Document ZipCfg

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

diff --git a/compiler/cmm/ZipCfg.hs b/compiler/cmm/ZipCfg.hs
index c7aa1ff..78eeaed 100644 (file)
--- a/compiler/cmm/ZipCfg.hs
+++ b/compiler/cmm/ZipCfg.hs
@@ -36,8 +36,9 @@ where
 
 #include "HsVersions.h"
 
+import BlockId ( BlockId, BlockEnv, emptyBlockEnv, lookupBlockEnv, extendBlockEnv
+               , BlockSet, emptyBlockSet, elemBlockSet, extendBlockSet)
 import CmmExpr ( UserOfLocalRegs(..) ) --for an instance
-import StackSlot
 
 import Outputable hiding (empty)
 import Panic
@@ -378,7 +379,7 @@ lastTail :: ZTail m l -> ZLast l
 lastTail (ZLast l) = l
 lastTail (ZTail _ t) = lastTail t
 
-tailOfLast l = ZLast (LastOther l) -- ^ tedious to write in every client
+tailOfLast l = ZLast (LastOther l) -- tedious to write in every client
 
 
 ------------------ simple graph manipulations
@@ -404,7 +405,7 @@ splitp_blocks p blocks = lift $ foldUFM scan (Nothing, emptyBlockEnv) blocks
           lift (Nothing, _) = Nothing
           lift (Just b, bs) = Just (b, bs)
 
--- | 'insertBlock' should not be used to *replace* an existing block
+-- | 'insertBlock' should not be used to /replace/ an existing block
 -- but only to insert a new one
 insertBlock :: Block m l -> BlockEnv (Block m l) -> BlockEnv (Block m l)
 insertBlock b bs =
@@ -442,9 +443,11 @@ single_exitg (Graph tail blocks) = foldUFM add (exit_count (lastTail tail)) bloc
 -- more mathematically elegant (but results in more complicated code).
 --
 -- Here's an easy way to go wrong!  Consider
+-- @
 --     A -> [B,C]
 --     B -> D
 --     C -> D
+-- @
 -- Then ordinary dfs would give [A,B,D,C] which has a back ref from C to D.
 -- Better to geot [A,B,C,D]