idSpecialisation, idWorkerInfo, setIdInfo
)
import IdInfo ( workerExists, vanillaIdInfo, isEmptySpecInfo )
-import Var ( Var )
+import Var
import VarSet
import VarEnv
import Name ( getOccName )
context @Level 0 0@.
-InlineCtxt
-~~~~~~~~~~
+Note [FloatOut inside INLINE]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@InlineCtxt@ very similar to @Level 0 0@, but is used for one purpose:
to say "don't float anything out of here". That's exactly what we
want for the body of an INLINE, where we don't want to float anything
-- We also use these envs when making a variable polymorphic
-- because we want to float it out past a big lambda.
--
- -- The SubstEnv and IdEnv always implement the same mapping, but the
- -- SubstEnv maps to CoreExpr and the IdEnv to LevelledExpr
+ -- The Subst and IdEnv always implement the same mapping, but the
+ -- Subst maps to CoreExpr and the IdEnv to LevelledExpr
-- Since the range is always a variable or type application,
-- there is never any difference between the two, but sadly
-- the types differ. The SubstEnv is used when substituting in
-- Find the variables in fvs, free vars of the target expresion,
-- whose level is greater than the destination level
-- These are the ones we are going to abstract out
-abstractVars dest_lvl env fvs
- = uniq (sortLe le [var | fv <- varSetElems fvs, var <- absVarsOf dest_lvl env fv])
+abstractVars dest_lvl (_, lvl_env, _, id_env) fvs
+ = map zap $ uniq $ sortLe le
+ [var | fv <- varSetElems fvs
+ , var <- absVarsOf id_env fv
+ , abstract_me var ]
+ -- NB: it's important to call abstract_me only on the OutIds the
+ -- come from absVarsOf (not on fv, which is an InId)
where
- -- Sort the variables so we don't get
- -- mixed-up tyvars and Ids; it's just messy
- v1 `le` v2 = case (isId v1, isId v2) of
- (True, False) -> False
- (False, True) -> True
+ -- Sort the variables so the true type variables come first;
+ -- the tyvars scope over Ids and coercion vars
+ v1 `le` v2 = case (is_tv v1, is_tv v2) of
+ (True, False) -> True
+ (False, True) -> False
other -> v1 <= v2 -- Same family
+ is_tv v = isTyVar v && not (isCoVar v)
+
uniq :: [Var] -> [Var]
-- Remove adjacent duplicates; the sort will have brought them together
uniq (v1:v2:vs) | v1 == v2 = uniq (v2:vs)
| otherwise = v1 : uniq (v2:vs)
uniq vs = vs
-absVarsOf :: Level -> LevelEnv -> Var -> [Var]
- -- If f is free in the expression, and f maps to poly_f a b c in the
- -- current substitution, then we must report a b c as candidate type
- -- variables
-absVarsOf dest_lvl (_, lvl_env, _, id_env) v
- | isId v
- = [zap av2 | av1 <- lookup_avs v, av2 <- add_tyvars av1, abstract_me av2]
-
- | otherwise
- = if abstract_me v then [v] else []
-
- where
abstract_me v = case lookupVarEnv lvl_env v of
Just lvl -> dest_lvl `ltLvl` lvl
Nothing -> False
- lookup_avs v = case lookupVarEnv id_env v of
- Just (abs_vars, _) -> abs_vars
- Nothing -> [v]
-
- add_tyvars v = v : varSetElems (varTypeTyVars v)
-
-- We are going to lambda-abstract, so nuke any IdInfo,
-- and add the tyvars of the Id (if necessary)
zap v | isId v = WARN( workerExists (idWorkerInfo v) ||
text "absVarsOf: discarding info on" <+> ppr v )
setIdInfo v vanillaIdInfo
| otherwise = v
+
+absVarsOf :: IdEnv ([Var], LevelledExpr) -> Var -> [Var]
+ -- If f is free in the expression, and f maps to poly_f a b c in the
+ -- current substitution, then we must report a b c as candidate type
+ -- variables
+ --
+ -- Also, if x::a is an abstracted variable, then so is a; that is,
+ -- we must look in x's type
+ -- And similarly if x is a coercion variable.
+absVarsOf id_env v
+ | isId v = [av2 | av1 <- lookup_avs v
+ , av2 <- add_tyvars av1]
+ | isCoVar v = add_tyvars v
+ | otherwise = [v]
+
+ where
+ lookup_avs v = case lookupVarEnv id_env v of
+ Just (abs_vars, _) -> abs_vars
+ Nothing -> [v]
+
+ add_tyvars v = v : varSetElems (varTypeTyVars v)
\end{code}
\begin{code}