X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fcmm%2FCmmCPS.hs;h=2726ef83041d3e84bef53fc7fe54a107bba3499c;hb=bdfa9495e95ba5701f27711b27d8e22ae7bb8335;hp=880b1b056d91d3985bbc52f467f0bfcab4e09e96;hpb=e82defdd837eb687ddaa6ac900cc481cc8774bd2;p=ghc-hetmet.git diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index 880b1b0..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 @@ -45,118 +136,142 @@ 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 - } - - -data BlockEntryInfo - = FunctionEntry -- Beginning of function - - | ContinuationEntry -- Return point of a call - CmmFormals -- return values - -- TODO: - -- | ProcPointEntry -- no return values, but some live might end up as params or possibly in the frame - - | ControlEntry -- A label in the input - -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) - -- TODO: | ProcPointExit (needed?) - +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. + +-- Describes the layout of a stack frame for a continuation 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 -} + (Maybe CLabel) -- The label occupying the top slot + WordOff -- Total frame size in words + [(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 +----------------------------------------------------------------------------- + +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) + +-- 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 +gatherBlocksIntoContinuation 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 -selectStackFormat2 :: BlockEnv CmmLive -> [BrokenBlock] -> BlockEnv StackFormat -selectStackFormat2 live blocks = fixedpoint dependants update (map brokenBlockId blocks) emptyUFM where - blocks_ufm = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks - dependants ident = - brokenBlockTargets $ lookupWithDefaultUFM blocks_ufm (panic "TODO") ident - update ident cause formats = - let BrokenBlock _ entry _ _ _ = lookupWithDefaultUFM blocks_ufm (panic "unknown BlockId in selectStackFormat:live") ident in - case cause of - -- Propagate only to blocks entered by branches (not function entry blocks or continuation entry blocks) - Just cause_name -> - let cause_format = lookupWithDefaultUFM formats (panic "update signaled for block not in format") cause_name - in case entry of - ControlEntry -> Just $ addToUFM formats ident cause_format - FunctionEntry -> Nothing - ContinuationEntry _ -> Nothing - -- Do initial calculates for function blocks - Nothing -> - case entry of - ControlEntry -> Nothing - FunctionEntry -> Just $ addToUFM formats ident $ StackFormat ident 0 [] - ContinuationEntry _ -> Just $ addToUFM formats ident $ live_to_format ident $ lookupWithDefaultUFM live (panic "TODO") ident - 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) - -slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1 - -constructContinuation2 :: BlockEnv StackFormat -> BrokenBlock -> CmmBasicBlock -constructContinuation2 formats (BrokenBlock ident entry stmts _ exit) = - BasicBlock ident (prefix++stmts++postfix) +selectStackFormat :: BlockEnv CmmLive -> [Continuation] -> [(CLabel, StackFormat)] +selectStackFormat live continuations = + map (\c -> (continuationLabel c, selectStackFormat' c)) continuations where - curr_format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident - prefix = case entry of - ControlEntry -> [] - FunctionEntry -> [] - ContinuationEntry formals -> unpack_continuation curr_format - postfix = case exit of - FinalBranch next -> [CmmBranch next] - 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 -> - let cont_format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique next)) next - in pack_continuation curr_format cont_format ++ - [CmmJump target arguments] - FinalCall next _ results arguments saves -> panic "unimplemented CmmCall" + selectStackFormat' (Continuation True info_table label formals blocks) = + StackFormat (Just label) 0 [] + selectStackFormat' (Continuation False info_table 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 live_to_format label formals $ 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))) + + extend_format :: StackFormat -> LocalReg -> StackFormat + extend_format (StackFormat label size offsets) reg = + StackFormat label (slot_size reg + size) ((CmmLocal reg, size) : offsets) + + slot_size :: LocalReg -> Int + slot_size reg = ((machRepByteWidth (localRegRep reg) - 1) `div` wORD_SIZE) + 1 + + unknown_block = panic "unknown BlockId in selectStackFormat" + +continuationToProc :: [(CLabel, StackFormat)] -> Continuation -> CmmTop +continuationToProc formats (Continuation is_entry info label formals blocks) = + CmmProc info label formals (map (continuationToProc' label formats) blocks) + where + 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 -> panic "unimplemented CmmCall" -------------------------------------------------------------------------------- -- Functions that generate CmmStmt sequences @@ -166,9 +281,11 @@ constructContinuation2 formats (BrokenBlock ident entry stmts _ exit) = 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))] + adjust_spReg = + if curr_frame_size == 0 + then [] + else [CmmAssign spReg + (CmmRegOff spReg (curr_frame_size*wORD_SIZE))] jump = [CmmJump target arguments] enter_function :: WordOff -> [CmmStmt] @@ -179,7 +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] @@ -193,9 +310,15 @@ pack_continuation (StackFormat curr_id curr_frame_size curr_offsets) 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 $ getUnique cont_id + 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] + continuation_function = CmmLit $ CmmLabel $ fromJust cont_id adjust_spReg = if curr_frame_size == cont_frame_size then [] @@ -215,106 +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 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 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)] - (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 block not implemented" - (CmmCall target results arguments saves:stmts) -> - let new_id = BlockId $ head uniques - rest = breakBlock' (tail uniques) new_id (ContinuationEntry results) [] [] stmts - in BrokenBlock current_id entry accum_stmts (new_id:exits) - (FinalCall new_id target results arguments saves) : rest - (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 - ------------------------------------------------------------------------------ -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] - 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 $ map (constructContinuation2 formats) broken_blocks] - where - uniqes :: [[Unique]] - uniqes = map uniqsFromSupply $ listSplitUniqSupply uniqSupply - - broken_blocks :: [BrokenBlock] - broken_blocks = concat $ zipWith3 breakBlock uniqes blocks (FunctionEntry:repeat ControlEntry) - - live :: BlockEntryLiveness - live = cmmLiveness $ map cmmBlockFromBrokenBlock broken_blocks - - -- TODO: branches for proc points - -- TODO: let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks - - formats :: BlockEnv StackFormat -- Stack format on entry - formats = selectStackFormat2 live broken_blocks - - --------------------------------------------------------------------------------- -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. - -- continuationC <- return abstractC - -- 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