-- | 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 -fno-warn-missing-signatures #-}
module RegAllocColor (
regAlloc,
import RegLiveness
import RegSpill
import RegSpillClean
+import RegSpillCost
import RegAllocStats
+-- import RegCoalesce
import MachRegs
import MachInstrs
-import RegCoalesce
import PprMach
import UniqSupply
import UniqFM
import Bag
import Outputable
+import DynFlags
import Data.List
import Data.Maybe
-- | 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.
( [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."
$ 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 =
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
let stat =
RegAllocStatsColored
{ raGraph = graph_colored
+ , raCoalesced = rmCoalesce
, raPatched = code_patched
, raSpillClean = code_spillclean
- , raFinal = code_final }
+ , raFinal = code_final
+ , 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
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.
buildGraph code
= do
- -- Add the reg-reg conflicts to the graph
- let conflictSets = unionManyBags (map slurpConflicts code)
- let graph_conflict = foldrBag graphAddConflictSet Color.initGraph conflictSets
+ -- Slurp out the conflicts and reg->reg moves from this code
+ let (conflictList, moveList) =
+ unzip $ map slurpConflicts code
+
+ -- 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 coalesce = unionManyBags (map slurpJoinMovs code)
- let graph_coalesce = foldrBag graphAddCoalesce graph_conflict coalesce
+ let moveBag = unionBags (unionManyBags moveList2) (unionManyBags moveList)
+ let graph_coalesce = foldrBag graphAddCoalesce graph_conflict moveBag
- return $ graph_coalesce
+ return graph_coalesce
-- | Add some conflict edges to the graph.
-> 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
= 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
+
+
projects / ghc-hetmet.git / blobdiff