-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
module CmmProcPointZ
- ( minimalProcPointSet
- , addProcPointProtocols
+ ( ProcPointSet, Status(..)
+ , callProcPoints, minimalProcPointSet
+ , addProcPointProtocols, splitAtProcPoints, procPointAnalysis
)
where
-import Prelude hiding (zip, unzip)
+import Prelude hiding (zip, unzip, last)
-import ClosureInfo
+import BlockId
+import CLabel
import Cmm hiding (blockId)
-import CmmExpr
import CmmContFlowOpt
+import CmmExpr
+import CmmInfo
import CmmLiveZ
import CmmTx
import DFMonad
-import ForeignCall -- used in protocol for the entry point
-import MachOp (MachHint(NoHint))
+import FiniteMap
+import List (sortBy)
import Maybes
+import MkZipCfg
+import MkZipCfgCmm hiding (CmmBlock, CmmGraph, CmmTopZ)
+import Monad
import Outputable
import Panic
-import UniqFM
import UniqSet
+import UniqSupply
import ZipCfg
import ZipCfgCmmRep
import ZipDataflow
You might think then that a criterion to make a node a proc point is
that it is directly reached by two distinct proc points. (Note
-[Direct reachability].) But this criterion is a bit two simple; for
+[Direct reachability].) But this criterion is a bit too simple; for
example, 'return x' is also reached by two proc points, yet there is
no point in pulling it out of k_join. A good criterion would be to
say that a node should be made a proc point if it is reached by a set
instance Outputable Status where
ppr (ReachedBy ps)
- | isEmptyUniqSet ps = text "<not-reached>"
+ | isEmptyBlockSet ps = text "<not-reached>"
| otherwise = text "reached by" <+>
- (hsep $ punctuate comma $ map ppr $ uniqSetToList ps)
+ (hsep $ punctuate comma $ map ppr $ blockSetToList ps)
ppr ProcPoint = text "<procpt>"
add_to _ ProcPoint = noTx ProcPoint
add_to ProcPoint _ = aTx ProcPoint -- aTx because of previous case again
add_to (ReachedBy p) (ReachedBy p') =
- let union = unionUniqSets p p'
- in if sizeUniqSet union > sizeUniqSet p' then
+ let union = unionBlockSets p p'
+ in if sizeBlockSet union > sizeBlockSet p' then
aTx (ReachedBy union)
else
noTx (ReachedBy p')
--------------------------------------------------
-- transfer equations
-forward :: FAnalysis Middle Last Status
-forward = FComp "proc-point reachability" first middle last exit
- where first ProcPoint id = ReachedBy $ unitUniqSet id
- first x _ = x
- middle x _ = x
- last _ (LastCall _ _ (Just id)) = LastOutFacts [(id, ProcPoint)]
- last x l = LastOutFacts $ map (\id -> (id, x)) (succs l)
- exit _ = LastOutFacts []
+forward :: ForwardTransfers Middle Last Status
+forward = ForwardTransfers first middle last exit
+ where first id ProcPoint = ReachedBy $ unitBlockSet id
+ first _ x = x
+ middle _ x = x
+ last (LastCall _ (Just id) _ _ _) _ = LastOutFacts [(id, ProcPoint)]
+ last l x = LastOutFacts $ map (\id -> (id, x)) (succs l)
+ exit x = x
-minimalProcPointSet :: CmmGraph -> ProcPointSet
-minimalProcPointSet g = extendPPSet g (postorder_dfs g) entryPoint
- where entryPoint = unitUniqSet (gr_entry g)
-
-extendPPSet :: CmmGraph -> [CmmBlock] -> ProcPointSet -> ProcPointSet
+-- It is worth distinguishing two sets of proc points:
+-- those that are induced by calls in the original graph
+-- and those that are introduced because they're reachable from multiple proc points.
+callProcPoints :: CmmGraph -> ProcPointSet
+minimalProcPointSet :: ProcPointSet -> CmmGraph -> FuelMonad ProcPointSet
+
+callProcPoints g = fold_blocks add (unitBlockSet (lg_entry g)) g
+ where add b set = case last $ unzip b of
+ LastOther (LastCall _ (Just k) _ _ _) -> extendBlockSet set k
+ _ -> set
+
+minimalProcPointSet callProcPoints g = extendPPSet g (postorder_dfs g) callProcPoints
+
+type PPFix = FuelMonad (ForwardFixedPoint Middle Last Status ())
+
+procPointAnalysis :: ProcPointSet -> CmmGraph -> FuelMonad (BlockEnv Status)
+procPointAnalysis procPoints g =
+ let addPP env id = extendBlockEnv env id ProcPoint
+ initProcPoints = foldl addPP emptyBlockEnv (blockSetToList procPoints)
+ in liftM zdfFpFacts $
+ (zdfSolveFrom initProcPoints "proc-point reachability" lattice
+ forward (fact_bot lattice) $ graphOfLGraph g :: PPFix)
+
+extendPPSet :: CmmGraph -> [CmmBlock] -> ProcPointSet -> FuelMonad ProcPointSet
extendPPSet g blocks procPoints =
- case newPoint of Just id ->
- if elemBlockSet id procPoints' then panic "added old proc pt"
- else extendPPSet g blocks (extendBlockSet procPoints' id)
- Nothing -> procPoints'
- where env = runDFA lattice $
- do refine_f_anal forward g set_init_points
- allFacts
- set_init_points = mapM_ (\id -> setFact id ProcPoint)
- (uniqSetToList procPoints)
- procPoints' = fold_blocks add emptyBlockSet g
- add block pps = let id = blockId block
- in case lookupBlockEnv env id of
- Just ProcPoint -> extendBlockSet pps id
- _ -> pps
-
- newPoint = listToMaybe (mapMaybe ppSuccessor blocks)
- ppSuccessor b@(Block id _) =
- let nreached id = case lookupBlockEnv env id `orElse` panic "no ppt" of
- ProcPoint -> 1
- ReachedBy ps -> sizeUniqSet ps
- my_nreached = nreached id
- -- | Looking for a successor of b that is reached by
- -- more proc points than b and is not already a proc
- -- point. If found, it can become a proc point.
- newId succ_id = not (elemBlockSet succ_id procPoints') &&
- nreached succ_id > my_nreached
- in listToMaybe $ filter newId $ succs b
-
+ do env <- procPointAnalysis procPoints g
+ let add block pps = let id = blockId block
+ in case lookupBlockEnv env id of
+ Just ProcPoint -> extendBlockSet pps id
+ _ -> pps
+ procPoints' = fold_blocks add emptyBlockSet g
+ newPoints = mapMaybe ppSuccessor blocks
+ newPoint = listToMaybe newPoints
+ ppSuccessor b@(Block bid _) =
+ let nreached id = case lookupBlockEnv env id `orElse`
+ pprPanic "no ppt" (ppr id <+> ppr b) of
+ ProcPoint -> 1
+ ReachedBy ps -> sizeBlockSet ps
+ block_procpoints = nreached bid
+ -- | Looking for a successor of b that is reached by
+ -- more proc points than b and is not already a proc
+ -- point. If found, it can become a proc point.
+ newId succ_id = not (elemBlockSet succ_id procPoints') &&
+ nreached succ_id > block_procpoints
+ in listToMaybe $ filter newId $ succs b
+{-
+ case newPoints of
+ [] -> return procPoints'
+ pps -> extendPPSet g blocks
+ (foldl extendBlockSet procPoints' pps)
+-}
+ case newPoint of Just id ->
+ if elemBlockSet id procPoints' then panic "added old proc pt"
+ else extendPPSet g blocks (extendBlockSet procPoints' id)
+ Nothing -> return procPoints'
+
------------------------------------------------------------------------
-- Computing Proc-Point Protocols --
-}
-data Protocol = Protocol Convention CmmFormals
+data Protocol = Protocol Convention CmmFormals Area
deriving Eq
+instance Outputable Protocol where
+ ppr (Protocol c fs a) = text "Protocol" <+> ppr c <+> ppr fs <+> ppr a
-- | Function 'optimize_calls' chooses protocols only for those proc
-- points that are relevant to the optimization explained above.
-- The others are assigned by 'add_unassigned', which is not yet clever.
-addProcPointProtocols :: ProcPointSet -> CmmFormalsWithoutKinds -> CmmGraph -> CmmGraph
-addProcPointProtocols procPoints formals g =
- snd $ add_unassigned procPoints $ optimize_calls g
- where optimize_calls g = -- see Note [Separate Adams optimization]
- let (protos, blocks') =
- fold_blocks maybe_add_call (init_protocols, emptyBlockEnv) g
- g' = LGraph (gr_entry g) (add_CopyIns protos blocks')
- in (protos, runTx removeUnreachableBlocksZ g')
+addProcPointProtocols :: ProcPointSet -> ProcPointSet -> CmmGraph -> FuelMonad CmmGraph
+addProcPointProtocols callPPs procPoints g =
+ do liveness <- cmmLivenessZ g
+ (protos, g') <- optimize_calls liveness g
+ blocks'' <- add_CopyOuts protos procPoints g'
+ return $ LGraph (lg_entry g) blocks''
+ where optimize_calls liveness g = -- see Note [Separate Adams optimization]
+ do let (protos, blocks') =
+ fold_blocks maybe_add_call (init_protocols, emptyBlockEnv) g
+ protos' = add_unassigned liveness procPoints protos
+ blocks <- add_CopyIns callPPs protos' blocks'
+ let g' = LGraph (lg_entry g) (mkBlockEnv (map withKey (concat blocks)))
+ withKey b@(Block bid _) = (bid, b)
+ return (protos', runTx removeUnreachableBlocksZ g')
maybe_add_call :: CmmBlock -> (BlockEnv Protocol, BlockEnv CmmBlock)
-> (BlockEnv Protocol, BlockEnv CmmBlock)
-- ^ If the block is a call whose continuation goes to a proc point
-- redirect the call (cf 'newblock') and set the protocol if necessary
maybe_add_call block (protos, blocks) =
case goto_end $ unzip block of
- (h, LastOther (LastCall tgt args (Just k)))
+ (h, LastOther (LastCall tgt (Just k) args res s))
| Just proto <- lookupBlockEnv protos k,
- Just pee <- jumpsToProcPoint k
- -> let newblock =
- zipht h (tailOfLast (LastCall tgt args (Just pee)))
+ Just pee <- branchesToProcPoint k
+ -> let newblock = zipht h (tailOfLast (LastCall tgt (Just pee)
+ args res s))
changed_blocks = insertBlock newblock blocks
unchanged_blocks = insertBlock block blocks
in case lookupBlockEnv protos pee of
else (protos, unchanged_blocks)
_ -> (protos, insertBlock block blocks)
- jumpsToProcPoint :: BlockId -> Maybe BlockId
- -- ^ Tells whether the named block is just a jump to a proc point
- jumpsToProcPoint id =
- let (Block _ t) = lookupBlockEnv (gr_blocks g) id `orElse`
- panic "jump out of graph"
+ branchesToProcPoint :: BlockId -> Maybe BlockId
+ -- ^ Tells whether the named block is just a branch to a proc point
+ branchesToProcPoint id =
+ let (Block _ t) = lookupBlockEnv (lg_blocks g) id `orElse`
+ panic "branch out of graph"
in case t of
- ZTail (CopyIn {}) (ZLast (LastOther (LastBranch pee [])))
+ ZLast (LastOther (LastBranch pee))
| elemBlockSet pee procPoints -> Just pee
_ -> Nothing
init_protocols = fold_blocks maybe_add_proto emptyBlockEnv g
maybe_add_proto :: CmmBlock -> BlockEnv Protocol -> BlockEnv Protocol
- maybe_add_proto (Block id (ZTail (CopyIn c fs _srt) _)) env =
- extendBlockEnv env id (Protocol c fs)
- maybe_add_proto (Block id _) env | id == gr_entry g =
- extendBlockEnv env id (Protocol (Argument CmmCallConv) hinted_formals)
+ --maybe_add_proto (Block id (ZTail (CopyIn c _ fs _srt) _)) env =
+ -- extendBlockEnv env id (Protocol c fs $ toArea id fs)
maybe_add_proto _ env = env
- hinted_formals = map (\x -> (x, NoHint)) formals
+ -- JD: Is this proto stuff even necessary, now that we have
+ -- common blockification?
-- | For now, following a suggestion by Ben Lippmeier, we pass all
-- live variables as arguments, hoping that a clever register
-- allocator might help.
-add_unassigned
- :: ProcPointSet -> (BlockEnv Protocol, CmmGraph) -> (BlockEnv Protocol, CmmGraph)
+add_unassigned :: BlockEnv CmmLive -> ProcPointSet -> BlockEnv Protocol ->
+ BlockEnv Protocol
add_unassigned = pass_live_vars_as_args
-pass_live_vars_as_args
- :: ProcPointSet -> (BlockEnv Protocol, CmmGraph) -> (BlockEnv Protocol, CmmGraph)
-pass_live_vars_as_args procPoints (protos, g) = (protos', g')
- where liveness = cmmLivenessZ g
- protos' = foldUniqSet addLiveVars protos procPoints
+pass_live_vars_as_args :: BlockEnv CmmLive -> ProcPointSet ->
+ BlockEnv Protocol -> BlockEnv Protocol
+pass_live_vars_as_args _liveness procPoints protos = protos'
+ where protos' = foldBlockSet addLiveVars protos procPoints
addLiveVars :: BlockId -> BlockEnv Protocol -> BlockEnv Protocol
addLiveVars id protos =
case lookupBlockEnv protos id of
- Just _ -> protos
- Nothing -> let live = lookupBlockEnv liveness id `orElse`
- emptyRegSet -- XXX there's a bug lurking!
- -- panic ("no liveness at block " ++ show id)
- formals = map (\x->(x,NoHint)) $ uniqSetToList live
- in extendBlockEnv protos id (Protocol Local formals)
- g' = g { gr_blocks = add_CopyIns protos' (gr_blocks g) }
-
-
--- | Add a CopyIn node to each block that has a protocol but lacks the
--- appropriate CopyIn node.
-
-add_CopyIns :: BlockEnv Protocol -> BlockEnv CmmBlock -> BlockEnv CmmBlock
-add_CopyIns protos = mapUFM (maybe_insert_CopyIn protos)
- where maybe_insert_CopyIn :: BlockEnv Protocol -> CmmBlock -> CmmBlock
- maybe_insert_CopyIn protos b@(Block id t) =
- case lookupBlockEnv protos id of
- Nothing -> b
- Just (Protocol c fs) ->
- case t of
- ZTail (CopyIn c' fs' _) _ ->
- if c == c' && fs == fs' then b
- else panic ("mismatched protocols for block " ++ show id)
- _ -> Block id (ZTail (CopyIn c fs NoC_SRT) t)
-
--- XXX also need to add the relevant CopyOut nodes!!!
+ Just _ -> protos
+ Nothing -> let live = emptyRegSet
+ --lookupBlockEnv _liveness id `orElse`
+ --panic ("no liveness at block " ++ show id)
+ formals = uniqSetToList live
+ prot = Protocol Private formals $ CallArea $ Young id
+ in extendBlockEnv protos id prot
+
+
+-- | Add copy-in instructions to each proc point that did not arise from a call
+-- instruction. (Proc-points that arise from calls already have their copy-in instructions.)
+
+add_CopyIns :: ProcPointSet -> BlockEnv Protocol -> BlockEnv CmmBlock ->
+ FuelMonad [[CmmBlock]]
+add_CopyIns callPPs protos blocks =
+ liftUniq $ mapM maybe_insert_CopyIns (blockEnvToList blocks)
+ where maybe_insert_CopyIns (_, b@(Block id t))
+ | not $ elemBlockSet id callPPs
+ = case lookupBlockEnv protos id of
+ Just (Protocol c fs _area) ->
+ do LGraph _ blocks <-
+ lgraphOfAGraph (mkLabel id <*> copyInSlot c fs <*> mkZTail t)
+ return (map snd $ blockEnvToList blocks)
+ Nothing -> return [b]
+ | otherwise = return [b]
+
+-- | Add a CopyOut node before each procpoint.
+-- If the predecessor is a call, then the copy outs should already be done by the callee.
+-- Note: If we need to add copy-out instructions, they may require stack space,
+-- so we accumulate a map from the successors to the necessary stack space,
+-- then update the successors after we have finished inserting the copy-outs.
+
+add_CopyOuts :: BlockEnv Protocol -> ProcPointSet -> CmmGraph ->
+ FuelMonad (BlockEnv CmmBlock)
+add_CopyOuts protos procPoints g = fold_blocks mb_copy_out (return emptyBlockEnv) g
+ where mb_copy_out :: CmmBlock -> FuelMonad (BlockEnv CmmBlock) ->
+ FuelMonad (BlockEnv CmmBlock)
+ mb_copy_out b@(Block bid _) z | bid == lg_entry g = skip b z
+ mb_copy_out b z =
+ case last $ unzip b of
+ LastOther (LastCall _ _ _ _ _) -> skip b z -- copy out done by callee
+ _ -> copy_out b z
+ copy_out b z = fold_succs trySucc b init >>= finish
+ where init = z >>= (\bmap -> return (b, bmap))
+ trySucc succId z =
+ if elemBlockSet succId procPoints then
+ case lookupBlockEnv protos succId of
+ Nothing -> z
+ Just (Protocol c fs _area) -> insert z succId $ copyOutSlot c fs
+ else z
+ insert z succId m =
+ do (b, bmap) <- z
+ (b, bs) <- insertBetween b m succId
+ -- pprTrace "insert for succ" (ppr succId <> ppr m) $ do
+ return $ (b, foldl (flip insertBlock) bmap bs)
+ finish (b@(Block bid _), bmap) =
+ return $ (extendBlockEnv bmap bid b)
+ skip b@(Block bid _) bs =
+ bs >>= (\bmap -> return (extendBlockEnv bmap bid b))
+
+-- At this point, we have found a set of procpoints, each of which should be
+-- the entry point of a procedure.
+-- Now, we create the procedure for each proc point,
+-- which requires that we:
+-- 1. build a map from proc points to the blocks reachable from the proc point
+-- 2. turn each branch to a proc point into a jump
+-- 3. turn calls and returns into jumps
+-- 4. build info tables for the procedures -- and update the info table for
+-- the SRTs in the entry procedure as well.
+-- Input invariant: A block should only be reachable from a single ProcPoint.
+splitAtProcPoints :: CLabel -> ProcPointSet-> ProcPointSet -> BlockEnv Status ->
+ CmmTopZ -> FuelMonad [CmmTopZ]
+splitAtProcPoints entry_label callPPs procPoints procMap
+ (CmmProc (CmmInfo gc upd_fr info_tbl) top_l top_args
+ (stackInfo, g@(LGraph entry blocks))) =
+ do -- Build a map from procpoints to the blocks they reach
+ let addBlock b@(Block bid _) graphEnv =
+ case lookupBlockEnv procMap bid of
+ Just ProcPoint -> add graphEnv bid bid b
+ Just (ReachedBy set) ->
+ case blockSetToList set of
+ [] -> graphEnv
+ [id] -> add graphEnv id bid b
+ _ -> panic "Each block should be reachable from only one ProcPoint"
+ Nothing -> pprPanic "block not reached by a proc point?" (ppr bid)
+ add graphEnv procId bid b = extendBlockEnv graphEnv procId graph'
+ where graph = lookupBlockEnv graphEnv procId `orElse` emptyBlockEnv
+ graph' = extendBlockEnv graph bid b
+ graphEnv <- return $ fold_blocks addBlock emptyBlockEnv g
+ -- Build a map from proc point BlockId to labels for their new procedures
+ -- Due to common blockification, we may overestimate the set of procpoints.
+ let add_label map pp = return $ addToFM map pp lbl
+ where lbl = if pp == entry then entry_label else blockLbl pp
+ procLabels <- foldM add_label emptyFM
+ (filter (elemBlockEnv blocks) (blockSetToList procPoints))
+ -- For each procpoint, we need to know the SP offset on entry.
+ -- If the procpoint is:
+ -- - continuation of a call, the SP offset is in the call
+ -- - otherwise, 0 -- no overflow for passing those variables
+ let add_sp_off b env =
+ case last (unzip b) of
+ LastOther (LastCall {cml_cont = Just succ, cml_ret_args = off,
+ cml_ret_off = updfr_off}) ->
+ extendBlockEnv env succ (off, updfr_off)
+ _ -> env
+ spEntryMap = fold_blocks add_sp_off (mkBlockEnv [(entry, stackInfo)]) g
+ getStackInfo id = lookupBlockEnv spEntryMap id `orElse` (0, Nothing)
+ -- In each new graph, add blocks jumping off to the new procedures,
+ -- and replace branches to procpoints with branches to the jump-off blocks
+ let add_jump_block (env, bs) (pp, l) =
+ do bid <- liftM mkBlockId getUniqueM
+ let b = Block bid (ZLast (LastOther jump))
+ (argSpace, _) = getStackInfo pp
+ jump = LastCall (CmmLit (CmmLabel l')) Nothing argSpace 0 Nothing
+ l' = if elemBlockSet pp callPPs then entryLblToInfoLbl l else l
+ return (extendBlockEnv env pp bid, b : bs)
+ add_jumps (newGraphEnv) (ppId, blockEnv) =
+ do let needed_jumps = -- find which procpoints we currently branch to
+ foldBlockEnv' add_if_branch_to_pp [] blockEnv
+ add_if_branch_to_pp block rst =
+ case last (unzip block) of
+ LastOther (LastBranch id) -> add_if_pp id rst
+ LastOther (LastCondBranch _ ti fi) ->
+ add_if_pp ti (add_if_pp fi rst)
+ LastOther (LastSwitch _ tbl) -> foldr add_if_pp rst (catMaybes tbl)
+ _ -> rst
+ add_if_pp id rst = case lookupFM procLabels id of
+ Just x -> (id, x) : rst
+ Nothing -> rst
+ (jumpEnv, jumpBlocks) <-
+ foldM add_jump_block (emptyBlockEnv, []) needed_jumps
+ -- update the entry block
+ let b = expectJust "block in env" $ lookupBlockEnv blockEnv ppId
+ off = getStackInfo ppId
+ blockEnv' = extendBlockEnv blockEnv ppId b
+ -- replace branches to procpoints with branches to jumps
+ LGraph _ blockEnv'' = replaceBranches jumpEnv $ LGraph ppId blockEnv'
+ -- add the jump blocks to the graph
+ blockEnv''' = foldl (flip insertBlock) blockEnv'' jumpBlocks
+ let g' = (off, LGraph ppId blockEnv''')
+ -- pprTrace "g' pre jumps" (ppr g') $ do
+ return (extendBlockEnv newGraphEnv ppId g')
+ graphEnv <- foldM add_jumps emptyBlockEnv $ blockEnvToList graphEnv
+ let to_proc (bid, g) | elemBlockSet bid callPPs =
+ if bid == entry then
+ CmmProc (CmmInfo gc upd_fr info_tbl) top_l top_args (replacePPIds g)
+ else
+ CmmProc emptyContInfoTable lbl [] (replacePPIds g)
+ where lbl = expectJust "pp label" $ lookupFM procLabels bid
+ to_proc (bid, g) =
+ CmmProc (CmmInfo Nothing Nothing CmmNonInfoTable) lbl [] (replacePPIds g)
+ where lbl = expectJust "pp label" $ lookupFM procLabels bid
+ -- References to procpoint IDs can now be replaced with the infotable's label
+ replacePPIds (x, g) = (x, map_nodes id (mapExpMiddle repl) (mapExpLast repl) g)
+ where repl e@(CmmLit (CmmBlock bid)) =
+ case lookupFM procLabels bid of
+ Just l -> CmmLit (CmmLabel (entryLblToInfoLbl l))
+ Nothing -> e
+ repl e = e
+ -- The C back end expects to see return continuations before the call sites.
+ -- Here, we sort them in reverse order -- it gets reversed later.
+ let (_, block_order) = foldl add_block_num (0::Int, emptyBlockEnv) (postorder_dfs g)
+ add_block_num (i, map) (Block bid _) = (i+1, extendBlockEnv map bid i)
+ sort_fn (bid, _) (bid', _) =
+ compare (expectJust "block_order" $ lookupBlockEnv block_order bid)
+ (expectJust "block_order" $ lookupBlockEnv block_order bid')
+ procs <- return $ map to_proc $ sortBy sort_fn $ blockEnvToList graphEnv
+ return -- pprTrace "procLabels" (ppr procLabels)
+ -- pprTrace "splitting graphs" (ppr procs)
+ procs
+splitAtProcPoints _ _ _ _ t@(CmmData _ _) = return [t]
----------------------------------------------------------------
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