-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 CmmInfo
+import CmmUtils
+
+import Bitmap
+import ClosureInfo
import MachOp
import ForeignCall
import CLabel
import IO
import Data.List
+-----------------------------------------------------------------------------
+-- |Top level driver for the CPS pass
+-----------------------------------------------------------------------------
+cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm
+ -> [GenCmm CmmStatic CmmInfo CmmStmt] -- ^ Input C-- with Proceedures
+ -> IO [GenCmm CmmStatic [CmmStatic] CmmStmt] -- ^ Output CPS transformed C--
+cmmCPS dflags abstractC = do
+ when (dopt Opt_DoCmmLinting dflags) $
+ do showPass dflags "CmmLint"
+ case firstJust $ map cmmLint abstractC of
+ Just err -> do printDump err
+ ghcExit dflags 1
+ Nothing -> return ()
+ showPass dflags "CPS"
+
+ -- TODO: more lint checking
+ -- check for use of branches to non-existant blocks
+ -- check for use of Sp, SpLim, R1, R2, etc.
+
+ uniqSupply <- mkSplitUniqSupply 'p'
+ let supplies = listSplitUniqSupply uniqSupply
+ let doCpsProc s (Cmm c) =
+ Cmm $ concat $ zipWith cpsProc (listSplitUniqSupply s) c
+ let continuationC = zipWith doCpsProc supplies abstractC
+
+ dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
+
+ -- TODO: add option to dump Cmm to file
+
+ return continuationC
+
+stg_gc_gen = mkRtsApFastLabel SLIT("gen_cg_TODO") --panic "Need the label for gc"
+make_gc_block block_id fun_label formals safety = BasicBlock block_id stmts
+ where
+ stmts = [CmmCall stg_gc_gen_target [] [] safety,
+ CmmJump fun_expr actuals]
+ stg_gc_gen_target =
+ CmmForeignCall (CmmLit (CmmLabel stg_gc_gen)) CmmCallConv
+ actuals = map (\x -> (CmmReg (CmmLocal x), NoHint)) formals
+ fun_expr = CmmLit (CmmLabel fun_label)
+
+force_gc_block old_info block_id fun_label formals blocks =
+ case old_info of
+ CmmNonInfo (Just _) -> (old_info, [])
+ CmmInfo _ (Just _) _ _ -> (old_info, [])
+ CmmNonInfo Nothing
+ -> (CmmNonInfo (Just block_id),
+ [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)])
+ CmmInfo prof Nothing type_tag type_info
+ -> (CmmInfo prof (Just block_id) type_tag type_info,
+ [make_gc_block block_id fun_label formals (CmmSafe srt)])
+ where
+ srt = case type_info of
+ ConstrInfo _ _ _ -> NoC_SRT
+ FunInfo _ srt' _ _ _ _ -> srt'
+ ThunkInfo _ srt' -> srt'
+ ThunkSelectorInfo _ srt' -> srt'
+ ContInfo _ srt' -> srt'
+
+-----------------------------------------------------------------------------
+-- |CPS a single CmmTop (proceedure)
+-- Only 'CmmProc' are transformed 'CmmData' will be left alone.
+-----------------------------------------------------------------------------
+
+cpsProc :: UniqSupply
+ -> GenCmmTop CmmStatic CmmInfo CmmStmt -- ^Input proceedure
+ -> [GenCmmTop CmmStatic [CmmStatic] CmmStmt] -- ^Output proceedure and continuations
+cpsProc uniqSupply (CmmData sec dat) = [CmmData sec dat]
+cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs
+ where
+ uniques :: [[Unique]]
+ uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply
+ (gc_unique:info_uniques):block_uniques = uniques
+
+ -- Ensure that
+ forced_gc :: (CmmInfo, [CmmBasicBlock])
+ forced_gc = force_gc_block info (BlockId gc_unique) ident params blocks
+
+ forced_info = fst forced_gc
+ forced_blocks = blocks ++ snd forced_gc
+ forced_gc_id = case forced_info of
+ CmmNonInfo (Just x) -> x
+ CmmInfo _ (Just x) _ _ -> x
+
+ -- Break the block at each function call.
+ -- The part after the function call will have to become a continuation.
+ broken_blocks :: [BrokenBlock]
+ broken_blocks =
+ concat $ zipWith3 breakBlock block_uniques forced_blocks
+ (FunctionEntry forced_info ident params:repeat ControlEntry)
+
+ -- Calculate live variables for each broken block.
+ --
+ -- Nothing can be live on entry to the first block
+ -- so we could take the tail, but for now we wont
+ -- to help future proof the code.
+ live :: BlockEntryLiveness
+ live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks
+
+ -- Calculate which blocks must be made into full fledged procedures.
+ proc_points :: UniqSet BlockId
+ proc_points = calculateProcPoints broken_blocks
+
+ -- Construct a map so we can lookup a broken block by its 'BlockId'.
+ block_env :: BlockEnv BrokenBlock
+ block_env = blocksToBlockEnv broken_blocks
+
+ -- Group the blocks into continuations based on the set of proc-points.
+ continuations :: [Continuation (Either C_SRT CmmInfo)]
+ continuations = zipWith
+ (gatherBlocksIntoContinuation proc_points block_env)
+ (uniqSetToList proc_points)
+ (Just forced_gc_id : repeat Nothing)
+
+ -- Select the stack format on entry to each continuation.
+ -- Return the max stack offset and an association list
+ --
+ -- This is an association list instead of a UniqFM because
+ -- CLabel's don't have a 'Uniqueable' instance.
+ formats :: [(CLabel, (Maybe CLabel, [Maybe LocalReg]))]
+ formats = selectStackFormat live continuations
+
+ -- Do a little meta-processing on the stack formats such as
+ -- getting the individual frame sizes and the maximum frame size
+ formats' :: (WordOff, [(CLabel, StackFormat)])
+ formats' = processFormats formats
+
+ -- TODO FIXME NOW: calculate a real max stack (including function call args)
+ -- TODO: from the maximum frame size get the maximum stack size.
+ -- The difference is due to the size taken by function calls.
+
+ -- Update the info table data on the continuations with
+ -- the selected stack formats.
+ continuations' :: [Continuation CmmInfo]
+ continuations' = map (applyStackFormat (snd formats')) continuations
+
+ -- Do the actual CPS transform.
+ cps_procs :: [CmmTop]
+ cps_procs = map (continuationToProc formats') continuations'
+
+ -- Convert the info tables from CmmInfo to [CmmStatic]
+ -- We might want to put this in another pass eventually
+ info_procs :: [RawCmmTop]
+ info_procs = concat (zipWith mkInfoTable info_uniques cps_procs)
+
--------------------------------------------------------------------------------
-- The format for the call to a continuation
-- and heap memory (not sure if that's usefull at all though, but it may
-- be worth exploring the design space).
-data BrokenBlock
- = BrokenBlock {
- brokenBlockId :: BlockId, -- Like a CmmBasicBlock
- brokenBlockEntry :: BlockEntryInfo,
- -- How this block can be entered
-
- brokenBlockStmts :: [CmmStmt],
- -- Like a CmmBasicBlock
- -- (but without the last statement)
-
- brokenBlockTargets :: [BlockId],
- -- Blocks that this block could
- -- branch to one either by conditional
- -- branches or via the last statement
-
- brokenBlockExit :: FinalStmt
- -- How the block can be left
- }
-
-continuationLabel (Continuation _ _ l _ _) = l
-data Continuation =
+continuationLabel (Continuation _ l _ _) = l
+data Continuation info =
Continuation
- Bool -- True => Function entry, False => Continuation/return point
- [CmmStatic] -- Info table, may be empty
+ info --(Either C_SRT CmmInfo) -- Left <=> Continuation created by the CPS
+ -- Right <=> Function or Proc point
CLabel -- Used to generate both info & entry labels
CmmFormals -- Argument locals live on entry (C-- procedure params)
- [BrokenBlock] -- Code, may be empty. The first block is
+ [BrokenBlock] -- Code, may be empty. The first block is
-- the entry point. The order is otherwise initially
-- unimportant, but at some point the code gen will
-- fix the order.
-- to a label. To jump to the first block in a Proc,
-- use the appropriate CLabel.
-data BlockEntryInfo
- = FunctionEntry -- Beginning of a function
- CLabel -- The function name
- CmmFormals -- Aguments to function
-
- | ContinuationEntry -- Return point of a call
- CmmFormals -- return values (argument to continuation)
- -- TODO:
- -- | ProcPointEntry -- no return values, but some live might end up as params or possibly in the frame
-
- | ControlEntry -- A label in the input
-
--- Final statement in a BlokenBlock
--- Constructors and arguments match those in Cmm,
--- but are restricted to branches, returns, jumps, calls and switches
-data FinalStmt
- = FinalBranch
- BlockId -- next block (must be a ControlEntry)
-
- | FinalReturn
- CmmActuals -- return values
-
- | FinalJump
- CmmExpr -- the function to call
- CmmActuals -- arguments to call
-
- | FinalCall
- BlockId -- next block after call (must be a ContinuationEntry)
- CmmCallTarget -- the function to call
- CmmFormals -- results from call (redundant with ContinuationEntry)
- CmmActuals -- arguments to call
- (Maybe [GlobalReg]) -- registers that must be saved (TODO)
-
- | FinalSwitch
- CmmExpr [Maybe BlockId] -- Table branch
-
- -- TODO: | ProcPointExit (needed?)
-
--- Describes the layout of a stack frame for a continuation
data StackFormat
- = StackFormat
- (Maybe CLabel) -- The label occupying the top slot
- WordOff -- Total frame size in words
- [(CmmReg, WordOff)] -- local reg offsets from stack top
+ = StackFormat {
+ stack_label :: Maybe CLabel, -- The label occupying the top slot
+ stack_frame_size :: WordOff, -- Total frame size in words (not including arguments)
+ stack_live :: [Maybe LocalReg] -- local reg offsets from stack top
+ }
-- A block can be a continuation of a call
-- A block can be a continuation of another block (w/ or w/o joins)
-- A block can be an entry to a function
-blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock
-blocksToBlockEnv blocks = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks
-
-----------------------------------------------------------------------------
-calculateOwnership :: UniqSet BlockId -> [BrokenBlock] -> BlockEnv (UniqSet BlockId)
-calculateOwnership proc_points blocks =
- fixedpoint dependants update (map brokenBlockId blocks) emptyUFM
- where
- blocks_ufm :: BlockEnv BrokenBlock
- blocks_ufm = blocksToBlockEnv blocks
-
- dependants :: BlockId -> [BlockId]
- dependants ident =
- brokenBlockTargets $ lookupWithDefaultUFM
- blocks_ufm unknown_block ident
-
- update :: BlockId -> Maybe BlockId
- -> BlockEnv (UniqSet BlockId) -> Maybe (BlockEnv (UniqSet BlockId))
- update ident cause owners =
- case (cause, ident `elementOfUniqSet` proc_points) of
- (Nothing, True) -> Just $ addToUFM owners ident (unitUniqSet ident)
- (Nothing, False) -> Nothing
- (Just cause', True) -> Nothing
- (Just cause', False) ->
- if (sizeUniqSet old) == (sizeUniqSet new)
- then Nothing
- else Just $ addToUFM owners ident new
- where
- old = lookupWithDefaultUFM owners emptyUniqSet ident
- new = old `unionUniqSets` lookupWithDefaultUFM owners emptyUniqSet cause'
-
- unknown_block = panic "unknown BlockId in selectStackFormat"
-
-calculateProcPoints :: [BrokenBlock] -> UniqSet BlockId
-calculateProcPoints blocks = calculateProcPoints' init_proc_points blocks
- where
- init_proc_points = mkUniqSet $
- map brokenBlockId $
- filter always_proc_point blocks
- always_proc_point BrokenBlock {
- brokenBlockEntry = FunctionEntry _ _ } = True
- always_proc_point BrokenBlock {
- brokenBlockEntry = ContinuationEntry _ } = True
- always_proc_point _ = False
-
-calculateProcPoints' :: UniqSet BlockId -> [BrokenBlock] -> UniqSet BlockId
-calculateProcPoints' old_proc_points blocks =
- if sizeUniqSet old_proc_points == sizeUniqSet new_proc_points
- then old_proc_points
- else calculateProcPoints' new_proc_points blocks
- where
- owners = calculateOwnership old_proc_points blocks
- new_proc_points = unionManyUniqSets (old_proc_points:(map (calculateProcPoints'' owners) blocks))
-
-calculateProcPoints'' :: BlockEnv (UniqSet BlockId) -> BrokenBlock -> UniqSet BlockId
-calculateProcPoints'' owners block =
- unionManyUniqSets (map (f parent_id) child_ids)
- where
- parent_id = brokenBlockId block
- child_ids = brokenBlockTargets block
- -- TODO: name for f
- f parent_id child_id =
- if needs_proc_point
- then unitUniqSet child_id
- else emptyUniqSet
- where
- parent_owners = lookupWithDefaultUFM owners emptyUniqSet parent_id
- child_owners = lookupWithDefaultUFM owners emptyUniqSet child_id
- needs_proc_point = not $ isEmptyUniqSet $ child_owners `minusUniqSet` parent_owners
collectNonProcPointTargets ::
UniqSet BlockId -> BlockEnv BrokenBlock
- -> UniqSet BlockId -> BlockId -> UniqSet BlockId
-collectNonProcPointTargets proc_points blocks current_targets block =
+ -> UniqSet BlockId -> [BlockId] -> UniqSet BlockId
+collectNonProcPointTargets proc_points blocks current_targets new_blocks =
if sizeUniqSet current_targets == sizeUniqSet new_targets
then current_targets
- else foldl (collectNonProcPointTargets proc_points blocks) new_targets targets
+ else foldl
+ (collectNonProcPointTargets proc_points blocks)
+ new_targets
+ (map (:[]) targets)
where
- block' = lookupWithDefaultUFM blocks (panic "TODO") block
+ blocks' = map (lookupWithDefaultUFM blocks (panic "TODO")) new_blocks
targets =
-- Note the subtlety that since the extra branch after a call
-- will always be to a block that is a proc-point,
-- this subtraction will always remove that case
- uniqSetToList $ (mkUniqSet $ brokenBlockTargets block') `minusUniqSet` proc_points
+ uniqSetToList $ (unionManyUniqSets $ map (mkUniqSet . brokenBlockTargets) blocks')
+ `minusUniqSet` proc_points
-- TODO: remove redundant uniqSetToList
new_targets = current_targets `unionUniqSets` (mkUniqSet targets)
-buildContinuation ::
+-- TODO: insert proc point code here
+-- * Branches and switches to proc points may cause new blocks to be created
+-- (or proc points could leave behind phantom blocks that just jump to them)
+-- * Proc points might get some live variables passed as arguments
+
+gatherBlocksIntoContinuation ::
UniqSet BlockId -> BlockEnv BrokenBlock
- -> BlockId -> Continuation
-buildContinuation proc_points blocks start =
- Continuation is_entry info_table clabel params body
+ -> BlockId -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo)
+gatherBlocksIntoContinuation proc_points blocks start gc =
+ Continuation info_table clabel params body
where
- children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start
+ start_and_gc = start : maybeToList gc
+ children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc)
start_block = lookupWithDefaultUFM blocks (panic "TODO") start
+ gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) (maybeToList gc)
children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children)
- body = start_block : children_blocks
- info_table = [] -- TODO
+ body = start_block : gc_block ++ children_blocks
+
+ -- We can't properly annotate the continuation's stack parameters
+ -- at this point because this is before stack selection
+ -- but we want to keep the C_SRT around so we use 'Either'.
+ info_table = case start_block_entry of
+ FunctionEntry info _ _ -> Right info
+ ContinuationEntry _ srt -> Left srt
+ ControlEntry -> Right (CmmNonInfo Nothing)
+
start_block_entry = brokenBlockEntry start_block
- is_entry = case start_block_entry of
- FunctionEntry _ _ -> True
- _ -> False
clabel = case start_block_entry of
- FunctionEntry label _ -> label
+ FunctionEntry _ label _ -> label
_ -> mkReturnPtLabel $ getUnique start
params = case start_block_entry of
- FunctionEntry _ args -> args
- ContinuationEntry args -> args
+ FunctionEntry _ _ args -> args
+ ContinuationEntry args _ -> args
ControlEntry -> [] -- TODO: it's a proc-point, we could pass lives in parameter registers
--------------------------------------------------------------------------------
-- For now just select the continuation orders in the order they are in the set with no gaps
-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 (Either C_SRT CmmInfo)]
+ -> [(CLabel, (Maybe CLabel, [Maybe LocalReg]))]
+selectStackFormat live continuations =
map (\c -> (continuationLabel c, selectStackFormat' c)) continuations
where
- selectStackFormat' (Continuation True info_table label formals blocks) =
- --let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this
- --in
- StackFormat (Just label) 0 []
- selectStackFormat' (Continuation False info_table label formals blocks) =
+ selectStackFormat' (Continuation
+ (Right (CmmInfo _ _ _ (ContInfo format srt)))
+ label _ _) = (Just label, format)
+ selectStackFormat' (Continuation (Right _) _ _ _) = (Nothing, [])
+ selectStackFormat' (Continuation (Left srt) label _ blocks) =
-- TODO: assumes the first block is the entry block
let ident = brokenBlockId $ head blocks -- TODO: CLabel isn't a uniquable, but we need a better way than this
- in live_to_format label formals $ lookupWithDefaultUFM live unknown_block ident
+ in (Just label,
+ map Just $ uniqSetToList $
+ lookupWithDefaultUFM live unknown_block ident)
- live_to_format :: CLabel -> CmmFormals -> CmmLive -> StackFormat
- live_to_format label formals live =
- foldl extend_format
- (StackFormat (Just label) retAddrSizeW [])
- (uniqSetToList (live `minusUniqSet` mkUniqSet (cmmFormalsToLiveLocals formals)))
+ unknown_block = panic "unknown BlockId in selectStackFormat"
- extend_format :: StackFormat -> LocalReg -> StackFormat
- extend_format (StackFormat label size offsets) reg =
- StackFormat label (slot_size reg + size) ((CmmLocal reg, size) : offsets)
+processFormats :: [(CLabel, (Maybe CLabel, [Maybe LocalReg]))]
+ -> (WordOff, [(CLabel, StackFormat)])
+processFormats formats = (max_size, formats')
+ where
+ max_size = foldl max 0 (map (stack_frame_size . snd) formats')
+ formats' = map make_format formats
+ make_format (label, format) =
+ (label,
+ StackFormat {
+ stack_label = fst format,
+ stack_frame_size = stack_size (snd format) +
+ if isJust (fst format)
+ then label_size
+ else 0,
+ stack_live = snd format })
+
+ -- TODO: get rid of "+ 1" etc.
+ label_size = 1 :: WordOff
+
+ stack_size [] = 0
+ stack_size (Nothing:formats) = 1 + stack_size formats -- one dead word
+ stack_size (Just reg:formats) = width + stack_size formats
+ where
+ width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
+ -- TODO: it would be better if we had a machRepWordWidth
- unknown_block = panic "unknown BlockId in selectStackFormat"
+-----------------------------------------------------------------------------
+applyStackFormat :: [(CLabel, StackFormat)]
+ -> Continuation (Either C_SRT CmmInfo)
+ -> Continuation CmmInfo
+
+-- User written continuations
+applyStackFormat formats (Continuation
+ (Right (CmmInfo prof gc tag (ContInfo _ srt)))
+ label formals blocks) =
+ Continuation (CmmInfo prof gc tag (ContInfo format srt))
+ label formals blocks
+ where
+ format = stack_live $ maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in applyStackFormat"
-slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1
+-- User written non-continuation code
+applyStackFormat formats (Continuation (Right info) label formals blocks) =
+ Continuation info label formals blocks
-constructContinuation :: [(CLabel, StackFormat)] -> Continuation -> CmmTop
-constructContinuation formats (Continuation is_entry info label formals blocks) =
- CmmProc info label formals (map (constructContinuation2' label formats) blocks)
+-- CPS generated continuations
+applyStackFormat formats (Continuation (Left srt) label formals blocks) =
+ Continuation (CmmInfo prof gc tag (ContInfo (stack_live $ format) srt))
+ label formals blocks
+ where
+ gc = Nothing -- Generated continuations never need a stack check
+ -- TODO prof: this is the same as the current implementation
+ -- but I think it could be improved
+ prof = ProfilingInfo zeroCLit zeroCLit
+ tag = rET_SMALL -- cmmToRawCmm will convert this to rET_BIG if needed
+ format = maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in applyStackFormat"
-constructContinuation2' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock
- -> CmmBasicBlock
-constructContinuation2' curr_ident formats (BrokenBlock ident entry stmts _ exit) =
- BasicBlock ident (prefix++stmts++postfix)
+-----------------------------------------------------------------------------
+continuationToProc :: (WordOff, [(CLabel, StackFormat)])
+ -> Continuation CmmInfo
+ -> CmmTop
+continuationToProc (max_stack, formats)
+ (Continuation info label formals blocks) =
+ CmmProc info label formals (map continuationToProc' blocks)
where
- curr_format = maybe unknown_block id $ lookup curr_ident formats
- unknown_block = panic "unknown BlockId in constructContinuation"
- prefix = case entry of
- ControlEntry -> []
- FunctionEntry _ _ -> []
- ContinuationEntry formals ->
- unpack_continuation curr_format
- postfix = case exit of
- FinalBranch next -> [CmmBranch next]
- FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalReturn arguments ->
- exit_function curr_format
- (CmmLoad (CmmReg spReg) wordRep)
- arguments
- FinalJump target arguments ->
- exit_function curr_format target arguments
- -- TODO: do something about global saves
- FinalCall next (CmmForeignCall target CmmCallConv)
- results arguments saves ->
+ curr_format = maybe unknown_block id $ lookup label formats
+ unknown_block = panic "unknown BlockId in continuationToProc"
+
+ continuationToProc' :: BrokenBlock -> CmmBasicBlock
+ continuationToProc' (BrokenBlock ident entry stmts _ exit) =
+ BasicBlock ident (prefix++stmts++postfix)
+ where
+ prefix = case entry of
+ ControlEntry -> []
+ FunctionEntry (CmmInfo _ (Just gc_block) _ _) _ formals ->
+ gc_stack_check gc_block max_stack ++
+ function_entry formals curr_format
+ FunctionEntry (CmmInfo _ Nothing _ _) _ formals ->
+ panic "continuationToProc: missing GC block"
+ FunctionEntry (CmmNonInfo (Just gc_block)) _ formals ->
+ gc_stack_check gc_block max_stack ++
+ function_entry formals curr_format
+ FunctionEntry (CmmNonInfo Nothing) _ formals ->
+ panic "continuationToProc: missing non-info GC block"
+ ContinuationEntry formals _ ->
+ function_entry formals curr_format
+ postfix = case exit of
+ FinalBranch next -> [CmmBranch next]
+ FinalSwitch expr targets -> [CmmSwitch expr targets]
+ FinalReturn arguments ->
+ tail_call (stack_frame_size curr_format)
+ (CmmLoad (CmmReg spReg) wordRep)
+ arguments
+ FinalJump target arguments ->
+ tail_call (stack_frame_size curr_format) target arguments
+ FinalCall next (CmmForeignCall target CmmCallConv)
+ results arguments ->
pack_continuation curr_format cont_format ++
- [CmmJump target arguments]
+ tail_call (stack_frame_size curr_format - stack_frame_size cont_format)
+ target arguments
where
cont_format = maybe unknown_block id $
lookup (mkReturnPtLabel $ getUnique next) formats
- FinalCall next _ results arguments saves -> panic "unimplemented CmmCall"
+ FinalCall next _ results arguments -> panic "unimplemented CmmCall"
---------------------------------------------------------------------------------
+-----------------------------------------------------------------------------
-- Functions that generate CmmStmt sequences
-- for packing/unpacking continuations
-- and entering/exiting functions
-exit_function :: StackFormat -> CmmExpr -> CmmActuals -> [CmmStmt]
-exit_function (StackFormat curr_id curr_frame_size curr_offsets) target arguments
- = adjust_spReg ++ jump where
+tail_call :: WordOff -> CmmExpr -> CmmActuals -> [CmmStmt]
+tail_call spRel target arguments
+ = store_arguments ++ adjust_spReg ++ jump where
+ store_arguments =
+ [stack_put spRel expr offset
+ | ((expr, _), StackParam offset) <- argument_formats] ++
+ [global_put expr global
+ | ((expr, _), RegisterParam global) <- argument_formats]
adjust_spReg =
- if curr_frame_size == 0
+ if spRel == 0
then []
- else [CmmAssign spReg
- (CmmRegOff spReg (curr_frame_size*wORD_SIZE))]
+ else [CmmAssign spReg (CmmRegOff spReg (spRel*wORD_SIZE))]
jump = [CmmJump target arguments]
-enter_function :: WordOff -> [CmmStmt]
-enter_function max_frame_size
+ argument_formats = assignArguments (cmmExprRep . fst) arguments
+
+gc_stack_check :: BlockId -> WordOff -> [CmmStmt]
+gc_stack_check gc_block max_frame_size
= check_stack_limit where
check_stack_limit = [
CmmCondBranch
(CmmMachOp (MO_U_Lt $ cmmRegRep spReg)
- [CmmRegOff spReg max_frame_size, CmmReg spLimReg])
+ [CmmRegOff spReg (-max_frame_size*wORD_SIZE),
+ CmmReg spLimReg])
gc_block]
- gc_block = undefined -- TODO: get stack and heap checks to go to same
--- TODO: fix branches to proc point (we have to insert a new block to marshel the continuation)
+-- TODO: fix branches to proc point
+-- (we have to insert a new block to marshel the continuation)
pack_continuation :: StackFormat -> StackFormat -> [CmmStmt]
-pack_continuation (StackFormat curr_id curr_frame_size curr_offsets)
- (StackFormat cont_id cont_frame_size cont_offsets)
- = save_live_values ++ set_stack_header ++ adjust_spReg where
+pack_continuation (StackFormat curr_id curr_frame_size _)
+ (StackFormat cont_id cont_frame_size live_regs)
+ = store_live_values ++ set_stack_header where
-- TODO: only save variables when actually needed
- save_live_values =
- [CmmStore
- (CmmRegOff
- spReg (wORD_SIZE*(curr_frame_size - cont_frame_size + offset)))
- (CmmReg reg)
+ -- (may be handled by latter pass)
+ store_live_values =
+ [stack_put spRel (CmmReg (CmmLocal reg)) offset
| (reg, offset) <- cont_offsets]
- needs_header =
- case (curr_id, cont_id) of
- (Just x, Just y) -> x /= y
- _ -> isJust cont_id
set_stack_header =
- if not needs_header
- then []
- else [CmmStore (CmmRegOff spReg (wORD_SIZE*(curr_frame_size - cont_frame_size))) continuation_function]
+ if needs_header_set
+ then [stack_put spRel continuation_function 0]
+ else []
+
+ -- TODO: factor with function_entry and CmmInfo.hs(?)
+ cont_offsets = mkOffsets label_size live_regs
+
+ label_size = 1 :: WordOff
+
+ mkOffsets size [] = []
+ mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
+ mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
+ where
+ width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
+ -- TODO: it would be better if we had a machRepWordWidth
+
+ spRel = curr_frame_size - cont_frame_size
continuation_function = CmmLit $ CmmLabel $ fromJust cont_id
- adjust_spReg =
- if curr_frame_size == cont_frame_size
- then []
- else [CmmAssign spReg (CmmRegOff spReg ((curr_frame_size - cont_frame_size)*wORD_SIZE))]
+ needs_header_set =
+ case (curr_id, cont_id) of
+ (Just x, Just y) -> x /= y
+ _ -> isJust cont_id
-- Lazy adjustment of stack headers assumes all blocks
-- that could branch to eachother (i.e. control blocks)
-- have the same stack format (this causes a problem
-- only for proc-point).
-unpack_continuation :: StackFormat -> [CmmStmt]
-unpack_continuation (StackFormat curr_id curr_frame_size curr_offsets)
- = load_live_values where
+function_entry :: CmmFormals -> StackFormat -> [CmmStmt]
+function_entry formals (StackFormat _ _ live_regs)
+ = load_live_values ++ load_args where
-- TODO: only save variables when actually needed
+ -- (may be handled by latter pass)
load_live_values =
- [CmmAssign
- reg
- (CmmLoad (CmmRegOff spReg (wORD_SIZE*offset)) (cmmRegRep reg))
+ [stack_get 0 reg offset
| (reg, offset) <- curr_offsets]
+ load_args =
+ [stack_get 0 reg offset
+ | (reg, StackParam offset) <- argument_formats] ++
+ [global_get reg global
+ | (reg, RegisterParam global) <- argument_formats]
------------------------------------------------------------------------------
--- Breaking basic blocks on function calls
------------------------------------------------------------------------------
+ argument_formats = assignArguments (localRegRep) formals
------------------------------------------------------------------------------
--- Takes a basic block and breaks it up into a list of broken blocks
---
--- Takes a basic block and returns a list of basic blocks that
--- each have at most 1 CmmCall in them which must occur at the end.
--- Also returns with each basic block, the variables that will
--- be arguments to the continuation of the block once the call (if any)
--- returns.
-
-breakBlock :: [Unique] -> CmmBasicBlock -> BlockEntryInfo -> [BrokenBlock]
-breakBlock uniques (BasicBlock ident stmts) entry =
- breakBlock' uniques ident entry [] [] stmts where
- breakBlock' uniques current_id entry exits accum_stmts stmts =
- case stmts of
- [] -> panic "block doesn't end in jump, goto or return"
- [CmmJump target arguments] ->
- [BrokenBlock current_id entry accum_stmts
- exits
- (FinalJump target arguments)]
- [CmmReturn arguments] ->
- [BrokenBlock current_id entry accum_stmts
- exits
- (FinalReturn arguments)]
- [CmmBranch target] ->
- [BrokenBlock current_id entry accum_stmts
- (target:exits)
- (FinalBranch target)]
- [CmmSwitch expr targets] ->
- [BrokenBlock current_id entry accum_stmts
- (mapMaybe id targets ++ exits)
- (FinalSwitch expr targets)]
- (CmmJump _ _:_) ->
- panic "jump in middle of block"
- (CmmReturn _:_) ->
- panic "return in middle of block"
- (CmmBranch _:_) ->
- panic "branch in middle of block"
- (CmmSwitch _ _:_) ->
- panic ("switch in middle of block" ++ (showSDoc $ ppr stmts))
- (CmmCall target results arguments saves:stmts) -> block : rest
- where
- new_id = BlockId $ head uniques
- block = BrokenBlock current_id entry accum_stmts
- (new_id:exits)
- (FinalCall new_id target results arguments saves)
- rest = breakBlock' (tail uniques) new_id
- (ContinuationEntry results) [] [] stmts
- (s@(CmmCondBranch test target):stmts) ->
- breakBlock' uniques current_id entry
- (target:exits) (accum_stmts++[s]) stmts
- (s:stmts) ->
- breakBlock' uniques current_id entry
- exits (accum_stmts++[s]) stmts
+ -- TODO: eliminate copy/paste with pack_continuation
+ curr_offsets = mkOffsets label_size live_regs
---------------------------------
--- Convert from a BrokenBlock
--- to a CmmBasicBlock so the
--- liveness analysis can run
--- on it.
---------------------------------
-cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock
-cmmBlockFromBrokenBlock (BrokenBlock ident _ stmts _ exit) =
- BasicBlock ident (stmts++exit_stmt)
- where
- exit_stmt =
- case exit of
- FinalBranch target -> [CmmBranch target]
- FinalReturn arguments -> [CmmReturn arguments]
- FinalJump target arguments -> [CmmJump target arguments]
- FinalSwitch expr targets -> [CmmSwitch expr targets]
- FinalCall branch_target call_target results arguments saves ->
- [CmmCall call_target results arguments saves,
- CmmBranch branch_target]
+ label_size = 1 :: WordOff
+
+ mkOffsets size [] = []
+ mkOffsets size (Nothing:regs) = mkOffsets (size+1) regs
+ mkOffsets size (Just reg:regs) = (reg, size):mkOffsets (size + width) regs
+ where
+ width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE
+ -- TODO: it would be better if we had a machRepWordWidth
-----------------------------------------------------------------------------
--- CPS a single CmmTop (proceedure)
+-- Section: Stack and argument register puts and gets
-----------------------------------------------------------------------------
+-- TODO: document
+
+-- |Construct a 'CmmStmt' that will save a value on the stack
+stack_put :: WordOff -- ^ Offset from the real 'Sp' that 'offset'
+ -- is relative to (added to offset)
+ -> CmmExpr -- ^ What to store onto the stack
+ -> WordOff -- ^ Where on the stack to store it
+ -- (positive <=> higher addresses)
+ -> CmmStmt
+stack_put spRel expr offset =
+ CmmStore (CmmRegOff spReg (wORD_SIZE*(spRel + offset))) expr
-cpsProc :: UniqSupply -> CmmTop -> [CmmTop]
-cpsProc uniqSupply x@(CmmData _ _) = [x]
-cpsProc uniqSupply x@(CmmProc info_table ident params blocks) =
- --[CmmProc info_table ident params cps_blocks]
- cps_continuations
- where
- uniqes :: [[Unique]]
- uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply
-
- -- Break the block at each function call
- broken_blocks :: [BrokenBlock]
- broken_blocks = concat $ zipWith3 breakBlock uniqes blocks
- (FunctionEntry ident params:repeat ControlEntry)
-
- -- Calculate live variables for each broken block
- live :: BlockEntryLiveness
- live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks
- -- nothing can be live on entry to the first block so we could take the tail
-
- proc_points :: UniqSet BlockId
- proc_points = calculateProcPoints broken_blocks
-
- continuations :: [Continuation]
- continuations = map (buildContinuation proc_points (blocksToBlockEnv broken_blocks)) (uniqSetToList proc_points)
-
- -- TODO: insert proc point code here
- -- * Branches and switches to proc points may cause new blocks to be created
- -- (or proc points could leave behind phantom blocks that just jump to them)
- -- * Proc points might get some live variables passed as arguments
-
- -- TODO: let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks
-
- --procs = groupBlocksIntoContinuations live broken_blocks
-
- -- Select the stack format on entry to each block
- formats2 :: [(CLabel, StackFormat)]
- formats2 = selectStackFormat2 live continuations
-
- -- Do the actual CPS transform
- cps_continuations :: [CmmTop]
- cps_continuations = map (constructContinuation formats2) continuations
-
---------------------------------------------------------------------------------
-cmmCPS :: DynFlags
- -> [Cmm] -- C-- with Proceedures
- -> IO [Cmm] -- Output: CPS transformed C--
-
-cmmCPS dflags abstractC = do
- when (dopt Opt_DoCmmLinting dflags) $
- do showPass dflags "CmmLint"
- case firstJust $ map cmmLint abstractC of
- Just err -> do printDump err
- ghcExit dflags 1
- Nothing -> return ()
- showPass dflags "CPS"
- -- TODO: check for use of branches to non-existant blocks
- -- TODO: check for use of Sp, SpLim, R1, R2, etc.
- -- TODO: find out if it is valid to create a new unique source like this
- uniqSupply <- mkSplitUniqSupply 'p'
- let supplies = listSplitUniqSupply uniqSupply
- let continuationC = zipWith (\s (Cmm c) -> Cmm $ concat $ zipWith (cpsProc) (listSplitUniqSupply s) c) supplies abstractC
+--------------------------------
+-- |Construct a
+stack_get :: WordOff
+ -> LocalReg
+ -> WordOff
+ -> CmmStmt
+stack_get spRel reg offset =
+ CmmAssign (CmmLocal reg)
+ (CmmLoad (CmmRegOff spReg (wORD_SIZE*(spRel + offset)))
+ (localRegRep reg))
+global_put :: CmmExpr -> GlobalReg -> CmmStmt
+global_put expr global = CmmAssign (CmmGlobal global) expr
+global_get :: LocalReg -> GlobalReg -> CmmStmt
+global_get reg global = CmmAssign (CmmLocal reg) (CmmReg (CmmGlobal global))
- dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
- -- TODO: add option to dump Cmm to file
- return continuationC
projects / ghc-hetmet.git / blobdiff