breakBlock,
cmmBlockFromBrokenBlock,
blocksToBlockEnv,
+ adaptBlockToFormat,
+ selectContinuations,
+ ContFormat,
+ makeContinuationEntries,
) where
#include "HsVersions.h"
import Cmm
import CLabel
+import MachOp (MachHint(..))
import ClosureInfo
import Maybes
+import List
import Panic
+import UniqSupply
import Unique
import UniqFM
| ContinuationEntry -- ^ Return point of a function call
CmmFormals -- ^ return values (argument to continuation)
C_SRT -- ^ SRT for the continuation's info table
+ Bool -- ^ True <=> GC block so ignore stack size
| ControlEntry -- ^ Any other kind of block.
-- Only entered due to control flow.
-- no return values, but some live might end up as
-- params or possibly in the frame
+data ContFormat = ContFormat
+ CmmHintFormals -- ^ return values (argument to continuation)
+ C_SRT -- ^ SRT for the continuation's info table
+ Bool -- ^ True <=> GC block so ignore stack size
+ deriving (Eq)
-- | Final statement in a 'BlokenBlock'.
-- Constructors and arguments match those in 'Cmm',
CmmHintFormals -- ^ Results from call
-- (redundant with ContinuationEntry)
CmmActuals -- ^ Arguments to call
+ C_SRT -- ^ SRT for the continuation's info table
+ Bool -- ^ True <=> GC block so ignore stack size
| FinalSwitch -- ^ Same as a 'CmmSwitch'
CmmExpr -- ^ Scrutinee (zero based)
-- Operations for broken blocks
-----------------------------------------------------------------------------
+-- Naively breaking at *every* CmmCall leads to sub-optimal code.
+-- In particular, a CmmCall followed by a CmmBranch would result
+-- in a continuation that has the single CmmBranch statement in it.
+-- It would be better have the CmmCall directly return to the block
+-- that the branch jumps to.
+--
+-- This requires the target of the branch to look like the parameter
+-- format that the CmmCall is expecting. If other CmmCall/CmmBranch
+-- sequences go to the same place they might not be expecting the
+-- same format. So this transformation uses the following solution.
+-- First the blocks are broken up but none of the blocks are marked
+-- as continuations yet. This is the 'breakBlock' function.
+-- Second, the blocks "vote" on what other blocks need to be continuations
+-- and how they should be layed out. Plurality wins, but other selection
+-- methods could be selected at a later time.
+-- This is the 'selectContinuations' function.
+-- Finally, the blocks are upgraded to 'ContEntry' continuations
+-- based on the results with the 'makeContinuationEntries' function,
+-- and the blocks that didn't get the format they wanted for their
+-- targets get a small adaptor block created for them by
+-- the 'adaptBlockToFormat' function.
+-- could be
+
+breakProc ::
+ [BlockId] -- ^ Any GC blocks that should be special
+ -> [[Unique]] -- ^ An infinite list of uniques
+ -- to create names of the new blocks with
+ -> CmmInfo -- ^ Info table for the procedure
+ -> CLabel -- ^ Name of the procedure
+ -> CmmFormals -- ^ Parameters of the procedure
+ -> [CmmBasicBlock] -- ^ Blocks of the procecure
+ -- (First block is the entry block)
+ -> [BrokenBlock]
+
+breakProc gc_block_idents uniques info ident params blocks =
+ let
+ (adaptor_uniques : block_uniques) = uniques
+
+ broken_blocks :: ([(BlockId, ContFormat)], [BrokenBlock])
+ broken_blocks =
+ let new_blocks =
+ zipWith3 (breakBlock gc_block_idents)
+ block_uniques
+ blocks
+ (FunctionEntry info ident params :
+ repeat ControlEntry)
+ in (concatMap fst new_blocks, concatMap snd new_blocks)
+
+ selected = selectContinuations (fst broken_blocks)
+
+ in map (makeContinuationEntries selected) $
+ concat $
+ zipWith (adaptBlockToFormat selected)
+ adaptor_uniques
+ (snd broken_blocks)
+
-----------------------------------------------------------------------------
-- | Takes a 'CmmBasicBlock' and breaks it up into a list of 'BrokenBlock'
-- by splitting on each 'CmmCall' in the 'CmmBasicBlock'.
breakBlock ::
- [Unique] -- ^ An infinite list of uniques
+ [BlockId] -- ^ Any GC blocks that should be special
+ -> [Unique] -- ^ An infinite list of uniques
-- to create names of the new blocks with
-> CmmBasicBlock -- ^ Input block to break apart
-> BlockEntryInfo -- ^ Info for the first created 'BrokenBlock'
- -> [BrokenBlock]
-breakBlock uniques (BasicBlock ident stmts) entry =
+ -> ([(BlockId, ContFormat)], [BrokenBlock])
+breakBlock gc_block_idents uniques (BasicBlock ident stmts) entry =
breakBlock' uniques ident entry [] [] stmts
where
breakBlock' uniques current_id entry exits accum_stmts stmts =
-- Last statement. Make the 'BrokenBlock'
[CmmJump target arguments] ->
- [BrokenBlock current_id entry accum_stmts
- exits
- (FinalJump target arguments)]
+ ([],
+ [BrokenBlock current_id entry accum_stmts
+ exits
+ (FinalJump target arguments)])
[CmmReturn arguments] ->
- [BrokenBlock current_id entry accum_stmts
+ ([],
+ [BrokenBlock current_id entry accum_stmts
exits
- (FinalReturn arguments)]
+ (FinalReturn arguments)])
[CmmBranch target] ->
- [BrokenBlock current_id entry accum_stmts
+ ([],
+ [BrokenBlock current_id entry accum_stmts
(target:exits)
- (FinalBranch target)]
+ (FinalBranch target)])
[CmmSwitch expr targets] ->
- [BrokenBlock current_id entry accum_stmts
+ ([],
+ [BrokenBlock current_id entry accum_stmts
(mapMaybe id targets ++ exits)
- (FinalSwitch expr targets)]
+ (FinalSwitch expr targets)])
-- These shouldn't happen in the middle of a block.
-- They would cause dead code.
-- Detect this special case to remain an inverse of
-- 'cmmBlockFromBrokenBlock'
- {- TODO: Interferes with proc point detection
- [CmmCall target results arguments,
- CmmBranch next_id] -> [block]
- where
- block = do_call current_id entry accum_stmts exits next_id
- target results arguments
- -}
+ [CmmCall target results arguments (CmmSafe srt),
+ CmmBranch next_id] ->
+ ([cont_info], [block])
+ where
+ cont_info = (next_id,
+ ContFormat results srt
+ (ident `elem` gc_block_idents))
+ block = do_call current_id entry accum_stmts exits next_id
+ target results arguments srt
-- Break the block on safe calls (the main job of this function)
(CmmCall target results arguments (CmmSafe srt):stmts) ->
- block : rest
+ (cont_info : cont_infos, block : blocks)
where
next_id = BlockId $ head uniques
block = do_call current_id entry accum_stmts exits next_id
- target results arguments
- rest = breakBlock' (tail uniques) next_id
- (ContinuationEntry (map fst results) srt)
- [] [] stmts
+ target results arguments srt
+ cont_info = (next_id,
+ ContFormat results srt
+ (ident `elem` gc_block_idents))
+ (cont_infos, blocks) = breakBlock' (tail uniques) next_id
+ ControlEntry [] [] stmts
-- Default case. Just keep accumulating statements
-- and branch targets.
stmts
do_call current_id entry accum_stmts exits next_id
- target results arguments =
+ target results arguments srt =
BrokenBlock current_id entry accum_stmts (next_id:exits)
- (FinalCall next_id target results arguments)
+ (FinalCall next_id target results arguments srt
+ (current_id `elem` gc_block_idents))
cond_branch_target (CmmCondBranch _ target) = [target]
cond_branch_target _ = []
-----------------------------------------------------------------------------
+
+selectContinuations :: [(BlockId, ContFormat)] -> [(BlockId, ContFormat)]
+selectContinuations needed_continuations = formats
+ where
+ formats = map select_format format_groups
+ format_groups = groupBy by_target needed_continuations
+ by_target x y = fst x == fst y
+
+ select_format formats = winner
+ where
+ winner = head $ head $ sortBy more_votes format_votes
+ format_votes = groupBy by_format formats
+ by_format x y = snd x == snd y
+ more_votes x y = compare (length y) (length x)
+ -- sort so the most votes goes *first*
+ -- (thus the order of x and y is reversed)
+
+makeContinuationEntries formats
+ block@(BrokenBlock ident entry stmts targets exit) =
+ case lookup ident formats of
+ Nothing -> block
+ Just (ContFormat formals srt is_gc) ->
+ BrokenBlock ident (ContinuationEntry (map fst formals) srt is_gc)
+ stmts targets exit
+
+adaptBlockToFormat :: [(BlockId, ContFormat)]
+ -> Unique
+ -> BrokenBlock
+ -> [BrokenBlock]
+adaptBlockToFormat formats unique
+ block@(BrokenBlock ident entry stmts targets
+ exit@(FinalCall next target formals
+ actuals srt is_gc)) =
+ if format_formals == formals &&
+ format_srt == srt &&
+ format_is_gc == is_gc
+ then [block] -- Woohoo! This block got the continuation format it wanted
+ else [adaptor_block, revised_block]
+ -- This block didn't get the format it wanted for the
+ -- continuation, so we have to build an adaptor.
+ where
+ (ContFormat format_formals format_srt format_is_gc) =
+ maybe unknown_block id $ lookup next formats
+ unknown_block = panic "unknown block in adaptBlockToFormat"
+
+ revised_block = BrokenBlock ident entry stmts revised_targets revised_exit
+ revised_targets = adaptor_ident : delete next targets
+ revised_exit = FinalCall
+ adaptor_ident -- ^ The only part that changed
+ target formals actuals srt is_gc
+
+ adaptor_block = mk_adaptor_block adaptor_ident
+ (ContinuationEntry (map fst formals) srt is_gc)
+ next format_formals
+ adaptor_ident = BlockId unique
+
+ mk_adaptor_block :: BlockId -> BlockEntryInfo -> BlockId -> CmmHintFormals -> BrokenBlock
+ mk_adaptor_block ident entry next formals =
+ BrokenBlock ident entry [] [next] exit
+ where
+ exit = FinalJump
+ (CmmLit (CmmLabel (mkReturnPtLabel (getUnique next))))
+ (map formal_to_actual format_formals)
+
+ formal_to_actual (reg, hint) = ((CmmReg (CmmLocal reg)), hint)
+ -- TODO: Check if NoHint is right. We're
+ -- jumping to a C-- function not a foreign one
+ -- so it might always be right.
+adaptBlockToFormat _ _ block = [block]
+
+-----------------------------------------------------------------------------
-- | Convert from a BrokenBlock back to an equivalent CmmBasicBlock
-- Needed by liveness analysis
cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock
FinalReturn arguments -> [CmmReturn arguments]
FinalJump target arguments -> [CmmJump target arguments]
FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalCall branch_target call_target results arguments ->
- [CmmCall call_target results arguments (panic "needed SRT from cmmBlockFromBrokenBlock"),
+ FinalCall branch_target call_target results arguments srt _ ->
+ [CmmCall call_target results arguments (CmmSafe srt),
CmmBranch branch_target]
-----------------------------------------------------------------------------
actuals = map (\x -> (CmmReg (CmmLocal x), NoHint)) formals
fun_expr = CmmLit (CmmLabel fun_label)
-force_gc_block old_info block_id fun_label formals =
+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 _) -> (old_info, [])
- CmmInfo _ (Just _) _ _ -> (old_info, [])
+ 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_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)])
- where
- srt = case type_info of
- ConstrInfo _ _ _ -> NoC_SRT
- FunInfo _ srt' _ _ _ _ -> srt'
- ThunkInfo _ srt' -> srt'
- ThunkSelectorInfo _ srt' -> srt'
- ContInfo _ srt' -> srt'
+ -> (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)
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 uniqSupply
- (gc_unique:info_uniques):block_uniques = uniques
+ uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1
+ (gc_unique:stack_use_unique:info_uniques):adaptor_uniques:block_uniques = uniques
+ proc_uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply2
+
+ stack_use = CmmLocal (LocalReg stack_use_unique (cmmRegRep spReg) KindPtr)
- -- Ensure that
- forced_gc :: (CmmInfo, [CmmBasicBlock])
- forced_gc = force_gc_block info (BlockId gc_unique) ident params
+ -- 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_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 :: ([(BlockId, ContFormat)], [BrokenBlock])
broken_blocks =
- concat $ zipWith3 breakBlock block_uniques forced_blocks
- (FunctionEntry forced_info ident params:repeat ControlEntry)
+ (\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.
--
-- 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
+ 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
+ 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
+ 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)
+ (gatherBlocksIntoContinuation live proc_points block_env)
(uniqSetToList proc_points)
- (Just forced_gc_id : repeat Nothing)
+ (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
- (Maybe CLabel, -- label in top slot
+ (CmmFormals, -- arguments
+ Maybe CLabel, -- label in top slot
[Maybe LocalReg]))] -- slots
- formats = selectStackFormat live continuations
+ 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, StackFormat)])
+ 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 (applyStackFormat (snd formats')) continuations
+ continuations' = map (applyContinuationFormat (snd formats')) continuations
-- Do the actual CPS transform.
cps_procs :: [CmmTop]
- cps_procs = map (continuationToProc formats') continuations'
+ 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
-- and heap memory (not sure if that's usefull at all though, but it may
-- be worth exploring the design space).
-continuationLabel (Continuation _ l _ _) = l
+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
-- to a label. To jump to the first block in a Proc,
-- use the appropriate CLabel.
-data StackFormat
- = 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
+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
-- * Proc points might get some live variables passed as arguments
gatherBlocksIntoContinuation ::
- UniqSet BlockId -> BlockEnv BrokenBlock
+ BlockEntryLiveness -> UniqSet BlockId -> BlockEnv BrokenBlock
-> BlockId -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo)
-gatherBlocksIntoContinuation proc_points blocks start gc =
- Continuation info_table clabel params body
+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)
+ --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
- gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) (maybeToList gc)
+ 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
+ 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
+ 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 -> [] -- TODO: it's a proc-point, we could pass lives in parameter registers
+ ContinuationEntry args _ _ -> args
+ ControlEntry ->
+ uniqSetToList $
+ lookupWithDefaultUFM live unknown_block start
+ -- it's a proc-point, pass lives in parameter registers
--------------------------------------------------------------------------------
-- For now just select the continuation orders in the order they are in the set with no gaps
-selectStackFormat :: BlockEnv CmmLive
+selectContinuationFormat :: BlockEnv CmmLive
-> [Continuation (Either C_SRT CmmInfo)]
- -> [(CLabel, (Maybe CLabel, [Maybe LocalReg]))]
-selectStackFormat live continuations =
- map (\c -> (continuationLabel c, selectStackFormat' c)) continuations
+ -> [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))]
+selectContinuationFormat live continuations =
+ map (\c -> (continuationLabel c, selectContinuationFormat' c)) continuations
where
- selectStackFormat' (Continuation
+ selectContinuationFormat' (Continuation
(Right (CmmInfo _ _ _ (ContInfo format srt)))
- label _ _) = (Just label, format)
- selectStackFormat' (Continuation (Right _) _ _ _) = (Nothing, [])
- selectStackFormat' (Continuation (Left srt) label _ blocks) =
+ label formals _ _) =
+ (formals, Just label, format)
+ 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 (Just label,
+ in (formals,
+ Just label,
map Just $ uniqSetToList $
lookupWithDefaultUFM live unknown_block ident)
- unknown_block = panic "unknown BlockId in selectStackFormat"
+ unknown_block = panic "unknown BlockId in selectContinuationFormat"
-processFormats :: [(CLabel, (Maybe CLabel, [Maybe LocalReg]))]
+processFormats :: [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))]
-> [Continuation (Either C_SRT CmmInfo)]
- -> (WordOff, [(CLabel, StackFormat)])
+ -> (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, format) =
+ make_format (label, (formals, top, stack)) =
(label,
- StackFormat {
- stack_label = fst format,
- stack_frame_size = stack_size (snd format) +
- if isJust (fst format)
+ ContinuationFormat {
+ continuation_formals = formals,
+ continuation_label = top,
+ continuation_frame_size = stack_size stack +
+ if isJust top
then label_size
else 0,
- stack_live = snd format })
+ continuation_stack = stack })
-- TODO: get rid of "+ 1" etc.
label_size = 1 :: WordOff
width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
-- TODO: it would be better if we had a machRepWordWidth
-continuationMaxStack :: [(CLabel, StackFormat)]
+continuationMaxStack :: [(CLabel, ContinuationFormat)]
-> Continuation a
-> WordOff
-continuationMaxStack formats (Continuation _ label _ blocks) =
- max_arg_size + stack_frame_size stack_format
+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"
argumentsSize (cmmExprRep . fst) args
final_arg_size (FinalJump _ args) =
argumentsSize (cmmExprRep . fst) args
- final_arg_size (FinalCall next _ _ 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 +
- stack_frame_size next_format
+ continuation_frame_size next_format
where
next_format = maybe unknown_format id $ lookup next' formats
next' = mkReturnPtLabel $ getUnique next
stmt_arg_size _ = 0
-----------------------------------------------------------------------------
-applyStackFormat :: [(CLabel, StackFormat)]
+applyContinuationFormat :: [(CLabel, ContinuationFormat)]
-> Continuation (Either C_SRT CmmInfo)
-> Continuation CmmInfo
-- User written continuations
-applyStackFormat formats (Continuation
+applyContinuationFormat formats (Continuation
(Right (CmmInfo prof gc tag (ContInfo _ srt)))
- label formals blocks) =
+ label formals is_gc blocks) =
Continuation (CmmInfo prof gc tag (ContInfo format srt))
- label formals blocks
+ label formals is_gc blocks
where
- format = stack_live $ maybe unknown_block id $ lookup label formats
- unknown_block = panic "unknown BlockId in applyStackFormat"
+ format = continuation_stack $ maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in applyContinuationFormat"
-- User written non-continuation code
-applyStackFormat formats (Continuation (Right info) label formals blocks) =
- Continuation info label formals blocks
+applyContinuationFormat formats (Continuation
+ (Right info) label formals is_gc blocks) =
+ Continuation info label formals is_gc 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
+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
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"
+ unknown_block = panic "unknown BlockId in applyContinuationFormat"
-----------------------------------------------------------------------------
-continuationToProc :: (WordOff, [(CLabel, StackFormat)])
+continuationToProc :: (WordOff, [(CLabel, ContinuationFormat)])
+ -> CmmReg
+ -> [Unique]
-> Continuation CmmInfo
-> CmmTop
-continuationToProc (max_stack, formats)
- (Continuation info label formals blocks) =
- CmmProc info label formals (map continuationToProc' blocks)
+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 = stack_frame_size curr_format
-
- continuationToProc' :: BrokenBlock -> CmmBasicBlock
- continuationToProc' (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
+ 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"
+
+ continuationToProc' :: Unique -> BrokenBlock -> Bool -> [CmmBasicBlock]
+ continuationToProc' unique (BrokenBlock ident entry stmts _ exit) is_entry =
+ case gc_prefix ++ param_prefix of
+ [] -> [main_block]
+ stmts -> [BasicBlock prefix_id (gc_prefix ++ param_prefix ++ [CmmBranch ident]),
+ main_block]
where
- prefix = case entry of
+ main_block = BasicBlock ident (stmts ++ postfix)
+ prefix_id = BlockId unique
+ gc_prefix = case entry of
+ FunctionEntry _ _ _ -> gc_stmts
ControlEntry -> []
- FunctionEntry (CmmInfo _ (Just gc_block) _ _) _ formals ->
- gc_stack_check gc_block (max_stack - curr_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 - curr_stack) ++
- function_entry formals curr_format
- FunctionEntry (CmmNonInfo Nothing) _ formals ->
- panic "continuationToProc: missing non-info GC block"
- ContinuationEntry formals _ ->
- function_entry formals curr_format
+ ContinuationEntry _ _ _ -> []
+ param_prefix = if is_entry
+ then param_stmts
+ else []
postfix = case exit of
- FinalBranch next -> [CmmBranch next]
+ 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)
+ formal_to_actual reg = (CmmReg (CmmLocal reg), NoHint)
FinalSwitch expr targets -> [CmmSwitch expr targets]
FinalReturn arguments ->
tail_call curr_stack
FinalJump target arguments ->
tail_call curr_stack target arguments
FinalCall next (CmmForeignCall target CmmCallConv)
- results arguments ->
- pack_continuation curr_format cont_format ++
+ 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 = stack_frame_size cont_format
- FinalCall next _ results arguments -> panic "unimplemented CmmCall"
+ cont_stack = continuation_frame_size cont_format
+ FinalCall next _ results arguments _ _ -> panic "unimplemented CmmCall"
-----------------------------------------------------------------------------
-- Functions that generate CmmStmt sequences
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
CmmReg spLimReg])
gc_block]
+
-- 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 _)
- (StackFormat cont_id cont_frame_size live_regs)
+pack_continuation :: Bool -> ContinuationFormat -> ContinuationFormat -> [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)
[stack_put spRel (CmmReg (CmmLocal reg)) offset
| (reg, offset) <- cont_offsets]
set_stack_header =
- if needs_header_set
+ if needs_header_set && allow_header_set
then [stack_put spRel continuation_function 0]
else []
-- that could branch to eachother (i.e. control blocks)
-- have the same stack format (this causes a problem
-- only for proc-point).
-function_entry :: CmmFormals -> StackFormat -> [CmmStmt]
-function_entry formals (StackFormat _ _ live_regs)
+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)
projects / ghc-hetmet.git / commitdiff