-- | Clean out unneeded spill\/reload instructions.
--
--   Handling of join points
--   ~~~~~~~~~~~~~~~~~~~~~~~
--
--   B1:                          B2:
--    ...                          ...
--       RELOAD SLOT(0), %r1          RELOAD SLOT(0), %r1
--       ... A ...                    ... B ...
--       jump B3                      jump B3
--
--                B3: ... C ...
--                    RELOAD SLOT(0), %r1
--                    ...
--
--   The Plan
--   ~~~~~~~~
--   As long as %r1 hasn't been written to in A, B or C then we don't need
--   the reload in B3.
--
--   What we really care about here is that on the entry to B3, %r1 will
--   always have the same value that is in SLOT(0) (ie, %r1 is _valid_)
--
--   This also works if the reloads in B1\/B2 were spills instead, because
--   spilling %r1 to a slot makes that slot have the same value as %r1.
--
module RegAlloc.Graph.SpillClean (
        cleanSpills
) where
import GhcPrelude

import RegAlloc.Liveness
import Instruction
import Reg

import BlockId
import Cmm
import UniqSet
import UniqFM
import Unique
import State
import Outputable
import Platform
import Hoopl.Collections

import Data.List
import Data.Maybe
import Data.IntSet              (IntSet)
import qualified Data.IntSet    as IntSet


-- | The identification number of a spill slot.
--   A value is stored in a spill slot when we don't have a free
--   register to hold it.
type Slot = Int


-- | Clean out unneeded spill\/reloads from this top level thing.
cleanSpills
        :: Instruction instr
        => Platform
        -> LiveCmmDecl statics instr
        -> LiveCmmDecl statics instr

cleanSpills :: Platform -> LiveCmmDecl statics instr -> LiveCmmDecl statics instr
cleanSpills platform :: Platform
platform cmm :: LiveCmmDecl statics instr
cmm
        = State CleanS (LiveCmmDecl statics instr)
-> CleanS -> LiveCmmDecl statics instr
forall s a. State s a -> s -> a
evalState (Platform
-> Int
-> LiveCmmDecl statics instr
-> State CleanS (LiveCmmDecl statics instr)
forall instr statics.
Instruction instr =>
Platform
-> Int
-> LiveCmmDecl statics instr
-> CleanM (LiveCmmDecl statics instr)
cleanSpin Platform
platform 0 LiveCmmDecl statics instr
cmm) CleanS
initCleanS


-- | Do one pass of cleaning.
cleanSpin
        :: Instruction instr
        => Platform
        -> Int                              -- ^ Iteration number for the cleaner.
        -> LiveCmmDecl statics instr        -- ^ Liveness annotated code to clean.
        -> CleanM (LiveCmmDecl statics instr)

cleanSpin :: Platform
-> Int
-> LiveCmmDecl statics instr
-> CleanM (LiveCmmDecl statics instr)
cleanSpin platform :: Platform
platform spinCount :: Int
spinCount code :: LiveCmmDecl statics instr
code
 = do
        -- Initialise count of cleaned spill and reload instructions.
        (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s
                { sCleanedSpillsAcc :: Int
sCleanedSpillsAcc     = 0
                , sCleanedReloadsAcc :: Int
sCleanedReloadsAcc    = 0
                , sReloadedBy :: UniqFM [BlockId]
sReloadedBy           = UniqFM [BlockId]
forall elt. UniqFM elt
emptyUFM }

        LiveCmmDecl statics instr
code_forward    <- (LiveBasicBlock instr -> State CleanS (LiveBasicBlock instr))
-> LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall (m :: * -> *) instr statics.
Monad m =>
(LiveBasicBlock instr -> m (LiveBasicBlock instr))
-> LiveCmmDecl statics instr -> m (LiveCmmDecl statics instr)
mapBlockTopM (Platform
-> LiveBasicBlock instr -> State CleanS (LiveBasicBlock instr)
forall instr.
Instruction instr =>
Platform -> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
cleanBlockForward Platform
platform) LiveCmmDecl statics instr
code
        LiveCmmDecl statics instr
code_backward   <- LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall instr statics.
Instruction instr =>
LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
cleanTopBackward LiveCmmDecl statics instr
code_forward

        -- During the cleaning of each block we collected information about
        -- what regs were valid across each jump. Based on this, work out
        -- whether it will be safe to erase reloads after join points for
        -- the next pass.
        State CleanS ()
collateJoinPoints

        -- Remember how many spill and reload instructions we cleaned in this pass.
        Int
spills          <- (CleanS -> Int) -> State CleanS Int
forall s a. (s -> a) -> State s a
gets CleanS -> Int
sCleanedSpillsAcc
        Int
reloads         <- (CleanS -> Int) -> State CleanS Int
forall s a. (s -> a) -> State s a
gets CleanS -> Int
sCleanedReloadsAcc
        (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s
                { sCleanedCount :: [(Int, Int)]
sCleanedCount = (Int
spills, Int
reloads) (Int, Int) -> [(Int, Int)] -> [(Int, Int)]
forall a. a -> [a] -> [a]
: CleanS -> [(Int, Int)]
sCleanedCount CleanS
s }

        -- If nothing was cleaned in this pass or the last one
        --      then we're done and it's time to bail out.
        [(Int, Int)]
cleanedCount    <- (CleanS -> [(Int, Int)]) -> State CleanS [(Int, Int)]
forall s a. (s -> a) -> State s a
gets CleanS -> [(Int, Int)]
sCleanedCount
        if Int -> [(Int, Int)] -> [(Int, Int)]
forall a. Int -> [a] -> [a]
take 2 [(Int, Int)]
cleanedCount [(Int, Int)] -> [(Int, Int)] -> Bool
forall a. Eq a => a -> a -> Bool
== [(0, 0), (0, 0)]
           then LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall (m :: * -> *) a. Monad m => a -> m a
return LiveCmmDecl statics instr
code

        -- otherwise go around again
           else Platform
-> Int
-> LiveCmmDecl statics instr
-> CleanM (LiveCmmDecl statics instr)
forall instr statics.
Instruction instr =>
Platform
-> Int
-> LiveCmmDecl statics instr
-> CleanM (LiveCmmDecl statics instr)
cleanSpin Platform
platform (Int
spinCount Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1) LiveCmmDecl statics instr
code_backward


-------------------------------------------------------------------------------
-- | Clean out unneeded reload instructions,
--   while walking forward over the code.
cleanBlockForward
        :: Instruction instr
        => Platform
        -> LiveBasicBlock instr
        -> CleanM (LiveBasicBlock instr)

cleanBlockForward :: Platform -> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
cleanBlockForward platform :: Platform
platform (BasicBlock blockId :: BlockId
blockId instrs :: [LiveInstr instr]
instrs)
 = do
        -- See if we have a valid association for the entry to this block.
        UniqFM (Assoc Store)
jumpValid       <- (CleanS -> UniqFM (Assoc Store))
-> State CleanS (UniqFM (Assoc Store))
forall s a. (s -> a) -> State s a
gets CleanS -> UniqFM (Assoc Store)
sJumpValid
        let assoc :: Assoc Store
assoc       = case UniqFM (Assoc Store) -> BlockId -> Maybe (Assoc Store)
forall key elt. Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM UniqFM (Assoc Store)
jumpValid BlockId
blockId of
                                Just assoc :: Assoc Store
assoc      -> Assoc Store
assoc
                                Nothing         -> Assoc Store
forall a. Assoc a
emptyAssoc

        [LiveInstr instr]
instrs_reload   <- Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc [] [LiveInstr instr]
instrs
        LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
forall (m :: * -> *) a. Monad m => a -> m a
return  (LiveBasicBlock instr -> CleanM (LiveBasicBlock instr))
-> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
forall a b. (a -> b) -> a -> b
$ BlockId -> [LiveInstr instr] -> LiveBasicBlock instr
forall i. BlockId -> [i] -> GenBasicBlock i
BasicBlock BlockId
blockId [LiveInstr instr]
instrs_reload



-- | Clean out unneeded reload instructions.
--
--   Walking forwards across the code
--     On a reload, if we know a reg already has the same value as a slot
--     then we don't need to do the reload.
--
cleanForward
        :: Instruction instr
        => Platform
        -> BlockId                  -- ^ the block that we're currently in
        -> Assoc Store              -- ^ two store locations are associated if
                                    --     they have the same value
        -> [LiveInstr instr]        -- ^ acc
        -> [LiveInstr instr]        -- ^ instrs to clean (in backwards order)
        -> CleanM [LiveInstr instr] -- ^ cleaned instrs  (in forward   order)

cleanForward :: Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward _ _ _ acc :: [LiveInstr instr]
acc []
        = [LiveInstr instr] -> CleanM [LiveInstr instr]
forall (m :: * -> *) a. Monad m => a -> m a
return [LiveInstr instr]
acc

-- Rewrite live range joins via spill slots to just a spill and a reg-reg move
-- hopefully the spill will be also be cleaned in the next pass
cleanForward platform :: Platform
platform blockId :: BlockId
blockId assoc :: Assoc Store
assoc acc :: [LiveInstr instr]
acc (li1 :: LiveInstr instr
li1 : li2 :: LiveInstr instr
li2 : instrs :: [LiveInstr instr]
instrs)

        | LiveInstr (SPILL  reg1 :: Reg
reg1  slot1 :: Int
slot1) _      <- LiveInstr instr
li1
        , LiveInstr (RELOAD slot2 :: Int
slot2 reg2 :: Reg
reg2)  _      <- LiveInstr instr
li2
        , Int
slot1 Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
slot2
        = do
                (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s { sCleanedReloadsAcc :: Int
sCleanedReloadsAcc = CleanS -> Int
sCleanedReloadsAcc CleanS
s Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1 }
                Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc [LiveInstr instr]
acc
                 ([LiveInstr instr] -> CleanM [LiveInstr instr])
-> [LiveInstr instr] -> CleanM [LiveInstr instr]
forall a b. (a -> b) -> a -> b
$ LiveInstr instr
li1 LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: InstrSR instr -> Maybe Liveness -> LiveInstr instr
forall instr. InstrSR instr -> Maybe Liveness -> LiveInstr instr
LiveInstr (Platform -> Reg -> Reg -> InstrSR instr
forall instr. Instruction instr => Platform -> Reg -> Reg -> instr
mkRegRegMoveInstr Platform
platform Reg
reg1 Reg
reg2) Maybe Liveness
forall a. Maybe a
Nothing
                       LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
instrs

cleanForward platform :: Platform
platform blockId :: BlockId
blockId assoc :: Assoc Store
assoc acc :: [LiveInstr instr]
acc (li :: LiveInstr instr
li@(LiveInstr i1 :: InstrSR instr
i1 _) : instrs :: [LiveInstr instr]
instrs)
        | Just (r1 :: Reg
r1, r2 :: Reg
r2) <- InstrSR instr -> Maybe (Reg, Reg)
forall instr. Instruction instr => instr -> Maybe (Reg, Reg)
takeRegRegMoveInstr InstrSR instr
i1
        = if Reg
r1 Reg -> Reg -> Bool
forall a. Eq a => a -> a -> Bool
== Reg
r2
                -- Erase any left over nop reg reg moves while we're here
                -- this will also catch any nop moves that the previous case
                -- happens to add.
                then Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc [LiveInstr instr]
acc [LiveInstr instr]
instrs

                -- If r1 has the same value as some slots and we copy r1 to r2,
                --      then r2 is now associated with those slots instead
                else do let assoc' :: Assoc Store
assoc'      = Store -> Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> a -> Assoc a -> Assoc a
addAssoc (Reg -> Store
SReg Reg
r1) (Reg -> Store
SReg Reg
r2)
                                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> Assoc a -> Assoc a
delAssoc (Reg -> Store
SReg Reg
r2)
                                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Assoc Store
assoc

                        Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs


cleanForward platform :: Platform
platform blockId :: BlockId
blockId assoc :: Assoc Store
assoc acc :: [LiveInstr instr]
acc (li :: LiveInstr instr
li : instrs :: [LiveInstr instr]
instrs)

        -- Update association due to the spill.
        | LiveInstr (SPILL reg :: Reg
reg slot :: Int
slot) _  <- LiveInstr instr
li
        = let   assoc' :: Assoc Store
assoc'  = Store -> Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> a -> Assoc a -> Assoc a
addAssoc (Reg -> Store
SReg Reg
reg)  (Int -> Store
SSlot Int
slot)
                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> Assoc a -> Assoc a
delAssoc (Int -> Store
SSlot Int
slot)
                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Assoc Store
assoc
          in    Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs

        -- Clean a reload instr.
        | LiveInstr (RELOAD{}) _        <- LiveInstr instr
li
        = do    (assoc' :: Assoc Store
assoc', mli :: Maybe (LiveInstr instr)
mli)   <- Platform
-> BlockId
-> Assoc Store
-> LiveInstr instr
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> LiveInstr instr
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
cleanReload Platform
platform BlockId
blockId Assoc Store
assoc LiveInstr instr
li
                case Maybe (LiveInstr instr)
mli of
                 Nothing        -> Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc' [LiveInstr instr]
acc
                                                [LiveInstr instr]
instrs

                 Just li' :: LiveInstr instr
li'       -> Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc' (LiveInstr instr
li' LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc)
                                                [LiveInstr instr]
instrs

        -- Remember the association over a jump.
        | LiveInstr instr :: InstrSR instr
instr _     <- LiveInstr instr
li
        , [BlockId]
targets               <- InstrSR instr -> [BlockId]
forall instr. Instruction instr => instr -> [BlockId]
jumpDestsOfInstr InstrSR instr
instr
        , Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ [BlockId] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [BlockId]
targets
        = do    (BlockId -> State CleanS ()) -> [BlockId] -> State CleanS ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Assoc Store -> BlockId -> State CleanS ()
accJumpValid Assoc Store
assoc) [BlockId]
targets
                Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs

        -- Writing to a reg changes its value.
        | LiveInstr instr :: InstrSR instr
instr _     <- LiveInstr instr
li
        , RU _ written :: [Reg]
written          <- Platform -> InstrSR instr -> RegUsage
forall instr. Instruction instr => Platform -> instr -> RegUsage
regUsageOfInstr Platform
platform InstrSR instr
instr
        = let assoc' :: Assoc Store
assoc'    = (Store -> Assoc Store -> Assoc Store)
-> Assoc Store -> [Store] -> Assoc Store
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> Assoc a -> Assoc a
delAssoc Assoc Store
assoc ((Reg -> Store) -> [Reg] -> [Store]
forall a b. (a -> b) -> [a] -> [b]
map Reg -> Store
SReg ([Reg] -> [Store]) -> [Reg] -> [Store]
forall a b. (a -> b) -> a -> b
$ [Reg] -> [Reg]
forall a. Eq a => [a] -> [a]
nub [Reg]
written)
          in  Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
Platform
-> BlockId
-> Assoc Store
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanForward Platform
platform BlockId
blockId Assoc Store
assoc' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs



-- | Try and rewrite a reload instruction to something more pleasing
cleanReload
        :: Instruction instr
        => Platform
        -> BlockId
        -> Assoc Store
        -> LiveInstr instr
        -> CleanM (Assoc Store, Maybe (LiveInstr instr))

cleanReload :: Platform
-> BlockId
-> Assoc Store
-> LiveInstr instr
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
cleanReload platform :: Platform
platform blockId :: BlockId
blockId assoc :: Assoc Store
assoc li :: LiveInstr instr
li@(LiveInstr (RELOAD slot :: Int
slot reg :: Reg
reg) _)

        -- If the reg we're reloading already has the same value as the slot
        --      then we can erase the instruction outright.
        | Store -> Store -> Assoc Store -> Bool
forall a. Uniquable a => a -> a -> Assoc a -> Bool
elemAssoc (Int -> Store
SSlot Int
slot) (Reg -> Store
SReg Reg
reg) Assoc Store
assoc
        = do    (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify  ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s { sCleanedReloadsAcc :: Int
sCleanedReloadsAcc = CleanS -> Int
sCleanedReloadsAcc CleanS
s Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1 }
                (Assoc Store, Maybe (LiveInstr instr))
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
forall (m :: * -> *) a. Monad m => a -> m a
return  (Assoc Store
assoc, Maybe (LiveInstr instr)
forall a. Maybe a
Nothing)

        -- If we can find another reg with the same value as this slot then
        --      do a move instead of a reload.
        | Just reg2 :: Reg
reg2     <- Assoc Store -> Int -> Maybe Reg
findRegOfSlot Assoc Store
assoc Int
slot
        = do    (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s { sCleanedReloadsAcc :: Int
sCleanedReloadsAcc = CleanS -> Int
sCleanedReloadsAcc CleanS
s Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1 }

                let assoc' :: Assoc Store
assoc'      = Store -> Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> a -> Assoc a -> Assoc a
addAssoc (Reg -> Store
SReg Reg
reg) (Reg -> Store
SReg Reg
reg2)
                                (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> Assoc a -> Assoc a
delAssoc (Reg -> Store
SReg Reg
reg)
                                (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Assoc Store
assoc

                (Assoc Store, Maybe (LiveInstr instr))
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
forall (m :: * -> *) a. Monad m => a -> m a
return  ( Assoc Store
assoc'
                        , LiveInstr instr -> Maybe (LiveInstr instr)
forall a. a -> Maybe a
Just (LiveInstr instr -> Maybe (LiveInstr instr))
-> LiveInstr instr -> Maybe (LiveInstr instr)
forall a b. (a -> b) -> a -> b
$ InstrSR instr -> Maybe Liveness -> LiveInstr instr
forall instr. InstrSR instr -> Maybe Liveness -> LiveInstr instr
LiveInstr (Platform -> Reg -> Reg -> InstrSR instr
forall instr. Instruction instr => Platform -> Reg -> Reg -> instr
mkRegRegMoveInstr Platform
platform Reg
reg2 Reg
reg) Maybe Liveness
forall a. Maybe a
Nothing)

        -- Gotta keep this instr.
        | Bool
otherwise
        = do    -- Update the association.
                let assoc' :: Assoc Store
assoc'
                        = Store -> Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> a -> Assoc a -> Assoc a
addAssoc (Reg -> Store
SReg Reg
reg)  (Int -> Store
SSlot Int
slot)
                                -- doing the reload makes reg and slot the same value
                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Store -> Assoc Store -> Assoc Store
forall a. Uniquable a => a -> Assoc a -> Assoc a
delAssoc (Reg -> Store
SReg Reg
reg)
                                -- reg value changes on reload
                        (Assoc Store -> Assoc Store) -> Assoc Store -> Assoc Store
forall a b. (a -> b) -> a -> b
$ Assoc Store
assoc

                -- Remember that this block reloads from this slot.
                BlockId -> Int -> State CleanS ()
accBlockReloadsSlot BlockId
blockId Int
slot

                (Assoc Store, Maybe (LiveInstr instr))
-> CleanM (Assoc Store, Maybe (LiveInstr instr))
forall (m :: * -> *) a. Monad m => a -> m a
return  (Assoc Store
assoc', LiveInstr instr -> Maybe (LiveInstr instr)
forall a. a -> Maybe a
Just LiveInstr instr
li)

cleanReload _ _ _ _
        = String -> CleanM (Assoc Store, Maybe (LiveInstr instr))
forall a. String -> a
panic "RegSpillClean.cleanReload: unhandled instr"


-------------------------------------------------------------------------------
-- | Clean out unneeded spill instructions,
--   while walking backwards over the code.
--
--      If there were no reloads from a slot between a spill and the last one
--      then the slot was never read and we don't need the spill.
--
--      SPILL   r0 -> s1
--      RELOAD  s1 -> r2
--      SPILL   r3 -> s1        <--- don't need this spill
--      SPILL   r4 -> s1
--      RELOAD  s1 -> r5
--
--      Maintain a set of
--              "slots which were spilled to but not reloaded from yet"
--
--      Walking backwards across the code:
--       a) On a reload from a slot, remove it from the set.
--
--       a) On a spill from a slot
--              If the slot is in set then we can erase the spill,
--               because it won't be reloaded from until after the next spill.
--
--              otherwise
--               keep the spill and add the slot to the set
--
-- TODO: This is mostly inter-block
--       we should really be updating the noReloads set as we cross jumps also.
--
-- TODO: generate noReloads from liveSlotsOnEntry
--
cleanTopBackward
        :: Instruction instr
        => LiveCmmDecl statics instr
        -> CleanM (LiveCmmDecl statics instr)

cleanTopBackward :: LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
cleanTopBackward cmm :: LiveCmmDecl statics instr
cmm
 = case LiveCmmDecl statics instr
cmm of
        CmmData{}
         -> LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall (m :: * -> *) a. Monad m => a -> m a
return LiveCmmDecl statics instr
cmm

        CmmProc info :: LiveInfo
info label :: CLabel
label live :: [GlobalReg]
live sccs :: [SCC (LiveBasicBlock instr)]
sccs
         | LiveInfo _ _ _ liveSlotsOnEntry :: BlockMap IntSet
liveSlotsOnEntry <- LiveInfo
info
         -> do  [SCC (LiveBasicBlock instr)]
sccs'   <- (SCC (LiveBasicBlock instr)
 -> State CleanS (SCC (LiveBasicBlock instr)))
-> [SCC (LiveBasicBlock instr)]
-> State CleanS [SCC (LiveBasicBlock instr)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM ((LiveBasicBlock instr -> State CleanS (LiveBasicBlock instr))
-> SCC (LiveBasicBlock instr)
-> State CleanS (SCC (LiveBasicBlock instr))
forall (m :: * -> *) a b.
Monad m =>
(a -> m b) -> SCC a -> m (SCC b)
mapSCCM (BlockMap IntSet
-> LiveBasicBlock instr -> State CleanS (LiveBasicBlock instr)
forall instr.
Instruction instr =>
BlockMap IntSet
-> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
cleanBlockBackward BlockMap IntSet
liveSlotsOnEntry)) [SCC (LiveBasicBlock instr)]
sccs
                LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall (m :: * -> *) a. Monad m => a -> m a
return  (LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr))
-> LiveCmmDecl statics instr -> CleanM (LiveCmmDecl statics instr)
forall a b. (a -> b) -> a -> b
$ LiveInfo
-> CLabel
-> [GlobalReg]
-> [SCC (LiveBasicBlock instr)]
-> LiveCmmDecl statics instr
forall d h g. h -> CLabel -> [GlobalReg] -> g -> GenCmmDecl d h g
CmmProc LiveInfo
info CLabel
label [GlobalReg]
live [SCC (LiveBasicBlock instr)]
sccs'


cleanBlockBackward
        :: Instruction instr
        => BlockMap IntSet
        -> LiveBasicBlock instr
        -> CleanM (LiveBasicBlock instr)

cleanBlockBackward :: BlockMap IntSet
-> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
cleanBlockBackward liveSlotsOnEntry :: BlockMap IntSet
liveSlotsOnEntry (BasicBlock blockId :: BlockId
blockId instrs :: [LiveInstr instr]
instrs)
 = do   [LiveInstr instr]
instrs_spill    <- BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry  UniqSet Int
forall a. UniqSet a
emptyUniqSet  [] [LiveInstr instr]
instrs
        LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
forall (m :: * -> *) a. Monad m => a -> m a
return  (LiveBasicBlock instr -> CleanM (LiveBasicBlock instr))
-> LiveBasicBlock instr -> CleanM (LiveBasicBlock instr)
forall a b. (a -> b) -> a -> b
$ BlockId -> [LiveInstr instr] -> LiveBasicBlock instr
forall i. BlockId -> [i] -> GenBasicBlock i
BasicBlock BlockId
blockId [LiveInstr instr]
instrs_spill



cleanBackward
        :: Instruction instr
        => BlockMap IntSet          -- ^ Slots live on entry to each block
        -> UniqSet Int              -- ^ Slots that have been spilled, but not reloaded from
        -> [LiveInstr instr]        -- ^ acc
        -> [LiveInstr instr]        -- ^ Instrs to clean (in forwards order)
        -> CleanM [LiveInstr instr] -- ^ Cleaned instrs  (in backwards order)

cleanBackward :: BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward liveSlotsOnEntry :: BlockMap IntSet
liveSlotsOnEntry noReloads :: UniqSet Int
noReloads acc :: [LiveInstr instr]
acc lis :: [LiveInstr instr]
lis
 = do   UniqFM [BlockId]
reloadedBy      <- (CleanS -> UniqFM [BlockId]) -> State CleanS (UniqFM [BlockId])
forall s a. (s -> a) -> State s a
gets CleanS -> UniqFM [BlockId]
sReloadedBy
        BlockMap IntSet
-> UniqFM [BlockId]
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqFM [BlockId]
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
cleanBackward' BlockMap IntSet
liveSlotsOnEntry UniqFM [BlockId]
reloadedBy UniqSet Int
noReloads [LiveInstr instr]
acc [LiveInstr instr]
lis


cleanBackward'
        :: Instruction instr
        => BlockMap IntSet
        -> UniqFM [BlockId]
        -> UniqSet Int
        -> [LiveInstr instr]
        -> [LiveInstr instr]
        -> State CleanS [LiveInstr instr]

cleanBackward' :: BlockMap IntSet
-> UniqFM [BlockId]
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
cleanBackward' _ _ _      acc :: [LiveInstr instr]
acc []
        = [LiveInstr instr] -> State CleanS [LiveInstr instr]
forall (m :: * -> *) a. Monad m => a -> m a
return  [LiveInstr instr]
acc

cleanBackward' liveSlotsOnEntry :: BlockMap IntSet
liveSlotsOnEntry reloadedBy :: UniqFM [BlockId]
reloadedBy noReloads :: UniqSet Int
noReloads acc :: [LiveInstr instr]
acc (li :: LiveInstr instr
li : instrs :: [LiveInstr instr]
instrs)

        -- If nothing ever reloads from this slot then we don't need the spill.
        | LiveInstr (SPILL _ slot :: Int
slot) _    <- LiveInstr instr
li
        , Maybe [BlockId]
Nothing       <- UniqFM [BlockId] -> Store -> Maybe [BlockId]
forall key elt. Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM UniqFM [BlockId]
reloadedBy (Int -> Store
SSlot Int
slot)
        = do    (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s { sCleanedSpillsAcc :: Int
sCleanedSpillsAcc = CleanS -> Int
sCleanedSpillsAcc CleanS
s Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1 }
                BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads [LiveInstr instr]
acc [LiveInstr instr]
instrs

        | LiveInstr (SPILL _ slot :: Int
slot) _    <- LiveInstr instr
li
        = if Int -> UniqSet Int -> Bool
forall a. Uniquable a => a -> UniqSet a -> Bool
elementOfUniqSet Int
slot UniqSet Int
noReloads

           -- We can erase this spill because the slot won't be read until
           -- after the next one
           then do
                (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s { sCleanedSpillsAcc :: Int
sCleanedSpillsAcc = CleanS -> Int
sCleanedSpillsAcc CleanS
s Int -> Int -> Int
forall a. Num a => a -> a -> a
+ 1 }
                BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads [LiveInstr instr]
acc [LiveInstr instr]
instrs

           else do
                -- This slot is being spilled to, but we haven't seen any reloads yet.
                let noReloads' :: UniqSet Int
noReloads'  = UniqSet Int -> Int -> UniqSet Int
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
addOneToUniqSet UniqSet Int
noReloads Int
slot
                BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs

        -- if we reload from a slot then it's no longer unused
        | LiveInstr (RELOAD slot :: Int
slot _) _   <- LiveInstr instr
li
        , UniqSet Int
noReloads'            <- UniqSet Int -> Int -> UniqSet Int
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet UniqSet Int
noReloads Int
slot
        = BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs

        -- If a slot is live in a jump target then assume it's reloaded there.
        --
        -- TODO: A real dataflow analysis would do a better job here.
        --       If the target block _ever_ used the slot then we assume
        --       it always does, but if those reloads are cleaned the slot
        --       liveness map doesn't get updated.
        | LiveInstr instr :: InstrSR instr
instr _     <- LiveInstr instr
li
        , [BlockId]
targets               <- InstrSR instr -> [BlockId]
forall instr. Instruction instr => instr -> [BlockId]
jumpDestsOfInstr InstrSR instr
instr
        = do
                let slotsReloadedByTargets :: IntSet
slotsReloadedByTargets
                        = [IntSet] -> IntSet
forall (f :: * -> *). Foldable f => f IntSet -> IntSet
IntSet.unions
                        ([IntSet] -> IntSet) -> [IntSet] -> IntSet
forall a b. (a -> b) -> a -> b
$ [Maybe IntSet] -> [IntSet]
forall a. [Maybe a] -> [a]
catMaybes
                        ([Maybe IntSet] -> [IntSet]) -> [Maybe IntSet] -> [IntSet]
forall a b. (a -> b) -> a -> b
$ (BlockId -> Maybe IntSet) -> [BlockId] -> [Maybe IntSet]
forall a b. (a -> b) -> [a] -> [b]
map ((BlockId -> BlockMap IntSet -> Maybe IntSet)
-> BlockMap IntSet -> BlockId -> Maybe IntSet
forall a b c. (a -> b -> c) -> b -> a -> c
flip BlockId -> BlockMap IntSet -> Maybe IntSet
forall (map :: * -> *) a.
IsMap map =>
KeyOf map -> map a -> Maybe a
mapLookup BlockMap IntSet
liveSlotsOnEntry)
                        ([BlockId] -> [Maybe IntSet]) -> [BlockId] -> [Maybe IntSet]
forall a b. (a -> b) -> a -> b
$ [BlockId]
targets

                let noReloads' :: UniqSet Int
noReloads'
                        = (UniqSet Int -> Int -> UniqSet Int)
-> UniqSet Int -> [Int] -> UniqSet Int
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' UniqSet Int -> Int -> UniqSet Int
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet UniqSet Int
noReloads
                        ([Int] -> UniqSet Int) -> [Int] -> UniqSet Int
forall a b. (a -> b) -> a -> b
$ IntSet -> [Int]
IntSet.toList IntSet
slotsReloadedByTargets

                BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads' (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs

        -- some other instruction
        | Bool
otherwise
        = BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> State CleanS [LiveInstr instr]
forall instr.
Instruction instr =>
BlockMap IntSet
-> UniqSet Int
-> [LiveInstr instr]
-> [LiveInstr instr]
-> CleanM [LiveInstr instr]
cleanBackward BlockMap IntSet
liveSlotsOnEntry UniqSet Int
noReloads (LiveInstr instr
li LiveInstr instr -> [LiveInstr instr] -> [LiveInstr instr]
forall a. a -> [a] -> [a]
: [LiveInstr instr]
acc) [LiveInstr instr]
instrs


-- | Combine the associations from all the inward control flow edges.
--
collateJoinPoints :: CleanM ()
collateJoinPoints :: State CleanS ()
collateJoinPoints
 = (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s
        { sJumpValid :: UniqFM (Assoc Store)
sJumpValid    = ([Assoc Store] -> Assoc Store)
-> UniqFM [Assoc Store] -> UniqFM (Assoc Store)
forall elt1 elt2. (elt1 -> elt2) -> UniqFM elt1 -> UniqFM elt2
mapUFM [Assoc Store] -> Assoc Store
intersects (CleanS -> UniqFM [Assoc Store]
sJumpValidAcc CleanS
s)
        , sJumpValidAcc :: UniqFM [Assoc Store]
sJumpValidAcc = UniqFM [Assoc Store]
forall elt. UniqFM elt
emptyUFM }

intersects :: [Assoc Store]     -> Assoc Store
intersects :: [Assoc Store] -> Assoc Store
intersects []           = Assoc Store
forall a. Assoc a
emptyAssoc
intersects assocs :: [Assoc Store]
assocs       = (Assoc Store -> Assoc Store -> Assoc Store)
-> [Assoc Store] -> Assoc Store
forall a. (a -> a -> a) -> [a] -> a
foldl1' Assoc Store -> Assoc Store -> Assoc Store
forall a. Assoc a -> Assoc a -> Assoc a
intersectAssoc [Assoc Store]
assocs


-- | See if we have a reg with the same value as this slot in the association table.
findRegOfSlot :: Assoc Store -> Int -> Maybe Reg
findRegOfSlot :: Assoc Store -> Int -> Maybe Reg
findRegOfSlot assoc :: Assoc Store
assoc slot :: Int
slot
        | UniqSet Store
close                 <- Store -> Assoc Store -> UniqSet Store
forall a. Uniquable a => a -> Assoc a -> UniqSet a
closeAssoc (Int -> Store
SSlot Int
slot) Assoc Store
assoc
        , Just (SReg reg :: Reg
reg)       <- (Store -> Bool) -> [Store] -> Maybe Store
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Maybe a
find Store -> Bool
isStoreReg ([Store] -> Maybe Store) -> [Store] -> Maybe Store
forall a b. (a -> b) -> a -> b
$ UniqSet Store -> [Store]
forall elt. UniqSet elt -> [elt]
nonDetEltsUniqSet UniqSet Store
close
           -- See Note [Unique Determinism and code generation]
        = Reg -> Maybe Reg
forall a. a -> Maybe a
Just Reg
reg

        | Bool
otherwise
        = Maybe Reg
forall a. Maybe a
Nothing


-------------------------------------------------------------------------------
-- | Cleaner monad.
type CleanM
        = State CleanS

-- | Cleaner state.
data CleanS
        = CleanS
        { -- | Regs which are valid at the start of each block.
          CleanS -> UniqFM (Assoc Store)
sJumpValid            :: UniqFM (Assoc Store)

          -- | Collecting up what regs were valid across each jump.
          --    in the next pass we can collate these and write the results
          --    to sJumpValid.
        , CleanS -> UniqFM [Assoc Store]
sJumpValidAcc         :: UniqFM [Assoc Store]

          -- | Map of (slot -> blocks which reload from this slot)
          --    used to decide if whether slot spilled to will ever be
          --    reloaded from on this path.
        , CleanS -> UniqFM [BlockId]
sReloadedBy           :: UniqFM [BlockId]

          -- | Spills and reloads cleaned each pass (latest at front)
        , CleanS -> [(Int, Int)]
sCleanedCount         :: [(Int, Int)]

          -- | Spills and reloads that have been cleaned in this pass so far.
        , CleanS -> Int
sCleanedSpillsAcc     :: Int
        , CleanS -> Int
sCleanedReloadsAcc    :: Int }


-- | Construct the initial cleaner state.
initCleanS :: CleanS
initCleanS :: CleanS
initCleanS
        = CleanS :: UniqFM (Assoc Store)
-> UniqFM [Assoc Store]
-> UniqFM [BlockId]
-> [(Int, Int)]
-> Int
-> Int
-> CleanS
CleanS
        { sJumpValid :: UniqFM (Assoc Store)
sJumpValid            = UniqFM (Assoc Store)
forall elt. UniqFM elt
emptyUFM
        , sJumpValidAcc :: UniqFM [Assoc Store]
sJumpValidAcc         = UniqFM [Assoc Store]
forall elt. UniqFM elt
emptyUFM

        , sReloadedBy :: UniqFM [BlockId]
sReloadedBy           = UniqFM [BlockId]
forall elt. UniqFM elt
emptyUFM

        , sCleanedCount :: [(Int, Int)]
sCleanedCount         = []

        , sCleanedSpillsAcc :: Int
sCleanedSpillsAcc     = 0
        , sCleanedReloadsAcc :: Int
sCleanedReloadsAcc    = 0 }


-- | Remember the associations before a jump.
accJumpValid :: Assoc Store -> BlockId -> CleanM ()
accJumpValid :: Assoc Store -> BlockId -> State CleanS ()
accJumpValid assocs :: Assoc Store
assocs target :: BlockId
target
 = (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s {
        sJumpValidAcc :: UniqFM [Assoc Store]
sJumpValidAcc = ([Assoc Store] -> [Assoc Store] -> [Assoc Store])
-> UniqFM [Assoc Store]
-> BlockId
-> [Assoc Store]
-> UniqFM [Assoc Store]
forall key elt.
Uniquable key =>
(elt -> elt -> elt) -> UniqFM elt -> key -> elt -> UniqFM elt
addToUFM_C [Assoc Store] -> [Assoc Store] -> [Assoc Store]
forall a. [a] -> [a] -> [a]
(++)
                                (CleanS -> UniqFM [Assoc Store]
sJumpValidAcc CleanS
s)
                                BlockId
target
                                [Assoc Store
assocs] }


accBlockReloadsSlot :: BlockId -> Slot -> CleanM ()
accBlockReloadsSlot :: BlockId -> Int -> State CleanS ()
accBlockReloadsSlot blockId :: BlockId
blockId slot :: Int
slot
 = (CleanS -> CleanS) -> State CleanS ()
forall s. (s -> s) -> State s ()
modify ((CleanS -> CleanS) -> State CleanS ())
-> (CleanS -> CleanS) -> State CleanS ()
forall a b. (a -> b) -> a -> b
$ \s :: CleanS
s -> CleanS
s {
        sReloadedBy :: UniqFM [BlockId]
sReloadedBy = ([BlockId] -> [BlockId] -> [BlockId])
-> UniqFM [BlockId] -> Store -> [BlockId] -> UniqFM [BlockId]
forall key elt.
Uniquable key =>
(elt -> elt -> elt) -> UniqFM elt -> key -> elt -> UniqFM elt
addToUFM_C [BlockId] -> [BlockId] -> [BlockId]
forall a. [a] -> [a] -> [a]
(++)
                                (CleanS -> UniqFM [BlockId]
sReloadedBy CleanS
s)
                                (Int -> Store
SSlot Int
slot)
                                [BlockId
blockId] }


-------------------------------------------------------------------------------
-- A store location can be a stack slot or a register
data Store
        = SSlot Int
        | SReg  Reg


-- | Check if this is a reg store.
isStoreReg :: Store -> Bool
isStoreReg :: Store -> Bool
isStoreReg ss :: Store
ss
 = case Store
ss of
        SSlot _ -> Bool
False
        SReg  _ -> Bool
True


-- Spill cleaning is only done once all virtuals have been allocated to realRegs
instance Uniquable Store where
    getUnique :: Store -> Unique
getUnique (SReg  r :: Reg
r)
        | RegReal (RealRegSingle i :: Int
i)     <- Reg
r
        = Int -> Unique
mkRegSingleUnique Int
i

        | RegReal (RealRegPair r1 :: Int
r1 r2 :: Int
r2)   <- Reg
r
        = Int -> Unique
mkRegPairUnique (Int
r1 Int -> Int -> Int
forall a. Num a => a -> a -> a
* 65535 Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
r2)

        | Bool
otherwise
        = String -> Unique
forall a. HasCallStack => String -> a
error (String -> Unique) -> String -> Unique
forall a b. (a -> b) -> a -> b
$ "RegSpillClean.getUnique: found virtual reg during spill clean,"
                String -> String -> String
forall a. [a] -> [a] -> [a]
++ "only real regs expected."

    getUnique (SSlot i :: Int
i) = Int -> Unique
mkRegSubUnique Int
i    -- [SLPJ] I hope "SubUnique" is ok


instance Outputable Store where
        ppr :: Store -> SDoc
ppr (SSlot i :: Int
i)   = String -> SDoc
text "slot" SDoc -> SDoc -> SDoc
<> Int -> SDoc
int Int
i
        ppr (SReg  r :: Reg
r)   = Reg -> SDoc
forall a. Outputable a => a -> SDoc
ppr Reg
r


-------------------------------------------------------------------------------
-- Association graphs.
-- In the spill cleaner, two store locations are associated if they are known
-- to hold the same value.
--
type Assoc a    = UniqFM (UniqSet a)

-- | An empty association
emptyAssoc :: Assoc a
emptyAssoc :: Assoc a
emptyAssoc      = Assoc a
forall elt. UniqFM elt
emptyUFM


-- | Add an association between these two things.
addAssoc :: Uniquable a
         => a -> a -> Assoc a -> Assoc a

addAssoc :: a -> a -> Assoc a -> Assoc a
addAssoc a :: a
a b :: a
b m :: Assoc a
m
 = let  m1 :: Assoc a
m1      = (UniqSet a -> UniqSet a -> UniqSet a)
-> Assoc a -> a -> UniqSet a -> Assoc a
forall key elt.
Uniquable key =>
(elt -> elt -> elt) -> UniqFM elt -> key -> elt -> UniqFM elt
addToUFM_C UniqSet a -> UniqSet a -> UniqSet a
forall a. UniqSet a -> UniqSet a -> UniqSet a
unionUniqSets Assoc a
m  a
a (a -> UniqSet a
forall a. Uniquable a => a -> UniqSet a
unitUniqSet a
b)
        m2 :: Assoc a
m2      = (UniqSet a -> UniqSet a -> UniqSet a)
-> Assoc a -> a -> UniqSet a -> Assoc a
forall key elt.
Uniquable key =>
(elt -> elt -> elt) -> UniqFM elt -> key -> elt -> UniqFM elt
addToUFM_C UniqSet a -> UniqSet a -> UniqSet a
forall a. UniqSet a -> UniqSet a -> UniqSet a
unionUniqSets Assoc a
m1 a
b (a -> UniqSet a
forall a. Uniquable a => a -> UniqSet a
unitUniqSet a
a)
   in   Assoc a
m2


-- | Delete all associations to a node.
delAssoc :: (Uniquable a)
         => a -> Assoc a -> Assoc a

delAssoc :: a -> Assoc a -> Assoc a
delAssoc a :: a
a m :: Assoc a
m
        | Just aSet :: UniqSet a
aSet     <- Assoc a -> a -> Maybe (UniqSet a)
forall key elt. Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM  Assoc a
m a
a
        , Assoc a
m1            <- Assoc a -> a -> Assoc a
forall key elt. Uniquable key => UniqFM elt -> key -> UniqFM elt
delFromUFM Assoc a
m a
a
        = (a -> Assoc a -> Assoc a) -> Assoc a -> UniqSet a -> Assoc a
forall elt a. (elt -> a -> a) -> a -> UniqSet elt -> a
nonDetFoldUniqSet (\x :: a
x m :: Assoc a
m -> a -> a -> Assoc a -> Assoc a
forall a. Uniquable a => a -> a -> Assoc a -> Assoc a
delAssoc1 a
x a
a Assoc a
m) Assoc a
m1 UniqSet a
aSet
          -- It's OK to use nonDetFoldUFM here because deletion is commutative

        | Bool
otherwise     = Assoc a
m


-- | Delete a single association edge (a -> b).
delAssoc1 :: Uniquable a
          => a -> a -> Assoc a -> Assoc a

delAssoc1 :: a -> a -> Assoc a -> Assoc a
delAssoc1 a :: a
a b :: a
b m :: Assoc a
m
        | Just aSet :: UniqSet a
aSet     <- Assoc a -> a -> Maybe (UniqSet a)
forall key elt. Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM Assoc a
m a
a
        = Assoc a -> a -> UniqSet a -> Assoc a
forall key elt.
Uniquable key =>
UniqFM elt -> key -> elt -> UniqFM elt
addToUFM Assoc a
m a
a (UniqSet a -> a -> UniqSet a
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet UniqSet a
aSet a
b)

        | Bool
otherwise     = Assoc a
m


-- | Check if these two things are associated.
elemAssoc :: (Uniquable a)
          => a -> a -> Assoc a -> Bool

elemAssoc :: a -> a -> Assoc a -> Bool
elemAssoc a :: a
a b :: a
b m :: Assoc a
m
        = a -> UniqSet a -> Bool
forall a. Uniquable a => a -> UniqSet a -> Bool
elementOfUniqSet a
b (a -> Assoc a -> UniqSet a
forall a. Uniquable a => a -> Assoc a -> UniqSet a
closeAssoc a
a Assoc a
m)


-- | Find the refl. trans. closure of the association from this point.
closeAssoc :: (Uniquable a)
        => a -> Assoc a -> UniqSet a

closeAssoc :: a -> Assoc a -> UniqSet a
closeAssoc a :: a
a assoc :: Assoc a
assoc
 =      Assoc a -> UniqSet a -> UniqSet a -> UniqSet a
forall a.
Uniquable a =>
UniqFM (UniqSet a) -> UniqSet a -> UniqSet a -> UniqSet a
closeAssoc' Assoc a
assoc UniqSet a
forall a. UniqSet a
emptyUniqSet (a -> UniqSet a
forall a. Uniquable a => a -> UniqSet a
unitUniqSet a
a)
 where
        closeAssoc' :: UniqFM (UniqSet a) -> UniqSet a -> UniqSet a -> UniqSet a
closeAssoc' assoc :: UniqFM (UniqSet a)
assoc visited :: UniqSet a
visited toVisit :: UniqSet a
toVisit
         = case UniqSet a -> [a]
forall elt. UniqSet elt -> [elt]
nonDetEltsUniqSet UniqSet a
toVisit of
             -- See Note [Unique Determinism and code generation]

                -- nothing else to visit, we're done
                []      -> UniqSet a
visited

                (x :: a
x:_)
                 -- we've already seen this node
                 |  a -> UniqSet a -> Bool
forall a. Uniquable a => a -> UniqSet a -> Bool
elementOfUniqSet a
x UniqSet a
visited
                 -> UniqFM (UniqSet a) -> UniqSet a -> UniqSet a -> UniqSet a
closeAssoc' UniqFM (UniqSet a)
assoc UniqSet a
visited (UniqSet a -> a -> UniqSet a
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet UniqSet a
toVisit a
x)

                 -- haven't seen this node before,
                 --     remember to visit all its neighbors
                 |  Bool
otherwise
                 -> let neighbors :: UniqSet a
neighbors
                         = case UniqFM (UniqSet a) -> a -> Maybe (UniqSet a)
forall key elt. Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM UniqFM (UniqSet a)
assoc a
x of
                                Nothing         -> UniqSet a
forall a. UniqSet a
emptyUniqSet
                                Just set :: UniqSet a
set        -> UniqSet a
set

                   in UniqFM (UniqSet a) -> UniqSet a -> UniqSet a -> UniqSet a
closeAssoc' UniqFM (UniqSet a)
assoc
                        (UniqSet a -> a -> UniqSet a
forall a. Uniquable a => UniqSet a -> a -> UniqSet a
addOneToUniqSet UniqSet a
visited a
x)
                        (UniqSet a -> UniqSet a -> UniqSet a
forall a. UniqSet a -> UniqSet a -> UniqSet a
unionUniqSets   UniqSet a
toVisit UniqSet a
neighbors)

-- | Intersect two associations.
intersectAssoc :: Assoc a -> Assoc a -> Assoc a
intersectAssoc :: Assoc a -> Assoc a -> Assoc a
intersectAssoc a :: Assoc a
a b :: Assoc a
b
        = (UniqSet a -> UniqSet a -> UniqSet a)
-> Assoc a -> Assoc a -> Assoc a
forall elt1 elt2 elt3.
(elt1 -> elt2 -> elt3) -> UniqFM elt1 -> UniqFM elt2 -> UniqFM elt3
intersectUFM_C (UniqSet a -> UniqSet a -> UniqSet a
forall a. UniqSet a -> UniqSet a -> UniqSet a
intersectUniqSets) Assoc a
a Assoc a
b