-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 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
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)
--------------------------------------------------------------------------------
-- 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
projects / ghc-hetmet.git / blobdiff