X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmCPS.hs;h=25683eebb1505764fbf453d1eb5f1a06f1cdad1f;hb=f96fcdc91b424aafca4d06572864fd20c475eaa0;hp=7cc89ba8ebba56eec66952ef97ed48e3abc4fa86;hpb=9a740fb96076fe9e02a62e391a905c6ca6d3a571;p=ghc-hetmet.git diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index 7cc89ba..25683ee 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" @@ -6,9 +10,15 @@ import Cmm import CmmLint import PprCmm -import Dataflow (fixedpoint) import CmmLive - +import CmmBrokenBlock +import CmmProcPoint +import CmmCallConv +import CmmInfo +import CmmUtils + +import Bitmap +import ClosureInfo import MachOp import ForeignCall import CLabel @@ -28,6 +38,149 @@ import Monad import IO import Data.List +----------------------------------------------------------------------------- +-- |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" + + -- 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 doCpsProc s (Cmm c) = + Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c + let continuationC = zipWith doCpsProc supplies abstractC + + dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC) + + -- TODO: add option to dump Cmm to file + + return continuationC + +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) + +force_gc_block old_info block_id fun_label formals = + case old_info of + CmmNonInfo (Just _) -> (old_info, []) + CmmInfo _ (Just _) _ _ -> (old_info, []) + CmmNonInfo Nothing + -> (CmmNonInfo (Just block_id), + [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)]) + 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)]) + 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 + uniques :: [[Unique]] + uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply + (gc_unique:info_uniques):block_uniques = uniques + + -- Ensure that + forced_gc :: (CmmInfo, [CmmBasicBlock]) + forced_gc = force_gc_block info (BlockId gc_unique) ident params + + forced_info = fst forced_gc + forced_blocks = blocks ++ snd forced_gc + 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 :: [BrokenBlock] + broken_blocks = + concat $ zipWith3 breakBlock block_uniques forced_blocks + (FunctionEntry forced_info ident params:repeat ControlEntry) + + -- 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 proc_points block_env) + (uniqSetToList proc_points) + (Just forced_gc_id : repeat Nothing) + + -- 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 + (Maybe CLabel, -- label in top slot + [Maybe LocalReg]))] -- slots + formats = selectStackFormat 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, StackFormat)]) + formats' = processFormats formats continuations + + -- Update the info table data on the continuations with + -- the selected stack formats. + continuations' :: [Continuation CmmInfo] + continuations' = map (applyStackFormat (snd formats')) continuations + + -- Do the actual CPS transform. + cps_procs :: [CmmTop] + cps_procs = map (continuationToProc formats') 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) + -------------------------------------------------------------------------------- -- The format for the call to a continuation @@ -45,33 +198,14 @@ import Data.List -- and heap memory (not sure if that's usefull at all though, but it may -- be worth exploring the design space). -data BrokenBlock - = BrokenBlock { - brokenBlockId :: BlockId, -- Like a CmmBasicBlock - brokenBlockEntry :: BlockEntryInfo, - -- How this block can be entered - - brokenBlockStmts :: [CmmStmt], - -- Like a CmmBasicBlock - -- (but without the last statement) - - brokenBlockTargets :: [BlockId], - -- Blocks that this block could - -- branch to one either by conditional - -- branches or via the last statement - - brokenBlockExit :: FinalStmt - -- How the block can be left - } - -continuationLabel (Continuation _ _ l _ _) = l -data Continuation = +continuationLabel (Continuation _ l _ _) = l +data Continuation info = Continuation - Bool -- True => Function entry, False => Continuation/return point - [CmmStatic] -- Info table, may be empty + 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) - [BrokenBlock] -- Code, may be empty. The first block is + [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. @@ -80,439 +214,368 @@ data Continuation = -- to a label. To jump to the first block in a Proc, -- use the appropriate CLabel. -data BlockEntryInfo - = FunctionEntry -- Beginning of a function - CLabel -- The function name - CmmFormals -- Aguments to function - - | ContinuationEntry -- Return point of a call - CmmFormals -- return values (argument to continuation) - -- TODO: - -- | ProcPointEntry -- no return values, but some live might end up as params or possibly in the frame - - | ControlEntry -- A label in the input - --- Final statement in a BlokenBlock --- Constructors and arguments match those in Cmm, --- but are restricted to branches, returns, jumps, calls and switches -data FinalStmt - = FinalBranch - BlockId -- next block (must be a ControlEntry) - - | FinalReturn - CmmActuals -- return values - - | FinalJump - CmmExpr -- the function to call - CmmActuals -- arguments to call - - | FinalCall - BlockId -- next block after call (must be a ContinuationEntry) - CmmCallTarget -- the function to call - CmmFormals -- results from call (redundant with ContinuationEntry) - CmmActuals -- arguments to call - (Maybe [GlobalReg]) -- registers that must be saved (TODO) - - | FinalSwitch - CmmExpr [Maybe BlockId] -- Table branch - - -- TODO: | ProcPointExit (needed?) - --- Describes the layout of a stack frame for a continuation data StackFormat - = StackFormat - (Maybe CLabel) -- The label occupying the top slot - WordOff -- Total frame size in words - [(CmmReg, WordOff)] -- local reg offsets from stack top + = StackFormat { + stack_label :: Maybe CLabel, -- The label occupying the top slot + stack_frame_size :: WordOff, -- Total frame size in words (not including arguments) + stack_live :: [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 -blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock -blocksToBlockEnv blocks = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks - ----------------------------------------------------------------------------- -calculateOwnership :: UniqSet BlockId -> [BrokenBlock] -> BlockEnv (UniqSet BlockId) -calculateOwnership proc_points blocks = - fixedpoint dependants update (map brokenBlockId blocks) emptyUFM - where - blocks_ufm :: BlockEnv BrokenBlock - blocks_ufm = blocksToBlockEnv blocks - - dependants :: BlockId -> [BlockId] - dependants ident = - brokenBlockTargets $ lookupWithDefaultUFM - blocks_ufm unknown_block ident - - update :: BlockId -> Maybe BlockId - -> BlockEnv (UniqSet BlockId) -> Maybe (BlockEnv (UniqSet BlockId)) - update ident cause owners = - case (cause, ident `elementOfUniqSet` proc_points) of - (Nothing, True) -> Just $ addToUFM owners ident (unitUniqSet ident) - (Nothing, False) -> Nothing - (Just cause', True) -> Nothing - (Just cause', False) -> - if (sizeUniqSet old) == (sizeUniqSet new) - then Nothing - else Just $ addToUFM owners ident new - where - old = lookupWithDefaultUFM owners emptyUniqSet ident - new = old `unionUniqSets` lookupWithDefaultUFM owners emptyUniqSet cause' - - unknown_block = panic "unknown BlockId in selectStackFormat" - -calculateProcPoints :: [BrokenBlock] -> UniqSet BlockId -calculateProcPoints blocks = calculateProcPoints' init_proc_points blocks - where - init_proc_points = mkUniqSet $ - map brokenBlockId $ - filter always_proc_point blocks - always_proc_point BrokenBlock { - brokenBlockEntry = FunctionEntry _ _ } = True - always_proc_point BrokenBlock { - brokenBlockEntry = ContinuationEntry _ } = True - always_proc_point _ = False - -calculateProcPoints' :: UniqSet BlockId -> [BrokenBlock] -> UniqSet BlockId -calculateProcPoints' old_proc_points blocks = - if sizeUniqSet old_proc_points == sizeUniqSet new_proc_points - then old_proc_points - else calculateProcPoints' new_proc_points blocks - where - owners = calculateOwnership old_proc_points blocks - new_proc_points = unionManyUniqSets (old_proc_points:(map (calculateProcPoints'' owners) blocks)) - -calculateProcPoints'' :: BlockEnv (UniqSet BlockId) -> BrokenBlock -> UniqSet BlockId -calculateProcPoints'' owners block = - unionManyUniqSets (map (f parent_id) child_ids) - where - parent_id = brokenBlockId block - child_ids = brokenBlockTargets block - -- TODO: name for f - f parent_id child_id = - if needs_proc_point - then unitUniqSet child_id - else emptyUniqSet - where - parent_owners = lookupWithDefaultUFM owners emptyUniqSet parent_id - child_owners = lookupWithDefaultUFM owners emptyUniqSet child_id - needs_proc_point = not $ isEmptyUniqSet $ child_owners `minusUniqSet` parent_owners collectNonProcPointTargets :: UniqSet BlockId -> BlockEnv BrokenBlock - -> UniqSet BlockId -> BlockId -> UniqSet BlockId -collectNonProcPointTargets proc_points blocks current_targets block = + -> 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 targets + else foldl + (collectNonProcPointTargets proc_points blocks) + new_targets + (map (:[]) targets) where - block' = lookupWithDefaultUFM blocks (panic "TODO") block + 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 $ (mkUniqSet $ brokenBlockTargets block') `minusUniqSet` proc_points + uniqSetToList $ (unionManyUniqSets $ map (mkUniqSet . brokenBlockTargets) blocks') + `minusUniqSet` proc_points -- TODO: remove redundant uniqSetToList new_targets = current_targets `unionUniqSets` (mkUniqSet targets) -buildContinuation :: +-- 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 :: UniqSet BlockId -> BlockEnv BrokenBlock - -> BlockId -> Continuation -buildContinuation proc_points blocks start = - Continuation is_entry info_table clabel params body + -> BlockId -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo) +gatherBlocksIntoContinuation proc_points blocks start gc = + Continuation info_table clabel params body where - children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start + start_and_gc = start : maybeToList gc + children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc) start_block = lookupWithDefaultUFM blocks (panic "TODO") start + gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) (maybeToList gc) children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children) - body = start_block : children_blocks - info_table = [] -- TODO + 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) + start_block_entry = brokenBlockEntry start_block - is_entry = case start_block_entry of - FunctionEntry _ _ -> True - _ -> False clabel = case start_block_entry of - FunctionEntry label _ -> label + FunctionEntry _ label _ -> label _ -> mkReturnPtLabel $ getUnique start params = case start_block_entry of - FunctionEntry _ args -> args - ContinuationEntry args -> args + FunctionEntry _ _ args -> args + ContinuationEntry args _ -> args ControlEntry -> [] -- TODO: it's a proc-point, we could pass lives in parameter registers -------------------------------------------------------------------------------- -- For now just select the continuation orders in the order they are in the set with no gaps -selectStackFormat2 :: BlockEnv CmmLive -> [Continuation] -> [(CLabel, StackFormat)] -selectStackFormat2 live continuations = +selectStackFormat :: BlockEnv CmmLive + -> [Continuation (Either C_SRT CmmInfo)] + -> [(CLabel, (Maybe CLabel, [Maybe LocalReg]))] +selectStackFormat live continuations = map (\c -> (continuationLabel c, selectStackFormat' c)) continuations where - selectStackFormat' (Continuation True info_table label formals blocks) = - --let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this - --in - StackFormat (Just label) 0 [] - selectStackFormat' (Continuation False info_table label formals blocks) = + selectStackFormat' (Continuation + (Right (CmmInfo _ _ _ (ContInfo format srt))) + label _ _) = (Just label, format) + selectStackFormat' (Continuation (Right _) _ _ _) = (Nothing, []) + selectStackFormat' (Continuation (Left srt) label _ 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 live_to_format label formals $ lookupWithDefaultUFM live unknown_block ident + in (Just label, + map Just $ uniqSetToList $ + lookupWithDefaultUFM live unknown_block ident) - live_to_format :: CLabel -> CmmFormals -> CmmLive -> StackFormat - live_to_format label formals live = - foldl extend_format - (StackFormat (Just label) retAddrSizeW []) - (uniqSetToList (live `minusUniqSet` mkUniqSet (cmmFormalsToLiveLocals formals))) + unknown_block = panic "unknown BlockId in selectStackFormat" - extend_format :: StackFormat -> LocalReg -> StackFormat - extend_format (StackFormat label size offsets) reg = - StackFormat label (slot_size reg + size) ((CmmLocal reg, size) : offsets) +processFormats :: [(CLabel, (Maybe CLabel, [Maybe LocalReg]))] + -> [Continuation (Either C_SRT CmmInfo)] + -> (WordOff, [(CLabel, StackFormat)]) +processFormats formats continuations = (max_size, formats') + where + max_size = maximum $ + 0 : map (continuationMaxStack formats') continuations + formats' = map make_format formats + make_format (label, format) = + (label, + StackFormat { + stack_label = fst format, + stack_frame_size = stack_size (snd format) + + if isJust (fst format) + then label_size + else 0, + stack_live = snd format }) + + -- 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, StackFormat)] + -> Continuation a + -> WordOff +continuationMaxStack formats (Continuation _ label _ blocks) = + max_arg_size + stack_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) = + -- We have to account for the stack used when we build a frame + -- for the *next* continuation from *this* continuation + argumentsSize (cmmExprRep . fst) args + + stack_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 - unknown_block = panic "unknown BlockId in selectStackFormat" +----------------------------------------------------------------------------- +applyStackFormat :: [(CLabel, StackFormat)] + -> Continuation (Either C_SRT CmmInfo) + -> Continuation CmmInfo + +-- User written continuations +applyStackFormat formats (Continuation + (Right (CmmInfo prof gc tag (ContInfo _ srt))) + label formals blocks) = + Continuation (CmmInfo prof gc tag (ContInfo format srt)) + label formals blocks + where + format = stack_live $ maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in applyStackFormat" -slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1 +-- User written non-continuation code +applyStackFormat formats (Continuation (Right info) label formals blocks) = + Continuation info label formals blocks -constructContinuation :: [(CLabel, StackFormat)] -> Continuation -> CmmTop -constructContinuation formats (Continuation is_entry info label formals blocks) = - CmmProc info label formals (map (constructContinuation2' label formats) blocks) +-- CPS generated continuations +applyStackFormat formats (Continuation (Left srt) label formals blocks) = + Continuation (CmmInfo prof gc tag (ContInfo (stack_live $ format) srt)) + label formals 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 applyStackFormat" -constructContinuation2' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock - -> CmmBasicBlock -constructContinuation2' curr_ident formats (BrokenBlock ident entry stmts _ exit) = - BasicBlock ident (prefix++stmts++postfix) +----------------------------------------------------------------------------- +continuationToProc :: (WordOff, [(CLabel, StackFormat)]) + -> Continuation CmmInfo + -> CmmTop +continuationToProc (max_stack, formats) + (Continuation info label formals blocks) = + CmmProc info label formals (map continuationToProc' blocks) where - curr_format = maybe unknown_block id $ lookup curr_ident formats - unknown_block = panic "unknown BlockId in constructContinuation" - prefix = case entry of - ControlEntry -> [] - FunctionEntry _ _ -> [] - ContinuationEntry formals -> - unpack_continuation curr_format - postfix = case exit of - FinalBranch next -> [CmmBranch next] - FinalSwitch expr targets -> [CmmSwitch expr targets] - FinalReturn arguments -> - exit_function curr_format - (CmmLoad (CmmReg spReg) wordRep) - arguments - FinalJump target arguments -> - exit_function curr_format target arguments - -- TODO: do something about global saves - FinalCall next (CmmForeignCall target CmmCallConv) - results arguments saves -> + curr_format = maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in continuationToProc" + + continuationToProc' :: BrokenBlock -> CmmBasicBlock + continuationToProc' (BrokenBlock ident entry stmts _ exit) = + BasicBlock ident (prefix++stmts++postfix) + where + prefix = case entry of + ControlEntry -> [] + FunctionEntry (CmmInfo _ (Just gc_block) _ _) _ formals -> + gc_stack_check gc_block max_stack ++ + function_entry formals curr_format + FunctionEntry (CmmInfo _ Nothing _ _) _ formals -> + panic "continuationToProc: missing GC block" + FunctionEntry (CmmNonInfo (Just gc_block)) _ formals -> + gc_stack_check gc_block max_stack ++ + function_entry formals curr_format + FunctionEntry (CmmNonInfo Nothing) _ formals -> + panic "continuationToProc: missing non-info GC block" + ContinuationEntry formals _ -> + function_entry formals curr_format + postfix = case exit of + FinalBranch next -> [CmmBranch next] + FinalSwitch expr targets -> [CmmSwitch expr targets] + FinalReturn arguments -> + tail_call (stack_frame_size curr_format) + (CmmLoad (CmmReg spReg) wordRep) + arguments + FinalJump target arguments -> + tail_call (stack_frame_size curr_format) target arguments + FinalCall next (CmmForeignCall target CmmCallConv) + results arguments -> pack_continuation curr_format cont_format ++ - [CmmJump target arguments] + tail_call (stack_frame_size curr_format - stack_frame_size cont_format) + target arguments where cont_format = maybe unknown_block id $ lookup (mkReturnPtLabel $ getUnique next) formats - FinalCall next _ results arguments saves -> panic "unimplemented CmmCall" + FinalCall next _ results arguments -> panic "unimplemented CmmCall" --------------------------------------------------------------------------------- +----------------------------------------------------------------------------- -- Functions that generate CmmStmt sequences -- for packing/unpacking continuations -- and entering/exiting functions -exit_function :: StackFormat -> CmmExpr -> CmmActuals -> [CmmStmt] -exit_function (StackFormat curr_id curr_frame_size curr_offsets) target arguments - = adjust_spReg ++ jump where +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 curr_frame_size == 0 + if spRel == 0 then [] - else [CmmAssign spReg - (CmmRegOff spReg (curr_frame_size*wORD_SIZE))] + else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))] jump = [CmmJump target arguments] -enter_function :: WordOff -> [CmmStmt] -enter_function max_frame_size + argument_formats = assignArguments (cmmExprRep . fst) arguments + +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, CmmReg spLimReg]) + [CmmRegOff spReg (-max_frame_size*wORD_SIZE), + CmmReg spLimReg]) gc_block] - gc_block = undefined -- TODO: get stack and heap checks to go to same --- TODO: fix branches to proc point (we have to insert a new block to marshel the continuation) +-- TODO: fix branches to proc point +-- (we have to insert a new block to marshel the continuation) pack_continuation :: StackFormat -> StackFormat -> [CmmStmt] -pack_continuation (StackFormat curr_id curr_frame_size curr_offsets) - (StackFormat cont_id cont_frame_size cont_offsets) - = save_live_values ++ set_stack_header ++ adjust_spReg where +pack_continuation (StackFormat curr_id curr_frame_size _) + (StackFormat cont_id cont_frame_size live_regs) + = store_live_values ++ set_stack_header where -- TODO: only save variables when actually needed - save_live_values = - [CmmStore - (CmmRegOff - spReg (wORD_SIZE*(curr_frame_size - cont_frame_size + offset))) - (CmmReg reg) + -- (may be handled by latter pass) + store_live_values = + [stack_put spRel (CmmReg (CmmLocal reg)) offset | (reg, offset) <- cont_offsets] - needs_header = - case (curr_id, cont_id) of - (Just x, Just y) -> x /= y - _ -> isJust cont_id set_stack_header = - if not needs_header - then [] - else [CmmStore (CmmRegOff spReg (wORD_SIZE*(curr_frame_size - cont_frame_size))) continuation_function] + if needs_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 - adjust_spReg = - if curr_frame_size == cont_frame_size - then [] - else [CmmAssign spReg (CmmRegOff spReg ((curr_frame_size - cont_frame_size)*wORD_SIZE))] + 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). -unpack_continuation :: StackFormat -> [CmmStmt] -unpack_continuation (StackFormat curr_id curr_frame_size curr_offsets) - = load_live_values where +function_entry :: CmmFormals -> StackFormat -> [CmmStmt] +function_entry formals (StackFormat _ _ live_regs) + = load_live_values ++ load_args where -- TODO: only save variables when actually needed + -- (may be handled by latter pass) load_live_values = - [CmmAssign - reg - (CmmLoad (CmmRegOff spReg (wORD_SIZE*offset)) (cmmRegRep reg)) + [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] ------------------------------------------------------------------------------ --- Breaking basic blocks on function calls ------------------------------------------------------------------------------ + argument_formats = assignArguments (localRegRep) formals ------------------------------------------------------------------------------ --- Takes a basic block and breaks it up into a list of broken blocks --- --- 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. - -breakBlock :: [Unique] -> CmmBasicBlock -> BlockEntryInfo -> [BrokenBlock] -breakBlock uniques (BasicBlock ident stmts) entry = - breakBlock' uniques ident entry [] [] stmts where - breakBlock' uniques current_id entry exits accum_stmts stmts = - case stmts of - [] -> panic "block doesn't end in jump, goto or return" - [CmmJump target arguments] -> - [BrokenBlock current_id entry accum_stmts - exits - (FinalJump target arguments)] - [CmmReturn arguments] -> - [BrokenBlock current_id entry accum_stmts - exits - (FinalReturn arguments)] - [CmmBranch target] -> - [BrokenBlock current_id entry accum_stmts - (target:exits) - (FinalBranch target)] - [CmmSwitch expr targets] -> - [BrokenBlock current_id entry accum_stmts - (mapMaybe id targets ++ exits) - (FinalSwitch expr targets)] - (CmmJump _ _:_) -> - panic "jump in middle of block" - (CmmReturn _:_) -> - panic "return in middle of block" - (CmmBranch _:_) -> - panic "branch in middle of block" - (CmmSwitch _ _:_) -> - panic ("switch in middle of block" ++ (showSDoc $ ppr stmts)) - (CmmCall target results arguments saves:stmts) -> block : rest - where - new_id = BlockId $ head uniques - block = BrokenBlock current_id entry accum_stmts - (new_id:exits) - (FinalCall new_id target results arguments saves) - rest = breakBlock' (tail uniques) new_id - (ContinuationEntry results) [] [] stmts - (s@(CmmCondBranch test target):stmts) -> - breakBlock' uniques current_id entry - (target:exits) (accum_stmts++[s]) stmts - (s:stmts) -> - breakBlock' uniques current_id entry - exits (accum_stmts++[s]) stmts + -- TODO: eliminate copy/paste with pack_continuation + curr_offsets = mkOffsets label_size live_regs --------------------------------- --- Convert from a BrokenBlock --- to a CmmBasicBlock so the --- liveness analysis can run --- on it. --------------------------------- -cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock -cmmBlockFromBrokenBlock (BrokenBlock ident _ stmts _ exit) = - BasicBlock ident (stmts++exit_stmt) - where - exit_stmt = - case exit of - FinalBranch target -> [CmmBranch target] - FinalReturn arguments -> [CmmReturn arguments] - FinalJump target arguments -> [CmmJump target arguments] - FinalSwitch expr targets -> [CmmSwitch expr targets] - FinalCall branch_target call_target results arguments saves -> - [CmmCall call_target results arguments saves, - CmmBranch branch_target] + 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 ----------------------------------------------------------------------------- --- CPS a single CmmTop (proceedure) +-- 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 -cpsProc :: UniqSupply -> CmmTop -> [CmmTop] -cpsProc uniqSupply x@(CmmData _ _) = [x] -cpsProc uniqSupply x@(CmmProc info_table ident params blocks) = - --[CmmProc info_table ident params cps_blocks] - cps_continuations - where - uniqes :: [[Unique]] - uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply - - -- Break the block at each function call - broken_blocks :: [BrokenBlock] - broken_blocks = concat $ zipWith3 breakBlock uniqes blocks - (FunctionEntry ident params:repeat ControlEntry) - - -- Calculate live variables for each broken block - live :: BlockEntryLiveness - live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks - -- nothing can be live on entry to the first block so we could take the tail - - proc_points :: UniqSet BlockId - proc_points = calculateProcPoints broken_blocks - - continuations :: [Continuation] - continuations = map (buildContinuation proc_points (blocksToBlockEnv broken_blocks)) (uniqSetToList proc_points) - - -- 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 - - -- TODO: let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks - - --procs = groupBlocksIntoContinuations live broken_blocks - - -- Select the stack format on entry to each block - formats2 :: [(CLabel, StackFormat)] - formats2 = selectStackFormat2 live continuations - - -- Do the actual CPS transform - cps_continuations :: [CmmTop] - cps_continuations = map (constructContinuation formats2) continuations - --------------------------------------------------------------------------------- -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" - -- TODO: check for use of branches to non-existant blocks - -- TODO: check for use of Sp, SpLim, R1, R2, etc. - -- TODO: find out if it is valid to create a new unique source like this - uniqSupply <- mkSplitUniqSupply 'p' - let supplies = listSplitUniqSupply uniqSupply - let continuationC = zipWith (\s (Cmm c) -> Cmm $ concat $ zipWith (cpsProc) (listSplitUniqSupply s) c) supplies abstractC +-------------------------------- +-- |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