import CmmLint
import PprCmm
-import Dataflow (mapCmmTop, onBasicBlock, cmmLivenessComment, cmmLiveness)
+import Dataflow (fixedpoint)
+import CmmLive
+
+import MachOp
+import ForeignCall
+import CLabel
+import SMRep
+import Constants
import DynFlags
import ErrUtils
import Maybes
import Outputable
+import UniqSupply
+import UniqFM
+import UniqSet
+import Unique
import Monad
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
+ }
+
+continuationLabel (Continuation _ _ l _ _) = l
+data Continuation =
+ Continuation
+ Bool -- True => Function entry, False => Continuation/return point
+ [CmmStatic] -- Info table, may be empty
+ 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
+ -- the entry point. The order is otherwise initially
+ -- unimportant, but at some point the code gen will
+ -- fix the order.
+
+ -- the BlockId of the first block does not give rise
+ -- to a label. To jump to the first block in a Proc,
+ -- use the appropriate CLabel.
+
+data 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?)
+
+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
+
+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 =
+ if sizeUniqSet current_targets == sizeUniqSet new_targets
+ then current_targets
+ else foldl (collectNonProcPointTargets proc_points blocks) new_targets targets
+ where
+ block' = lookupWithDefaultUFM blocks (panic "TODO") block
+ 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
+ -- TODO: remove redundant uniqSetToList
+ new_targets = current_targets `unionUniqSets` (mkUniqSet targets)
+
+buildContinuation ::
+ UniqSet BlockId -> BlockEnv BrokenBlock
+ -> BlockId -> Continuation
+buildContinuation proc_points blocks start =
+ Continuation is_entry info_table clabel params body
+ where
+ children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start
+ start_block = lookupWithDefaultUFM blocks (panic "TODO") start
+ children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children)
+ body = start_block : children_blocks
+ info_table = [] -- TODO
+ 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
+ _ -> 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
+
+--------------------------------------------------------------------------------
+-- 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 =
+ 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 ident 0 []
+ selectStackFormat' (Continuation False 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 live_to_format ident $ lookupWithDefaultUFM live unknown_block ident
+
+ 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)
+
+ unknown_block = panic "unknown BlockId in selectStackFormat"
+
+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)
+
+constructContinuation2' :: CLabel -> [(CLabel, StackFormat)] -> BrokenBlock
+ -> CmmBasicBlock
+constructContinuation2' 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 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 ->
+ 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"
+
+--------------------------------------------------------------------------------
+-- 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 {-TODO: use the correct function -} $ 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]
+
+-----------------------------------------------------------------------------
+-- Breaking basic blocks on function calls
+-----------------------------------------------------------------------------
+
+-----------------------------------------------------------------------------
+-- 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
+
+--------------------------------
+-- 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]
+
+-----------------------------------------------------------------------------
+-- CPS a single CmmTop (proceedure)
+-----------------------------------------------------------------------------
+
+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--
ghcExit dflags 1
Nothing -> return ()
showPass dflags "CPS"
- -- continuationC <- return abstractC
- continuationC <- return $ map (mapCmmTop (onBasicBlock (\bs -> map (cmmLivenessComment (cmmLiveness bs)) bs))) abstractC
+ -- 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
dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
-- TODO: add option to dump Cmm to file
projects / ghc-hetmet.git / blobdiff