X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FnativeGen%2FRegAllocColor.hs;h=fc62157b98bdee163036453f8070714b0d0d5cc5;hb=d5938fb228511bfdce45e148ea4906129692e67f;hp=c49a94dc8fa0ec5f311a16df9020b27793d03933;hpb=589238c4c2712d29092086926cc48eeb5e9b8fa7;p=ghc-hetmet.git diff --git a/compiler/nativeGen/RegAllocColor.hs b/compiler/nativeGen/RegAllocColor.hs index c49a94d..fc62157 100644 --- a/compiler/nativeGen/RegAllocColor.hs +++ b/compiler/nativeGen/RegAllocColor.hs @@ -1,24 +1,10 @@ -- | Graph coloring register allocator. -- -- TODO: --- Live range splitting: --- At the moment regs that are spilled are spilled for all time, even though --- we might be able to allocate them a hardreg in different parts of the code. --- --- As we're aggressively coalescing before register allocation proper we're not currently --- using the coalescence information present in the graph. --- -- The function that choosing the potential spills could be a bit cleverer. --- -- Colors in graphviz graphs could be nicer. -- - -{-# OPTIONS_GHC -w #-} --- The above warning supression flag is a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings --- for details +{-# OPTIONS -fno-warn-missing-signatures #-} module RegAllocColor ( regAlloc, @@ -31,7 +17,9 @@ import qualified GraphColor as Color import RegLiveness import RegSpill import RegSpillClean +import RegSpillCost import RegAllocStats +-- import RegCoalesce import MachRegs import MachInstrs import PprMach @@ -41,6 +29,7 @@ import UniqSet import UniqFM import Bag import Outputable +import DynFlags import Data.List import Data.Maybe @@ -57,7 +46,7 @@ maxSpinCount = 10 -- | The top level of the graph coloring register allocator. -- regAlloc - :: Bool -- ^ whether to generate RegAllocStats, or not. + :: DynFlags -> UniqFM (UniqSet Reg) -- ^ the registers we can use for allocation -> UniqSet Int -- ^ the set of available spill slots. -> [LiveCmmTop] -- ^ code annotated with liveness information. @@ -65,16 +54,24 @@ regAlloc ( [NatCmmTop] -- ^ code with registers allocated. , [RegAllocStats] ) -- ^ stats for each stage of allocation -regAlloc dump regsFree slotsFree code +regAlloc dflags regsFree slotsFree code = do - (code_final, debug_codeGraphs, graph_final) - <- regAlloc_spin dump 0 trivColorable regsFree slotsFree [] code + (code_final, debug_codeGraphs, _) + <- regAlloc_spin dflags 0 trivColorable regsFree slotsFree [] code return ( code_final , reverse debug_codeGraphs ) -regAlloc_spin dump (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs code +regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs code = do + -- if any of these dump flags are turned on we want to hang on to + -- intermediate structures in the allocator - otherwise tell the + -- allocator to ditch them early so we don't end up creating space leaks. + let dump = or + [ dopt Opt_D_dump_asm_regalloc_stages dflags + , dopt Opt_D_dump_asm_stats dflags + , dopt Opt_D_dump_asm_conflicts dflags ] + -- check that we're not running off down the garden path. when (spinCount > maxSpinCount) $ pprPanic "regAlloc_spin: max build/spill cycle count exceeded." @@ -84,13 +81,36 @@ regAlloc_spin dump (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs c $ uniqSetToList $ unionManyUniqSets $ eltsUFM regsFree) $$ text "slotsFree = " <> ppr (sizeUniqSet slotsFree)) + + -- Brig's algorithm does reckless coalescing for all but the first allocation stage + -- Doing this seems to reduce the number of reg-reg moves, but at the cost- + -- of creating more spills. Probably better just to stick with conservative + -- coalescing in Color.colorGraph for now. + -- + {- code_coalesced1 <- if (spinCount > 0) + then regCoalesce code + else return code -} + + let code_coalesced1 = code + -- build a conflict graph from the code. - graph <- buildGraph code + graph <- {-# SCC "BuildGraph" #-} buildGraph code_coalesced1 + + -- VERY IMPORTANT: + -- We really do want the graph to be fully evaluated _before_ we start coloring. + -- If we don't do this now then when the call to Color.colorGraph forces bits of it, + -- the heap will be filled with half evaluated pieces of graph and zillions of apply thunks. + -- + seqGraph graph `seq` return () - -- build a map of how many instructions each reg lives for. - -- this is lazy, it won't be computed unless we need to spill - let fmLife = plusUFMs_C (\(r1, l1) (r2, l2) -> (r1, l1 + l2)) - $ map lifetimeCount code + + -- build a map of the cost of spilling each instruction + -- this will only actually be computed if we have to spill something. + let spillCosts = foldl' plusSpillCostInfo zeroSpillCostInfo + $ map slurpSpillCostInfo code_coalesced1 + + -- the function to choose regs to leave uncolored + let spill = chooseSpill spillCosts -- record startup state let stat1 = @@ -98,30 +118,37 @@ regAlloc_spin dump (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs c then Just $ RegAllocStatsStart { raLiveCmm = code , raGraph = graph - , raLifetimes = fmLife } + , raSpillCosts = spillCosts } else Nothing - - - -- the function to choose regs to leave uncolored - let spill = chooseSpill_maxLife fmLife -- try and color the graph - let (graph_colored, rsSpill) - = Color.colorGraph regsFree triv spill graph + let (graph_colored, rsSpill, rmCoalesce) + = {-# SCC "ColorGraph" #-} + Color.colorGraph + (dopt Opt_RegsIterative dflags) + regsFree triv spill graph + + -- rewrite regs in the code that have been coalesced + let patchF reg = case lookupUFM rmCoalesce reg of + Just reg' -> patchF reg' + Nothing -> reg + let code_coalesced2 + = map (patchEraseLive patchF) code_coalesced1 + -- see if we've found a coloring if isEmptyUniqSet rsSpill then do -- patch the registers using the info in the graph - let code_patched = map (patchRegsFromGraph graph_colored) code + let code_patched = map (patchRegsFromGraph graph_colored) code_coalesced2 -- clean out unneeded SPILL/RELOADs let code_spillclean = map cleanSpills code_patched -- strip off liveness information - let code_nat = map stripLive code_patched + let code_nat = map stripLive code_spillclean - -- rewrite SPILL/REALOAD pseudos into real instructions + -- rewrite SPILL/RELOAD pseudos into real instructions let spillNatTop = mapGenBlockTop spillNatBlock let code_final = map spillNatTop code_nat @@ -129,22 +156,30 @@ regAlloc_spin dump (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs c let stat = RegAllocStatsColored { raGraph = graph_colored + , raCoalesced = rmCoalesce , raPatched = code_patched , raSpillClean = code_spillclean , raFinal = code_final - , raSRMs = foldl addSRM (0, 0, 0) $ map countSRMs code_spillclean } + , raSRMs = foldl' addSRM (0, 0, 0) $ map countSRMs code_spillclean } - return ( code_final - , if dump - then [stat] ++ maybeToList stat1 ++ debug_codeGraphs + + let statList = + if dump then [stat] ++ maybeToList stat1 ++ debug_codeGraphs else [] + + -- space leak avoidance + seqList statList `seq` return () + + return ( code_final + , statList , graph_colored) + -- we couldn't find a coloring, time to spill something else do -- spill the uncolored regs (code_spilled, slotsFree', spillStats) - <- regSpill code slotsFree rsSpill - + <- regSpill code_coalesced2 slotsFree rsSpill + -- recalculate liveness let code_nat = map stripLive code_spilled code_relive <- mapM regLiveness code_nat @@ -153,57 +188,24 @@ regAlloc_spin dump (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs c let stat = RegAllocStatsSpill { raGraph = graph_colored + , raCoalesced = rmCoalesce , raSpillStats = spillStats - , raLifetimes = fmLife + , raSpillCosts = spillCosts , raSpilled = code_spilled } - -- try again - regAlloc_spin dump (spinCount + 1) triv regsFree slotsFree' - (if dump + let statList = + if dump then [stat] ++ maybeToList stat1 ++ debug_codeGraphs - else []) - code_relive + else [] - ------ --- Simple maxconflicts isn't always good, because we --- can naievely end up spilling vregs that only live for one or two instrs. --- -{- -chooseSpill_maxConflicts - :: Color.Graph Reg RegClass Reg - -> Reg - -chooseSpill_maxConflicts graph - = let node = maximumBy - (\n1 n2 -> compare - (sizeUniqSet $ Color.nodeConflicts n1) - (sizeUniqSet $ Color.nodeConflicts n2)) - $ eltsUFM $ Color.graphMap graph - - in Color.nodeId node --} - ------ -chooseSpill_maxLife - :: UniqFM (Reg, Int) - -> Color.Graph Reg RegClass Reg - -> Reg + -- space leak avoidance + seqList statList `seq` return () -chooseSpill_maxLife life graph - = let node = maximumBy (\n1 n2 -> compare (getLife n1) (getLife n2)) - $ eltsUFM $ Color.graphMap graph + regAlloc_spin dflags (spinCount + 1) triv regsFree slotsFree' + statList + code_relive - -- Orphan vregs die in the same instruction they are born in. - -- They will be in the graph, but not in the liveness map. - -- Their liveness is 0. - getLife n - = case lookupUFM life (Color.nodeId n) of - Just (_, l) -> l - Nothing -> 0 - in Color.nodeId node - -- | Build a graph from the liveness and coalesce information in this code. @@ -217,13 +219,15 @@ buildGraph code let (conflictList, moveList) = unzip $ map slurpConflicts code - let conflictBag = unionManyBags conflictList - let moveBag = unionManyBags moveList + -- Slurp out the spill/reload coalesces + let moveList2 = map slurpReloadCoalesce code -- Add the reg-reg conflicts to the graph + let conflictBag = unionManyBags conflictList let graph_conflict = foldrBag graphAddConflictSet Color.initGraph conflictBag -- Add the coalescences edges to the graph. + let moveBag = unionBags (unionManyBags moveList2) (unionManyBags moveList) let graph_coalesce = foldrBag graphAddCoalesce graph_conflict moveBag return graph_coalesce @@ -260,10 +264,10 @@ graphAddCoalesce -> Color.Graph Reg RegClass Reg graphAddCoalesce (r1, r2) graph - | RealReg regno <- r1 + | RealReg _ <- r1 = Color.addPreference (regWithClass r2) r1 graph - | RealReg regno <- r2 + | RealReg _ <- r2 = Color.addPreference (regWithClass r1) r2 graph | otherwise @@ -296,12 +300,65 @@ patchRegsFromGraph graph code = pprPanic "patchRegsFromGraph: register mapping failed." ( text "There is no node in the graph for register " <> ppr reg $$ ppr code - $$ Color.dotGraph (\x -> text "white") trivColorable graph) - + $$ Color.dotGraph (\_ -> text "white") trivColorable graph) + in patchEraseLive patchF code -plusUFMs_C :: (elt -> elt -> elt) -> [UniqFM elt] -> UniqFM elt -plusUFMs_C f maps - = foldl (plusUFM_C f) emptyUFM maps - +----- +-- for when laziness just isn't what you wanted... +-- +seqGraph :: Color.Graph Reg RegClass Reg -> () +seqGraph graph = seqNodes (eltsUFM (Color.graphMap graph)) + +seqNodes :: [Color.Node Reg RegClass Reg] -> () +seqNodes ns + = case ns of + [] -> () + (n : ns) -> seqNode n `seq` seqNodes ns + +seqNode :: Color.Node Reg RegClass Reg -> () +seqNode node + = seqReg (Color.nodeId node) + `seq` seqRegClass (Color.nodeClass node) + `seq` seqMaybeReg (Color.nodeColor node) + `seq` (seqRegList (uniqSetToList (Color.nodeConflicts node))) + `seq` (seqRegList (uniqSetToList (Color.nodeExclusions node))) + `seq` (seqRegList (Color.nodePreference node)) + `seq` (seqRegList (uniqSetToList (Color.nodeCoalesce node))) + +seqReg :: Reg -> () +seqReg reg + = case reg of + RealReg _ -> () + VirtualRegI _ -> () + VirtualRegHi _ -> () + VirtualRegF _ -> () + VirtualRegD _ -> () + +seqRegClass :: RegClass -> () +seqRegClass c + = case c of + RcInteger -> () + RcFloat -> () + RcDouble -> () + +seqMaybeReg :: Maybe Reg -> () +seqMaybeReg mr + = case mr of + Nothing -> () + Just r -> seqReg r + +seqRegList :: [Reg] -> () +seqRegList rs + = case rs of + [] -> () + (r : rs) -> seqReg r `seq` seqRegList rs + +seqList :: [a] -> () +seqList ls + = case ls of + [] -> () + (r : rs) -> r `seq` seqList rs + +