X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmCPS.hs;h=2726ef83041d3e84bef53fc7fe54a107bba3499c;hb=bdfa9495e95ba5701f27711b27d8e22ae7bb8335;hp=7cc89ba8ebba56eec66952ef97ed48e3abc4fa86;hpb=9a740fb96076fe9e02a62e391a905c6ca6d3a571;p=ghc-hetmet.git diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index 7cc89ba..2726ef8 100644 --- a/compiler/cmm/CmmCPS.hs +++ b/compiler/cmm/CmmCPS.hs @@ -1,4 +1,8 @@ -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" @@ -6,8 +10,11 @@ import Cmm import CmmLint import PprCmm -import Dataflow (fixedpoint) +import Dataflow import CmmLive +import CmmBrokenBlock +import CmmProcPoint +import CmmCallConv import MachOp import ForeignCall @@ -28,6 +35,90 @@ import Monad import IO import Data.List +----------------------------------------------------------------------------- +-- |Top level driver for the CPS pass +----------------------------------------------------------------------------- +cmmCPS :: DynFlags -- ^ Dynamic flags: -dcmm-lint -ddump-cps-cmm + -> [Cmm] -- ^ Input 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: 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 + +----------------------------------------------------------------------------- +-- |CPS a single CmmTop (proceedure) +-- Only 'CmmProc' are transformed 'CmmData' will be left alone. +----------------------------------------------------------------------------- + +cpsProc :: UniqSupply + -> CmmTop -- ^Input proceedure + -> [CmmTop] -- ^Output proceedure and continuations +cpsProc uniqSupply x@(CmmData _ _) = [x] +cpsProc uniqSupply x@(CmmProc info_table ident params blocks) = cps_procs + where + uniqes :: [[Unique]] + uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply + + -- 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 uniqes blocks + (FunctionEntry 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] + continuations = map (gatherBlocksIntoContinuation proc_points block_env) + (uniqSetToList proc_points) + + -- Select the stack format on entry to each continuation. + -- + -- This is an association list instead of a UniqFM because + -- CLabel's don't have a 'Uniqueable' instance. + formats :: [(CLabel, StackFormat)] + formats = selectStackFormat live continuations + + -- Do the actual CPS transform. + cps_procs :: [CmmTop] + cps_procs = map (continuationToProc formats) continuations + -------------------------------------------------------------------------------- -- The format for the call to a continuation @@ -45,25 +136,6 @@ import Data.List -- 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 @@ -80,44 +152,6 @@ data 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 @@ -129,75 +163,7 @@ data 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 @@ -216,10 +182,15 @@ collectNonProcPointTargets proc_points blocks current_targets block = -- 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 = +gatherBlocksIntoContinuation proc_points blocks start = Continuation is_entry info_table clabel params body where children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) start) `delOneFromUniqSet` start @@ -242,13 +213,11 @@ buildContinuation proc_points blocks start = -------------------------------------------------------------------------------- -- For now just select the continuation orders in the order they are in the set with no gaps -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) = - --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) = -- TODO: assumes the first block is the entry block @@ -265,44 +234,44 @@ selectStackFormat2 live continuations = 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) - results arguments saves -> + 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 + FinalCall next (CmmForeignCall target CmmCallConv) + results arguments -> 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 -> panic "unimplemented CmmCall" -------------------------------------------------------------------------------- -- Functions that generate CmmStmt sequences @@ -327,7 +296,7 @@ enter_function max_frame_size (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 + gc_block = panic "gc_check not implemented" -- 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] @@ -369,150 +338,3 @@ unpack_continuation (StackFormat curr_id curr_frame_size curr_offsets) (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-- - -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 - - dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC) - -- TODO: add option to dump Cmm to file - return continuationC