X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreFVs.lhs;h=90d76196495b8122587ea16a8390d28d3b67cd4a;hp=a15362a5853b0e7cb587a90545efc47721475b09;hb=a51fe79ebcdcb8285573a18f12cade2101533419;hpb=d95ce839533391e7118257537044f01cbb1d6694

diff --git a/compiler/coreSyn/CoreFVs.lhs b/compiler/coreSyn/CoreFVs.lhs
index a15362a..90d7619 100644
--- a/compiler/coreSyn/CoreFVs.lhs
+++ b/compiler/coreSyn/CoreFVs.lhs
@@ -26,8 +26,9 @@ module CoreFVs (
 	exprFreeNames, exprsFreeNames,
 
         -- * Free variables of Rules, Vars and Ids
-	idRuleVars, idRuleRhsVars, idFreeVars, idInlineFreeVars,
-	varTypeTyVars, 
+        varTypeTyVars, varTypeTcTyVars, 
+	idUnfoldingVars, idFreeVars, idRuleAndUnfoldingVars,
+	idRuleVars, idRuleRhsVars,
 	ruleRhsFreeVars, rulesFreeVars,
 	ruleLhsFreeNames, ruleLhsFreeIds, 
 
@@ -200,7 +201,8 @@ expr_fvs (Let (Rec pairs) body)
 
 ---------
 rhs_fvs :: (Id,CoreExpr) -> FV
-rhs_fvs (bndr, rhs) = expr_fvs rhs `union` someVars (bndrRuleVars bndr)
+rhs_fvs (bndr, rhs) = expr_fvs rhs `union` 
+                      someVars (bndrRuleAndUnfoldingVars bndr)
 	-- Treat any RULES as extra RHSs of the binding
 
 ---------
@@ -277,6 +279,7 @@ ruleRhsFreeVars (Rule { ru_fn = fn, ru_bndrs = bndrs, ru_rhs = rhs })
 
 -- | Those variables free in the both the left right hand sides of a rule
 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]
   where
@@ -340,8 +343,8 @@ delBinderFV :: Var -> VarSet -> VarSet
 
 -- (b `delBinderFV` s) removes the binder b from the free variable set s,
 -- but *adds* to s
---	(a) the free variables of b's type
---	(b) the idSpecVars of b
+--
+--	the free variables of b's type
 --
 -- This is really important for some lambdas:
 -- 	In (\x::a -> x) the only mention of "a" is in the binder.
@@ -376,32 +379,53 @@ varTypeTyVars var
   | isLocalId var || isCoVar var = tyVarsOfType (idType var)
   | otherwise = emptyVarSet	-- Global Ids and non-coercion TyVars
 
-idFreeVars :: Id -> VarSet
-idFreeVars id = ASSERT( isId id) idRuleVars id `unionVarSet` varTypeTyVars id
-
-bndrRuleVars ::Var -> VarSet
-bndrRuleVars v | isTyVar v = emptyVarSet
-	       | otherwise = idRuleVars v
-
-idRuleVars ::Id -> VarSet
-idRuleVars id = ASSERT( isId id) 
-		specInfoFreeVars (idSpecialisation id) `unionVarSet` 
-		idInlineFreeVars id	-- And the variables in an INLINE rule
+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
 
-idRuleRhsVars :: Id -> VarSet
+idFreeVars :: Id -> VarSet
+-- Type variables, rule variables, and inline variables
+idFreeVars id = ASSERT( isId id) 
+		varTypeTyVars id `unionVarSet`
+	        idRuleAndUnfoldingVars id
+
+bndrRuleAndUnfoldingVars ::Var -> VarSet
+-- A 'let' can bind a type variable, and idRuleVars assumes 
+-- it's seeing an Id. This function tests first.
+bndrRuleAndUnfoldingVars v | isTyCoVar v = emptyVarSet
+	                   | otherwise = idRuleAndUnfoldingVars v
+
+idRuleAndUnfoldingVars :: Id -> VarSet
+idRuleAndUnfoldingVars id = ASSERT( isId id) 
+			    idRuleVars id    `unionVarSet` 
+			    idUnfoldingVars id
+
+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) 
-			 (idInlineFreeVars id)
+			 emptyVarSet
 			 (idCoreRules id)
 
-idInlineFreeVars :: Id -> VarSet
--- Produce free vars for an InlineRule, BUT NOT for an ordinary unfolding
--- An InlineRule behaves *very like* a RULE, and that is what we are after here
-idInlineFreeVars id
-  = case idUnfolding id of
-	InlineRule { uf_tmpl = tmpl } -> exprFreeVars tmpl
-	_				   -> emptyVarSet
+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 }
+      		             | isStableSource src
+	                     -> exprFreeVars rhs
+      DFunUnfolding _ _ args -> exprsFreeVars args
+      _                      -> emptyVarSet
 \end{code}
 
 
@@ -452,7 +476,9 @@ freeVars (Case scrut bndr ty alts)
 			     rhs2 = freeVars rhs
 
 freeVars (Let (NonRec binder rhs) body)
-  = (freeVarsOf rhs2 `unionFVs` body_fvs `unionFVs` bndrRuleVars binder,
+  = (freeVarsOf rhs2 
+       `unionFVs` body_fvs 
+       `unionFVs` bndrRuleAndUnfoldingVars binder,
 		-- Remember any rules; cf rhs_fvs above
      AnnLet (AnnNonRec binder rhs2) body2)
   where
@@ -468,7 +494,7 @@ freeVars (Let (Rec binds) body)
 
     rhss2     = map freeVars rhss
     rhs_body_fvs = foldr (unionFVs . freeVarsOf) body_fvs rhss2
-    all_fvs      = foldr (unionFVs . idRuleVars) rhs_body_fvs binders
+    all_fvs      = foldr (unionFVs . idRuleAndUnfoldingVars) rhs_body_fvs binders
 	-- The "delBinderFV" happens after adding the idSpecVars,
 	-- since the latter may add some of the binders as fvs