-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 (fixedpoint)
import CmmLive
+import CmmBrokenBlock
+import CmmProcPoint
+import CmmCallConv
+import CmmCPSGen
+import CmmUtils
+import ClosureInfo
import MachOp
import ForeignCall
import CLabel
import IO
import Data.List
---------------------------------------------------------------------------------
-
--- The format for the call to a continuation
--- The fst is the arguments that must be passed to the continuation
--- by the continuation's caller.
--- The snd is the live values that must be saved on stack.
--- A Nothing indicates an ignored slot.
--- The head of each list is the stack top or the first parameter.
-
--- The format for live values for a particular continuation
--- All on stack for now.
--- Head element is the top of the stack (or just under the header).
--- Nothing means an empty slot.
--- Future possibilities include callee save registers (i.e. passing slots in register)
--- 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
- }
-
-
-data BlockEntryInfo
- = FunctionEntry -- Beginning of function
-
- | ContinuationEntry -- Return point of a call
- CmmFormals -- return values
- -- TODO:
- -- | ProcPointEntry -- no return values, but some live might end up as params or possibly in the frame
-
- | ControlEntry -- A label in the input
-
-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)
- -- TODO: | ProcPointExit (needed?)
-
-data StackFormat
- = StackFormat
- BlockId {- block that is the start of the continuation. may or may not be the current block -}
- WordOff {- total frame size -}
- [(CmmReg, WordOff)] {- 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
+-----------------------------------------------------------------------------
+-- |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 CmmInfo 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"
---------------------------------------------------------------------------------
--- For now just select the continuation orders in the order they are in the set with no gaps
+ -- TODO: more lint checking
+ -- check for use of branches to non-existant blocks
+ -- check for use of Sp, SpLim, R1, R2, etc.
-selectStackFormat2 :: BlockEnv CmmLive -> [BrokenBlock] -> BlockEnv StackFormat
-selectStackFormat2 live blocks = fixedpoint dependants update (map brokenBlockId blocks) emptyUFM where
- blocks_ufm = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks
- dependants ident =
- brokenBlockTargets $ lookupWithDefaultUFM blocks_ufm (panic "TODO") ident
- update ident cause formats =
- let BrokenBlock _ entry _ _ _ = lookupWithDefaultUFM blocks_ufm (panic "unknown BlockId in selectStackFormat:live") ident in
- case cause of
- -- Propagate only to blocks entered by branches (not function entry blocks or continuation entry blocks)
- Just cause_name ->
- let cause_format = lookupWithDefaultUFM formats (panic "update signaled for block not in format") cause_name
- in case entry of
- ControlEntry -> Just $ addToUFM formats ident cause_format
- FunctionEntry -> Nothing
- ContinuationEntry _ -> Nothing
- -- Do initial calculates for function blocks
- Nothing ->
- case entry of
- ControlEntry -> Nothing
- FunctionEntry -> Just $ addToUFM formats ident $ StackFormat ident 0 []
- ContinuationEntry _ -> Just $ addToUFM formats ident $ live_to_format ident $ lookupWithDefaultUFM live (panic "TODO") ident
- live_to_format label live =
- foldl extend_format
- (StackFormat label retAddrSizeW [])
- (uniqSetToList live)
- extend_format :: StackFormat -> LocalReg -> StackFormat
- extend_format (StackFormat block size offsets) reg =
- StackFormat block (slot_size reg + size) ((CmmLocal reg, size) : offsets)
-
-slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1
-
-constructContinuation2 :: BlockEnv StackFormat -> BrokenBlock -> CmmBasicBlock
-constructContinuation2 formats (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
- where
- curr_format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident
- prefix = case entry of
- ControlEntry -> []
- FunctionEntry -> []
- ContinuationEntry formals -> unpack_continuation curr_format
- postfix = case exit of
- FinalBranch next -> [CmmBranch next]
- 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 ->
- let cont_format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique next)) next
- in pack_continuation curr_format cont_format ++
- [CmmJump target arguments]
- FinalCall next _ results arguments saves -> panic "unimplemented CmmCall"
+ 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
---------------------------------------------------------------------------------
--- 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
- adjust_spReg = [
- CmmAssign spReg
- (CmmRegOff spReg (curr_frame_size*wORD_SIZE))]
- jump = [CmmJump target arguments]
-
-enter_function :: WordOff -> [CmmStmt]
-enter_function max_frame_size
- = check_stack_limit where
- check_stack_limit = [
- CmmCondBranch
- (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
- [CmmRegOff spReg max_frame_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)
-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
- -- TODO: only save variables when actually needed
- save_live_values =
- [CmmStore
- (CmmRegOff
- spReg (wORD_SIZE*(curr_frame_size - cont_frame_size + offset)))
- (CmmReg reg)
- | (reg, offset) <- cont_offsets]
- set_stack_header = -- TODO: only set when needed
- [CmmStore (CmmRegOff spReg (wORD_SIZE*(curr_frame_size - cont_frame_size))) continuation_function]
- continuation_function = CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique 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))]
-
--- 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
- -- TODO: only save variables when actually needed
- load_live_values =
- [CmmAssign
- reg
- (CmmLoad (CmmRegOff spReg (wORD_SIZE*offset)) (cmmRegRep reg))
- | (reg, offset) <- curr_offsets]
+ dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
------------------------------------------------------------------------------
--- Breaking basic blocks on function calls
------------------------------------------------------------------------------
+ -- TODO: add option to dump Cmm to file
------------------------------------------------------------------------------
--- 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 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)]
- (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 block not implemented"
- (CmmCall target results arguments saves:stmts) ->
- let new_id = BlockId $ head uniques
- rest = breakBlock' (tail uniques) new_id (ContinuationEntry results) [] [] stmts
- in BrokenBlock current_id entry accum_stmts (new_id:exits)
- (FinalCall new_id target results arguments saves) : rest
- (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
+ return continuationC
------------------------------------------------------------------------------
-cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock
-cmmBlockFromBrokenBlock (BrokenBlock ident _ stmts _ exit) = BasicBlock ident (stmts++exit_stmt)
+make_stack_check stack_check_block_id info stack_use next_block_id =
+ BasicBlock stack_check_block_id $
+ check_stmts ++ [CmmBranch next_block_id]
where
- exit_stmt =
- case exit of
- FinalBranch target -> [CmmBranch target]
- FinalReturn arguments -> [CmmReturn arguments]
- FinalJump target arguments -> [CmmJump target arguments]
- FinalCall branch_target call_target results arguments saves -> [CmmCall call_target results arguments saves, CmmBranch branch_target]
+ check_stmts =
+ case info of
+ -- If we are given a stack check handler,
+ -- then great, well check the stack.
+ CmmInfo (Just gc_block) _ _
+ -> [CmmCondBranch
+ (CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
+ [CmmReg stack_use, CmmReg spLimReg])
+ gc_block]
+ -- If we aren't given a stack check handler,
+ -- then humph! we just won't check the stack for them.
+ CmmInfo Nothing _ _
+ -> []
-----------------------------------------------------------------------------
--- CPS a single CmmTop (proceedure)
+-- |CPS a single CmmTop (proceedure)
+-- Only 'CmmProc' are transformed 'CmmData' will be left alone.
-----------------------------------------------------------------------------
-cpsProc :: UniqSupply -> CmmTop -> [CmmTop]
-cpsProc uniqSupply x@(CmmData _ _) = [x]
-cpsProc uniqSupply x@(CmmProc info_table ident params blocks) =
- [CmmProc info_table ident params $ map (constructContinuation2 formats) broken_blocks]
- where
- uniqes :: [[Unique]]
- uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply
+cpsProc :: UniqSupply
+ -> GenCmmTop CmmStatic CmmInfo CmmStmt -- ^Input proceedure
+ -> [GenCmmTop CmmStatic CmmInfo CmmStmt] -- ^Output proceedure and continuations
- broken_blocks :: [BrokenBlock]
- broken_blocks = concat $ zipWith3 breakBlock uniqes blocks (FunctionEntry:repeat ControlEntry)
-
- live :: BlockEntryLiveness
- live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks
+-- Data blocks don't need to be CPS transformed
+cpsProc uniqSupply proc@(CmmData _ _) = [proc]
- -- TODO: branches for proc points
- -- TODO: let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks
+-- Empty functions just don't work with the CPS algorithm, but
+-- they don't need the transformation anyway so just output them directly
+cpsProc uniqSupply proc@(CmmProc _ _ _ []) = [proc]
- formats :: BlockEnv StackFormat -- Stack format on entry
- formats = selectStackFormat2 live broken_blocks
+-- CPS transform for those procs that actually need it
+cpsProc uniqSupply (CmmProc info ident params blocks) = cps_procs
+ where
+ -- We need to be generating uniques for several things.
+ -- We could make this function monadic to handle that
+ -- but since there is no other reason to make it monadic,
+ -- we instead will just split them all up right here.
+ (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply
+ uniques :: [[Unique]]
+ uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1
+ (stack_check_block_unique:stack_use_unique: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)
+ stack_check_block_id = BlockId stack_check_block_unique
+ stack_check_block = make_stack_check stack_check_block_id info stack_use (blockId $ head blocks)
+
+ forced_blocks = stack_check_block : blocks
+
+ CmmInfo maybe_gc_block_id update_frame _ = info
+
+ -- Break the block at each function call.
+ -- The part after the function call will have to become a continuation.
+ broken_blocks :: ([(BlockId, ContFormat)], [BrokenBlock])
+ broken_blocks =
+ (\x -> (concatMap fst x, concatMap snd x)) $
+ zipWith3 (breakBlock (maybeToList maybe_gc_block_id))
+ block_uniques
+ forced_blocks
+ (FunctionEntry info ident params :
+ repeat ControlEntry)
+
+ f' = selectContinuations (fst broken_blocks)
+ broken_blocks' = map (makeContinuationEntries f') $
+ concat $
+ zipWith (adaptBlockToFormat f')
+ adaptor_uniques
+ (snd broken_blocks)
+
+ -- Calculate live variables for each broken block.
+ --
+ -- Nothing can be live on entry to the first block
+ -- so we could take the tail, but for now we wont
+ -- to help future proof the code.
+ live :: BlockEntryLiveness
+ live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks'
+
+ -- Calculate which blocks must be made into full fledged procedures.
+ proc_points :: UniqSet BlockId
+ proc_points = calculateProcPoints broken_blocks'
+
+ -- Construct a map so we can lookup a broken block by its 'BlockId'.
+ block_env :: BlockEnv BrokenBlock
+ block_env = blocksToBlockEnv broken_blocks'
+
+ -- Group the blocks into continuations based on the set of proc-points.
+ continuations :: [Continuation (Either C_SRT CmmInfo)]
+ continuations = map (gatherBlocksIntoContinuation live proc_points block_env)
+ (uniqSetToList proc_points)
+
+ -- Select the stack format on entry to each continuation.
+ -- Return the max stack offset and an association list
+ --
+ -- This is an association list instead of a UniqFM because
+ -- CLabel's don't have a 'Uniqueable' instance.
+ formats :: [(CLabel, -- key
+ (CmmFormals, -- arguments
+ Maybe CLabel, -- label in top slot
+ [Maybe LocalReg]))] -- slots
+ formats = selectContinuationFormat live continuations
+
+ -- Do a little meta-processing on the stack formats such as
+ -- getting the individual frame sizes and the maximum frame size
+ formats' :: (WordOff, WordOff, [(CLabel, ContinuationFormat)])
+ formats'@(_, _, format_list) = processFormats formats update_frame continuations
+
+ -- Update the info table data on the continuations with
+ -- the selected stack formats.
+ continuations' :: [Continuation CmmInfo]
+ continuations' = map (applyContinuationFormat format_list) continuations
+
+ -- Do the actual CPS transform.
+ cps_procs :: [CmmTop]
+ cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations'
+-----------------------------------------------------------------------------
+
+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 -> Continuation (Either C_SRT CmmInfo)
+gatherBlocksIntoContinuation live proc_points blocks start =
+ Continuation info_table clabel params is_gc_cont body
+ where
+ children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) [start]) `minusUniqSet` (unitUniqSet start)
+ start_block = lookupWithDefaultUFM blocks unknown_block start
+ children_blocks = map (lookupWithDefaultUFM blocks unknown_block) (uniqSetToList children)
+ unknown_block = panic "unknown block in gatherBlocksIntoContinuation"
+ body = start_block : children_blocks
+
+ -- We can't properly annotate the continuation's stack parameters
+ -- at this point because this is before stack selection
+ -- but we want to keep the C_SRT around so we use 'Either'.
+ info_table = case start_block_entry of
+ FunctionEntry info _ _ -> Right info
+ ContinuationEntry _ srt _ -> Left srt
+ ControlEntry -> Right (CmmInfo Nothing Nothing CmmNonInfoTable)
+
+ is_gc_cont = case start_block_entry of
+ FunctionEntry _ _ _ -> False
+ ContinuationEntry _ _ gc_cont -> gc_cont
+ ControlEntry -> False
+
+ start_block_entry = brokenBlockEntry start_block
+ clabel = case start_block_entry of
+ FunctionEntry _ label _ -> label
+ _ -> mkReturnPtLabel $ getUnique start
+ params = case start_block_entry of
+ FunctionEntry _ _ args -> args
+ ContinuationEntry args _ _ -> args
+ ControlEntry ->
+ uniqSetToList $
+ lookupWithDefaultUFM live unknown_block start
+ -- it's a proc-point, pass lives in parameter registers
--------------------------------------------------------------------------------
-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 supplies = listSplitUniqSupply uniqSupply
- let continuationC = zipWith (\s (Cmm c) -> Cmm $ concat $ zipWith (cpsProc) (listSplitUniqSupply s) c) supplies abstractC
+selectContinuationFormat :: BlockEnv CmmLive
+ -> [Continuation (Either C_SRT CmmInfo)]
+ -> [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))]
+selectContinuationFormat live continuations =
+ map (\c -> (continuationLabel c, selectContinuationFormat' c)) continuations
+ where
+ -- User written continuations
+ selectContinuationFormat' (Continuation
+ (Right (CmmInfo _ _ (CmmInfoTable _ _ (ContInfo format 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]))]
+ -> Maybe UpdateFrame
+ -> [Continuation (Either C_SRT CmmInfo)]
+ -> (WordOff, WordOff, [(CLabel, ContinuationFormat)])
+processFormats formats update_frame continuations =
+ (max_size + update_frame_size, update_frame_size, formats')
+ where
+ max_size = maximum $
+ 0 : map (continuationMaxStack formats') continuations
+ formats' = map make_format formats
+ make_format (label, (formals, top, stack)) =
+ (label,
+ ContinuationFormat {
+ continuation_formals = formals,
+ continuation_label = top,
+ continuation_frame_size = stack_size stack +
+ if isJust top
+ then label_size
+ else 0,
+ continuation_stack = stack })
+
+ update_frame_size = case update_frame of
+ Nothing -> 0
+ (Just (UpdateFrame _ args))
+ -> label_size + update_size args
+
+ update_size [] = 0
+ update_size (expr:exprs) = width + update_size exprs
+ where
+ width = machRepByteWidth (cmmExprRep expr) `quot` wORD_SIZE
+ -- TODO: it would be better if we had a machRepWordWidth
+
+ -- TODO: get rid of "+ 1" etc.
+ label_size = 1 :: WordOff
+
+ stack_size [] = 0
+ stack_size (Nothing:formats) = 1 + stack_size formats -- one dead word
+ stack_size (Just reg:formats) = width + stack_size formats
+ where
+ width = 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 gc update_frame (CmmInfoTable prof tag (ContInfo _ srt))))
+ label formals is_gc blocks) =
+ Continuation (CmmInfo gc update_frame (CmmInfoTable prof tag (ContInfo format srt)))
+ label formals is_gc blocks
+ where
+ format = continuation_stack $ maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in applyContinuationFormat"
+
+-- Either user written non-continuation code or CPS generated proc-point
+applyContinuationFormat 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 gc Nothing (CmmInfoTable prof tag (ContInfo (continuation_stack $ format) srt)))
+ label formals is_gc blocks
+ where
+ gc = Nothing -- Generated continuations never need a stack check
+ -- TODO prof: this is the same as the current implementation
+ -- but I think it could be improved
+ prof = ProfilingInfo zeroCLit zeroCLit
+ tag = rET_SMALL -- cmmToRawCmm may convert it to rET_BIG
+ format = maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in applyContinuationFormat"
- dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
- -- TODO: add option to dump Cmm to file
- return continuationC