{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE TypeFamilies #-}

-- | Hides away distracting bookkeeping while lambda lifting into a 'LiftM'
-- monad.
module GHC.Stg.Lift.Monad (
    decomposeStgBinding, mkStgBinding,
    Env (..),
    -- * #floats# Handling floats
    -- $floats
    FloatLang (..), collectFloats, -- Exported just for the docs
    -- * Transformation monad
    LiftM, runLiftM,
    -- ** Get config
    getConfig,
    -- ** Adding bindings
    startBindingGroup, endBindingGroup, addTopStringLit, addLiftedBinding,
    -- ** Substitution and binders
    withSubstBndr, withSubstBndrs, withLiftedBndr, withLiftedBndrs,
    -- ** Occurrences
    substOcc, isLifted, formerFreeVars, liftedIdsExpander
  ) where

import GHC.Prelude

import GHC.Types.Basic
import GHC.Types.CostCentre ( isCurrentCCS, dontCareCCS )
import GHC.Data.FastString
import GHC.Types.Id
import GHC.Types.Name
import GHC.Utils.Outputable
import GHC.Data.OrdList

import GHC.Stg.Lift.Config
import GHC.Stg.Subst
import GHC.Stg.Syntax

import GHC.Core.Utils
import GHC.Types.Unique.Supply
import GHC.Utils.Panic
import GHC.Utils.Panic.Plain
import GHC.Types.Var.Env
import GHC.Types.Var.Set
import GHC.Core.Multiplicity

import Control.Arrow ( second )
import Control.Monad.Trans.Class
import Control.Monad.Trans.RWS.Strict ( RWST, runRWST )
import qualified Control.Monad.Trans.RWS.Strict as RWS
import Control.Monad.Trans.Cont ( ContT (..) )
import Data.ByteString ( ByteString )

-- | @uncurry 'mkStgBinding' . 'decomposeStgBinding' = id@
decomposeStgBinding :: GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
decomposeStgBinding :: forall (pass :: StgPass).
GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
decomposeStgBinding (StgRec [(BinderP pass, GenStgRhs pass)]
pairs) = (RecFlag
Recursive, [(BinderP pass, GenStgRhs pass)]
pairs)
decomposeStgBinding (StgNonRec BinderP pass
bndr GenStgRhs pass
rhs) = (RecFlag
NonRecursive, [(BinderP pass
bndr, GenStgRhs pass
rhs)])

mkStgBinding :: RecFlag -> [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
mkStgBinding :: forall (pass :: StgPass).
RecFlag -> [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
mkStgBinding RecFlag
Recursive = [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
forall (pass :: StgPass).
[(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
StgRec
mkStgBinding RecFlag
NonRecursive = (BinderP pass -> GenStgRhs pass -> GenStgBinding pass)
-> (BinderP pass, GenStgRhs pass) -> GenStgBinding pass
forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry BinderP pass -> GenStgRhs pass -> GenStgBinding pass
forall (pass :: StgPass).
BinderP pass -> GenStgRhs pass -> GenStgBinding pass
StgNonRec ((BinderP pass, GenStgRhs pass) -> GenStgBinding pass)
-> ([(BinderP pass, GenStgRhs pass)]
    -> (BinderP pass, GenStgRhs pass))
-> [(BinderP pass, GenStgRhs pass)]
-> GenStgBinding pass
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [(BinderP pass, GenStgRhs pass)] -> (BinderP pass, GenStgRhs pass)
forall a. HasCallStack => [a] -> a
head

-- | Environment threaded around in a scoped, @Reader@-like fashion.
data Env
  = Env
  { Env -> StgLiftConfig
e_config     :: StgLiftConfig
  -- ^ Read-only.
  , Env -> Subst
e_subst      :: !Subst
  -- ^ We need to track the renamings of local 'InId's to their lifted 'OutId',
  -- because shadowing might make a closure's free variables unavailable at its
  -- call sites. Consider:
  -- @
  --    let f y = x + y in let x = 4 in f x
  -- @
  -- Here, @f@ can't be lifted to top-level, because its free variable @x@ isn't
  -- available at its call site.
  , Env -> IdEnv DIdSet
e_expansions :: !(IdEnv DIdSet)
  -- ^ Lifted 'Id's don't occur as free variables in any closure anymore, because
  -- they are bound at the top-level. Every occurrence must supply the formerly
  -- free variables of the lifted 'Id', so they in turn become free variables of
  -- the call sites. This environment tracks this expansion from lifted 'Id's to
  -- their free variables.
  --
  -- 'InId's to 'OutId's.
  --
  -- Invariant: 'Id's not present in this map won't be substituted.
  }

emptyEnv :: StgLiftConfig -> Env
emptyEnv :: StgLiftConfig -> Env
emptyEnv StgLiftConfig
cfg = Env
  { e_config :: StgLiftConfig
e_config = StgLiftConfig
cfg
  , e_subst :: Subst
e_subst = Subst
emptySubst
  , e_expansions :: IdEnv DIdSet
e_expansions = IdEnv DIdSet
forall a. VarEnv a
emptyVarEnv
  }


-- Note [Handling floats]
-- ~~~~~~~~~~~~~~~~~~~~~~
-- $floats
-- Consider the following expression:
--
-- @
--     f x =
--       let g y = ... f y ...
--       in g x
-- @
--
-- What happens when we want to lift @g@? Normally, we'd put the lifted @l_g@
-- binding above the binding for @f@:
--
-- @
--     g f y = ... f y ...
--     f x = g f x
-- @
--
-- But this very unnecessarily turns a known call to @f@ into an unknown one, in
-- addition to complicating matters for the analysis.
-- Instead, we'd really like to put both functions in the same recursive group,
-- thereby preserving the known call:
--
-- @
--     Rec {
--       g y = ... f y ...
--       f x = g x
--     }
-- @
--
-- But we don't want this to happen for just /any/ binding. That would create
-- possibly huge recursive groups in the process, calling for an occurrence
-- analyser on STG.
-- So, we need to track when we lift a binding out of a recursive RHS and add
-- the binding to the same recursive group as the enclosing recursive binding
-- (which must have either already been at the top-level or decided to be
-- lifted itself in order to preserve the known call).
--
-- This is done by expressing this kind of nesting structure as a 'Writer' over
-- @['FloatLang']@ and flattening this expression in 'runLiftM' by a call to
-- 'collectFloats'.
-- API-wise, the analysis will not need to know about the whole 'FloatLang'
-- business and will just manipulate it indirectly through actions in 'LiftM'.

-- | We need to detect when we are lifting something out of the RHS of a
-- recursive binding (c.f. "GHC.Stg.Lift.Monad#floats"), in which case that
-- binding needs to be added to the same top-level recursive group. This
-- requires we detect a certain nesting structure, which is encoded by
-- 'StartBindingGroup' and 'EndBindingGroup'.
--
-- Although 'collectFloats' will only ever care if the current binding to be
-- lifted (through 'LiftedBinding') will occur inside such a binding group or
-- not, e.g. doesn't care about the nesting level as long as its greater than 0.
data FloatLang
  = StartBindingGroup
  | EndBindingGroup
  | PlainTopBinding OutStgTopBinding
  | LiftedBinding OutStgBinding

instance Outputable FloatLang where
  ppr :: FloatLang -> SDoc
ppr FloatLang
StartBindingGroup = Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'('
  ppr FloatLang
EndBindingGroup = Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
')'
  ppr (PlainTopBinding StgTopStringLit{}) = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"<str>"
  ppr (PlainTopBinding (StgTopLifted GenStgBinding 'Vanilla
b)) = FloatLang -> SDoc
forall a. Outputable a => a -> SDoc
ppr (GenStgBinding 'Vanilla -> FloatLang
LiftedBinding GenStgBinding 'Vanilla
b)
  ppr (LiftedBinding GenStgBinding 'Vanilla
bind) = (if RecFlag -> Bool
isRec RecFlag
rec then Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'r' else Char -> SDoc
forall doc. IsLine doc => Char -> doc
char Char
'n') SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> [Id] -> SDoc
forall a. Outputable a => a -> SDoc
ppr (((Id, GenStgRhs 'Vanilla) -> Id)
-> [(Id, GenStgRhs 'Vanilla)] -> [Id]
forall a b. (a -> b) -> [a] -> [b]
map (Id, GenStgRhs 'Vanilla) -> Id
forall a b. (a, b) -> a
fst [(Id, GenStgRhs 'Vanilla)]
[(BinderP 'Vanilla, GenStgRhs 'Vanilla)]
pairs)
    where
      (RecFlag
rec, [(BinderP 'Vanilla, GenStgRhs 'Vanilla)]
pairs) = GenStgBinding 'Vanilla
-> (RecFlag, [(BinderP 'Vanilla, GenStgRhs 'Vanilla)])
forall (pass :: StgPass).
GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
decomposeStgBinding GenStgBinding 'Vanilla
bind

-- | Flattens an expression in @['FloatLang']@ into an STG program, see "GHC.Stg.Lift.Monad#floats".
-- Important pre-conditions: The nesting of opening 'StartBindinGroup's and
-- closing 'EndBindinGroup's is balanced. Also, it is crucial that every binding
-- group has at least one recursive binding inside. Otherwise there's no point
-- in announcing the binding group in the first place and an @ASSERT@ will
-- trigger.
collectFloats :: [FloatLang] -> [OutStgTopBinding]
collectFloats :: [FloatLang] -> [GenStgTopBinding 'Vanilla]
collectFloats = Int
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
forall {a}.
(Eq a, Num a) =>
a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go (Int
0 :: Int) []
  where
    go :: a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go a
0 [] [] = []
    go a
_ [GenStgBinding 'Vanilla]
_ [] = String -> SDoc -> [GenStgTopBinding 'Vanilla]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"collectFloats" (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"unterminated group")
    go a
n [GenStgBinding 'Vanilla]
binds (FloatLang
f:[FloatLang]
rest) = case FloatLang
f of
      FloatLang
StartBindingGroup -> a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go (a
na -> a -> a
forall a. Num a => a -> a -> a
+a
1) [GenStgBinding 'Vanilla]
binds [FloatLang]
rest
      FloatLang
EndBindingGroup
        | a
n a -> a -> Bool
forall a. Eq a => a -> a -> Bool
== a
0 -> String -> SDoc -> [GenStgTopBinding 'Vanilla]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"collectFloats" (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"no group to end")
        | a
n a -> a -> Bool
forall a. Eq a => a -> a -> Bool
== a
1 -> GenStgBinding 'Vanilla -> GenStgTopBinding 'Vanilla
forall (pass :: StgPass).
GenStgBinding pass -> GenStgTopBinding pass
StgTopLifted ([GenStgBinding 'Vanilla] -> GenStgBinding 'Vanilla
forall {t :: * -> *} {pass :: StgPass}.
Foldable t =>
t (GenStgBinding pass) -> GenStgBinding pass
merge_binds [GenStgBinding 'Vanilla]
binds) GenStgTopBinding 'Vanilla
-> [GenStgTopBinding 'Vanilla] -> [GenStgTopBinding 'Vanilla]
forall a. a -> [a] -> [a]
: a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go a
0 [] [FloatLang]
rest
        | Bool
otherwise -> a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go (a
na -> a -> a
forall a. Num a => a -> a -> a
-a
1) [GenStgBinding 'Vanilla]
binds [FloatLang]
rest
      PlainTopBinding GenStgTopBinding 'Vanilla
top_bind
        | a
n a -> a -> Bool
forall a. Eq a => a -> a -> Bool
== a
0 -> GenStgTopBinding 'Vanilla
top_bind GenStgTopBinding 'Vanilla
-> [GenStgTopBinding 'Vanilla] -> [GenStgTopBinding 'Vanilla]
forall a. a -> [a] -> [a]
: a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go a
n [GenStgBinding 'Vanilla]
binds [FloatLang]
rest
        | Bool
otherwise -> String -> SDoc -> [GenStgTopBinding 'Vanilla]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"collectFloats" (String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"plain top binding inside group")
      LiftedBinding GenStgBinding 'Vanilla
bind
        | a
n a -> a -> Bool
forall a. Eq a => a -> a -> Bool
== a
0 -> GenStgBinding 'Vanilla -> GenStgTopBinding 'Vanilla
forall (pass :: StgPass).
GenStgBinding pass -> GenStgTopBinding pass
StgTopLifted (GenStgBinding 'Vanilla -> GenStgBinding 'Vanilla
forall {pass :: StgPass}. GenStgBinding pass -> GenStgBinding pass
rm_cccs GenStgBinding 'Vanilla
bind) GenStgTopBinding 'Vanilla
-> [GenStgTopBinding 'Vanilla] -> [GenStgTopBinding 'Vanilla]
forall a. a -> [a] -> [a]
: a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go a
n [GenStgBinding 'Vanilla]
binds [FloatLang]
rest
        | Bool
otherwise -> a
-> [GenStgBinding 'Vanilla]
-> [FloatLang]
-> [GenStgTopBinding 'Vanilla]
go a
n (GenStgBinding 'Vanilla
bindGenStgBinding 'Vanilla
-> [GenStgBinding 'Vanilla] -> [GenStgBinding 'Vanilla]
forall a. a -> [a] -> [a]
:[GenStgBinding 'Vanilla]
binds) [FloatLang]
rest

    map_rhss :: (GenStgRhs pass -> GenStgRhs pass)
-> GenStgBinding pass -> GenStgBinding pass
map_rhss GenStgRhs pass -> GenStgRhs pass
f = (RecFlag -> [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass)
-> (RecFlag, [(BinderP pass, GenStgRhs pass)])
-> GenStgBinding pass
forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry RecFlag -> [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
forall (pass :: StgPass).
RecFlag -> [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
mkStgBinding ((RecFlag, [(BinderP pass, GenStgRhs pass)]) -> GenStgBinding pass)
-> (GenStgBinding pass
    -> (RecFlag, [(BinderP pass, GenStgRhs pass)]))
-> GenStgBinding pass
-> GenStgBinding pass
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ([(BinderP pass, GenStgRhs pass)]
 -> [(BinderP pass, GenStgRhs pass)])
-> (RecFlag, [(BinderP pass, GenStgRhs pass)])
-> (RecFlag, [(BinderP pass, GenStgRhs pass)])
forall b c d. (b -> c) -> (d, b) -> (d, c)
forall (a :: * -> * -> *) b c d.
Arrow a =>
a b c -> a (d, b) (d, c)
second (((BinderP pass, GenStgRhs pass) -> (BinderP pass, GenStgRhs pass))
-> [(BinderP pass, GenStgRhs pass)]
-> [(BinderP pass, GenStgRhs pass)]
forall a b. (a -> b) -> [a] -> [b]
map ((GenStgRhs pass -> GenStgRhs pass)
-> (BinderP pass, GenStgRhs pass) -> (BinderP pass, GenStgRhs pass)
forall b c d. (b -> c) -> (d, b) -> (d, c)
forall (a :: * -> * -> *) b c d.
Arrow a =>
a b c -> a (d, b) (d, c)
second GenStgRhs pass -> GenStgRhs pass
f)) ((RecFlag, [(BinderP pass, GenStgRhs pass)])
 -> (RecFlag, [(BinderP pass, GenStgRhs pass)]))
-> (GenStgBinding pass
    -> (RecFlag, [(BinderP pass, GenStgRhs pass)]))
-> GenStgBinding pass
-> (RecFlag, [(BinderP pass, GenStgRhs pass)])
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
forall (pass :: StgPass).
GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
decomposeStgBinding
    rm_cccs :: GenStgBinding pass -> GenStgBinding pass
rm_cccs = (GenStgRhs pass -> GenStgRhs pass)
-> GenStgBinding pass -> GenStgBinding pass
forall {pass :: StgPass} {pass :: StgPass}.
(BinderP pass ~ BinderP pass) =>
(GenStgRhs pass -> GenStgRhs pass)
-> GenStgBinding pass -> GenStgBinding pass
map_rhss GenStgRhs pass -> GenStgRhs pass
forall (pass :: StgPass). GenStgRhs pass -> GenStgRhs pass
removeRhsCCCS
    merge_binds :: t (GenStgBinding pass) -> GenStgBinding pass
merge_binds t (GenStgBinding pass)
binds = Bool -> GenStgBinding pass -> GenStgBinding pass
forall a. HasCallStack => Bool -> a -> a
assert ((GenStgBinding pass -> Bool) -> t (GenStgBinding pass) -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any GenStgBinding pass -> Bool
forall {pass :: StgPass}. GenStgBinding pass -> Bool
is_rec t (GenStgBinding pass)
binds) (GenStgBinding pass -> GenStgBinding pass)
-> GenStgBinding pass -> GenStgBinding pass
forall a b. (a -> b) -> a -> b
$
                        [(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
forall (pass :: StgPass).
[(BinderP pass, GenStgRhs pass)] -> GenStgBinding pass
StgRec ((GenStgBinding pass -> [(BinderP pass, GenStgRhs pass)])
-> t (GenStgBinding pass) -> [(BinderP pass, GenStgRhs pass)]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap ((RecFlag, [(BinderP pass, GenStgRhs pass)])
-> [(BinderP pass, GenStgRhs pass)]
forall a b. (a, b) -> b
snd ((RecFlag, [(BinderP pass, GenStgRhs pass)])
 -> [(BinderP pass, GenStgRhs pass)])
-> (GenStgBinding pass
    -> (RecFlag, [(BinderP pass, GenStgRhs pass)]))
-> GenStgBinding pass
-> [(BinderP pass, GenStgRhs pass)]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
forall (pass :: StgPass).
GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)])
decomposeStgBinding (GenStgBinding pass -> (RecFlag, [(BinderP pass, GenStgRhs pass)]))
-> (GenStgBinding pass -> GenStgBinding pass)
-> GenStgBinding pass
-> (RecFlag, [(BinderP pass, GenStgRhs pass)])
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenStgBinding pass -> GenStgBinding pass
forall {pass :: StgPass}. GenStgBinding pass -> GenStgBinding pass
rm_cccs) t (GenStgBinding pass)
binds)
    is_rec :: GenStgBinding pass -> Bool
is_rec StgRec{} = Bool
True
    is_rec GenStgBinding pass
_ = Bool
False

-- | Omitting this makes for strange closure allocation schemes that crash the
-- GC.
removeRhsCCCS :: GenStgRhs pass -> GenStgRhs pass
removeRhsCCCS :: forall (pass :: StgPass). GenStgRhs pass -> GenStgRhs pass
removeRhsCCCS (StgRhsClosure XRhsClosure pass
ext CostCentreStack
ccs UpdateFlag
upd [BinderP pass]
bndrs GenStgExpr pass
body Type
typ)
  | CostCentreStack -> Bool
isCurrentCCS CostCentreStack
ccs
  = XRhsClosure pass
-> CostCentreStack
-> UpdateFlag
-> [BinderP pass]
-> GenStgExpr pass
-> Type
-> GenStgRhs pass
forall (pass :: StgPass).
XRhsClosure pass
-> CostCentreStack
-> UpdateFlag
-> [BinderP pass]
-> GenStgExpr pass
-> Type
-> GenStgRhs pass
StgRhsClosure XRhsClosure pass
ext CostCentreStack
dontCareCCS UpdateFlag
upd [BinderP pass]
bndrs GenStgExpr pass
body Type
typ
removeRhsCCCS (StgRhsCon CostCentreStack
ccs DataCon
con ConstructorNumber
mu [StgTickish]
ts [StgArg]
args Type
typ)
  | CostCentreStack -> Bool
isCurrentCCS CostCentreStack
ccs
  = CostCentreStack
-> DataCon
-> ConstructorNumber
-> [StgTickish]
-> [StgArg]
-> Type
-> GenStgRhs pass
forall (pass :: StgPass).
CostCentreStack
-> DataCon
-> ConstructorNumber
-> [StgTickish]
-> [StgArg]
-> Type
-> GenStgRhs pass
StgRhsCon CostCentreStack
dontCareCCS DataCon
con ConstructorNumber
mu [StgTickish]
ts [StgArg]
args Type
typ
removeRhsCCCS GenStgRhs pass
rhs = GenStgRhs pass
rhs

-- | The analysis monad consists of the following 'RWST' components:
--
--     * 'Env': Reader-like context. Contains a substitution, info about how
--       how lifted identifiers are to be expanded into applications and
--       configuration options.
--
--     * @'OrdList' 'FloatLang'@: Writer output for the resulting STG program.
--
--     * No pure state component
--
--     * But wrapping around 'UniqSM' for generating fresh lifted binders.
--       (The @uniqAway@ approach could give the same name to two different
--       lifted binders, so this is necessary.)
newtype LiftM a
  = LiftM { forall a. LiftM a -> RWST Env (OrdList FloatLang) () UniqSM a
unwrapLiftM :: RWST Env (OrdList FloatLang) () UniqSM a }
  deriving ((forall a b. (a -> b) -> LiftM a -> LiftM b)
-> (forall a b. a -> LiftM b -> LiftM a) -> Functor LiftM
forall a b. a -> LiftM b -> LiftM a
forall a b. (a -> b) -> LiftM a -> LiftM b
forall (f :: * -> *).
(forall a b. (a -> b) -> f a -> f b)
-> (forall a b. a -> f b -> f a) -> Functor f
$cfmap :: forall a b. (a -> b) -> LiftM a -> LiftM b
fmap :: forall a b. (a -> b) -> LiftM a -> LiftM b
$c<$ :: forall a b. a -> LiftM b -> LiftM a
<$ :: forall a b. a -> LiftM b -> LiftM a
Functor, Functor LiftM
Functor LiftM =>
(forall a. a -> LiftM a)
-> (forall a b. LiftM (a -> b) -> LiftM a -> LiftM b)
-> (forall a b c. (a -> b -> c) -> LiftM a -> LiftM b -> LiftM c)
-> (forall a b. LiftM a -> LiftM b -> LiftM b)
-> (forall a b. LiftM a -> LiftM b -> LiftM a)
-> Applicative LiftM
forall a. a -> LiftM a
forall a b. LiftM a -> LiftM b -> LiftM a
forall a b. LiftM a -> LiftM b -> LiftM b
forall a b. LiftM (a -> b) -> LiftM a -> LiftM b
forall a b c. (a -> b -> c) -> LiftM a -> LiftM b -> LiftM c
forall (f :: * -> *).
Functor f =>
(forall a. a -> f a)
-> (forall a b. f (a -> b) -> f a -> f b)
-> (forall a b c. (a -> b -> c) -> f a -> f b -> f c)
-> (forall a b. f a -> f b -> f b)
-> (forall a b. f a -> f b -> f a)
-> Applicative f
$cpure :: forall a. a -> LiftM a
pure :: forall a. a -> LiftM a
$c<*> :: forall a b. LiftM (a -> b) -> LiftM a -> LiftM b
<*> :: forall a b. LiftM (a -> b) -> LiftM a -> LiftM b
$cliftA2 :: forall a b c. (a -> b -> c) -> LiftM a -> LiftM b -> LiftM c
liftA2 :: forall a b c. (a -> b -> c) -> LiftM a -> LiftM b -> LiftM c
$c*> :: forall a b. LiftM a -> LiftM b -> LiftM b
*> :: forall a b. LiftM a -> LiftM b -> LiftM b
$c<* :: forall a b. LiftM a -> LiftM b -> LiftM a
<* :: forall a b. LiftM a -> LiftM b -> LiftM a
Applicative, Applicative LiftM
Applicative LiftM =>
(forall a b. LiftM a -> (a -> LiftM b) -> LiftM b)
-> (forall a b. LiftM a -> LiftM b -> LiftM b)
-> (forall a. a -> LiftM a)
-> Monad LiftM
forall a. a -> LiftM a
forall a b. LiftM a -> LiftM b -> LiftM b
forall a b. LiftM a -> (a -> LiftM b) -> LiftM b
forall (m :: * -> *).
Applicative m =>
(forall a b. m a -> (a -> m b) -> m b)
-> (forall a b. m a -> m b -> m b)
-> (forall a. a -> m a)
-> Monad m
$c>>= :: forall a b. LiftM a -> (a -> LiftM b) -> LiftM b
>>= :: forall a b. LiftM a -> (a -> LiftM b) -> LiftM b
$c>> :: forall a b. LiftM a -> LiftM b -> LiftM b
>> :: forall a b. LiftM a -> LiftM b -> LiftM b
$creturn :: forall a. a -> LiftM a
return :: forall a. a -> LiftM a
Monad)

instance MonadUnique LiftM where
  getUniqueSupplyM :: LiftM UniqSupply
getUniqueSupplyM = RWST Env (OrdList FloatLang) () UniqSM UniqSupply
-> LiftM UniqSupply
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (UniqSM UniqSupply
-> RWST Env (OrdList FloatLang) () UniqSM UniqSupply
forall (m :: * -> *) a.
Monad m =>
m a -> RWST Env (OrdList FloatLang) () m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift UniqSM UniqSupply
forall (m :: * -> *). MonadUnique m => m UniqSupply
getUniqueSupplyM)
  getUniqueM :: LiftM Unique
getUniqueM = RWST Env (OrdList FloatLang) () UniqSM Unique -> LiftM Unique
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (UniqSM Unique -> RWST Env (OrdList FloatLang) () UniqSM Unique
forall (m :: * -> *) a.
Monad m =>
m a -> RWST Env (OrdList FloatLang) () m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift UniqSM Unique
forall (m :: * -> *). MonadUnique m => m Unique
getUniqueM)
  getUniquesM :: LiftM [Unique]
getUniquesM = RWST Env (OrdList FloatLang) () UniqSM [Unique] -> LiftM [Unique]
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (UniqSM [Unique] -> RWST Env (OrdList FloatLang) () UniqSM [Unique]
forall (m :: * -> *) a.
Monad m =>
m a -> RWST Env (OrdList FloatLang) () m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift UniqSM [Unique]
forall (m :: * -> *). MonadUnique m => m [Unique]
getUniquesM)

runLiftM :: StgLiftConfig -> UniqSupply -> LiftM () -> [OutStgTopBinding]
runLiftM :: StgLiftConfig
-> UniqSupply -> LiftM () -> [GenStgTopBinding 'Vanilla]
runLiftM StgLiftConfig
cfg UniqSupply
us (LiftM RWST Env (OrdList FloatLang) () UniqSM ()
m) = [FloatLang] -> [GenStgTopBinding 'Vanilla]
collectFloats (OrdList FloatLang -> [FloatLang]
forall a. OrdList a -> [a]
fromOL OrdList FloatLang
floats)
  where
    (()
_, ()
_, OrdList FloatLang
floats) = UniqSupply
-> UniqSM ((), (), OrdList FloatLang)
-> ((), (), OrdList FloatLang)
forall a. UniqSupply -> UniqSM a -> a
initUs_ UniqSupply
us (RWST Env (OrdList FloatLang) () UniqSM ()
-> Env -> () -> UniqSM ((), (), OrdList FloatLang)
forall r w s (m :: * -> *) a.
RWST r w s m a -> r -> s -> m (a, s, w)
runRWST RWST Env (OrdList FloatLang) () UniqSM ()
m (StgLiftConfig -> Env
emptyEnv StgLiftConfig
cfg) ())

getConfig :: LiftM StgLiftConfig
getConfig :: LiftM StgLiftConfig
getConfig = RWST Env (OrdList FloatLang) () UniqSM StgLiftConfig
-> LiftM StgLiftConfig
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM StgLiftConfig
 -> LiftM StgLiftConfig)
-> RWST Env (OrdList FloatLang) () UniqSM StgLiftConfig
-> LiftM StgLiftConfig
forall a b. (a -> b) -> a -> b
$ Env -> StgLiftConfig
e_config (Env -> StgLiftConfig)
-> RWST Env (OrdList FloatLang) () UniqSM Env
-> RWST Env (OrdList FloatLang) () UniqSM StgLiftConfig
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> RWST Env (OrdList FloatLang) () UniqSM Env
forall w (m :: * -> *) r s. (Monoid w, Monad m) => RWST r w s m r
RWS.ask

-- | Writes a plain 'StgTopStringLit' to the output.
addTopStringLit :: OutId -> ByteString -> LiftM ()
addTopStringLit :: Id -> ByteString -> LiftM ()
addTopStringLit Id
id = RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ())
-> (ByteString -> RWST Env (OrdList FloatLang) () UniqSM ())
-> ByteString
-> LiftM ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall (m :: * -> *) w r s. Monad m => w -> RWST r w s m ()
RWS.tell (OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ())
-> (ByteString -> OrdList FloatLang)
-> ByteString
-> RWST Env (OrdList FloatLang) () UniqSM ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. FloatLang -> OrdList FloatLang
forall a. a -> OrdList a
unitOL (FloatLang -> OrdList FloatLang)
-> (ByteString -> FloatLang) -> ByteString -> OrdList FloatLang
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenStgTopBinding 'Vanilla -> FloatLang
PlainTopBinding (GenStgTopBinding 'Vanilla -> FloatLang)
-> (ByteString -> GenStgTopBinding 'Vanilla)
-> ByteString
-> FloatLang
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Id -> ByteString -> GenStgTopBinding 'Vanilla
forall (pass :: StgPass). Id -> ByteString -> GenStgTopBinding pass
StgTopStringLit Id
id

-- | Starts a recursive binding group. See "GHC.Stg.Lift.Monad#floats" and 'collectFloats'.
startBindingGroup :: LiftM ()
startBindingGroup :: LiftM ()
startBindingGroup = RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ())
-> RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a b. (a -> b) -> a -> b
$ OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall (m :: * -> *) w r s. Monad m => w -> RWST r w s m ()
RWS.tell (OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ())
-> OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall a b. (a -> b) -> a -> b
$ FloatLang -> OrdList FloatLang
forall a. a -> OrdList a
unitOL (FloatLang -> OrdList FloatLang) -> FloatLang -> OrdList FloatLang
forall a b. (a -> b) -> a -> b
$ FloatLang
StartBindingGroup

-- | Ends a recursive binding group. See "GHC.Stg.Lift.Monad#floats" and 'collectFloats'.
endBindingGroup :: LiftM ()
endBindingGroup :: LiftM ()
endBindingGroup = RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ())
-> RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a b. (a -> b) -> a -> b
$ OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall (m :: * -> *) w r s. Monad m => w -> RWST r w s m ()
RWS.tell (OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ())
-> OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall a b. (a -> b) -> a -> b
$ FloatLang -> OrdList FloatLang
forall a. a -> OrdList a
unitOL (FloatLang -> OrdList FloatLang) -> FloatLang -> OrdList FloatLang
forall a b. (a -> b) -> a -> b
$ FloatLang
EndBindingGroup

-- | Lifts a binding to top-level. Depending on whether it's declared inside
-- a recursive RHS (see "GHC.Stg.Lift.Monad#floats" and 'collectFloats'), this might be added to
-- an existing recursive top-level binding group.
addLiftedBinding :: OutStgBinding -> LiftM ()
addLiftedBinding :: GenStgBinding 'Vanilla -> LiftM ()
addLiftedBinding = RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ()
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM () -> LiftM ())
-> (GenStgBinding 'Vanilla
    -> RWST Env (OrdList FloatLang) () UniqSM ())
-> GenStgBinding 'Vanilla
-> LiftM ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ()
forall (m :: * -> *) w r s. Monad m => w -> RWST r w s m ()
RWS.tell (OrdList FloatLang -> RWST Env (OrdList FloatLang) () UniqSM ())
-> (GenStgBinding 'Vanilla -> OrdList FloatLang)
-> GenStgBinding 'Vanilla
-> RWST Env (OrdList FloatLang) () UniqSM ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. FloatLang -> OrdList FloatLang
forall a. a -> OrdList a
unitOL (FloatLang -> OrdList FloatLang)
-> (GenStgBinding 'Vanilla -> FloatLang)
-> GenStgBinding 'Vanilla
-> OrdList FloatLang
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenStgBinding 'Vanilla -> FloatLang
LiftedBinding

-- | Takes a binder and a continuation which is called with the substituted
-- binder. The continuation will be evaluated in a 'LiftM' context in which that
-- binder is deemed in scope. Think of it as a 'RWS.local' computation: After
-- the continuation finishes, the new binding won't be in scope anymore.
withSubstBndr :: Id -> (Id -> LiftM a) -> LiftM a
withSubstBndr :: forall a. Id -> (Id -> LiftM a) -> LiftM a
withSubstBndr Id
bndr Id -> LiftM a
inner = RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a)
-> RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
forall a b. (a -> b) -> a -> b
$ do
  Subst
subst <- (Env -> Subst) -> RWST Env (OrdList FloatLang) () UniqSM Subst
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks Env -> Subst
e_subst
  let (Id
bndr', Subst
subst') = Id -> Subst -> (Id, Subst)
substBndr Id
bndr Subst
subst
  (Env -> Env)
-> RWST Env (OrdList FloatLang) () UniqSM a
-> RWST Env (OrdList FloatLang) () UniqSM a
forall r w s (m :: * -> *) a.
(r -> r) -> RWST r w s m a -> RWST r w s m a
RWS.local (\Env
e -> Env
e { e_subst = subst' }) (LiftM a -> RWST Env (OrdList FloatLang) () UniqSM a
forall a. LiftM a -> RWST Env (OrdList FloatLang) () UniqSM a
unwrapLiftM (Id -> LiftM a
inner Id
bndr'))

-- | See 'withSubstBndr'.
withSubstBndrs :: Traversable f => f Id -> (f Id -> LiftM a) -> LiftM a
withSubstBndrs :: forall (f :: * -> *) a.
Traversable f =>
f Id -> (f Id -> LiftM a) -> LiftM a
withSubstBndrs = ContT a LiftM (f Id) -> (f Id -> LiftM a) -> LiftM a
forall {k} (r :: k) (m :: k -> *) a.
ContT r m a -> (a -> m r) -> m r
runContT (ContT a LiftM (f Id) -> (f Id -> LiftM a) -> LiftM a)
-> (f Id -> ContT a LiftM (f Id))
-> f Id
-> (f Id -> LiftM a)
-> LiftM a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Id -> ContT a LiftM Id) -> f Id -> ContT a LiftM (f Id)
forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
forall (f :: * -> *) a b.
Applicative f =>
(a -> f b) -> f a -> f (f b)
traverse (((Id -> LiftM a) -> LiftM a) -> ContT a LiftM Id
forall {k} (r :: k) (m :: k -> *) a.
((a -> m r) -> m r) -> ContT r m a
ContT (((Id -> LiftM a) -> LiftM a) -> ContT a LiftM Id)
-> (Id -> (Id -> LiftM a) -> LiftM a) -> Id -> ContT a LiftM Id
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Id -> (Id -> LiftM a) -> LiftM a
forall a. Id -> (Id -> LiftM a) -> LiftM a
withSubstBndr)

-- | Similarly to 'withSubstBndr', this function takes a set of variables to
-- abstract over, the binder to lift (and generate a fresh, substituted name
-- for) and a continuation in which that fresh, lifted binder is in scope.
--
-- It takes care of all the details involved with copying and adjusting the
-- binder and fresh name generation.
withLiftedBndr :: DIdSet -> Id -> (Id -> LiftM a) -> LiftM a
withLiftedBndr :: forall a. DIdSet -> Id -> (Id -> LiftM a) -> LiftM a
withLiftedBndr DIdSet
abs_ids Id
bndr Id -> LiftM a
inner = do
  let str :: FastString
str = String -> FastString
fsLit String
"$l" FastString -> FastString -> FastString
`appendFS` OccName -> FastString
occNameFS (Id -> OccName
forall a. NamedThing a => a -> OccName
getOccName Id
bndr)
  let ty :: Type
ty = [Id] -> Type -> Type
mkLamTypes (DIdSet -> [Id]
dVarSetElems DIdSet
abs_ids) (Id -> Type
idType Id
bndr)
  Id
bndr' <-
        -- See Note [transferPolyIdInfo] in GHC.Types.Id. We need to do this at least
        -- for arity information.
            Id -> [Id] -> Id -> Id
transferPolyIdInfo Id
bndr (DIdSet -> [Id]
dVarSetElems DIdSet
abs_ids)
        (Id -> Id) -> LiftM Id -> LiftM Id
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> FastString -> Type -> Type -> LiftM Id
forall (m :: * -> *).
MonadUnique m =>
FastString -> Type -> Type -> m Id
mkSysLocalM FastString
str Type
ManyTy Type
ty
  RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a)
-> RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
forall a b. (a -> b) -> a -> b
$ (Env -> Env)
-> RWST Env (OrdList FloatLang) () UniqSM a
-> RWST Env (OrdList FloatLang) () UniqSM a
forall r w s (m :: * -> *) a.
(r -> r) -> RWST r w s m a -> RWST r w s m a
RWS.local
    (\Env
e -> Env
e
      { e_subst = extendSubst bndr bndr' $ extendInScope bndr' $ e_subst e
      , e_expansions = extendVarEnv (e_expansions e) bndr abs_ids
      })
    (LiftM a -> RWST Env (OrdList FloatLang) () UniqSM a
forall a. LiftM a -> RWST Env (OrdList FloatLang) () UniqSM a
unwrapLiftM (Id -> LiftM a
inner Id
bndr'))

-- | See 'withLiftedBndr'.
withLiftedBndrs :: Traversable f => DIdSet -> f Id -> (f Id -> LiftM a) -> LiftM a
withLiftedBndrs :: forall (f :: * -> *) a.
Traversable f =>
DIdSet -> f Id -> (f Id -> LiftM a) -> LiftM a
withLiftedBndrs DIdSet
abs_ids = ContT a LiftM (f Id) -> (f Id -> LiftM a) -> LiftM a
forall {k} (r :: k) (m :: k -> *) a.
ContT r m a -> (a -> m r) -> m r
runContT (ContT a LiftM (f Id) -> (f Id -> LiftM a) -> LiftM a)
-> (f Id -> ContT a LiftM (f Id))
-> f Id
-> (f Id -> LiftM a)
-> LiftM a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Id -> ContT a LiftM Id) -> f Id -> ContT a LiftM (f Id)
forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
forall (f :: * -> *) a b.
Applicative f =>
(a -> f b) -> f a -> f (f b)
traverse (((Id -> LiftM a) -> LiftM a) -> ContT a LiftM Id
forall {k} (r :: k) (m :: k -> *) a.
((a -> m r) -> m r) -> ContT r m a
ContT (((Id -> LiftM a) -> LiftM a) -> ContT a LiftM Id)
-> (Id -> (Id -> LiftM a) -> LiftM a) -> Id -> ContT a LiftM Id
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DIdSet -> Id -> (Id -> LiftM a) -> LiftM a
forall a. DIdSet -> Id -> (Id -> LiftM a) -> LiftM a
withLiftedBndr DIdSet
abs_ids)

-- | Substitutes a binder /occurrence/, which was brought in scope earlier by
-- 'withSubstBndr' \/ 'withLiftedBndr'.
substOcc :: Id -> LiftM Id
substOcc :: Id -> LiftM Id
substOcc Id
id = RWST Env (OrdList FloatLang) () UniqSM Id -> LiftM Id
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM ((Env -> Id) -> RWST Env (OrdList FloatLang) () UniqSM Id
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks (HasDebugCallStack => Id -> Subst -> Id
Id -> Subst -> Id
lookupIdSubst Id
id (Subst -> Id) -> (Env -> Subst) -> Env -> Id
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Env -> Subst
e_subst))

-- | Whether the given binding was decided to be lambda lifted.
isLifted :: InId -> LiftM Bool
isLifted :: Id -> LiftM Bool
isLifted Id
bndr = RWST Env (OrdList FloatLang) () UniqSM Bool -> LiftM Bool
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM ((Env -> Bool) -> RWST Env (OrdList FloatLang) () UniqSM Bool
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks (Id -> IdEnv DIdSet -> Bool
forall a. Id -> VarEnv a -> Bool
elemVarEnv Id
bndr (IdEnv DIdSet -> Bool) -> (Env -> IdEnv DIdSet) -> Env -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Env -> IdEnv DIdSet
e_expansions))

-- | Returns an empty list for a binding that was not lifted and the list of all
-- local variables the binding abstracts over (so, exactly the additional
-- arguments at adjusted call sites) otherwise.
formerFreeVars :: InId -> LiftM [OutId]
formerFreeVars :: Id -> LiftM [Id]
formerFreeVars Id
f = RWST Env (OrdList FloatLang) () UniqSM [Id] -> LiftM [Id]
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM [Id] -> LiftM [Id])
-> RWST Env (OrdList FloatLang) () UniqSM [Id] -> LiftM [Id]
forall a b. (a -> b) -> a -> b
$ do
  IdEnv DIdSet
expansions <- (Env -> IdEnv DIdSet)
-> RWST Env (OrdList FloatLang) () UniqSM (IdEnv DIdSet)
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks Env -> IdEnv DIdSet
e_expansions
  [Id] -> RWST Env (OrdList FloatLang) () UniqSM [Id]
forall a. a -> RWST Env (OrdList FloatLang) () UniqSM a
forall (f :: * -> *) a. Applicative f => a -> f a
pure ([Id] -> RWST Env (OrdList FloatLang) () UniqSM [Id])
-> [Id] -> RWST Env (OrdList FloatLang) () UniqSM [Id]
forall a b. (a -> b) -> a -> b
$ case IdEnv DIdSet -> Id -> Maybe DIdSet
forall a. VarEnv a -> Id -> Maybe a
lookupVarEnv IdEnv DIdSet
expansions Id
f of
    Maybe DIdSet
Nothing -> []
    Just DIdSet
fvs -> DIdSet -> [Id]
dVarSetElems DIdSet
fvs

-- | Creates an /expander function/ for the current set of lifted binders.
-- This expander function will replace any 'InId' by their corresponding 'OutId'
-- and, in addition, will expand any lifted binders by the former free variables
-- it abstracts over.
liftedIdsExpander :: LiftM (DIdSet -> DIdSet)
liftedIdsExpander :: LiftM (DIdSet -> DIdSet)
liftedIdsExpander = RWST Env (OrdList FloatLang) () UniqSM (DIdSet -> DIdSet)
-> LiftM (DIdSet -> DIdSet)
forall a. RWST Env (OrdList FloatLang) () UniqSM a -> LiftM a
LiftM (RWST Env (OrdList FloatLang) () UniqSM (DIdSet -> DIdSet)
 -> LiftM (DIdSet -> DIdSet))
-> RWST Env (OrdList FloatLang) () UniqSM (DIdSet -> DIdSet)
-> LiftM (DIdSet -> DIdSet)
forall a b. (a -> b) -> a -> b
$ do
  IdEnv DIdSet
expansions <- (Env -> IdEnv DIdSet)
-> RWST Env (OrdList FloatLang) () UniqSM (IdEnv DIdSet)
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks Env -> IdEnv DIdSet
e_expansions
  Subst
subst <- (Env -> Subst) -> RWST Env (OrdList FloatLang) () UniqSM Subst
forall w (m :: * -> *) r a s.
(Monoid w, Monad m) =>
(r -> a) -> RWST r w s m a
RWS.asks Env -> Subst
e_subst
  -- We use @noWarnLookupIdSubst@ here in order to suppress "not in scope"
  -- warnings generated by 'lookupIdSubst' due to local bindings within RHS.
  -- These are not in the InScopeSet of @subst@ and extending the InScopeSet in
  -- @goodToLift@/@closureGrowth@ before passing it on to @expander@ is too much
  -- trouble.
  let go :: DIdSet -> Id -> DIdSet
go DIdSet
set Id
fv = case IdEnv DIdSet -> Id -> Maybe DIdSet
forall a. VarEnv a -> Id -> Maybe a
lookupVarEnv IdEnv DIdSet
expansions Id
fv of
        Maybe DIdSet
Nothing -> DIdSet -> Id -> DIdSet
extendDVarSet DIdSet
set (HasDebugCallStack => Id -> Subst -> Id
Id -> Subst -> Id
noWarnLookupIdSubst Id
fv Subst
subst) -- Not lifted
        Just DIdSet
fvs' -> DIdSet -> DIdSet -> DIdSet
unionDVarSet DIdSet
set DIdSet
fvs'
  let expander :: DIdSet -> DIdSet
expander DIdSet
fvs = (DIdSet -> Id -> DIdSet) -> DIdSet -> [Id] -> DIdSet
forall b a. (b -> a -> b) -> b -> [a] -> b
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' DIdSet -> Id -> DIdSet
go DIdSet
emptyDVarSet (DIdSet -> [Id]
dVarSetElems DIdSet
fvs)
  (DIdSet -> DIdSet)
-> RWST Env (OrdList FloatLang) () UniqSM (DIdSet -> DIdSet)
forall a. a -> RWST Env (OrdList FloatLang) () UniqSM a
forall (f :: * -> *) a. Applicative f => a -> f a
pure DIdSet -> DIdSet
expander