import Dataflow (fixedpoint)
import CmmLive
+import CmmCPSData
+import CmmProcPoint
import MachOp
import ForeignCall
-- and heap memory (not sure if that's usefull at all though, but it may
-- be worth exploring the design space).
-data BrokenBlock
- = BrokenBlock {
- brokenBlockId :: BlockId, -- Like a CmmBasicBlock
- brokenBlockEntry :: BlockEntryInfo,
- -- How this block can be entered
-
- brokenBlockStmts :: [CmmStmt],
- -- Like a CmmBasicBlock
- -- (but without the last statement)
-
- brokenBlockTargets :: [BlockId],
- -- Blocks that this block could
- -- branch to one either by conditional
- -- branches or via the last statement
-
- brokenBlockExit :: FinalStmt
- -- How the block can be left
- }
-
continuationLabel (Continuation _ _ l _ _) = l
data Continuation =
Continuation
-- to a label. To jump to the first block in a Proc,
-- use the appropriate CLabel.
-data BlockEntryInfo
- = FunctionEntry -- Beginning of a function
- CLabel -- The function name
- CmmFormals -- Aguments to function
-
- | ContinuationEntry -- Return point of a call
- CmmFormals -- return values (argument to continuation)
- -- TODO:
- -- | ProcPointEntry -- no return values, but some live might end up as params or possibly in the frame
-
- | ControlEntry -- A label in the input
-
--- Final statement in a BlokenBlock
--- Constructors and arguments match those in Cmm,
--- but are restricted to branches, returns, jumps, calls and switches
-data FinalStmt
- = FinalBranch
- BlockId -- next block (must be a ControlEntry)
-
- | FinalReturn
- CmmActuals -- return values
-
- | FinalJump
- CmmExpr -- the function to call
- CmmActuals -- arguments to call
-
- | FinalCall
- BlockId -- next block after call (must be a ContinuationEntry)
- CmmCallTarget -- the function to call
- CmmFormals -- results from call (redundant with ContinuationEntry)
- CmmActuals -- arguments to call
- (Maybe [GlobalReg]) -- registers that must be saved (TODO)
-
- | FinalSwitch
- CmmExpr [Maybe BlockId] -- Table branch
-
- -- TODO: | ProcPointExit (needed?)
-
-- Describes the layout of a stack frame for a continuation
data StackFormat
= StackFormat
-- A block can be a continuation of another block (w/ or w/o joins)
-- A block can be an entry to a function
-blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock
-blocksToBlockEnv blocks = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks
-
-----------------------------------------------------------------------------
-calculateOwnership :: UniqSet BlockId -> [BrokenBlock] -> BlockEnv (UniqSet BlockId)
-calculateOwnership proc_points blocks =
- fixedpoint dependants update (map brokenBlockId blocks) emptyUFM
- where
- blocks_ufm :: BlockEnv BrokenBlock
- blocks_ufm = blocksToBlockEnv blocks
-
- dependants :: BlockId -> [BlockId]
- dependants ident =
- brokenBlockTargets $ lookupWithDefaultUFM
- blocks_ufm unknown_block ident
-
- update :: BlockId -> Maybe BlockId
- -> BlockEnv (UniqSet BlockId) -> Maybe (BlockEnv (UniqSet BlockId))
- update ident cause owners =
- case (cause, ident `elementOfUniqSet` proc_points) of
- (Nothing, True) -> Just $ addToUFM owners ident (unitUniqSet ident)
- (Nothing, False) -> Nothing
- (Just cause', True) -> Nothing
- (Just cause', False) ->
- if (sizeUniqSet old) == (sizeUniqSet new)
- then Nothing
- else Just $ addToUFM owners ident new
- where
- old = lookupWithDefaultUFM owners emptyUniqSet ident
- new = old `unionUniqSets` lookupWithDefaultUFM owners emptyUniqSet cause'
-
- unknown_block = panic "unknown BlockId in selectStackFormat"
-
-calculateProcPoints :: [BrokenBlock] -> UniqSet BlockId
-calculateProcPoints blocks = calculateProcPoints' init_proc_points blocks
- where
- init_proc_points = mkUniqSet $
- map brokenBlockId $
- filter always_proc_point blocks
- always_proc_point BrokenBlock {
- brokenBlockEntry = FunctionEntry _ _ } = True
- always_proc_point BrokenBlock {
- brokenBlockEntry = ContinuationEntry _ } = True
- always_proc_point _ = False
-
-calculateProcPoints' :: UniqSet BlockId -> [BrokenBlock] -> UniqSet BlockId
-calculateProcPoints' old_proc_points blocks =
- if sizeUniqSet old_proc_points == sizeUniqSet new_proc_points
- then old_proc_points
- else calculateProcPoints' new_proc_points blocks
- where
- owners = calculateOwnership old_proc_points blocks
- new_proc_points = unionManyUniqSets (old_proc_points:(map (calculateProcPoints'' owners) blocks))
-
-calculateProcPoints'' :: BlockEnv (UniqSet BlockId) -> BrokenBlock -> UniqSet BlockId
-calculateProcPoints'' owners block =
- unionManyUniqSets (map (f parent_id) child_ids)
- where
- parent_id = brokenBlockId block
- child_ids = brokenBlockTargets block
- -- TODO: name for f
- f parent_id child_id =
- if needs_proc_point
- then unitUniqSet child_id
- else emptyUniqSet
- where
- parent_owners = lookupWithDefaultUFM owners emptyUniqSet parent_id
- child_owners = lookupWithDefaultUFM owners emptyUniqSet child_id
- needs_proc_point = not $ isEmptyUniqSet $ child_owners `minusUniqSet` parent_owners
collectNonProcPointTargets ::
UniqSet BlockId -> BlockEnv BrokenBlock
-- TODO: remove redundant uniqSetToList
new_targets = current_targets `unionUniqSets` (mkUniqSet targets)
-buildContinuation ::
+procPointToContinuation ::
UniqSet BlockId -> BlockEnv BrokenBlock
-> BlockId -> Continuation
-buildContinuation proc_points blocks start =
+procPointToContinuation proc_points blocks start =
Continuation is_entry info_table clabel params body
where
children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start
--------------------------------------------------------------------------------
-- For now just select the continuation orders in the order they are in the set with no gaps
-selectStackFormat :: BlockEnv CmmLive -> [BrokenBlock] -> BlockEnv StackFormat
-selectStackFormat live blocks =
- fixedpoint dependants update (map brokenBlockId blocks) emptyUFM
- where
- blocks_ufm :: BlockEnv BrokenBlock
- blocks_ufm = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks
-
- dependants :: BlockId -> [BlockId]
- dependants ident =
- brokenBlockTargets $ lookupWithDefaultUFM
- blocks_ufm unknown_block ident
-
- update :: BlockId -> Maybe BlockId
- -> BlockEnv StackFormat -> Maybe (BlockEnv StackFormat)
- update ident cause formats =
- if ident `elemUFM` formats
- then Nothing -- Blocks only need to be updated once
- else case (cause,
- brokenBlockEntry $ lookupWithDefaultUFM blocks_ufm
- unknown_block ident) of
- -- Propagate only to blocks entered by branches
- -- (not function entry blocks or continuation entry blocks)
- (Just cause_name, ControlEntry) ->
- Just $ addToUFM formats ident cause_format
- where cause_format = lookupWithDefaultUFM
- formats unknown_block
- cause_name
- -- Do initial calculates for function blocks
- (Nothing, FunctionEntry _ _) ->
- Just $
- addToUFM formats ident $
- StackFormat ident 0 []
- -- Do initial calculates for continuation blocks
- (Nothing, ContinuationEntry _) ->
- Just $
- addToUFM formats ident $
- live_to_format ident $
- lookupWithDefaultUFM live unknown_block ident
- _ -> Nothing
-
- unknown_block = panic "unknown BlockId in selectStackFormat"
-
- live_to_format :: BlockId -> CmmLive -> StackFormat
- 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)
-
-selectStackFormat2 :: BlockEnv CmmLive -> [Continuation] -> [(CLabel, StackFormat)]
-selectStackFormat2 live continuations =
+selectStackFormat :: BlockEnv CmmLive -> [Continuation] -> [(CLabel, StackFormat)]
+selectStackFormat live continuations =
map (\c -> (continuationLabel c, selectStackFormat' c)) continuations
where
selectStackFormat' (Continuation True info_table label formals blocks) =
extend_format (StackFormat label size offsets) reg =
StackFormat label (slot_size reg + size) ((CmmLocal reg, size) : offsets)
- unknown_block = panic "unknown BlockId in selectStackFormat"
-
-slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1
+ slot_size :: LocalReg -> Int
+ slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1
-constructContinuation :: [(CLabel, StackFormat)] -> Continuation -> CmmTop
-constructContinuation formats (Continuation is_entry info label formals blocks) =
- CmmProc info label formals (map (constructContinuation2' label formats) blocks)
+ unknown_block = panic "unknown BlockId in selectStackFormat"
-constructContinuation2' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock
- -> CmmBasicBlock
-constructContinuation2' curr_ident formats (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
+continuationToProc :: [(CLabel, StackFormat)] -> Continuation -> CmmTop
+continuationToProc formats (Continuation is_entry info label formals blocks) =
+ CmmProc info label formals (map (continuationToProc' label formats) blocks)
where
- curr_format = maybe unknown_block id $ lookup curr_ident formats
- unknown_block = panic "unknown BlockId in constructContinuation"
- prefix = case entry of
- ControlEntry -> []
- FunctionEntry _ _ -> []
- ContinuationEntry formals ->
- unpack_continuation curr_format
- postfix = case exit of
- FinalBranch next -> [CmmBranch next]
- FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalReturn arguments ->
- exit_function curr_format
- (CmmLoad (CmmReg spReg) wordRep)
- arguments
- FinalJump target arguments ->
- exit_function curr_format target arguments
- -- TODO: do something about global saves
- FinalCall next (CmmForeignCall target CmmCallConv)
+ continuationToProc' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock
+ -> CmmBasicBlock
+ continuationToProc' curr_ident formats (BrokenBlock ident entry stmts _ exit) =
+ BasicBlock ident (prefix++stmts++postfix)
+ where
+ curr_format = maybe unknown_block id $ lookup curr_ident formats
+ unknown_block = panic "unknown BlockId in continuationToProc"
+ prefix = case entry of
+ ControlEntry -> []
+ FunctionEntry _ _ -> []
+ ContinuationEntry formals ->
+ unpack_continuation curr_format
+ postfix = case exit of
+ FinalBranch next -> [CmmBranch next]
+ FinalSwitch expr targets -> [CmmSwitch expr targets]
+ FinalReturn arguments ->
+ exit_function curr_format
+ (CmmLoad (CmmReg spReg) wordRep)
+ arguments
+ FinalJump target arguments ->
+ exit_function curr_format target arguments
+ -- TODO: do something about global saves
+ FinalCall next (CmmForeignCall target CmmCallConv)
results arguments saves ->
pack_continuation curr_format cont_format ++
[CmmJump target arguments]
where
cont_format = maybe unknown_block id $
lookup (mkReturnPtLabel $ getUnique next) formats
- FinalCall next _ results arguments saves -> panic "unimplemented CmmCall"
+ FinalCall next _ results arguments saves -> panic "unimplemented CmmCall"
--------------------------------------------------------------------------------
-- Functions that generate CmmStmt sequences
cpsProc :: UniqSupply -> CmmTop -> [CmmTop]
cpsProc uniqSupply x@(CmmData _ _) = [x]
-cpsProc uniqSupply x@(CmmProc info_table ident params blocks) =
- --[CmmProc info_table ident params cps_blocks]
- cps_continuations
+cpsProc uniqSupply x@(CmmProc info_table ident params blocks) = cps_procs
where
uniqes :: [[Unique]]
uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply
proc_points :: UniqSet BlockId
proc_points = calculateProcPoints broken_blocks
- continuations :: [Continuation]
- continuations = map (buildContinuation proc_points (blocksToBlockEnv broken_blocks)) (uniqSetToList proc_points)
-
-- TODO: insert proc point code here
-- * Branches and switches to proc points may cause new blocks to be created
-- (or proc points could leave behind phantom blocks that just jump to them)
-- * Proc points might get some live variables passed as arguments
- -- TODO: let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks
-
- --procs = groupBlocksIntoContinuations live broken_blocks
+ continuations :: [Continuation]
+ continuations = map (procPointToContinuation proc_points (blocksToBlockEnv broken_blocks)) (uniqSetToList proc_points)
-- Select the stack format on entry to each block
- formats2 :: [(CLabel, StackFormat)]
- formats2 = selectStackFormat2 live continuations
+ formats :: [(CLabel, StackFormat)]
+ formats = selectStackFormat live continuations
-- Do the actual CPS transform
- cps_continuations :: [CmmTop]
- cps_continuations = map (constructContinuation formats2) continuations
+ cps_procs :: [CmmTop]
+ cps_procs = map (continuationToProc formats) continuations
--------------------------------------------------------------------------------
cmmCPS :: DynFlags
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