X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmCPS.hs;h=7bfdf8437e054485c7b3f64602f3def17f53ed89;hb=8350c21760d8610b0b2f329095ffb80bb1bc20d9;hp=4ec2fc60f15935d29be70ee306d3f850871974af;hpb=d0f6db5b0cf1189d84e292aeca350211f3b810dd;p=ghc-hetmet.git diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index 4ec2fc6..7bfdf84 100644 --- a/compiler/cmm/CmmCPS.hs +++ b/compiler/cmm/CmmCPS.hs @@ -1,36 +1,412 @@ -module CmmCPS (cmmCPS) where +module CmmCPS ( + -- | Converts C-- with full proceedures and parameters + -- to a CPS transformed C-- with the stack made manifest. + cmmCPS +) where #include "HsVersions.h" +import BlockId import Cmm import CmmLint import PprCmm -import Dataflow (mapCmmTop, onBasicBlock, cmmLivenessComment, cmmLiveness) +import CmmLive +import CmmBrokenBlock +import CmmProcPoint +import CmmCallConv +import CmmCPSGen +import CmmUtils + +import ClosureInfo +import CLabel +import SMRep +import Constants import DynFlags import ErrUtils import Maybes import Outputable +import UniqSupply +import UniqSet +import Unique + +import Control.Monad + +----------------------------------------------------------------------------- +-- |Top level driver for the CPS pass +----------------------------------------------------------------------------- +cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm + -> [Cmm] -- ^ Input C-- with Proceedures + -> IO [Cmm] -- ^ Output CPS transformed C-- +cmmCPS dflags cmm_with_calls + = do { when (dopt Opt_DoCmmLinting dflags) $ + do showPass dflags "CmmLint" + case firstJusts $ map cmmLint cmm_with_calls of + Just err -> do printDump err + ghcExit dflags 1 + Nothing -> return () + ; showPass dflags "CPS" + + -- TODO: more lint checking + -- check for use of branches to non-existant blocks + -- check for use of Sp, SpLim, R1, R2, etc. + + ; uniqSupply <- mkSplitUniqSupply 'p' + ; let supplies = listSplitUniqSupply uniqSupply + ; let cpsd_cmm = zipWith doCpsProc supplies cmm_with_calls + + ; dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms cpsd_cmm) -import Monad -import IO - -cmmCPS :: DynFlags - -> [Cmm] -- C-- with Proceedures - -> IO [Cmm] -- Output: CPS transformed C-- - -cmmCPS dflags abstractC = do - when (dopt Opt_DoCmmLinting dflags) $ - do showPass dflags "CmmLint" - case firstJust $ map cmmLint abstractC of - Just err -> do printDump err - ghcExit dflags 1 - Nothing -> return () - showPass dflags "CPS" - -- continuationC <- return abstractC - continuationC <- return $ map (mapCmmTop (onBasicBlock (\bs -> map (cmmLivenessComment (cmmLiveness bs)) bs))) abstractC - - dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC) -- TODO: add option to dump Cmm to file - return continuationC + + ; return cpsd_cmm } + + +----------------------------------------------------------------------------- +-- |CPS a single CmmTop (proceedure) +-- Only 'CmmProc' are transformed 'CmmData' will be left alone. +----------------------------------------------------------------------------- + +doCpsProc :: UniqSupply -> Cmm -> Cmm +doCpsProc s (Cmm c) + = Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c + +cpsProc :: UniqSupply + -> CmmTop -- ^Input procedure + -> [CmmTop] -- ^Output procedures; + -- a single input procedure is converted to + -- multiple output procedures + +-- Data blocks don't need to be CPS transformed +cpsProc _ proc@(CmmData _ _) = [proc] + +-- Empty functions just don't work with the CPS algorithm, but +-- they don't need the transformation anyway so just output them directly +cpsProc _ proc@(CmmProc _ _ _ (ListGraph [])) + = pprTrace "cpsProc: unexpected empty proc" (ppr proc) [proc] + +-- CPS transform for those procs that actually need it +-- The plan is this: +-- +-- * Introduce a stack-check block as the first block +-- * The first blocks gets a FunctionEntry; the rest are ControlEntry +-- * Now break each block into a bunch of blocks (at call sites); +-- all but the first will be ContinuationEntry +-- +cpsProc uniqSupply (CmmProc info ident params (ListGraph blocks)) = cps_procs + where + -- We need to be generating uniques for several things. + -- We could make this function monadic to handle that + -- but since there is no other reason to make it monadic, + -- we instead will just split them all up right here. + (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply + uniques :: [[Unique]] + uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1 + (stack_check_block_unique:stack_use_unique:adaptor_uniques) : + block_uniques = uniques + proc_uniques = map (map (map uniqsFromSupply . listSplitUniqSupply) . listSplitUniqSupply) $ listSplitUniqSupply uniqSupply2 + + stack_use = CmmLocal (LocalReg stack_use_unique (cmmRegType spReg)) + stack_check_block_id = BlockId stack_check_block_unique + stack_check_block = make_stack_check stack_check_block_id info stack_use (blockId $ head blocks) + + forced_blocks = stack_check_block : blocks + + CmmInfo maybe_gc_block_id update_frame _ = info + + -- Break the block at each function call. + -- The part after the function call will have to become a continuation. + broken_blocks :: ([(BlockId, ContFormat)], [BrokenBlock]) + broken_blocks = + (\x -> (concatMap fst x, concatMap snd x)) $ + zipWith3 (breakBlock (maybeToList maybe_gc_block_id)) + block_uniques + forced_blocks + (FunctionEntry info ident params : + repeat ControlEntry) + + f' = selectContinuations (fst broken_blocks) + broken_blocks' = map (makeContinuationEntries f') $ + concat $ + zipWith (adaptBlockToFormat f') + adaptor_uniques + (snd broken_blocks) + + -- Calculate live variables for each broken block. + -- + -- Nothing can be live on entry to the first block + -- so we could take the tail, but for now we wont + -- to help future proof the code. + live :: BlockEntryLiveness + live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks' + + -- Calculate which blocks must be made into full fledged procedures. + proc_points :: UniqSet BlockId + proc_points = calculateProcPoints broken_blocks' + + -- Construct a map so we can lookup a broken block by its 'BlockId'. + block_env :: BlockEnv BrokenBlock + block_env = blocksToBlockEnv broken_blocks' + + -- Group the blocks into continuations based on the set of proc-points. + continuations :: [Continuation (Either C_SRT CmmInfo)] + continuations = map (gatherBlocksIntoContinuation live proc_points block_env) + (uniqSetToList proc_points) + + -- Select the stack format on entry to each continuation. + -- Return the max stack offset and an association list + -- + -- This is an association list instead of a UniqFM because + -- CLabel's don't have a 'Uniqueable' instance. + formats :: [(CLabel, -- key + (CmmFormals, -- arguments + Maybe CLabel, -- label in top slot + [Maybe LocalReg]))] -- slots + formats = selectContinuationFormat live continuations + + -- Do a little meta-processing on the stack formats such as + -- getting the individual frame sizes and the maximum frame size + formats' :: (WordOff, WordOff, [(CLabel, ContinuationFormat)]) + formats'@(_, _, format_list) = processFormats formats update_frame continuations + + -- Update the info table data on the continuations with + -- the selected stack formats. + continuations' :: [Continuation CmmInfo] + continuations' = map (applyContinuationFormat format_list) continuations + + -- Do the actual CPS transform. + cps_procs :: [CmmTop] + cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations' + +make_stack_check :: BlockId -> CmmInfo -> CmmReg -> BlockId + -> GenBasicBlock CmmStmt +make_stack_check stack_check_block_id info stack_use next_block_id = + BasicBlock stack_check_block_id $ + check_stmts ++ [CmmBranch next_block_id] + where + check_stmts = + case info of + -- If we are given a stack check handler, + -- then great, well check the stack. + CmmInfo (Just gc_block) _ _ + -> [CmmCondBranch + (CmmMachOp (MO_U_Lt (typeWidth (cmmRegType spReg))) + [CmmReg stack_use, CmmReg spLimReg]) + gc_block] + -- If we aren't given a stack check handler, + -- then humph! we just won't check the stack for them. + CmmInfo Nothing _ _ + -> [] +----------------------------------------------------------------------------- + +collectNonProcPointTargets :: + UniqSet BlockId -> BlockEnv BrokenBlock + -> UniqSet BlockId -> [BlockId] -> UniqSet BlockId +collectNonProcPointTargets proc_points blocks current_targets new_blocks = + if sizeUniqSet current_targets == sizeUniqSet new_targets + then current_targets + else foldl + (collectNonProcPointTargets proc_points blocks) + new_targets + (map (:[]) targets) + where + blocks' = map (lookupWithDefaultBEnv blocks (panic "TODO")) new_blocks + targets = + -- Note the subtlety that since the extra branch after a call + -- will always be to a block that is a proc-point, + -- this subtraction will always remove that case + uniqSetToList $ (unionManyUniqSets $ map (mkUniqSet . brokenBlockTargets) blocks') + `minusUniqSet` proc_points + -- TODO: remove redundant uniqSetToList + new_targets = current_targets `unionUniqSets` (mkUniqSet targets) + +-- TODO: insert proc point code here +-- * Branches and switches to proc points may cause new blocks to be created +-- (or proc points could leave behind phantom blocks that just jump to them) +-- * Proc points might get some live variables passed as arguments + +gatherBlocksIntoContinuation :: + BlockEntryLiveness -> UniqSet BlockId -> BlockEnv BrokenBlock + -> BlockId -> Continuation (Either C_SRT CmmInfo) +gatherBlocksIntoContinuation live proc_points blocks start = + Continuation info_table clabel params is_gc_cont body + where + children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) [start]) `minusUniqSet` (unitUniqSet start) + start_block = lookupWithDefaultBEnv blocks unknown_block start + children_blocks = map (lookupWithDefaultBEnv blocks unknown_block) (uniqSetToList children) + unknown_block :: a -- Used at more than one type + unknown_block = panic "unknown block in gatherBlocksIntoContinuation" + body = start_block : children_blocks + + -- We can't properly annotate the continuation's stack parameters + -- at this point because this is before stack selection + -- but we want to keep the C_SRT around so we use 'Either'. + info_table = case start_block_entry of + FunctionEntry info _ _ -> Right info + ContinuationEntry _ srt _ -> Left srt + ControlEntry -> Right (CmmInfo Nothing Nothing CmmNonInfoTable) + + is_gc_cont = case start_block_entry of + FunctionEntry _ _ _ -> False + ContinuationEntry _ _ gc_cont -> gc_cont + ControlEntry -> False + + start_block_entry = brokenBlockEntry start_block + clabel = case start_block_entry of + FunctionEntry _ label _ -> label + _ -> mkReturnPtLabel $ getUnique start + params = case start_block_entry of + FunctionEntry _ _ args -> args + ContinuationEntry args _ _ -> args + ControlEntry -> + uniqSetToList $ + lookupWithDefaultBEnv live unknown_block start + -- it's a proc-point, pass lives in parameter registers + +-------------------------------------------------------------------------------- +-- For now just select the continuation orders in the order they are in the set with no gaps + +selectContinuationFormat :: BlockEnv CmmLive + -> [Continuation (Either C_SRT CmmInfo)] + -> [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))] +selectContinuationFormat live continuations = + map (\c -> (continuationLabel c, selectContinuationFormat' c)) continuations + where + -- User written continuations + selectContinuationFormat' (Continuation + (Right (CmmInfo _ _ (CmmInfoTable _ _ _ (ContInfo format _)))) + label formals _ _) = + (formals, Just label, format) + -- Either user written non-continuation code + -- or CPS generated proc-points + selectContinuationFormat' (Continuation (Right _) _ formals _ _) = + (formals, Nothing, []) + -- CPS generated continuations + selectContinuationFormat' (Continuation (Left _) label formals _ blocks) = + -- TODO: assumes the first block is the entry block + let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this + in (formals, + Just label, + map Just $ uniqSetToList $ + lookupWithDefaultBEnv live unknown_block ident) + + unknown_block = panic "unknown BlockId in selectContinuationFormat" + +processFormats :: [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))] + -> Maybe UpdateFrame + -> [Continuation (Either C_SRT CmmInfo)] + -> (WordOff, WordOff, [(CLabel, ContinuationFormat)]) +processFormats formats update_frame continuations = + (max_size + update_frame_size, update_frame_size, formats') + where + max_size = maximum $ + 0 : map (continuationMaxStack formats') continuations + formats' = map make_format formats + make_format (label, (formals, top, stack)) = + (label, + ContinuationFormat { + continuation_formals = formals, + continuation_label = top, + continuation_frame_size = stack_size stack + + if isJust top + then label_size + else 0, + continuation_stack = stack }) + + update_frame_size = case update_frame of + Nothing -> 0 + (Just (UpdateFrame _ args)) + -> label_size + update_size args + + update_size [] = 0 + update_size (expr:exprs) = width + update_size exprs + where + width = (widthInBytes $ typeWidth $ cmmExprType expr) `quot` wORD_SIZE + -- TODO: it would be better if we had a machRepWordWidth + + -- TODO: get rid of "+ 1" etc. + label_size = 1 :: WordOff + + stack_size [] = 0 + stack_size (Nothing:formats) = 1 + stack_size formats -- one dead word + stack_size (Just reg:formats) = width + stack_size formats + where + width = (widthInBytes $ typeWidth $ localRegType reg) `quot` wORD_SIZE + -- TODO: it would be better if we had a machRepWordWidth + +continuationMaxStack :: [(CLabel, ContinuationFormat)] + -> Continuation a + -> WordOff +continuationMaxStack _ (Continuation _ _ _ True _) = 0 +continuationMaxStack formats (Continuation _ label _ False blocks) = + max_arg_size + continuation_frame_size stack_format + where + stack_format = maybe unknown_format id $ lookup label formats + unknown_format = panic "Unknown format in continuationMaxStack" + + max_arg_size = maximum $ 0 : map block_max_arg_size blocks + + block_max_arg_size block = + maximum (final_arg_size (brokenBlockExit block) : + map stmt_arg_size (brokenBlockStmts block)) + + final_arg_size (FinalReturn args) = + argumentsSize (cmmExprType . hintlessCmm) args + final_arg_size (FinalJump _ args) = + argumentsSize (cmmExprType . hintlessCmm) args + final_arg_size (FinalCall _ _ _ _ _ _ True) = 0 + final_arg_size (FinalCall next _ _ args _ _ False) = + -- We have to account for the stack used when we build a frame + -- for the *next* continuation from *this* continuation + argumentsSize (cmmExprType . hintlessCmm) args + + continuation_frame_size next_format + where + next_format = maybe unknown_format id $ lookup next' formats + next' = mkReturnPtLabel $ getUnique next + + final_arg_size _ = 0 + + stmt_arg_size (CmmJump _ args) = + argumentsSize (cmmExprType . hintlessCmm) args + stmt_arg_size (CmmCall _ _ _ (CmmSafe _) _) = + panic "Safe call in processFormats" + stmt_arg_size (CmmReturn _) = + panic "CmmReturn in processFormats" + stmt_arg_size _ = 0 + +----------------------------------------------------------------------------- +applyContinuationFormat :: [(CLabel, ContinuationFormat)] + -> Continuation (Either C_SRT CmmInfo) + -> Continuation CmmInfo + +-- User written continuations +applyContinuationFormat formats + (Continuation (Right (CmmInfo gc update_frame + (CmmInfoTable clos prof tag (ContInfo _ srt)))) + label formals is_gc blocks) = + Continuation (CmmInfo gc update_frame (CmmInfoTable clos prof tag (ContInfo format srt))) + label formals is_gc blocks + where + format = continuation_stack $ maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in applyContinuationFormat" + +-- Either user written non-continuation code or CPS generated proc-point +applyContinuationFormat _ (Continuation + (Right info) label formals is_gc blocks) = + Continuation info label formals is_gc blocks + +-- CPS generated continuations +applyContinuationFormat formats (Continuation + (Left srt) label formals is_gc blocks) = + Continuation (CmmInfo gc Nothing (CmmInfoTable undefined prof tag (ContInfo (continuation_stack $ format) srt))) + label formals is_gc blocks + where + gc = Nothing -- Generated continuations never need a stack check + -- TODO prof: this is the same as the current implementation + -- but I think it could be improved + prof = ProfilingInfo zeroCLit zeroCLit + tag = rET_SMALL -- cmmToRawCmm may convert it to rET_BIG + format = maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in applyContinuationFormat" +