( CmmLive
, cmmLivenessZ
, liveLattice
- , middleLiveness, lastLiveness
+ , middleLiveness, noLiveOnEntry
)
where
-import Cmm
+import BlockId
import CmmExpr
import CmmTx
import DFMonad
-import Maybes
+import Monad
import PprCmm()
import PprCmmZ()
-import UniqSet
+import ZipCfg
import ZipDataflow
import ZipCfgCmmRep
+import Maybes
+import Outputable
+import UniqSet
+
-----------------------------------------------------------------------------
-- Calculating what variables are live on entry to a basic block
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
-- | Calculated liveness info for a CmmGraph
-----------------------------------------------------------------------------
-cmmLivenessZ :: CmmGraph -> BlockEntryLiveness
-cmmLivenessZ g = env
- where env = runDFA liveLattice $
- do run_b_anal transfer g
- allFacts
- transfer = BComp "liveness analysis" exit last middle first
- exit = emptyUniqSet
- first live _ = live
- middle = flip middleLiveness
- last = flip lastLiveness
+cmmLivenessZ :: CmmGraph -> FuelMonad BlockEntryLiveness
+cmmLivenessZ g@(LGraph entry _) =
+ liftM (check . zdfFpFacts) (res :: FuelMonad (CmmBackwardFixedPoint CmmLive))
+ where res = zdfSolveFrom emptyBlockEnv "liveness analysis" liveLattice transfers
+ emptyUniqSet (graphOfLGraph g)
+ transfers = BackwardTransfers (flip const) mid last
+ mid m = gen_kill m . midLive m
+ last l = gen_kill l . lastLive l
+ check facts =
+ noLiveOnEntry entry (expectJust "check" $ lookupBlockEnv facts entry) facts
+
+gen_kill :: (DefinerOfLocalRegs a, UserOfLocalRegs a) => a -> CmmLive -> CmmLive
+gen_kill a = gen a . kill a
+
+middleLiveness :: Middle -> CmmLive -> CmmLive
+middleLiveness = gen_kill
+
+-- | On entry to the procedure, there had better not be any LocalReg's live-in.
+noLiveOnEntry :: BlockId -> CmmLive -> a -> a
+noLiveOnEntry bid in_fact x =
+ if isEmptyUniqSet in_fact then x
+ else pprPanic "LocalReg's live-in to graph" (ppr bid <+> ppr in_fact)
-- | The transfer equations use the traditional 'gen' and 'kill'
-- notations, which should be familiar from the dragon book.
-gen, kill :: UserOfLocalRegs a => a -> RegSet -> RegSet
-gen a live = foldRegsUsed extendRegSet live a
-kill a live = foldRegsUsed delOneFromUniqSet live a
+gen :: UserOfLocalRegs a => a -> RegSet -> RegSet
+gen a live = foldRegsUsed extendRegSet live a
+kill :: DefinerOfLocalRegs a => a -> RegSet -> RegSet
+kill a live = foldRegsDefd delOneFromUniqSet live a
-middleLiveness :: Middle -> CmmLive -> CmmLive
-middleLiveness m = middle m
- where middle (MidNop) = id
- middle (MidComment {}) = id
- middle (MidAssign lhs expr) = gen expr . kill lhs
- middle (MidStore addr rval) = gen addr . gen rval
- middle (MidUnsafeCall tgt ress args) = gen tgt . gen args . kill ress
- middle (CopyIn _ formals _) = kill formals
- middle (CopyOut _ formals) = gen formals
+midLive :: Middle -> CmmLive -> CmmLive
+midLive (MidForeignCall {}) _ = emptyUniqSet
+midLive _ live = live
-lastLiveness :: Last -> (BlockId -> CmmLive) -> CmmLive
-lastLiveness l env = last l
- where last (LastReturn ress) = gen ress emptyUniqSet
- last (LastJump e args) = gen e $ gen args emptyUniqSet
- last (LastBranch id args) = gen args $ env id
- last (LastCall tgt (Just k)) = gen tgt $ env k
- last (LastCall tgt Nothing) = gen tgt $ emptyUniqSet
- last (LastCondBranch e t f) = gen e $ unionUniqSets (env t) (env f)
- last (LastSwitch e tbl) = gen e $ unionManyUniqSets $ map env (catMaybes tbl)
+lastLive :: Last -> (BlockId -> CmmLive) -> CmmLive
+lastLive l env = last l
+ where last (LastBranch id) = env id
+ last (LastCall _ _ _ _ _) = emptyUniqSet
+ last (LastCondBranch _ t f) = unionUniqSets (env t) (env f)
+ last (LastSwitch _ tbl) = unionManyUniqSets $ map env (catMaybes tbl)