Big collection of patches for the new codegen branch.

[ghc-hetmet.git] / compiler / cmm / CmmLiveZ.hs

diff --git a/compiler/cmm/CmmLiveZ.hs b/compiler/cmm/CmmLiveZ.hs
index b239ae3..7bafc91 100644 (file)
--- a/compiler/cmm/CmmLiveZ.hs
+++ b/compiler/cmm/CmmLiveZ.hs
@@ -3,7 +3,7 @@ module CmmLiveZ
     ( CmmLive
     , cmmLivenessZ
     , liveLattice
-    , middleLiveness, lastLiveness
+    , middleLiveness, lastLiveness, noLiveOnEntry
     ) 
 where
 
@@ -19,6 +19,7 @@ import ZipDataflow
 import ZipCfgCmmRep
 
 import Maybes
+import Outputable
 import UniqSet
 
 -----------------------------------------------------------------------------
@@ -30,7 +31,7 @@ type CmmLive = RegSet
 
 -- | The dataflow lattice
 liveLattice :: DataflowLattice CmmLive
-liveLattice = DataflowLattice "live LocalReg's" emptyUniqSet add False
+liveLattice = DataflowLattice "live LocalReg's" emptyUniqSet add True
     where add new old =
             let join = unionUniqSets new old in
             (if sizeUniqSet join > sizeUniqSet old then aTx else noTx) join
@@ -42,13 +43,22 @@ type BlockEntryLiveness = BlockEnv CmmLive
 -- | Calculated liveness info for a CmmGraph
 -----------------------------------------------------------------------------
 cmmLivenessZ :: CmmGraph -> FuelMonad BlockEntryLiveness
-cmmLivenessZ g = liftM zdfFpFacts $ (res :: FuelMonad (CmmBackwardFixedPoint CmmLive))
+cmmLivenessZ g@(LGraph entry _ _) =
+  liftM (check . zdfFpFacts) (res :: FuelMonad (CmmBackwardFixedPoint CmmLive))
   where res = zdfSolveFrom emptyBlockEnv "liveness analysis" liveLattice transfers
                            emptyUniqSet (graphOfLGraph g)
         transfers = BackwardTransfers first middle last
         first live _ = live
         middle       = flip middleLiveness
         last         = flip lastLiveness
+        check facts  =
+          noLiveOnEntry entry (expectJust "check" $ lookupBlockEnv facts entry) facts
+
+-- | 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.
@@ -56,20 +66,18 @@ gen, kill :: UserOfLocalRegs a => a -> RegSet -> RegSet
 gen  a live = foldRegsUsed extendRegSet      live a
 kill a live = foldRegsUsed delOneFromUniqSet live a
 
+-- Why aren't these function using the typeclasses on Middle and Last?
 middleLiveness :: Middle -> CmmLive -> CmmLive
-middleLiveness m = middle m
-  where 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 (MidAddToContext ra args)     = gen ra . gen args
+middleLiveness (MidComment {})            live = live
+middleLiveness (MidAssign lhs expr)       live = gen expr $ kill lhs live
+middleLiveness (MidStore addr rval)       live = gen addr $ gen rval live
+middleLiveness (MidForeignCall _ tgt _ args) _ = gen tgt $ gen args emptyUniqSet
 
 lastLiveness :: Last -> (BlockId -> CmmLive) -> CmmLive
 lastLiveness l env = last l
-  where last (LastReturn _)            = emptyUniqSet
-        last (LastJump e _)            = gen e $ emptyUniqSet
-        last (LastBranch id)           = 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)
+  where last (LastBranch id)             = env id
+        last (LastCall tgt Nothing  _ _) = gen tgt $ emptyUniqSet
+        last (LastCall tgt (Just k) _ _) = gen tgt $ env k
+        last (LastCondBranch e t f)      = gen e $ unionUniqSets (env t) (env f)
+        last (LastSwitch e tbl)          =
+          gen e $ unionManyUniqSets $ map env (catMaybes tbl)