-- (c) The University of Glasgow 2004
--
-----------------------------------------------------------------------------
-{-# OPTIONS -fno-warn-missing-signatures #-}
+{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
module RegLiveness (
RegSet,
stripLive,
spillNatBlock,
slurpConflicts,
- lifetimeCount,
+ slurpReloadCoalesce,
eraseDeltasLive,
patchEraseLive,
patchRegsLiveInstr,
import MachInstrs
import PprMach
import RegAllocInfo
-import Cmm
+import Cmm hiding (RegSet)
import Digraph
import Outputable
import UniqSupply
import Bag
import State
+import FastString
import Data.List
import Data.Maybe
= do comps' <- mapM (mapBlockCompM f) comps
return $ CmmProc header label params (ListGraph comps')
+mapBlockCompM :: Monad m => (a -> m a') -> (GenBasicBlock a) -> m (GenBasicBlock a')
mapBlockCompM f (BasicBlock i blocks)
= do blocks' <- mapM f blocks
return $ BasicBlock i blocks'
, moves) lis
+-- | For spill/reloads
+--
+-- SPILL v1, slot1
+-- ...
+-- RELOAD slot1, v2
+--
+-- If we can arrange that v1 and v2 are allocated to the same hreg it's more likely
+-- the spill/reload instrs can be cleaned and replaced by a nop reg-reg move.
+--
+--
+slurpReloadCoalesce :: LiveCmmTop -> Bag (Reg, Reg)
+slurpReloadCoalesce live
+ = slurpCmm emptyBag live
+
+ where slurpCmm cs CmmData{} = cs
+ slurpCmm cs (CmmProc _ _ _ (ListGraph blocks))
+ = foldl' slurpComp cs blocks
+
+ slurpComp cs comp
+ = let (moveBags, _) = runState (slurpCompM comp) emptyUFM
+ in unionManyBags (cs : moveBags)
+
+ slurpCompM (BasicBlock _ blocks)
+ = do -- run the analysis once to record the mapping across jumps.
+ mapM_ (slurpBlock False) blocks
+
+ -- run it a second time while using the information from the last pass.
+ -- We /could/ run this many more times to deal with graphical control
+ -- flow and propagating info across multiple jumps, but it's probably
+ -- not worth the trouble.
+ mapM (slurpBlock True) blocks
+
+ slurpBlock propagate (BasicBlock blockId instrs)
+ = do -- grab the slot map for entry to this block
+ slotMap <- if propagate
+ then getSlotMap blockId
+ else return emptyUFM
+
+ (_, mMoves) <- mapAccumLM slurpLI slotMap instrs
+ return $ listToBag $ catMaybes mMoves
+
+ slurpLI :: UniqFM Reg -- current slotMap
+ -> LiveInstr
+ -> State (UniqFM [UniqFM Reg]) -- blockId -> [slot -> reg]
+ -- for tracking slotMaps across jumps
+
+ ( UniqFM Reg -- new slotMap
+ , Maybe (Reg, Reg)) -- maybe a new coalesce edge
+
+ slurpLI slotMap (Instr instr _)
+
+ -- remember what reg was stored into the slot
+ | SPILL reg slot <- instr
+ , slotMap' <- addToUFM slotMap slot reg
+ = return (slotMap', Nothing)
+
+ -- add an edge betwen the this reg and the last one stored into the slot
+ | RELOAD slot reg <- instr
+ = case lookupUFM slotMap slot of
+ Just reg2
+ | reg /= reg2 -> return (slotMap, Just (reg, reg2))
+ | otherwise -> return (slotMap, Nothing)
+
+ Nothing -> return (slotMap, Nothing)
+
+ -- if we hit a jump, remember the current slotMap
+ | targets <- jumpDests instr []
+ , not $ null targets
+ = do mapM_ (accSlotMap slotMap) targets
+ return (slotMap, Nothing)
+
+ | otherwise
+ = return (slotMap, Nothing)
+
+ -- record a slotmap for an in edge to this block
+ accSlotMap slotMap blockId
+ = modify (\s -> addToUFM_C (++) s blockId [slotMap])
+
+ -- work out the slot map on entry to this block
+ -- if we have slot maps for multiple in-edges then we need to merge them.
+ getSlotMap blockId
+ = do map <- get
+ let slotMaps = fromMaybe [] (lookupUFM map blockId)
+ return $ foldr mergeSlotMaps emptyUFM slotMaps
+
+ mergeSlotMaps :: UniqFM Reg -> UniqFM Reg -> UniqFM Reg
+ mergeSlotMaps map1 map2
+ = listToUFM
+ $ [ (k, r1) | (k, r1) <- ufmToList map1
+ , case lookupUFM map2 k of
+ Nothing -> False
+ Just r2 -> r1 == r2 ]
+
+
-- | Strip away liveness information, yielding NatCmmTop
stripLive :: LiveCmmTop -> NatCmmTop
= spillNat (instr : acc) instrs
--- | Slurp out a map of how many times each register was live upon entry to an instruction.
-
-lifetimeCount
- :: LiveCmmTop
- -> UniqFM (Reg, Int) -- ^ reg -> (reg, count)
-
-lifetimeCount cmm
- = countCmm emptyUFM cmm
- where
- countCmm fm CmmData{} = fm
- countCmm fm (CmmProc info _ _ (ListGraph blocks))
- = foldl' (countComp info) fm blocks
-
- countComp info fm (BasicBlock _ blocks)
- = foldl' (countBlock info) fm blocks
-
- countBlock info fm (BasicBlock blockId instrs)
- | LiveInfo _ _ blockLive <- info
- , Just rsLiveEntry <- lookupUFM blockLive blockId
- = countLIs rsLiveEntry fm instrs
-
- | otherwise
- = error "RegLiveness.countBlock: bad block"
-
- countLIs _ fm [] = fm
- countLIs rsLive fm (Instr _ Nothing : lis) = countLIs rsLive fm lis
-
- countLIs rsLiveEntry fm (Instr _ (Just live) : lis)
- = let
- rsLiveAcross = rsLiveEntry `minusUniqSet` (liveDieRead live)
-
- rsLiveNext = (rsLiveAcross `unionUniqSets` (liveBorn live))
- `minusUniqSet` (liveDieWrite live)
-
- add r fm = addToUFM_C
- (\(r1, l1) (_, l2) -> (r1, l1 + l2))
- fm r (r, 1)
-
- fm' = foldUniqSet add fm rsLiveEntry
- in countLIs rsLiveNext fm' lis
-
-
-- | Erase Delta instructions.
eraseDeltasLive :: LiveCmmTop -> LiveCmmTop
in livenessBack liveregs' blockmap (instr' : acc) instrs
-- don't bother tagging comments or deltas with liveness
+liveness1 :: RegSet -> BlockMap RegSet -> Instr -> (RegSet, LiveInstr)
liveness1 liveregs _ (instr@COMMENT{})
= (liveregs, Instr instr Nothing)
projects / ghc-hetmet.git / blobdiff