X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FZipCfg.hs;h=5681694aeed5fb0e35a631789fd8bbbffa2f51c8;hb=b025092d120eb8799ba0408cf96fb7cacb55db76;hp=bf8d49f963d3ad0efa89fe789669f2fa1f712a7e;hpb=b9bcf6e71abe0d861c99618ee5a7ae9e2c45d26c;p=ghc-hetmet.git

diff --git a/compiler/cmm/ZipCfg.hs b/compiler/cmm/ZipCfg.hs
index bf8d49f..5681694 100644
--- a/compiler/cmm/ZipCfg.hs
+++ b/compiler/cmm/ZipCfg.hs
@@ -1,36 +1,34 @@
-{-# LANGUAGE ScopedTypeVariables #-}
 module ZipCfg
     ( 	-- These data types and names are carefully thought out
-      BlockId(..), freshBlockId		-- ToDo: BlockId should be abstract,
-					--	 but it isn't yet
-    , BlockEnv, emptyBlockEnv, lookupBlockEnv, extendBlockEnv, insertBlock, mkBlockEnv
-    , BlockSet, emptyBlockSet, elemBlockSet, extendBlockSet, mkBlockSet
-    , Graph(..), LGraph(..), FGraph(..)
+      Graph(..), LGraph(..), FGraph(..)
     , Block(..), ZBlock(..), ZHead(..), ZTail(..), ZLast(..)
+    , insertBlock
     , HavingSuccessors, succs, fold_succs
     , LastNode, mkBranchNode, isBranchNode, branchNodeTarget
 
         -- Observers and transformers
 	-- (open to renaming suggestions here)
     , blockId, zip, unzip, last, goto_end, zipht, tailOfLast
-    , remove_entry_label
     , splice_tail, splice_head, splice_head_only', splice_head'
     , of_block_list, to_block_list
-    , map_nodes
+    , graphOfLGraph
+    , map_blocks, map_nodes, mapM_blocks
     , postorder_dfs, postorder_dfs_from, postorder_dfs_from_except
     , fold_layout
-    , fold_blocks
+    , fold_blocks, fold_fwd_block
     , translate
 
     , pprLgraph, pprGraph
 
+    , entry -- exported for the convenience of ZipDataflow0, at least for now
+
     {-
     -- the following functions might one day be useful and can be found
     -- either below or in ZipCfgExtras:
     , entry, exit, focus, focusp, unfocus
     , ht_to_block, ht_to_last, 
     , splice_focus_entry, splice_focus_exit
-    , fold_fwd_block, foldM_fwd_block
+    , foldM_fwd_block
     -}
 
     )
@@ -38,12 +36,14 @@ where
 
 #include "HsVersions.h"
 
+import BlockId ( BlockId, BlockEnv, emptyBlockEnv, lookupBlockEnv, extendBlockEnv
+               , BlockSet, emptyBlockSet, elemBlockSet, extendBlockSet)
+import CmmExpr ( UserOfLocalRegs(..) ) --for an instance
+
 import Outputable hiding (empty)
 import Panic
-import Unique
 import UniqFM
 import UniqSet
-import UniqSupply
 
 import Maybe
 import Prelude hiding (zip, unzip, last)
@@ -77,7 +77,7 @@ the data constructor 'LastExit'.  A graph may contain at most one
 'LastExit' node, and a graph representing a full procedure should not
 contain any 'LastExit' nodes.  'LastExit' nodes are used only to splice
 graphs together, either during graph construction (see module 'MkZipCfg')
-or during optimization (see module 'ZipDataflow').
+or during optimization (see module 'ZipDataflow0').
 
 A graph is parameterized over the types of middle and last nodes.  Each of
 these types will typically be instantiated with a subset of C-- statements
@@ -99,13 +99,13 @@ increasing complexity, they are:
 There are three types because each type offers a slightly different
 invariant or cost model.  
 
-  * The distinguished entry of a Graph has no label.  Because labels must
-    be unique, acquiring one requires a monadic operation ('freshBlockId').
-    The primary advantage of the Graph representation is that we can build
-    a small Graph purely functionally, without entering a monad.  For
-    example, during optimization we can easily rewrite a single middle
-    node into a Graph containing a sequence of two middle nodes followed by
-    LastExit.
+  * The distinguished entry of a Graph has no label.  Because labels must be
+    unique, acquiring one requires a supply of Unique labels (BlockId's).
+    The primary advantage of the Graph representation is that we can build a
+    small Graph purely functionally, without needing a fresh BlockId or
+    Unique.  For example, during optimization we can easily rewrite a single
+    middle node into a Graph containing a sequence of two middle nodes
+    followed by LastExit.
 
   * In an LGraph, every basic block is labelled.  The primary advantage of
     this representation is its simplicity: each basic block can be treated
@@ -142,6 +142,14 @@ data ZLast l
                  -- so we don't want to pollute the 'l' type parameter with it
   | LastOther l
 
+--So that we don't have orphan instances, this goes here or in CmmExpr.
+--At least UserOfLocalRegs (ZLast Last) is needed (Last defined elsewhere),
+--but there's no need for non-Haskell98 instances for that.
+instance UserOfLocalRegs a => UserOfLocalRegs (ZLast a) where
+    foldRegsUsed  f z (LastOther l) = foldRegsUsed f z l
+    foldRegsUsed _f z LastExit      = z
+
+
 data ZHead m   = ZFirst BlockId  | ZHead (ZHead m) m
     -- ZHead is a (reversed) sequence of middle nodes labeled by a BlockId
 data ZTail m l = ZLast (ZLast l) | ZTail m (ZTail m l)
@@ -167,11 +175,6 @@ data FGraph m l = FGraph { fg_entry  :: BlockId
 
 ----  Utility functions ---
 
--- | The string argument to 'freshBlockId' was originally helpful in debugging the Quick C--
--- compiler, so I have kept it here even though at present it is thrown away at
--- this spot---there's no reason a BlockId couldn't one day carry a string.
-freshBlockId :: String -> UniqSM BlockId
-
 blockId   :: Block  m l -> BlockId
 zip       :: ZBlock m l -> Block  m l
 unzip     :: Block  m l -> ZBlock m l
@@ -235,6 +238,11 @@ splice_head_only' :: ZHead m -> Graph m l -> LGraph m l
 of_block_list :: BlockId -> [Block m l] -> LGraph m l  -- N log N
 to_block_list :: LGraph m l -> [Block m l]  -- N log N
 
+-- | Conversion from LGraph to Graph
+graphOfLGraph :: LastNode l => LGraph m l -> Graph m l
+graphOfLGraph (LGraph eid blocks) = Graph (ZLast $ mkBranchNode eid) blocks
+
+
 -- | Traversal: 'postorder_dfs' returns a list of blocks reachable
 -- from the entry node.  This list has the following property:
 --
@@ -270,14 +278,23 @@ fold_layout ::
 -- haven't needed (else it would be here).
 fold_blocks :: (Block m l -> a -> a) -> a -> LGraph m l -> a
 
+-- | Fold from first to last
+fold_fwd_block ::
+  (BlockId -> a -> a) -> (m -> a -> a) -> (ZLast l -> a -> a) -> Block m l -> a -> a
+
 map_nodes :: (BlockId -> BlockId) -> (m -> m') -> (l -> l') -> LGraph m l -> LGraph m' l'
    -- mapping includes the entry id!
 
+map_blocks  :: (Block m l -> Block m' l') -> LGraph m l -> LGraph m' l'
+mapM_blocks :: Monad mm
+            => (Block m l -> mm (Block m' l')) -> LGraph m l -> mm (LGraph m' l')
+
 -- | These translation functions are speculative.  I hope eventually
 -- they will be used in the native-code back ends ---NR
-translate :: (m          -> UniqSM (LGraph m' l')) ->
-             (l          -> UniqSM (LGraph m' l')) ->
-             (LGraph m l -> UniqSM (LGraph m' l'))
+translate :: Monad tm =>
+             (m          -> tm (LGraph m' l')) ->
+             (l          -> tm (LGraph m' l')) ->
+             (LGraph m l -> tm (LGraph m' l'))
 
 {-
 -- | It's possible that another form of translation would be more suitable:
@@ -335,8 +352,6 @@ instance LastNode l => HavingSuccessors (ZTail m l) where
 
 blockId (Block id _) = id
 
-freshBlockId _ = do { u <- getUniqueUs; return $ BlockId u }
-
 -- | Convert block between forms.
 -- These functions are tail-recursive, so we can go as deep as we like
 -- without fear of stack overflow.  
@@ -364,7 +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
@@ -428,47 +443,21 @@ 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]
 
 
-postorder_dfs' :: LastNode l => LGraph m l -> [Block m l]
-postorder_dfs' g@(LGraph _ blocks) =
-  let FGraph _ eblock _ = entry g
-  in  vnode (zip eblock) (\acc _visited -> acc) [] emptyBlockSet
-  where
-    -- vnode ::
-    --    Block m l -> ([Block m l] -> BlockSet -> a) -> [Block m l] -> BlockSet -> a
-    vnode block@(Block id _) cont acc visited =
-        if elemBlockSet id visited then
-            cont acc visited
-        else
-            vchildren block (get_children block) cont acc (extendBlockSet visited id)
-    vchildren block bs cont acc visited =
-        let next children acc visited =
-                case children of []     -> cont (block : acc) visited
-                                 (b:bs) -> vnode b (next bs) acc visited
-        in next bs acc visited
-    get_children block = foldl add_id [] (succs block)
-    add_id rst id = case lookupBlockEnv blocks id of
-                      Just b -> b : rst
-                      Nothing -> rst
-
 postorder_dfs g@(LGraph _ blockenv) =
-    let FGraph id eblock _ = entry g
-        dfs1 = zip eblock :
-               postorder_dfs_from_except blockenv eblock (unitUniqSet id)
-        dfs2 = postorder_dfs' g
-    in  ASSERT (map blockId dfs1 == map blockId dfs2) dfs2
+    let FGraph id eblock _ = entry g in
+     zip eblock : postorder_dfs_from_except blockenv eblock (unitUniqSet id)
 
-postorder_dfs_from
-    :: (HavingSuccessors b, LastNode l) => BlockEnv (Block m l) -> b -> [Block m l]
-postorder_dfs_from blocks b = postorder_dfs_from_except blocks b emptyBlockSet
-
-postorder_dfs_from_except :: forall b m l . (HavingSuccessors b, LastNode l) => BlockEnv (Block m l) -> b -> BlockSet -> [Block m l]
+postorder_dfs_from_except :: (HavingSuccessors b, LastNode l)
+                          => BlockEnv (Block m l) -> b -> BlockSet -> [Block m l]
 postorder_dfs_from_except blocks b visited =
   vchildren (get_children b) (\acc _visited -> acc) [] visited
   where
@@ -490,6 +479,11 @@ postorder_dfs_from_except blocks b visited =
                       Just b -> b : rst
                       Nothing -> rst
 
+postorder_dfs_from
+    :: (HavingSuccessors b, LastNode l) => BlockEnv (Block m l) -> b -> [Block m l]
+postorder_dfs_from blocks b = postorder_dfs_from_except blocks b emptyBlockSet
+
+
 
 -- | Slightly more complicated than the usual fold because we want to tell block
 -- 'b1' what its inline successor is going to be, so that if 'b1' ends with
@@ -506,13 +500,26 @@ fold_layout f z g@(LGraph eid _) = fold (postorder_dfs g) z
 
 -- | The rest of the traversals are straightforward
 
+map_blocks f (LGraph eid blocks) = LGraph eid (mapUFM f blocks)
+
 map_nodes idm middle last (LGraph eid blocks) = LGraph (idm eid) (mapUFM block blocks)
     where block (Block id t) = Block (idm id) (tail t)
           tail (ZTail m t) = ZTail (middle m) (tail t)
           tail (ZLast LastExit) = ZLast LastExit
           tail (ZLast (LastOther l)) = ZLast (LastOther (last l))
 
+
+mapM_blocks f (LGraph eid blocks) = blocks' >>= return . LGraph eid 
+    where blocks' =
+            foldUFM (\b mblocks -> do { blocks <- mblocks
+                                      ; b <- f b
+                                      ; return $ insertBlock b blocks })
+                    (return emptyBlockEnv) blocks
+
 fold_blocks f z (LGraph _ blocks) = foldUFM f z blocks
+fold_fwd_block first middle last (Block id t) z = tail t (first id z)
+    where tail (ZTail m t) z = tail t (middle m z)
+          tail (ZLast l)   z = last l z
 
 of_block_list e blocks = LGraph e $ foldr insertBlock emptyBlockEnv blocks 
 to_block_list (LGraph _ blocks) = eltsUFM blocks
@@ -622,12 +629,12 @@ translate txm txl (LGraph eid blocks) =
        return $ LGraph eid blocks'
     where
       -- txblock ::
-      -- Block m l -> UniqSM (BlockEnv (Block m' l')) -> UniqSM (BlockEnv (Block m' l'))
+      -- Block m l -> tm (BlockEnv (Block m' l')) -> tm (BlockEnv (Block m' l'))
       txblock (Block id t) expanded =
         do blocks' <- expanded
            txtail (ZFirst id) t blocks'
       -- txtail :: ZHead m' -> ZTail m l -> BlockEnv (Block m' l') ->
-      --           UniqSM (BlockEnv (Block m' l'))
+      --           tm (BlockEnv (Block m' l'))
       txtail h (ZTail m t) blocks' =
         do m' <- txm m 
            let (g, h') = splice_head h m' 
@@ -639,51 +646,6 @@ translate txm txl (LGraph eid blocks) =
         return $ insertBlock (zipht h (ZLast LastExit)) blocks'
 
 ----------------------------------------------------------------
---- Block Ids, their environments, and their sets
-
-{- Note [Unique BlockId]
-~~~~~~~~~~~~~~~~~~~~~~~~
-Although a 'BlockId' is a local label, for reasons of implementation,
-'BlockId's must be unique within an entire compilation unit.  The reason
-is that each local label is mapped to an assembly-language label, and in
-most assembly languages allow, a label is visible throughout the enitre
-compilation unit in which it appears.
--}
-
-newtype BlockId = BlockId Unique
-  deriving (Eq,Ord)
-
-instance Uniquable BlockId where
-  getUnique (BlockId u) = u
-
-instance Show BlockId where
-  show (BlockId u) = show u
-
-instance Outputable BlockId where
-  ppr = ppr . getUnique
-
-
-type BlockEnv a = UniqFM {- BlockId -} a
-emptyBlockEnv :: BlockEnv a
-emptyBlockEnv = emptyUFM
-lookupBlockEnv :: BlockEnv a -> BlockId -> Maybe a
-lookupBlockEnv = lookupUFM
-extendBlockEnv :: BlockEnv a -> BlockId -> a -> BlockEnv a
-extendBlockEnv = addToUFM
-mkBlockEnv :: [(BlockId,a)] -> BlockEnv a
-mkBlockEnv = listToUFM
-
-type BlockSet = UniqSet BlockId
-emptyBlockSet :: BlockSet
-emptyBlockSet = emptyUniqSet
-elemBlockSet :: BlockId -> BlockSet -> Bool
-elemBlockSet = elementOfUniqSet
-extendBlockSet :: BlockSet -> BlockId -> BlockSet
-extendBlockSet = addOneToUniqSet
-mkBlockSet :: [BlockId] -> BlockSet
-mkBlockSet = mkUniqSet
-
-----------------------------------------------------------------
 ---- Prettyprinting
 ----------------------------------------------------------------
 
@@ -692,21 +654,35 @@ mkBlockSet = mkUniqSet
 instance (Outputable m, Outputable l) => Outputable (ZTail m l) where
     ppr = pprTail
 
+instance (Outputable m, Outputable l, LastNode l) => Outputable (Graph m l) where
+    ppr = pprGraph
+
+instance (Outputable m, Outputable l, LastNode l) => Outputable (LGraph m l) where
+    ppr = pprLgraph
+
+instance (Outputable m, Outputable l, LastNode l) => Outputable (Block m l) where
+    ppr = pprBlock
+
+instance (Outputable l) => Outputable (ZLast l) where
+    ppr = pprLast
+
 pprTail :: (Outputable m, Outputable l) => ZTail m l -> SDoc 
 pprTail (ZTail m t) = ppr m $$ ppr t
-pprTail (ZLast LastExit) = text "<exit>"
-pprTail (ZLast (LastOther l)) = ppr l
+pprTail (ZLast l) = ppr l
+
+pprLast :: (Outputable l) => ZLast l -> SDoc
+pprLast LastExit = text "<exit>"
+pprLast (LastOther l) = ppr l
+
+pprBlock :: (Outputable m, Outputable l, LastNode l) => Block m l -> SDoc
+pprBlock (Block id tail) = ppr id <> colon $$ ppr tail
 
 pprLgraph :: (Outputable m, Outputable l, LastNode l) => LGraph m l -> SDoc
-pprLgraph g = text "{" $$ nest 2 (vcat $ map pprBlock blocks) $$ text "}"
-    where pprBlock (Block id tail) = ppr id <> colon $$ ppr tail
-          blocks = postorder_dfs g
+pprLgraph g = text "{" $$ nest 2 (vcat $ map ppr blocks) $$ text "}"
+    where blocks = postorder_dfs g
 
 pprGraph :: (Outputable m, Outputable l, LastNode l) => Graph m l -> SDoc
 pprGraph (Graph tail blockenv) =
-        text "{" $$ nest 2 (ppr tail $$ (vcat $ map pprBlock blocks)) $$ text "}"
-    where pprBlock (Block id tail) = ppr id <> colon $$ ppr tail
-          blocks = postorder_dfs_from blockenv tail
+        text "{" $$ nest 2 (ppr tail $$ (vcat $ map ppr blocks)) $$ text "}"
+    where blocks = postorder_dfs_from blockenv tail
 
-_unused :: FS.FastString
-_unused = undefined