X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fcmm%2FZipCfg.hs;h=67a4ecdde60e9cff77c33f6f7c76f1be6d86e864;hp=6158435171c7e0ad3b94828a34a4329ffa2d16e3;hb=ba60dc74fdb18fe655cfac605130cf6480116e47;hpb=4ddba4629c5396bec766b598fe32d874a378d7bb diff --git a/compiler/cmm/ZipCfg.hs b/compiler/cmm/ZipCfg.hs index 6158435..67a4ecd 100644 --- a/compiler/cmm/ZipCfg.hs +++ b/compiler/cmm/ZipCfg.hs @@ -1,8 +1,6 @@ -{-# 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 + BlockId(..), mkBlockId -- ToDo: BlockId should be abstract, but it isn't yet , BlockEnv, emptyBlockEnv, lookupBlockEnv, extendBlockEnv, insertBlock, mkBlockEnv , BlockSet, emptyBlockSet, elemBlockSet, extendBlockSet, mkBlockSet , Graph(..), LGraph(..), FGraph(..) @@ -13,16 +11,17 @@ module ZipCfg -- 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_tail, splice_head, splice_head_only', splice_head' , of_block_list, to_block_list - , map_nodes - , postorder_dfs + , map_blocks, map_nodes, mapM_blocks + , postorder_dfs, postorder_dfs_from, postorder_dfs_from_except , fold_layout , fold_blocks , translate - , pprLgraph + , 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 @@ -38,12 +37,13 @@ where #include "HsVersions.h" +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) @@ -150,7 +158,7 @@ data ZTail m l = ZLast (ZLast l) | ZTail m (ZTail m l) -- | Blocks and flow graphs; see Note [Kinds of graphs] data Block m l = Block BlockId (ZTail m l) -data Graph m l = Graph (ZTail m l) (BlockEnv (Block m l)) +data Graph m l = Graph { g_entry :: (ZTail m l), g_blocks :: (BlockEnv (Block m l)) } data LGraph m l = LGraph { lg_entry :: BlockId , lg_blocks :: BlockEnv (Block 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 @@ -217,15 +220,16 @@ ht_to_last :: ZHead m -> ZTail m l -> (ZHead m, ZLast l) -- , (???, [, -- N: y:=x; return (y,x)]) -splice_head :: ZHead m -> LGraph m l -> (LGraph m l, ZHead m) -splice_tail :: LGraph m l -> ZTail m l -> (ZTail m l, LGraph m l) +splice_head :: ZHead m -> LGraph m l -> (LGraph m l, ZHead m) +splice_head' :: ZHead m -> Graph m l -> (BlockEnv (Block m l), ZHead m) +splice_tail :: Graph m l -> ZTail m l -> Graph m l --- | We can also splice a single-entry, no-exit LGraph into a head. +-- | We can also splice a single-entry, no-exit Graph into a head. splice_head_only :: ZHead m -> LGraph m l -> LGraph m l +splice_head_only' :: ZHead m -> Graph m l -> LGraph m l --- | Finally, we can remove the entry label of an LGraph and remove --- it, leaving a Graph: -remove_entry_label :: LGraph m l -> Graph m l + +-- | A safe operation -- | Conversion to and from the environment form is convenient. For -- layout or dataflow, however, one will want to use 'postorder_dfs' @@ -272,11 +276,16 @@ fold_blocks :: (Block m l -> a -> a) -> a -> LGraph m l -> 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: @@ -323,6 +332,10 @@ instance LastNode l => HavingSuccessors (ZBlock m l) where instance LastNode l => HavingSuccessors (Block m l) where succs b = succs (unzip b) +instance LastNode l => HavingSuccessors (ZTail m l) where + succs b = succs (lastTail b) + + -- ================ IMPLEMENTATION ================-- @@ -330,8 +343,6 @@ instance LastNode l => HavingSuccessors (Block 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. @@ -353,9 +364,11 @@ head_id :: ZHead m -> BlockId head_id (ZFirst id) = id head_id (ZHead h _) = head_id h -last (ZBlock _ t) = lastt t - where lastt (ZLast l) = l - lastt (ZTail _ t) = lastt t +last (ZBlock _ t) = lastTail t + +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 @@ -398,6 +411,13 @@ single_exit g = foldUFM check 0 (lg_blocks g) == 1 LastExit -> count + (1 :: Int) _ -> count +-- | Used in assertions; tells if a graph has exactly one exit +single_exitg :: Graph l m -> Bool +single_exitg (Graph tail blocks) = foldUFM add (exit_count (lastTail tail)) blocks == 1 + where add block count = count + exit_count (last (unzip block)) + exit_count LastExit = 1 :: Int + exit_count _ = 0 + ------------------ graph traversals -- | This is the most important traversal over this data structure. It drops @@ -420,10 +440,15 @@ single_exit g = foldUFM check 0 (lg_blocks g) == 1 -- 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 + +postorder_dfs g@(LGraph _ blockenv) = + let FGraph id eblock _ = entry g in + zip eblock : postorder_dfs_from_except blockenv eblock (unitUniqSet id) + +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 -- vnode :: -- Block m l -> ([Block m l] -> BlockSet -> a) -> [Block m l] -> BlockSet -> a @@ -431,10 +456,11 @@ postorder_dfs g@(LGraph _ blocks) = 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 cont' acc visited = cont (block:acc) visited in + vchildren (get_children block) cont' acc (extendBlockSet visited id) + vchildren bs cont acc visited = let next children acc visited = - case children of [] -> cont (block : acc) visited + case children of [] -> cont acc visited (b:bs) -> vnode b (next bs) acc visited in next bs acc visited get_children block = foldl add_id [] (succs block) @@ -442,6 +468,11 @@ postorder_dfs g@(LGraph _ blocks) = 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 @@ -458,12 +489,22 @@ 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 of_block_list e blocks = LGraph e $ foldr insertBlock emptyBlockEnv blocks @@ -494,6 +535,22 @@ prepare_for_splicing g single multi = case gl of LastExit -> multi etail gh gblocks _ -> panic "exit is not exit?!" +prepare_for_splicing' :: + Graph m l -> (ZTail m l -> a) -> (ZTail m l -> ZHead m -> BlockEnv (Block m l) -> a) + -> a +prepare_for_splicing' (Graph etail gblocks) single multi = + if isNullUFM gblocks then + case lastTail etail of + LastExit -> single etail + _ -> panic "bad single block" + else + case splitp_blocks is_exit gblocks of + Nothing -> panic "Can't find an exit block" + Just (gexit, gblocks) -> + let (gh, gl) = goto_end $ unzip gexit in + case gl of LastExit -> multi etail gh gblocks + _ -> panic "exit is not exit?!" + is_exit :: Block m l -> Bool is_exit b = case last (unzip b) of { LastExit -> True; _ -> False } @@ -507,8 +564,28 @@ splice_head head g = splice_many_blocks entry exit others = (LGraph eid (insertBlock (zipht head entry) others), exit) +splice_head' head g = + ASSERT (single_exitg g) prepare_for_splicing' g splice_one_block splice_many_blocks + where splice_one_block tail' = + case ht_to_last head tail' of + (head, LastExit) -> (emptyBlockEnv, head) + _ -> panic "spliced LGraph without exit" + splice_many_blocks entry exit others = + (insertBlock (zipht head entry) others, exit) + +-- splice_tail :: Graph m l -> ZTail m l -> Graph m l splice_tail g tail = - ASSERT (single_exit g) prepare_for_splicing g splice_one_block splice_many_blocks + ASSERT (single_exitg g) prepare_for_splicing' g splice_one_block splice_many_blocks + where splice_one_block tail' = Graph (tail' `append_tails` tail) emptyBlockEnv + append_tails (ZLast LastExit) tail = tail + append_tails (ZLast _) _ = panic "spliced single block without LastExit" + append_tails (ZTail m t) tail = ZTail m (append_tails t tail) + splice_many_blocks entry exit others = + Graph entry (insertBlock (zipht exit tail) others) + +{- +splice_tail g tail = + AS SERT (single_exit g) prepare_for_splicing g splice_one_block splice_many_blocks where splice_one_block tail' = -- return tail' .. tail case ht_to_last (ZFirst (lg_entry g)) tail' of (head', LastExit) -> @@ -518,6 +595,7 @@ splice_tail g tail = _ -> panic "spliced single block without Exit" splice_many_blocks entry exit others = (entry, LGraph (lg_entry g) (insertBlock (zipht exit tail) others)) +-} splice_head_only head g = let FGraph eid gentry gblocks = entry g @@ -525,12 +603,10 @@ splice_head_only head g = ZBlock (ZFirst _) tail -> LGraph eid (insertBlock (zipht head tail) gblocks) _ -> panic "entry not at start of block?!" -remove_entry_label g = - let FGraph e eblock others = entry g - in case eblock of - ZBlock (ZFirst id) tail - | id == e -> Graph tail others - _ -> panic "id doesn't match on entry block" +splice_head_only' head (Graph tail gblocks) = + let eblock = zipht head tail in + LGraph (blockId eblock) (insertBlock eblock gblocks) + --- Translation @@ -539,12 +615,12 @@ 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' @@ -573,6 +649,9 @@ newtype BlockId = BlockId Unique instance Uniquable BlockId where getUnique (BlockId u) = u +mkBlockId :: Unique -> BlockId +mkBlockId uniq = BlockId uniq + instance Show BlockId where show (BlockId u) = show u @@ -609,15 +688,28 @@ mkBlockSet = mkUniqSet instance (Outputable m, Outputable l) => Outputable (ZTail m l) where ppr = pprTail +instance (Outputable m, Outputable l, LastNode l) => Outputable (LGraph m l) where + ppr = pprLgraph + +instance (Outputable l) => Outputable (ZLast l) where + ppr = pprLast + pprTail :: (Outputable m, Outputable l) => ZTail m l -> SDoc pprTail (ZTail m t) = ppr m $$ ppr t -pprTail (ZLast LastExit) = text "" -pprTail (ZLast (LastOther l)) = ppr l +pprTail (ZLast l) = ppr l + +pprLast :: (Outputable l) => ZLast l -> SDoc +pprLast LastExit = text "" +pprLast (LastOther l) = ppr l pprLgraph :: (Outputable m, Outputable l, LastNode l) => LGraph m l -> SDoc pprLgraph g = text "{" $$ nest 2 (vcat $ map pprBlock blocks) $$ text "}" where pprBlock (Block id tail) = ppr id <> colon $$ ppr tail blocks = postorder_dfs g -_unused :: FS.FastString -_unused = undefined +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 +