linearscan-0.5.0.0: LinearScan.hs
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# OPTIONS_GHC -Wall -Werror -fno-warn-orphans #-}
module LinearScan
( -- * Main entry point
allocate
-- * Blocks
, LinearScan.BlockInfo(..)
-- * Operations
, LinearScan.OpInfo(..)
, OpKind(..)
-- * Variables
, VarId
, LinearScan.VarInfo(..)
, LS.VarKind(..)
, PhysReg
) where
import Control.Applicative
import Control.Monad.State
import Data.IntMap (IntMap)
import qualified Data.IntMap as M
import Data.IntSet (IntSet)
import qualified Data.IntSet as S
import qualified Data.List as L
import Debug.Trace
import qualified LinearScan.Blocks as LS
import LinearScan.Blocks as LS
import qualified LinearScan.IntMap as LS
import qualified LinearScan.Interval as LS
import qualified LinearScan.LiveSets as LS
import qualified LinearScan.Loops as LS
import qualified LinearScan.Main as LS
import qualified LinearScan.Monad as LS
import qualified LinearScan.Morph as LS
import qualified LinearScan.Range as LS
import qualified LinearScan.UsePos as LS
import qualified LinearScan.Utils as LS
import LinearScan.Yoneda (Any)
import qualified Unsafe.Coerce as U
-- | Each variable has associated allocation details, and a flag to indicate
-- whether it must be loaded into a register at its point of use. Variables
-- are also distinguished by their kind, which allows for restricting the
-- scope of their lifetime. For example, output variables are not needed in a
-- basic block until the first point of use, while the lifetime of input
-- variables extends until their final use.
data VarInfo = VarInfo
{ varId :: Either PhysReg VarId
, varKind :: LS.VarKind
, regRequired :: Bool
}
deriving instance Eq LS.VarKind
deriving instance Show LS.VarKind
fromVarInfo :: LinearScan.VarInfo -> LS.VarInfo
fromVarInfo (VarInfo a b c) = LS.Build_VarInfo a b c
-- | Every operation may reference multiple variables and/or specific physical
-- registers. If a physical register is referenced, then that register is
-- considered unavailable for allocation over the range of such references.
--
-- Certain operations have special significance as to how basic blocks are
-- organized, and the lifetime of allocations. Thus, if an operation begins
-- or ends a loop, or represents a method call, it should be indicated using
-- the 'OpKind' field. Indication of calls is necessary in order to save
-- and restore all registers around a call, but indication of loops is
-- optional, as it's merely avoids reloading of spilled variables inside
-- loop bodies.
data OpInfo m op1 op2 = OpInfo
{ opKind :: op1 -> OpKind
, opRefs :: op1 -> [LinearScan.VarInfo]
, moveOp :: PhysReg -> PhysReg -> m [op2]
, swapOp :: PhysReg -> PhysReg -> m [op2]
, saveOp :: PhysReg -> Maybe Int -> m [op2]
, restoreOp :: Maybe Int -> PhysReg -> m [op2]
, applyAllocs :: op1 -> [(Int, PhysReg)] -> m [op2]
, showOp1 :: op1 -> String
}
showOp1' :: (op1 -> String)
-> LS.OpId
-- Interval Id, it's identity, and possible assigned reg
-> [(Int, Either PhysReg LS.VarId, Maybe PhysReg)]
-> [(Int, Either PhysReg LS.VarId, Maybe PhysReg)]
-> op1
-> String
showOp1' showop pos ins outs o =
let showerv (Left r) = "r" ++ show r
showerv (Right v) = "v" ++ show v in
let render Nothing = ""
render (Just r) = "=r" ++ show r in
let marker label (i, erv, reg) =
"<" ++ label ++ " " ++ showerv erv ++
(if i == either id id erv
then ""
else "[" ++ show i ++ "]") ++ render reg ++ ">\n" in
concatMap (marker "End") outs ++
concatMap (marker "Beg") ins ++
show pos ++ ": " ++ showop o ++ "\n"
deriving instance Eq OpKind
deriving instance Show OpKind
fromOpInfo :: Monad m
=> LinearScan.OpInfo m op1 op2 -> LS.OpInfo (m Any) op1 op2
fromOpInfo (OpInfo a b c d e f g h) =
LS.Build_OpInfo a (map fromVarInfo . b)
(\r1 r2 _ k -> liftM k (c r1 r2))
(\r1 r2 _ k -> liftM k (d r1 r2))
(\r1 r2 _ k -> liftM k (e r1 r2))
(\r1 r2 _ k -> liftM k (f r1 r2))
(\r1 r2 _ k -> liftM k (g r1 r2)) h
type IntervalId = Int
data ScanStateDesc = ScanStateDesc
{ _nextInterval :: Int
, intervals :: [LS.IntervalDesc]
, fixedIntervals :: [Maybe LS.IntervalDesc]
, unhandled :: [(IntervalId, Int)]
, active :: [(IntervalId, PhysReg)]
, inactive :: [(IntervalId, PhysReg)]
, handled :: [(IntervalId, Maybe PhysReg)]
, allocations :: IntMap PhysReg
}
deriving instance Show LS.IntervalDesc
deriving instance Show LS.RangeDesc
deriving instance Show LS.UsePos
deriving instance Show LS.SplitReason
deriving instance Show LS.SpillDetails
deriving instance Show LS.SplitPosition
instance Show ScanStateDesc where
show sd =
"Unhandled:\n"
++ concatMap (\(i, _) -> " " ++ showInterval i ++ "\n")
(unhandled sd) ++
"Active:\n"
++ concatMap (\(i, r) ->
" r" ++ show r ++ showInterval i ++ "\n")
(active sd) ++
"Inactive:\n"
++ concatMap (\(i, r) ->
" r" ++ show r ++ showInterval i ++ "\n")
(inactive sd) ++
"Handled:\n"
++ concatMap (\(i, r) ->
" " ++ showReg r ++ showInterval i ++ "\n")
(handled sd) ++
"Fixed:\n"
++ concatMap (\(reg, mi) ->
case mi of
Nothing -> ""
Just i -> " " ++ showIntervalDesc reg i ++ "\n")
(zip [0..] (fixedIntervals sd))
where
showInterval i = showIntervalDesc i (intervals sd !! i)
showReg Nothing = "<stack>"
showReg (Just r) = "r" ++ show r
showIntervalDesc :: Int -> LS.IntervalDesc -> String
showIntervalDesc i (LS.Build_IntervalDesc iv ib ie rs) =
"[" ++ show i ++ "]: " ++ " v" ++ show iv ++ " "
++ show ib ++ "-" ++ show ie ++ " =>" ++ showRanges rs
showRanges :: [LS.RangeDesc] -> String
showRanges [] = ""
showRanges (LS.Build_RangeDesc rb re us:rs) =
" " ++ show rb ++ "-" ++ show re
++ (case us of
[] -> ""
_ -> " [" ++ showUsePositions us ++ "]")
++ showRanges rs
showUsePositions :: [LS.UsePos] -> String
showUsePositions [] = ""
showUsePositions [u] = go u
where
go (LS.Build_UsePos n req _v) = show n ++ (if req then "" else "?")
showUsePositions (u:us) = go u ++ " " ++ showUsePositions us
where
go (LS.Build_UsePos n req _v) = show n ++ (if req then "" else "?")
toScanStateDesc :: LS.ScanStateDescSet -> ScanStateDesc
toScanStateDesc (LS.Build_ScanStateDescSet a b c d e f g) =
let rs = L.foldl' (\m (k, mx) -> case mx of
Nothing -> m
Just r -> M.insert k r m)
M.empty g in
let xs = L.foldl' (\m (k, r) -> M.insert k r m) rs (e ++ f) in
ScanStateDesc a b c d e f g xs
data LoopState = LoopState
{ activeBlocks :: IntSet
, visitedBlocks :: IntSet
, loopHeaderBlocks :: [BlockId]
, loopEndBlocks :: IntSet
, forwardBranches :: IntMap IntSet
, backwardBranches :: IntMap IntSet
, loopIndices :: IntMap IntSet
, loopDepths :: IntMap (Int, Int)
}
instance Show LoopState where
show LoopState {..} = "LoopState = " ++
"\n activeBlocks = " ++ show (S.toList activeBlocks) ++
"\n visitedBlocks = " ++ show (S.toList visitedBlocks) ++
"\n loopHeaderBlocks = " ++ show loopHeaderBlocks ++
"\n loopEndBlocks = " ++ show (S.toList loopEndBlocks) ++
"\n forwardBranches = " ++ show (map (fmap S.toList) $
M.toList forwardBranches) ++
"\n backwardBranches = " ++ show (map (fmap S.toList) $
M.toList backwardBranches) ++
"\n loopIndices = " ++ show (map (fmap S.toList) $
M.toList loopIndices) ++
"\n loopDepths = " ++ show (M.toList loopDepths)
toLoopState :: LS.LoopState -> LinearScan.LoopState
toLoopState (LS.Build_LoopState a b c d e f g h) =
LoopState (S.fromList a) (S.fromList b) c (S.fromList d)
(M.fromList (map (fmap S.fromList) e))
(M.fromList (map (fmap S.fromList) f))
(M.fromList (map (fmap S.fromList) g))
(M.fromList h)
tracer :: String -> a -> a
tracer x = Debug.Trace.trace ("====================\n" ++ x)
showBlock1 :: (blk1 -> [op1])
-> LS.BlockId
-> LS.OpId
-> [Int]
-> [Int]
-> (LS.OpId -> [op1] -> String)
-> blk1
-> String
showBlock1 getops bid pos liveIns liveOuts showops b =
"\nBlock " ++ show bid ++
" => IN:" ++ show liveIns ++ " OUT:" ++ show liveOuts ++ "\n" ++
showops pos (getops b)
showOps1 :: LinearScan.OpInfo accType op1 op2 -> ScanStateDesc -> Int -> [op1]
-> String
showOps1 _ _ _ [] = ""
showOps1 oinfo sd pos (o:os) =
let here = pos*2+1 in
let allocs = allocations sd in
let k idx (bacc, eacc) i =
let mreg = M.lookup idx allocs in
(if LS.ibeg i == here
then (idx, Right (LS.ivar i), mreg) : bacc
else bacc,
if LS.iend i == here
then (idx, Right (LS.ivar i), mreg) : eacc
else eacc) in
let r _idx acc Nothing = acc
r idx (bacc, eacc) (Just i) =
let mreg = M.lookup idx allocs in
(if LS.ibeg i == here
then (idx, Left idx, mreg) : bacc
else bacc,
if LS.iend i == here
then (idx, Left idx, mreg) : eacc
else eacc) in
let (begs, ends) =
LS.vfoldl'_with_index (0 :: Int) k ([], []) (intervals sd) in
let (begs', ends') =
LS.vfoldl'_with_index (0 :: Int) r (begs, ends)
(fixedIntervals sd) in
showOp1' (showOp1 oinfo) (pos*2+1) begs' ends' o
++ showOps1 oinfo sd (pos+1) os
-- | From the point of view of this library, a basic block is nothing more
-- than an ordered sequence of operations.
data BlockInfo m blk1 blk2 op1 op2 = BlockInfo
{ blockId :: blk1 -> m Int
, blockSuccessors :: blk1 -> m [Int]
, splitCriticalEdge :: blk1 -> blk1 -> m (blk1, blk1)
, blockOps :: blk1 -> ([op1], [op1], [op1])
, setBlockOps :: blk1 -> [op2] -> [op2] -> [op2] -> blk2
}
showBlocks1 :: Monad m
=> LinearScan.BlockInfo m blk1 blk2 op1 op2
-> LinearScan.OpInfo m op1 op2
-> ScanStateDesc
-> LS.IntMap LS.BlockLiveSets
-> [blk1]
-> m String
showBlocks1 binfo oinfo sd ls = go 0
where
go _ [] = return ""
go pos (b:bs) = do
bid <- LinearScan.blockId binfo b
let (liveIn, liveOut) =
case LS.coq_IntMap_lookup bid ls of
Nothing -> (LS.emptyIntSet, LS.emptyIntSet)
Just s -> (LS.blockLiveIn s, LS.blockLiveOut s)
let allops blk =
let (x, y, z) = LinearScan.blockOps binfo blk in
x ++ y ++ z
(showBlock1 allops bid pos liveIn liveOut (showOps1 oinfo sd) b ++)
`liftM` go (pos + length (allops b)) bs
fromBlockInfo :: Monad m
=> LinearScan.BlockInfo m blk1 blk2 op1 op2
-> LS.BlockInfo (m Any) blk1 blk2 op1 op2
fromBlockInfo (BlockInfo a b c d e) =
LS.Build_BlockInfo
(\r1 _ k -> liftM k (a r1))
(\r1 _ k -> liftM k (b r1))
(\r1 r2 _ k -> liftM k (c r1 r2))
(\blk -> let (x, y, z) = d blk in ((x, y), z)) e
data Details m blk1 blk2 op1 op2 = Details
{ reason :: Maybe (LS.SSError, LS.FinalStage)
, liveSets :: [(Int, LS.BlockLiveSets)]
, inputBlocks :: [blk1]
, allocatedBlocks :: [blk2]
, scanStatePre :: Maybe ScanStateDesc
, scanStatePost :: Maybe ScanStateDesc
, blockInfo :: LinearScan.BlockInfo m blk1 blk2 op1 op2
, opInfo :: LinearScan.OpInfo m op1 op2
, loopState :: LoopState
}
showDetails :: Monad m => Details m blk1 blk2 op1 op2 -> m String
showDetails err = do
pre <- showScanStateDesc (scanStatePre err)
post <- showScanStateDesc (scanStatePost err)
return $ "Reason: " ++ show (reason err) ++ "\n\n"
++ ">>> ScanState before allocation:\n"
++ pre ++ "\n"
++ ">>> ScanState after allocation:\n"
++ post ++ "\n"
++ ">>> " ++ show (loopState err) ++ "\n"
where
showScanStateDesc Nothing = return ""
showScanStateDesc (Just sd) =
liftM2 (++)
(showBlocks1 (blockInfo err) (opInfo err) sd
(liveSets err) (inputBlocks err))
(return ("\n" ++ show sd))
deriving instance Show LS.SSError
deriving instance Show LS.FinalStage
deriving instance Show LS.BlockLiveSets
toDetails :: LS.Details blk1 blk2
-> LinearScan.BlockInfo m blk1 blk2 op1 op2
-> LinearScan.OpInfo m op1 op2
-> Details m blk1 blk2 op1 op2
toDetails (LS.Build_Details a b c d e f g) binfo oinfo =
Details a b c d (fmap toScanStateDesc e) (fmap toScanStateDesc f)
binfo oinfo (toLoopState g)
-- | Transform a list of basic blocks containing variable references, into an
-- equivalent list where each reference is associated with a register
-- allocation. Artificial save and restore instructions may also be
-- inserted into blocks to indicate spilling and reloading of variables.
--
-- In order to call this function, the caller must provide records that
-- allow viewing and mutating of the original program graph.
--
-- If allocation is found to be impossible -- for example if there are
-- simply not enough registers -- a 'Left' value is returned, with a string
-- describing the error.
allocate :: forall m blk1 blk2 op1 op2. (Functor m, Applicative m, Monad m)
=> Int -- ^ Maximum number of registers to use
-> LinearScan.BlockInfo m blk1 blk2 op1 op2
-> LinearScan.OpInfo m op1 op2
-> [blk1] -> m (Either String [blk2])
allocate 0 _ _ _ = return $ Left "Cannot allocate with no registers"
allocate _ _ _ [] = return $ Left "No basic blocks were provided"
allocate maxReg binfo oinfo blocks = do
x <- LS.linearScan dict maxReg
(fromBlockInfo binfo) (fromOpInfo oinfo) blocks $ \res ->
toDetails res binfo oinfo
let res' = U.unsafeCoerce (x :: Any) :: Details m blk1 blk2 op1 op2
dets <- showDetails res'
return $ tracer dets $ case reason res' of
Just (err, _) -> Left $ reasonToStr err
Nothing -> Right $ allocatedBlocks res'
where
dict :: LS.Monad (m Any)
dict = LS.Build_Monad
(LS.Build_Applicative
(\(_ :: ()) (_ :: ()) (f :: Any -> Any) x ->
U.unsafeCoerce (fmap f (U.unsafeCoerce x :: m Any)))
(\(_ :: ()) -> pure)
(\(_ :: ()) (_ :: ()) f x ->
U.unsafeCoerce (U.unsafeCoerce f <*> U.unsafeCoerce x :: m Any)))
(\(_ :: ()) x ->
U.unsafeCoerce (join (U.unsafeCoerce x :: m (m Any)) :: m Any))
reasonToStr r = case r of
LS.ECannotInsertUnhAtPos spillDets pos ->
"Cannot insert interval " ++ show spillDets
++ " onto unhandled list (use at position "
++ show pos ++ ")"
LS.EIntervalBeginsBeforeUnhandled xid ->
"Cannot spill interval " ++ show xid
++ " (begins before current position)"
LS.ENoValidSplitPositionUnh splitPos xid ->
"No split position found for unhandled interval " ++ show xid
++ " @ " ++ show splitPos
LS.ENoValidSplitPosition splitPos xid ->
"No split position found for " ++ show xid ++ " @ " ++ show splitPos
LS.ECannotSplitSingleton splitPos xid ->
"Interval " ++ show xid ++ " is a singleton @ " ++ show splitPos
LS.ERegisterAlreadyAssigned reg ->
"Register " ++ show reg ++ " already assigned"
LS.ERegisterAssignmentsOverlap reg ->
"Register assignments overlap at " ++ show reg
LS.EUnexpectedNoMoreUnhandled ->
"The unexpected happened: no more unhandled intervals"
LS.ECannotSpillIfRegisterRequired i ->
"Cannot spill interval " ++ show i
++ " with use positions requiring registers"
LS.EFuelExhausted -> "Fuel was exhausted"
LS.ENotYetImplemented n -> "Not Yet Implemented (#" ++ show n ++ ")"