreRule -> NameSet
-ruleLhsFreeNames (BuiltinRule { ru_fn = fn }) = unitNameSet fn
-ruleLhsFreeNames (Rule { ru_fn = fn, ru_args = tpl_args })
- = addOneToNameSet (exprsFreeNames tpl_args) fn
+ruleLhsOrphNames :: CoreRule -> NameSet
+ruleLhsOrphNames (BuiltinRule { ru_fn = fn }) = unitNameSet fn
+ruleLhsOrphNames (Rule { ru_fn = fn, ru_args = tpl_args })
+ = addOneToNameSet (exprsOrphNames tpl_args) fn
+ -- No need to delete bndrs, because
+ -- exprsOrphNames finds only External names
-- | Finds the free /external/ names of an expression, notably
-- including the names of type constructors (which of course do not show
-- up in 'exprFreeVars').
-exprFreeNames :: CoreExpr -> NameSet
+exprOrphNames :: CoreExpr -> NameSet
-- There's no need to delete local binders, because they will all
-- be /internal/ names.
-exprFreeNames e
+exprOrphNames e
= go e
where
go (Var v)
| otherwise = emptyNameSet
where n = idName v
go (Lit _) = emptyNameSet
- go (Type ty) = tyClsNamesOfType ty -- Don't need free tyvars
+ go (Type ty) = orphNamesOfType ty -- Don't need free tyvars
+ go (Coercion co) = orphNamesOfCo co
go (App e1 e2) = go e1 `unionNameSets` go e2
go (Lam v e) = go e `delFromNameSet` idName v
go (Note _ e) = go e
- go (Cast e co) = go e `unionNameSets` tyClsNamesOfType co
+ go (Cast e co) = go e `unionNameSets` orphNamesOfCo co
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 _ ty as) = go e `unionNameSets` tyClsNamesOfType ty
+ go (Let (Rec prs) e) = exprsOrphNames (map snd prs) `unionNameSets` go e
+ go (Case e _ ty as) = go e `unionNameSets` orphNamesOfType ty
`unionNameSets` unionManyNameSets (map go_alt as)
go_alt (_,_,r) = go r
--- | Finds the free /external/ names of several expressions: see 'exprFreeNames' for details
-exprsFreeNames :: [CoreExpr] -> NameSet
-exprsFreeNames es = foldr (unionNameSets . exprFreeNames) emptyNameSet es
+-- | Finds the free /external/ names of several expressions: see 'exprOrphNames' for details
+exprsOrphNames :: [CoreExpr] -> NameSet
+exprsOrphNames es = foldr (unionNameSets . exprOrphNames) emptyNameSet es
\end{code}
%************************************************************************
-%* *
+%* *
\section[freevars-everywhere]{Attaching free variables to every sub-expression}
-%* *
+%* *
%************************************************************************
\begin{code}
ruleRhsFreeVars :: CoreRule -> VarSet
ruleRhsFreeVars (BuiltinRule {}) = noFVs
ruleRhsFreeVars (Rule { ru_fn = fn, ru_bndrs = bndrs, ru_rhs = rhs })
- = delFromUFM fvs fn -- Note [Rule free var hack]
+ = delFromUFM fvs fn -- Note [Rule free var hack]
where
fvs = addBndrs bndrs (expr_fvs rhs) isLocalVar emptyVarSet
ruleFreeVars :: CoreRule -> VarSet
ruleFreeVars (BuiltinRule {}) = noFVs
ruleFreeVars (Rule { ru_fn = fn, ru_bndrs = bndrs, ru_rhs = rhs, ru_args = args })
- = delFromUFM fvs fn -- Note [Rule free var hack]
+ = delFromUFM fvs fn -- Note [Rule free var hack]
where
fvs = addBndrs bndrs (exprs_fvs (rhs:args)) isLocalVar emptyVarSet
+idRuleRhsVars :: (Activation -> Bool) -> Id -> VarSet
+-- Just the variables free on the *rhs* of a rule
+idRuleRhsVars is_active id
+ = foldr (unionVarSet . get_fvs) emptyVarSet (idCoreRules id)
+ where
+ get_fvs (Rule { ru_fn = fn, ru_bndrs = bndrs
+ , ru_rhs = rhs, ru_act = act })
+ | is_active act
+ -- See Note [Finding rule RHS free vars] in OccAnal.lhs
+ = delFromUFM fvs fn -- Note [Rule free var hack]
+ where
+ fvs = addBndrs bndrs (expr_fvs rhs) isLocalVar emptyVarSet
+ get_fvs _ = noFVs
+
-- | Those variables free in the right hand side of several rules
rulesFreeVars :: [CoreRule] -> VarSet
rulesFreeVars rules = foldr (unionVarSet . ruleFreeVars) emptyVarSet rules
= 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)
+ 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.
+
+\begin{code}
+-- |Free variables of a vectorisation declaration
+vectsFreeVars :: [CoreVect] -> VarSet
+vectsFreeVars = foldr (unionVarSet . vectFreeVars) emptyVarSet
+ where
+ vectFreeVars (Vect _ Nothing) = noFVs
+ vectFreeVars (Vect _ (Just rhs)) = expr_fvs rhs isLocalId emptyVarSet
+ vectFreeVars (NoVect _) = noFVs
+\end{code}
+
+
%************************************************************************
-%* *
+%* *
\section[freevars-everywhere]{Attaching free variables to every sub-expression}
-%* *
+%* *
%************************************************************************
The free variable pass annotates every node in the expression with its
-- Find the type variables free in the type of the variable
-- Remember, coercion variables can mention type variables...
varTypeTyVars var
- | isLocalId var || isCoVar var = tyVarsOfType (idType var)
- | otherwise = emptyVarSet -- Global Ids and non-coercion TyVars
+ | isLocalId var = tyVarsOfType (idType var)
+ | otherwise = emptyVarSet -- Global Ids and non-coercion TyVars
varTypeTcTyVars :: Var -> TyVarSet
-- Find the type variables free in the type of the variable
-- Remember, coercion variables can mention type variables...
varTypeTcTyVars var
- | isLocalId var || isCoVar var = tcTyVarsOfType (idType var)
- | otherwise = emptyVarSet -- Global Ids and non-coercion TyVars
+ | isLocalId var = tcTyVarsOfType (idType var)
+ | otherwise = emptyVarSet -- Global Ids and non-coercion TyVars
idFreeVars :: Id -> VarSet
-- Type variables, rule variables, and inline variables
idRuleVars ::Id -> VarSet -- Does *not* include CoreUnfolding vars
idRuleVars id = ASSERT( isId id) specInfoFreeVars (idSpecialisation id)
-idRuleRhsVars :: Id -> VarSet -- Does *not* include the CoreUnfolding vars
--- Just the variables free on the *rhs* of a rule
--- See Note [Choosing loop breakers] in Simplify.lhs
-idRuleRhsVars id = foldr (unionVarSet . ruleRhsFreeVars)
- emptyVarSet
- (idCoreRules id)
-
idUnfoldingVars :: Id -> VarSet
-- Produce free vars for an unfolding, but NOT for an ordinary
-- (non-inline) unfolding, since it is a dup of the rhs
-- and we'll get exponential behaviour if we look at both unf and rhs!
-- But do look at the *real* unfolding, even for loop breakers, else
-- we might get out-of-scope variables
-idUnfoldingVars id
- = case realIdUnfolding id of
- CoreUnfolding { uf_tmpl = rhs, uf_src = src }
- | isInlineRuleSource src
- -> exprFreeVars rhs
- DFunUnfolding _ args -> exprsFreeVars args
- _ -> emptyVarSet
+idUnfoldingVars id = stableUnfoldingVars (realIdUnfolding id)
+
+stableUnfoldingVars :: Unfolding -> VarSet
+stableUnfoldingVars (CoreUnfolding { uf_tmpl = rhs, uf_src = src })
+ | isStableSource src = exprFreeVars rhs
+stableUnfoldingVars (DFunUnfolding _ _ args) = exprsFreeVars (dfunArgExprs args)
+stableUnfoldingVars _ = emptyVarSet
\end{code}
body2 = freeVars body
body_fvs = freeVarsOf body2
-
freeVars (Cast expr co)
- = (freeVarsOf expr2 `unionFVs` cfvs, AnnCast expr2 co)
+ = (freeVarsOf expr2 `unionFVs` cfvs, AnnCast expr2 (cfvs, co))
where
expr2 = freeVars expr
- cfvs = tyVarsOfType co
+ cfvs = tyCoVarsOfCo co
freeVars (Note other_note expr)
= (freeVarsOf expr2, AnnNote other_note expr2)
expr2 = freeVars expr
freeVars (Type ty) = (tyVarsOfType ty, AnnType ty)
+
+freeVars (Coercion co) = (tyCoVarsOfCo co, AnnCoercion co)
\end{code}
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