X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmProcPointZ.hs;h=13f6421d08b1701b468ce1ef7453be8fe273bd51;hb=f4b727487a65e6b611bbaafbd2207bd63a8df706;hp=b477f4c2336071341fe51b4835df5639ad0da982;hpb=d436c70d43fb905c63220040168295e473f4b90a;p=ghc-hetmet.git

diff --git a/compiler/cmm/CmmProcPointZ.hs b/compiler/cmm/CmmProcPointZ.hs
index b477f4c..13f6421 100644
--- a/compiler/cmm/CmmProcPointZ.hs
+++ b/compiler/cmm/CmmProcPointZ.hs
@@ -11,19 +11,17 @@ import BlockId
 import CLabel
 import Cmm hiding (blockId)
 import CmmContFlowOpt
-import CmmExpr
 import CmmInfo
 import CmmLiveZ
 import CmmTx
 import DFMonad
 import FiniteMap
-import List (sortBy)
+import Data.List (sortBy)
 import Maybes
 import MkZipCfg
 import MkZipCfgCmm hiding (CmmBlock, CmmGraph, CmmTopZ)
-import Monad
+import Control.Monad
 import Outputable
-import Panic
 import UniqSet
 import UniqSupply
 import ZipCfg
@@ -129,18 +127,21 @@ forward = ForwardTransfers first middle last exit
 -- 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 :: ProcPointSet -> CmmGraph -> FuelMonad ProcPointSet
+-- Given the set of successors of calls (which must be proc-points)
+-- figure ou the minimal set of necessary proc-points
 minimalProcPointSet callProcPoints g = extendPPSet g (postorder_dfs g) callProcPoints
 
 type PPFix = FuelMonad (ForwardFixedPoint Middle Last Status ())
 
 procPointAnalysis :: ProcPointSet -> CmmGraph -> FuelMonad (BlockEnv Status)
+-- Once you know what the proc-points are, figure out
+-- what proc-points each block is reachable from
 procPointAnalysis procPoints g =
   let addPP env id = extendBlockEnv env id ProcPoint
       initProcPoints = foldl addPP emptyBlockEnv (blockSetToList procPoints)