X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmCPS.hs;h=4394fb595e8e8f8faed34c99e7dec3eba1e88170;hb=af452780391355f7008fe97e556ced25a3dd2d21;hp=e708ebbdad36e0f9cb92316ed54c67a8333142bb;hpb=4343368be10030e61acaa8fde2cedbb5fb26918c;p=ghc-hetmet.git diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index e708ebb..4394fb5 100644 --- a/compiler/cmm/CmmCPS.hs +++ b/compiler/cmm/CmmCPS.hs @@ -1,4 +1,8 @@ -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" @@ -6,12 +10,24 @@ import Cmm import CmmLint import PprCmm -import Dataflow (cmmLivenessComment, cmmLiveness, CmmLive) - +import CmmLive +import CmmBrokenBlock +import CmmProcPoint +import CmmCallConv +import CmmInfo +import CmmUtils + +import CgProf (curCCS, curCCSAddr) +import CgUtils (cmmOffsetW) +import Bitmap +import ClosureInfo import MachOp import ForeignCall import CLabel +import SMRep +import Constants +import StaticFlags import DynFlags import ErrUtils import Maybes @@ -23,36 +39,185 @@ import Unique import Monad import IO +import Data.List + +import MachRegs (callerSaveVolatileRegs) + -- HACK: this is part of the NCG so we shouldn't use this, but we need + -- it for now to eliminate the need for saved regs to be in CmmCall. + -- The long term solution is to factor callerSaveVolatileRegs + -- from nativeGen into CPS + +----------------------------------------------------------------------------- +-- |Top level driver for the CPS pass +----------------------------------------------------------------------------- +cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm + -> [GenCmm CmmStatic CmmInfo CmmStmt] -- ^ Input C-- with Proceedures + -> IO [GenCmm CmmStatic [CmmStatic] CmmStmt] -- ^ 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" --------------------------------------------------------------------------------- --- Monad for the CPSer --- Contains: --- * State for the uniqSupply - -data CPSState = CPSState { cps_uniqs :: UniqSupply } - -data CPS a = CPS { runCPS :: CPSState -> (CPSState, a) } + -- TODO: more lint checking + -- check for use of branches to non-existant blocks + -- check for use of Sp, SpLim, R1, R2, etc. -instance Monad CPS where - return a = CPS $ \s -> (s, a) - (CPS m) >>= f = CPS $ \s -> - let (s', m') = m s - in runCPS (f m') s' + uniqSupply <- mkSplitUniqSupply 'p' + let supplies = listSplitUniqSupply uniqSupply + let doCpsProc s (Cmm c) = + Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c + let continuationC = zipWith doCpsProc supplies abstractC --------------------------------------------------------------------------------- --- Utility functions + dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC) -getState = CPS $ \s -> (s, s) -putState s = CPS $ \_ -> (s, ()) + -- TODO: add option to dump Cmm to file -newLabelCPS = do - state <- getState - let (us1, us2) = splitUniqSupply (cps_uniqs state) - putState $ state { cps_uniqs = us1 } - return $ BlockId (uniqFromSupply us2) + return continuationC -mapMCmmTop :: (Monad m) => (CmmTop -> m [CmmTop]) -> Cmm -> m Cmm -mapMCmmTop f (Cmm xs) = liftM Cmm $ liftM concat $ mapM f xs +stg_gc_gen = mkRtsApFastLabel SLIT("gen_cg_TODO") --panic "Need the label for gc" +make_gc_block block_id fun_label formals safety = BasicBlock block_id stmts + where + stmts = [CmmCall stg_gc_gen_target [] [] safety, + CmmJump fun_expr actuals] + stg_gc_gen_target = + CmmForeignCall (CmmLit (CmmLabel stg_gc_gen)) CmmCallConv + actuals = map (\x -> (CmmReg (CmmLocal x), NoHint)) formals + fun_expr = CmmLit (CmmLabel fun_label) + +make_gc_check stack_use gc_block = + [CmmCondBranch + (CmmMachOp (MO_U_Lt $ cmmRegRep spReg) + [CmmReg stack_use, CmmReg spLimReg]) + gc_block] + +force_gc_block old_info stack_use block_id fun_label formals = + case old_info of + CmmNonInfo (Just existing) -> (old_info, [], make_gc_check stack_use existing) + CmmInfo _ (Just existing) _ _ -> (old_info, [], make_gc_check stack_use existing) + CmmNonInfo Nothing + -> (CmmNonInfo (Just block_id), + [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)], + make_gc_check stack_use block_id) + CmmInfo prof Nothing type_tag type_info + -> (CmmInfo prof (Just block_id) type_tag type_info, + [make_gc_block block_id fun_label formals (CmmSafe srt)], + make_gc_check stack_use block_id) + where + srt = case type_info of + ConstrInfo _ _ _ -> NoC_SRT + FunInfo _ srt' _ _ _ _ -> srt' + ThunkInfo _ srt' -> srt' + ThunkSelectorInfo _ srt' -> srt' + ContInfo _ srt' -> srt' + +----------------------------------------------------------------------------- +-- |CPS a single CmmTop (proceedure) +-- Only 'CmmProc' are transformed 'CmmData' will be left alone. +----------------------------------------------------------------------------- + +cpsProc :: UniqSupply + -> GenCmmTop CmmStatic CmmInfo CmmStmt -- ^Input proceedure + -> [GenCmmTop CmmStatic [CmmStatic] CmmStmt] -- ^Output proceedure and continuations +cpsProc uniqSupply (CmmData sec dat) = [CmmData sec dat] +cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs + where + (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply + uniques :: [[Unique]] + uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1 + (gc_unique:stack_use_unique:info_uniques):adaptor_uniques:block_uniques = uniques + proc_uniques = map (map uniqsFromSupply . listSplitUniqSupply) $ listSplitUniqSupply uniqSupply2 + + stack_use = CmmLocal (LocalReg stack_use_unique (cmmRegRep spReg) KindPtr) + + -- TODO: doc + forced_gc :: (CmmInfo, [CmmBasicBlock], [CmmStmt]) + forced_gc = force_gc_block info stack_use (BlockId gc_unique) ident params + (forced_info, gc_blocks, check_stmts) = forced_gc + + forced_blocks = + case blocks of + (BasicBlock id stmts) : bs -> + (BasicBlock id (check_stmts ++ stmts)) : (bs ++ gc_blocks) + [] -> [] -- If there is no code then we don't need a stack check + + forced_gc_id = case forced_info of + CmmNonInfo (Just x) -> x + CmmInfo _ (Just x) _ _ -> x + + -- 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 [forced_gc_id]) + block_uniques + forced_blocks + (FunctionEntry forced_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 = zipWith + (gatherBlocksIntoContinuation live proc_points block_env) + (uniqSetToList proc_points) + (Just forced_gc_id : repeat Nothing) {-dead-} + + -- 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, [(CLabel, ContinuationFormat)]) + formats' = processFormats formats continuations + + -- Update the info table data on the continuations with + -- the selected stack formats. + continuations' :: [Continuation CmmInfo] + continuations' = map (applyContinuationFormat (snd formats')) continuations + + -- Do the actual CPS transform. + cps_procs :: [CmmTop] + cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations' + + -- Convert the info tables from CmmInfo to [CmmStatic] + -- We might want to put this in another pass eventually + info_procs :: [RawCmmTop] + info_procs = concat (zipWith mkInfoTable info_uniques cps_procs) -------------------------------------------------------------------------------- @@ -71,141 +236,630 @@ mapMCmmTop f (Cmm xs) = liftM Cmm $ liftM concat $ mapM f xs -- and heap memory (not sure if that's usefull at all though, but it may -- be worth exploring the design space). -data CPSBlockInfo - = ControlBlock -- Consider whether a proc-point might want arguments on stack - | ContinuationBlock [(CmmReg,MachHint)] {- params -} - -type ContinuationFormat = [Maybe LocalReg] -- TODO: consider params as part of format +continuationLabel (Continuation _ l _ _ _) = l +data Continuation info = + Continuation + info -- Left <=> Continuation created by the CPS + -- Right <=> Function or Proc point + CLabel -- Used to generate both info & entry labels + CmmFormals -- Argument locals live on entry (C-- procedure params) + Bool -- ^ True <=> GC block so ignore stack size + [BrokenBlock] -- Code, may be empty. The first block is + -- the entry point. The order is otherwise initially + -- unimportant, but at some point the code gen will + -- fix the order. + + -- the BlockId of the first block does not give rise + -- to a label. To jump to the first block in a Proc, + -- use the appropriate CLabel. + +data ContinuationFormat + = ContinuationFormat { + continuation_formals :: CmmFormals, + continuation_label :: Maybe CLabel, -- The label occupying the top slot + continuation_frame_size :: WordOff, -- Total frame size in words (not including arguments) + continuation_stack :: [Maybe LocalReg] -- local reg offsets from stack top + } -- A block can be a continuation of a call -- A block can be a continuation of another block (w/ or w/o joins) -- A block can be an entry to a function -type CmmParam = [(CmmReg,MachHint)] - --- For now just select the continuation orders in the order they are in the set with no gaps -selectContinuationFormat :: UniqFM {-BlockId-} CmmParam -> UniqFM {-BlockId-} CmmLive -> UniqFM {-BlockId-} ContinuationFormat -selectContinuationFormat param live = mapUFM (map Just . uniqSetToList) live - -transformReturn block_infos formats (BasicBlock ident stmts) = - case last $ init stmts of - CmmReturn arguments -> - BasicBlock ident $ (init $ init stmts) ++ - [CmmJump (CmmReg spReg) arguments] - -- TODO: tail calls - -- TODO: return direct at the end of a block - _ -> BasicBlock ident stmts - -destructContinuation :: UniqFM {-BlockId-} CPSBlockInfo -> UniqFM {-BlockId-} ContinuationFormat -> CmmBasicBlock -> CmmBasicBlock -destructContinuation block_infos formats (BasicBlock ident stmts) = - case info of - ControlBlock -> BasicBlock ident stmts - ContinuationBlock _ -> BasicBlock ident (unpack_continuation ++ stmts) - where - info = lookupWithDefaultUFM block_infos (panic $ "info: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident - format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident - unpack_continuation = CmmAssign spReg (CmmRegOff spReg frame_size) : - [CmmAssign (CmmLocal reg) (CmmLoad (CmmRegOff spReg (i*stack_slot_size)) (localRegRep reg)) - | (i, Just reg) <- zip [1..] format] - frame_size = stack_header_size + stack_slot_size * (length format) - stack_header_size = stack_slot_size -- TODO: check if this could be different than stack_slot_size - stack_slot_size = 4 -- TODO: find actual variables to be used instead of this - -constructContinuation :: UniqFM {-BlockId-} CPSBlockInfo -> UniqFM {-BlockId-} ContinuationFormat -> CmmBasicBlock -> CmmBasicBlock -constructContinuation block_infos formats (BasicBlock ident stmts) = - case last $ init stmts of - -- TODO: global_saves - --CmmCall (CmmForeignCall target CmmCallConv) results arguments (Just []) -> --TODO: handle globals - CmmCall (CmmForeignCall target CmmCallConv) results arguments _ -> - BasicBlock ident $ - init (init stmts) ++ - pack_continuation ++ - [CmmJump target arguments] - CmmCall target results arguments _ -> panic "unimplemented CmmCall" - _ -> BasicBlock ident $ (init stmts) ++ build_block_branch - where - info = lookupWithDefaultUFM block_infos (panic $ "info: unknown block " ++ (showSDoc $ ppr $ getUnique next_block)) next_block - format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique next_block)) next_block - next_block = case last stmts of - CmmBranch next -> next - -- TODO: blocks with jump at end - -- TODO: blocks with return at end - _ -> panic "basic block without a branch at the end (unimplemented)" - next_block_as_proc_expr = CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique next_block - pack_continuation = CmmAssign spReg (CmmRegOff spReg (-frame_size)) : - CmmStore (CmmReg spReg) next_block_as_proc_expr : - [CmmStore (CmmRegOff spReg (i*stack_slot_size)) (CmmReg $ CmmLocal reg) - | (i, Just reg) <- zip [1..] format] - frame_size = stack_header_size + stack_slot_size * (length format) - stack_header_size = stack_slot_size -- TODO: check if this could be different than stack_slot_size (e.g. fixedHdrSize depends on PAR and GRAN) - stack_slot_size = 4 -- TODO: find actual variables to be used instead of this (e.g. cgRepSizeW) - block_needs_call = True -- TODO: use a table (i.e. proc-point) - build_block_branch = - if block_needs_call - then [CmmJump next_block_as_proc_expr [] {- TODO: pass live -}] {- NOTE: a block can never be both a continuation and a controll block -} - else [CmmBranch next_block] - --- TODO: TBD when to adjust the stack - -cpsProc :: CmmTop -> CPS [CmmTop] -cpsProc x@(CmmData _ _) = return [x] -cpsProc x@(CmmProc info_table ident params blocks) = do - broken_blocks <- liftM concat $ mapM breakBlock blocks - let live = cmmLiveness (map snd broken_blocks) - let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks - let formats = selectContinuationFormat (undefined {-TODO-}) live - let block_infos = listToUFM $ map (\(info, block) -> (blockId block, info)) broken_blocks - let blocks_with_live' = map (constructContinuation block_infos formats) blocks_with_live - let blocks_with_live'' = map (destructContinuation block_infos formats) blocks_with_live' - let blocks_with_live''' = map (transformReturn block_infos formats) blocks_with_live'' - - return $ [CmmProc info_table ident params blocks_with_live'''] +----------------------------------------------------------------------------- + +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 (lookupWithDefaultUFM 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 -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo) +gatherBlocksIntoContinuation live proc_points blocks start gc = + Continuation info_table clabel params is_gc_cont body + where + --start_and_gc = [start] -- : maybeToList gc + --children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc) + children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) [start]) `minusUniqSet` (unitUniqSet start) + start_block = lookupWithDefaultUFM blocks (panic "TODO") start + unknown_block = panic "unknown block in gatherBlocksIntoContinuation" + --gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) + -- (maybeToList gc) + children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children) + body = start_block : {-gc_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 (CmmNonInfo Nothing) + + 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 $ + lookupWithDefaultUFM live unknown_block start + -- it's a proc-point, pass lives in parameter registers -------------------------------------------------------------------------------- --- Takes a basic block and returns a list of basic blocks that --- each have at most 1 CmmCall in them which must occur at the end. --- Also returns with each basic block, the variables that will --- be arguments to the continuation of the block once the call (if any) returns. - -cmmBlockifyCalls :: [CmmBasicBlock] -> CPS [(CPSBlockInfo, CmmBasicBlock)] -cmmBlockifyCalls blocks = liftM concat $ mapM breakBlock blocks - --- [(CmmReg,MachHint)] is the results from the previous block that are expected as parameters ---breakBlock :: CmmBasicBlock -> CPS [(Maybe BlockId, CmmBasicBlock)] -breakBlock :: CmmBasicBlock -> CPS [(CPSBlockInfo, CmmBasicBlock)] -breakBlock (BasicBlock ident stmts) = breakBlock' ident ControlBlock [] stmts - -breakBlock' current_id block_info accum_stmts [] = - return [(block_info, BasicBlock current_id accum_stmts)] --- TODO: notice a call just before a branch, jump, call, etc. -breakBlock' current_id block_info accum_stmts (stmt@(CmmCall _ results _ _):stmts) = do - new_id <- newLabelCPS - let new_block = (block_info, BasicBlock current_id (accum_stmts ++ [stmt, CmmBranch new_id])) - rest <- breakBlock' new_id (ContinuationBlock results) [] stmts - return $ (new_block:rest) -breakBlock' current_id arguments accum_stmts (stmt:stmts) = - breakBlock' current_id arguments (accum_stmts ++ [stmt]) stmts - --------------------------------------------------------------------------------- -cmmCPS :: DynFlags - -> [Cmm] -- C-- with Proceedures - -> IO [Cmm] -- Output: CPS transformed C-- +-- For now just select the continuation orders in the order they are in the set with no gaps -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" - -- TODO: check for use of branches to non-existant blocks - -- TODO: check for use of Sp, SpLim, R1, R2, etc. - -- continuationC <- return abstractC - -- TODO: find out if it is valid to create a new unique source like this - uniqSupply <- mkSplitUniqSupply 'p' - let (_, continuationC) = runCPS (mapM (mapMCmmTop cpsProc) abstractC) (CPSState uniqSupply) +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 _ _ _ (ContInfo format srt))) + 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 srt) 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 $ + lookupWithDefaultUFM live unknown_block ident) + + unknown_block = panic "unknown BlockId in selectContinuationFormat" + +processFormats :: [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))] + -> [Continuation (Either C_SRT CmmInfo)] + -> (WordOff, [(CLabel, ContinuationFormat)]) +processFormats formats continuations = (max_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 }) + + -- 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 = machRepByteWidth (localRegRep 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 (cmmExprRep . fst) args + final_arg_size (FinalJump _ args) = + argumentsSize (cmmExprRep . fst) args + final_arg_size (FinalCall next _ _ args _ 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 (cmmExprRep . fst) 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 (cmmExprRep . fst) 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 prof gc tag (ContInfo _ srt))) + label formals is_gc blocks) = + Continuation (CmmInfo prof gc 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 formats (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 prof gc 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" + +----------------------------------------------------------------------------- +continuationToProc :: (WordOff, [(CLabel, ContinuationFormat)]) + -> CmmReg + -> [[Unique]] + -> Continuation CmmInfo + -> CmmTop +continuationToProc (max_stack, formats) stack_use uniques + (Continuation info label formals _ blocks) = + CmmProc info label formals (concat $ zipWith3 continuationToProc' uniques blocks (True : repeat False)) + where + curr_format = maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in continuationToProc" + curr_stack = continuation_frame_size curr_format + arg_stack = argumentsSize localRegRep formals + + param_stmts :: [CmmStmt] + param_stmts = function_entry curr_format + + gc_stmts :: [CmmStmt] + gc_stmts = + case info of + CmmInfo _ (Just gc_block) _ _ -> + gc_stack_check' stack_use arg_stack (max_stack - curr_stack) + CmmInfo _ Nothing _ _ -> + panic "continuationToProc: missing GC block" + CmmNonInfo (Just gc_block) -> + gc_stack_check' stack_use arg_stack (max_stack - curr_stack) + CmmNonInfo Nothing -> + panic "continuationToProc: missing non-info GC block" + +-- At present neither the Cmm parser nor the code generator +-- produce code that will allow the target of a CmmCondBranch +-- or a CmmSwitch to become a continuation or a proc-point. +-- If future revisions, might allow these to happen +-- then special care will have to be take to allow for that case. + continuationToProc' :: [Unique] + -> BrokenBlock + -> Bool + -> [CmmBasicBlock] + continuationToProc' uniques (BrokenBlock ident entry stmts _ exit) is_entry = + prefix_blocks ++ [main_block] + where + prefix_blocks = + case gc_prefix ++ param_prefix of + [] -> [] + entry_stmts -> [BasicBlock prefix_id + (entry_stmts ++ [CmmBranch ident])] + + prefix_unique : call_uniques = uniques + toCLabel = mkReturnPtLabel . getUnique + + block_for_branch unique next + | (Just cont_format) <- lookup (toCLabel next) formats + = let + new_next = BlockId unique + cont_stack = continuation_frame_size cont_format + arguments = map formal_to_actual (continuation_formals cont_format) + in (new_next, + [BasicBlock new_next $ + pack_continuation False curr_format cont_format ++ + tail_call (curr_stack - cont_stack) + (CmmLit $ CmmLabel $ toCLabel next) + arguments]) + | otherwise + = (next, []) + + block_for_branch' :: Unique -> Maybe BlockId -> (Maybe BlockId, [CmmBasicBlock]) + block_for_branch' _ Nothing = (Nothing, []) + block_for_branch' unique (Just next) = (Just new_next, new_blocks) + where (new_next, new_blocks) = block_for_branch unique next + + main_block = BasicBlock ident (stmts ++ postfix_stmts) + prefix_id = BlockId prefix_unique + gc_prefix = case entry of + FunctionEntry _ _ _ -> gc_stmts + ControlEntry -> [] + ContinuationEntry _ _ _ -> [] + param_prefix = if is_entry + then param_stmts + else [] + postfix_stmts = case exit of + FinalBranch next -> + if (mkReturnPtLabel $ getUnique next) == label + then [CmmBranch next] + else case lookup (mkReturnPtLabel $ getUnique next) formats of + Nothing -> [CmmBranch next] + Just cont_format -> + pack_continuation False curr_format cont_format ++ + tail_call (curr_stack - cont_stack) + (CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique next) + arguments + where + cont_stack = continuation_frame_size cont_format + arguments = map formal_to_actual (continuation_formals cont_format) + FinalSwitch expr targets -> [CmmSwitch expr targets] + FinalReturn arguments -> + tail_call curr_stack + (CmmLoad (CmmReg spReg) wordRep) + arguments + FinalJump target arguments -> + tail_call curr_stack target arguments + + -- A regular Cmm function call + FinalCall next (CmmForeignCall target CmmCallConv) + results arguments _ _ -> + pack_continuation True curr_format cont_format ++ + tail_call (curr_stack - cont_stack) + target arguments + where + cont_format = maybe unknown_block id $ + lookup (mkReturnPtLabel $ getUnique next) formats + cont_stack = continuation_frame_size cont_format + + -- A safe foreign call + FinalCall next (CmmForeignCall target conv) + results arguments _ _ -> + target_stmts ++ + foreignCall call_uniques' (CmmForeignCall new_target conv) + results arguments + where + (call_uniques', target_stmts, new_target) = + maybeAssignTemp call_uniques target + + -- A safe prim call + FinalCall next (CmmPrim target) + results arguments _ _ -> + foreignCall call_uniques (CmmPrim target) + results arguments + +formal_to_actual reg = (CmmReg (CmmLocal reg), NoHint) + +foreignCall :: [Unique] -> CmmCallTarget -> CmmHintFormals -> CmmActuals -> [CmmStmt] +foreignCall uniques call results arguments = + arg_stmts ++ + saveThreadState ++ + caller_save ++ + [CmmCall (CmmForeignCall suspendThread CCallConv) + [ (id,PtrHint) ] + [ (CmmReg (CmmGlobal BaseReg), PtrHint) ] + CmmUnsafe, + CmmCall call results new_args CmmUnsafe, + CmmCall (CmmForeignCall resumeThread CCallConv) + [ (new_base, PtrHint) ] + [ (CmmReg (CmmLocal id), PtrHint) ] + CmmUnsafe, + -- Assign the result to BaseReg: we + -- might now have a different Capability! + CmmAssign (CmmGlobal BaseReg) (CmmReg (CmmLocal new_base))] ++ + caller_load ++ + loadThreadState tso_unique ++ + [CmmJump (CmmReg spReg) (map (formal_to_actual . fst) results)] + where + (_, arg_stmts, new_args) = + loadArgsIntoTemps argument_uniques arguments + (caller_save, caller_load) = + callerSaveVolatileRegs (Just [{-only system regs-}]) + new_base = LocalReg base_unique (cmmRegRep (CmmGlobal BaseReg)) KindNonPtr + id = LocalReg id_unique wordRep KindNonPtr + tso_unique : base_unique : id_unique : argument_uniques = uniques + +-- ----------------------------------------------------------------------------- +-- Save/restore the thread state in the TSO + +suspendThread = CmmLit (CmmLabel (mkRtsCodeLabel SLIT("suspendThread"))) +resumeThread = CmmLit (CmmLabel (mkRtsCodeLabel SLIT("resumeThread"))) + +-- This stuff can't be done in suspendThread/resumeThread, because it +-- refers to global registers which aren't available in the C world. + +saveThreadState = + -- CurrentTSO->sp = Sp; + [CmmStore (cmmOffset stgCurrentTSO tso_SP) stgSp, + closeNursery] ++ + -- and save the current cost centre stack in the TSO when profiling: + if opt_SccProfilingOn + then [CmmStore (cmmOffset stgCurrentTSO tso_CCCS) curCCS] + else [] + + -- CurrentNursery->free = Hp+1; +closeNursery = CmmStore nursery_bdescr_free (cmmOffsetW stgHp 1) + +loadThreadState tso_unique = + [ + -- tso = CurrentTSO; + CmmAssign (CmmLocal tso) stgCurrentTSO, + -- Sp = tso->sp; + CmmAssign sp (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_SP) + wordRep), + -- SpLim = tso->stack + RESERVED_STACK_WORDS; + CmmAssign spLim (cmmOffsetW (cmmOffset (CmmReg (CmmLocal tso)) tso_STACK) + rESERVED_STACK_WORDS) + ] ++ + openNursery ++ + -- and load the current cost centre stack from the TSO when profiling: + if opt_SccProfilingOn + then [CmmStore curCCSAddr + (CmmLoad (cmmOffset (CmmReg (CmmLocal tso)) tso_CCCS) wordRep)] + else [] + where tso = LocalReg tso_unique wordRep KindNonPtr -- TODO FIXME NOW + + +openNursery = [ + -- Hp = CurrentNursery->free - 1; + CmmAssign hp (cmmOffsetW (CmmLoad nursery_bdescr_free wordRep) (-1)), + + -- HpLim = CurrentNursery->start + + -- CurrentNursery->blocks*BLOCK_SIZE_W - 1; + CmmAssign hpLim + (cmmOffsetExpr + (CmmLoad nursery_bdescr_start wordRep) + (cmmOffset + (CmmMachOp mo_wordMul [ + CmmMachOp (MO_S_Conv I32 wordRep) + [CmmLoad nursery_bdescr_blocks I32], + CmmLit (mkIntCLit bLOCK_SIZE) + ]) + (-1) + ) + ) + ] + + +nursery_bdescr_free = cmmOffset stgCurrentNursery oFFSET_bdescr_free +nursery_bdescr_start = cmmOffset stgCurrentNursery oFFSET_bdescr_start +nursery_bdescr_blocks = cmmOffset stgCurrentNursery oFFSET_bdescr_blocks + +tso_SP = tsoFieldB oFFSET_StgTSO_sp +tso_STACK = tsoFieldB oFFSET_StgTSO_stack +tso_CCCS = tsoProfFieldB oFFSET_StgTSO_CCCS + +-- The TSO struct has a variable header, and an optional StgTSOProfInfo in +-- the middle. The fields we're interested in are after the StgTSOProfInfo. +tsoFieldB :: ByteOff -> ByteOff +tsoFieldB off + | opt_SccProfilingOn = off + sIZEOF_StgTSOProfInfo + fixedHdrSize * wORD_SIZE + | otherwise = off + fixedHdrSize * wORD_SIZE + +tsoProfFieldB :: ByteOff -> ByteOff +tsoProfFieldB off = off + fixedHdrSize * wORD_SIZE + +stgSp = CmmReg sp +stgHp = CmmReg hp +stgCurrentTSO = CmmReg currentTSO +stgCurrentNursery = CmmReg currentNursery + +sp = CmmGlobal Sp +spLim = CmmGlobal SpLim +hp = CmmGlobal Hp +hpLim = CmmGlobal HpLim +currentTSO = CmmGlobal CurrentTSO +currentNursery = CmmGlobal CurrentNursery + +----------------------------------------------------------------------------- +-- Functions that generate CmmStmt sequences +-- for packing/unpacking continuations +-- and entering/exiting functions + +tail_call :: WordOff -> CmmExpr -> CmmActuals -> [CmmStmt] +tail_call spRel target arguments + = store_arguments ++ adjust_spReg ++ jump where + store_arguments = + [stack_put spRel expr offset + | ((expr, _), StackParam offset) <- argument_formats] ++ + [global_put expr global + | ((expr, _), RegisterParam global) <- argument_formats] + adjust_spReg = + if spRel == 0 + then [] + else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))] + jump = [CmmJump target arguments] + + argument_formats = assignArguments (cmmExprRep . fst) arguments + +gc_stack_check' stack_use arg_stack max_frame_size = + if max_frame_size > arg_stack + then [CmmAssign stack_use (CmmRegOff spReg (-max_frame_size*wORD_SIZE))] + else [CmmAssign stack_use (CmmReg spLimReg)] + -- Trick the optimizer into eliminating the branch for us + +gc_stack_check :: BlockId -> WordOff -> [CmmStmt] +gc_stack_check gc_block max_frame_size + = check_stack_limit where + check_stack_limit = [ + CmmCondBranch + (CmmMachOp (MO_U_Lt $ cmmRegRep spReg) + [CmmRegOff spReg (-max_frame_size*wORD_SIZE), + CmmReg spLimReg]) + gc_block] + + +-- TODO: fix branches to proc point +-- (we have to insert a new block to marshel the continuation) + + +pack_continuation :: Bool -- ^ Whether to set the top/header + -- of the stack. We only need to + -- set it if we are calling down + -- as opposed to continuation + -- adaptors. + -> ContinuationFormat -- ^ The current format + -> ContinuationFormat -- ^ The return point format + -> [CmmStmt] +pack_continuation allow_header_set + (ContinuationFormat _ curr_id curr_frame_size _) + (ContinuationFormat _ cont_id cont_frame_size live_regs) + = store_live_values ++ set_stack_header where + -- TODO: only save variables when actually needed + -- (may be handled by latter pass) + store_live_values = + [stack_put spRel (CmmReg (CmmLocal reg)) offset + | (reg, offset) <- cont_offsets] + set_stack_header = + if needs_header_set && allow_header_set + then [stack_put spRel continuation_function 0] + else [] + + -- TODO: factor with function_entry and CmmInfo.hs(?) + cont_offsets = mkOffsets label_size live_regs + + label_size = 1 :: WordOff + + mkOffsets size [] = [] + mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs + mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs + where + width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE + -- TODO: it would be better if we had a machRepWordWidth + + spRel = curr_frame_size - cont_frame_size + continuation_function = CmmLit $ CmmLabel $ fromJust cont_id + needs_header_set = + case (curr_id, cont_id) of + (Just x, Just y) -> x /= y + _ -> isJust cont_id + +-- Lazy adjustment of stack headers assumes all blocks +-- that could branch to eachother (i.e. control blocks) +-- have the same stack format (this causes a problem +-- only for proc-point). +function_entry :: ContinuationFormat -> [CmmStmt] +function_entry (ContinuationFormat formals _ _ live_regs) + = load_live_values ++ load_args where + -- TODO: only save variables when actually needed + -- (may be handled by latter pass) + load_live_values = + [stack_get 0 reg offset + | (reg, offset) <- curr_offsets] + load_args = + [stack_get 0 reg offset + | (reg, StackParam offset) <- argument_formats] ++ + [global_get reg global + | (reg, RegisterParam global) <- argument_formats] + + argument_formats = assignArguments (localRegRep) formals + + -- TODO: eliminate copy/paste with pack_continuation + curr_offsets = mkOffsets label_size live_regs + + label_size = 1 :: WordOff + + mkOffsets size [] = [] + mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs + mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs + where + width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE + -- TODO: it would be better if we had a machRepWordWidth + +----------------------------------------------------------------------------- +-- Section: Stack and argument register puts and gets +----------------------------------------------------------------------------- +-- TODO: document + +-- |Construct a 'CmmStmt' that will save a value on the stack +stack_put :: WordOff -- ^ Offset from the real 'Sp' that 'offset' + -- is relative to (added to offset) + -> CmmExpr -- ^ What to store onto the stack + -> WordOff -- ^ Where on the stack to store it + -- (positive <=> higher addresses) + -> CmmStmt +stack_put spRel expr offset = + CmmStore (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) expr + +-------------------------------- +-- |Construct a +stack_get :: WordOff + -> LocalReg + -> WordOff + -> CmmStmt +stack_get spRel reg offset = + CmmAssign (CmmLocal reg) + (CmmLoad (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) + (localRegRep reg)) +global_put :: CmmExpr -> GlobalReg -> CmmStmt +global_put expr global = CmmAssign (CmmGlobal global) expr +global_get :: LocalReg -> GlobalReg -> CmmStmt +global_get reg global = CmmAssign (CmmLocal reg) (CmmReg (CmmGlobal global)) - dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC) - -- TODO: add option to dump Cmm to file - return continuationC