From a2d5d3c9677a740ace920a976d03dfbd82f7697b Mon Sep 17 00:00:00 2001 From: "Michael D. Adams" Date: Mon, 2 Jul 2007 08:42:21 +0000 Subject: [PATCH] Multiple improvements to CPS algorithm. These include: - Stack size detection now includes function arguments. - Stack size detection now avoids stack checks just because of the GC block. - A CmmCall followed by a CmmBranch will no longer generate an extra continuation consisting just of the brach. - Multiple CmmCall/CmmBranch pairs that all go to the same place will try to use the same continuation. If they can't (because the return value signature is different), adaptor block are built. - Function entry statements are now in a separate block. (Fixed bug with branches to the entry block having unintended effects.) - Other changes that I can't recall right now. --- compiler/cmm/Cmm.hs | 4 +- compiler/cmm/CmmBrokenBlock.hs | 208 ++++++++++++++++++++---- compiler/cmm/CmmCPS.hs | 322 ++++++++++++++++++++++++-------------- compiler/cmm/CmmProcPoint.hs | 2 +- compiler/codeGen/ClosureInfo.lhs | 1 + 5 files changed, 390 insertions(+), 147 deletions(-) diff --git a/compiler/cmm/Cmm.hs b/compiler/cmm/Cmm.hs index 530fab5..1f7161b 100644 --- a/compiler/cmm/Cmm.hs +++ b/compiler/cmm/Cmm.hs @@ -10,7 +10,7 @@ module Cmm ( GenCmm(..), Cmm, RawCmm, GenCmmTop(..), CmmTop, RawCmmTop, CmmInfo(..), ClosureTypeInfo(..), ProfilingInfo(..), ClosureTypeTag, - GenBasicBlock(..), CmmBasicBlock, blockId, blockStmts, + GenBasicBlock(..), CmmBasicBlock, blockId, blockStmts, mapBlockStmts, CmmStmt(..), CmmActuals, CmmFormal, CmmFormals, CmmHintFormals, CmmSafety(..), CmmCallTarget(..), @@ -104,6 +104,8 @@ blockId (BasicBlock blk_id _ ) = blk_id blockStmts :: GenBasicBlock i -> [i] blockStmts (BasicBlock _ stmts) = stmts +mapBlockStmts f (BasicBlock id bs) = BasicBlock id (map f bs) + ----------------------------------------------------------------------------- -- Info Tables ----------------------------------------------------------------------------- diff --git a/compiler/cmm/CmmBrokenBlock.hs b/compiler/cmm/CmmBrokenBlock.hs index af47e8d..14259c6 100644 --- a/compiler/cmm/CmmBrokenBlock.hs +++ b/compiler/cmm/CmmBrokenBlock.hs @@ -5,17 +5,24 @@ module CmmBrokenBlock ( breakBlock, cmmBlockFromBrokenBlock, blocksToBlockEnv, + adaptBlockToFormat, + selectContinuations, + ContFormat, + makeContinuationEntries, ) where #include "HsVersions.h" import Cmm import CLabel +import MachOp (MachHint(..)) import ClosureInfo import Maybes +import List import Panic +import UniqSupply import Unique import UniqFM @@ -59,6 +66,7 @@ data BlockEntryInfo | ContinuationEntry -- ^ Return point of a function call CmmFormals -- ^ return values (argument to continuation) C_SRT -- ^ SRT for the continuation's info table + Bool -- ^ True <=> GC block so ignore stack size | ControlEntry -- ^ Any other kind of block. -- Only entered due to control flow. @@ -67,6 +75,11 @@ data BlockEntryInfo -- no return values, but some live might end up as -- params or possibly in the frame +data ContFormat = ContFormat + CmmHintFormals -- ^ return values (argument to continuation) + C_SRT -- ^ SRT for the continuation's info table + Bool -- ^ True <=> GC block so ignore stack size + deriving (Eq) -- | Final statement in a 'BlokenBlock'. -- Constructors and arguments match those in 'Cmm', @@ -90,6 +103,8 @@ data FinalStmt CmmHintFormals -- ^ Results from call -- (redundant with ContinuationEntry) CmmActuals -- ^ Arguments to call + C_SRT -- ^ SRT for the continuation's info table + Bool -- ^ True <=> GC block so ignore stack size | FinalSwitch -- ^ Same as a 'CmmSwitch' CmmExpr -- ^ Scrutinee (zero based) @@ -99,17 +114,74 @@ data FinalStmt -- Operations for broken blocks ----------------------------------------------------------------------------- +-- Naively breaking at *every* CmmCall leads to sub-optimal code. +-- In particular, a CmmCall followed by a CmmBranch would result +-- in a continuation that has the single CmmBranch statement in it. +-- It would be better have the CmmCall directly return to the block +-- that the branch jumps to. +-- +-- This requires the target of the branch to look like the parameter +-- format that the CmmCall is expecting. If other CmmCall/CmmBranch +-- sequences go to the same place they might not be expecting the +-- same format. So this transformation uses the following solution. +-- First the blocks are broken up but none of the blocks are marked +-- as continuations yet. This is the 'breakBlock' function. +-- Second, the blocks "vote" on what other blocks need to be continuations +-- and how they should be layed out. Plurality wins, but other selection +-- methods could be selected at a later time. +-- This is the 'selectContinuations' function. +-- Finally, the blocks are upgraded to 'ContEntry' continuations +-- based on the results with the 'makeContinuationEntries' function, +-- and the blocks that didn't get the format they wanted for their +-- targets get a small adaptor block created for them by +-- the 'adaptBlockToFormat' function. +-- could be + +breakProc :: + [BlockId] -- ^ Any GC blocks that should be special + -> [[Unique]] -- ^ An infinite list of uniques + -- to create names of the new blocks with + -> CmmInfo -- ^ Info table for the procedure + -> CLabel -- ^ Name of the procedure + -> CmmFormals -- ^ Parameters of the procedure + -> [CmmBasicBlock] -- ^ Blocks of the procecure + -- (First block is the entry block) + -> [BrokenBlock] + +breakProc gc_block_idents uniques info ident params blocks = + let + (adaptor_uniques : block_uniques) = uniques + + broken_blocks :: ([(BlockId, ContFormat)], [BrokenBlock]) + broken_blocks = + let new_blocks = + zipWith3 (breakBlock gc_block_idents) + block_uniques + blocks + (FunctionEntry info ident params : + repeat ControlEntry) + in (concatMap fst new_blocks, concatMap snd new_blocks) + + selected = selectContinuations (fst broken_blocks) + + in map (makeContinuationEntries selected) $ + concat $ + zipWith (adaptBlockToFormat selected) + adaptor_uniques + (snd broken_blocks) + ----------------------------------------------------------------------------- -- | Takes a 'CmmBasicBlock' and breaks it up into a list of 'BrokenBlock' -- by splitting on each 'CmmCall' in the 'CmmBasicBlock'. breakBlock :: - [Unique] -- ^ An infinite list of uniques + [BlockId] -- ^ Any GC blocks that should be special + -> [Unique] -- ^ An infinite list of uniques -- to create names of the new blocks with -> CmmBasicBlock -- ^ Input block to break apart -> BlockEntryInfo -- ^ Info for the first created 'BrokenBlock' - -> [BrokenBlock] -breakBlock uniques (BasicBlock ident stmts) entry = + -> ([(BlockId, ContFormat)], [BrokenBlock]) +breakBlock gc_block_idents uniques (BasicBlock ident stmts) entry = breakBlock' uniques ident entry [] [] stmts where breakBlock' uniques current_id entry exits accum_stmts stmts = @@ -118,21 +190,25 @@ breakBlock uniques (BasicBlock ident stmts) entry = -- Last statement. Make the 'BrokenBlock' [CmmJump target arguments] -> - [BrokenBlock current_id entry accum_stmts - exits - (FinalJump target arguments)] + ([], + [BrokenBlock current_id entry accum_stmts + exits + (FinalJump target arguments)]) [CmmReturn arguments] -> - [BrokenBlock current_id entry accum_stmts + ([], + [BrokenBlock current_id entry accum_stmts exits - (FinalReturn arguments)] + (FinalReturn arguments)]) [CmmBranch target] -> - [BrokenBlock current_id entry accum_stmts + ([], + [BrokenBlock current_id entry accum_stmts (target:exits) - (FinalBranch target)] + (FinalBranch target)]) [CmmSwitch expr targets] -> - [BrokenBlock current_id entry accum_stmts + ([], + [BrokenBlock current_id entry accum_stmts (mapMaybe id targets ++ exits) - (FinalSwitch expr targets)] + (FinalSwitch expr targets)]) -- These shouldn't happen in the middle of a block. -- They would cause dead code. @@ -143,24 +219,28 @@ breakBlock uniques (BasicBlock ident stmts) entry = -- Detect this special case to remain an inverse of -- 'cmmBlockFromBrokenBlock' - {- TODO: Interferes with proc point detection - [CmmCall target results arguments, - CmmBranch next_id] -> [block] - where - block = do_call current_id entry accum_stmts exits next_id - target results arguments - -} + [CmmCall target results arguments (CmmSafe srt), + CmmBranch next_id] -> + ([cont_info], [block]) + where + cont_info = (next_id, + ContFormat results srt + (ident `elem` gc_block_idents)) + block = do_call current_id entry accum_stmts exits next_id + target results arguments srt -- Break the block on safe calls (the main job of this function) (CmmCall target results arguments (CmmSafe srt):stmts) -> - block : rest + (cont_info : cont_infos, block : blocks) where next_id = BlockId $ head uniques block = do_call current_id entry accum_stmts exits next_id - target results arguments - rest = breakBlock' (tail uniques) next_id - (ContinuationEntry (map fst results) srt) - [] [] stmts + target results arguments srt + cont_info = (next_id, + ContFormat results srt + (ident `elem` gc_block_idents)) + (cont_infos, blocks) = breakBlock' (tail uniques) next_id + ControlEntry [] [] stmts -- Default case. Just keep accumulating statements -- and branch targets. @@ -171,14 +251,86 @@ breakBlock uniques (BasicBlock ident stmts) entry = stmts do_call current_id entry accum_stmts exits next_id - target results arguments = + target results arguments srt = BrokenBlock current_id entry accum_stmts (next_id:exits) - (FinalCall next_id target results arguments) + (FinalCall next_id target results arguments srt + (current_id `elem` gc_block_idents)) cond_branch_target (CmmCondBranch _ target) = [target] cond_branch_target _ = [] ----------------------------------------------------------------------------- + +selectContinuations :: [(BlockId, ContFormat)] -> [(BlockId, ContFormat)] +selectContinuations needed_continuations = formats + where + formats = map select_format format_groups + format_groups = groupBy by_target needed_continuations + by_target x y = fst x == fst y + + select_format formats = winner + where + winner = head $ head $ sortBy more_votes format_votes + format_votes = groupBy by_format formats + by_format x y = snd x == snd y + more_votes x y = compare (length y) (length x) + -- sort so the most votes goes *first* + -- (thus the order of x and y is reversed) + +makeContinuationEntries formats + block@(BrokenBlock ident entry stmts targets exit) = + case lookup ident formats of + Nothing -> block + Just (ContFormat formals srt is_gc) -> + BrokenBlock ident (ContinuationEntry (map fst formals) srt is_gc) + stmts targets exit + +adaptBlockToFormat :: [(BlockId, ContFormat)] + -> Unique + -> BrokenBlock + -> [BrokenBlock] +adaptBlockToFormat formats unique + block@(BrokenBlock ident entry stmts targets + exit@(FinalCall next target formals + actuals srt is_gc)) = + if format_formals == formals && + format_srt == srt && + format_is_gc == is_gc + then [block] -- Woohoo! This block got the continuation format it wanted + else [adaptor_block, revised_block] + -- This block didn't get the format it wanted for the + -- continuation, so we have to build an adaptor. + where + (ContFormat format_formals format_srt format_is_gc) = + maybe unknown_block id $ lookup next formats + unknown_block = panic "unknown block in adaptBlockToFormat" + + revised_block = BrokenBlock ident entry stmts revised_targets revised_exit + revised_targets = adaptor_ident : delete next targets + revised_exit = FinalCall + adaptor_ident -- ^ The only part that changed + target formals actuals srt is_gc + + adaptor_block = mk_adaptor_block adaptor_ident + (ContinuationEntry (map fst formals) srt is_gc) + next format_formals + adaptor_ident = BlockId unique + + mk_adaptor_block :: BlockId -> BlockEntryInfo -> BlockId -> CmmHintFormals -> BrokenBlock + mk_adaptor_block ident entry next formals = + BrokenBlock ident entry [] [next] exit + where + exit = FinalJump + (CmmLit (CmmLabel (mkReturnPtLabel (getUnique next)))) + (map formal_to_actual format_formals) + + formal_to_actual (reg, hint) = ((CmmReg (CmmLocal reg)), hint) + -- TODO: Check if NoHint is right. We're + -- jumping to a C-- function not a foreign one + -- so it might always be right. +adaptBlockToFormat _ _ block = [block] + +----------------------------------------------------------------------------- -- | Convert from a BrokenBlock back to an equivalent CmmBasicBlock -- Needed by liveness analysis cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock @@ -191,8 +343,8 @@ cmmBlockFromBrokenBlock (BrokenBlock ident _ stmts _ exit) = FinalReturn arguments -> [CmmReturn arguments] FinalJump target arguments -> [CmmJump target arguments] FinalSwitch expr targets -> [CmmSwitch expr targets] - FinalCall branch_target call_target results arguments -> - [CmmCall call_target results arguments (panic "needed SRT from cmmBlockFromBrokenBlock"), + FinalCall branch_target call_target results arguments srt _ -> + [CmmCall call_target results arguments (CmmSafe srt), CmmBranch branch_target] ----------------------------------------------------------------------------- diff --git a/compiler/cmm/CmmCPS.hs b/compiler/cmm/CmmCPS.hs index afb55d5..e6d70d4 100644 --- a/compiler/cmm/CmmCPS.hs +++ b/compiler/cmm/CmmCPS.hs @@ -79,23 +79,31 @@ make_gc_block block_id fun_label formals safety = BasicBlock block_id stmts actuals = map (\x -> (CmmReg (CmmLocal x), NoHint)) formals fun_expr = CmmLit (CmmLabel fun_label) -force_gc_block old_info block_id fun_label formals = +make_gc_check stack_use gc_block = + [CmmCondBranch + (CmmMachOp (MO_U_Lt $ cmmRegRep spReg) + [CmmReg stack_use, CmmReg spLimReg]) + gc_block] + +force_gc_block old_info stack_use block_id fun_label formals = case old_info of - CmmNonInfo (Just _) -> (old_info, []) - CmmInfo _ (Just _) _ _ -> (old_info, []) + CmmNonInfo (Just existing) -> (old_info, [], make_gc_check stack_use existing) + CmmInfo _ (Just existing) _ _ -> (old_info, [], make_gc_check stack_use existing) CmmNonInfo Nothing -> (CmmNonInfo (Just block_id), - [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)]) + [make_gc_block block_id fun_label formals (CmmSafe NoC_SRT)], + make_gc_check stack_use block_id) 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' + -> (CmmInfo prof (Just block_id) type_tag type_info, + [make_gc_block block_id fun_label formals (CmmSafe srt)], + make_gc_check stack_use block_id) + 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) @@ -108,26 +116,46 @@ cpsProc :: UniqSupply cpsProc uniqSupply (CmmData sec dat) = [CmmData sec dat] cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs where + (uniqSupply1, uniqSupply2) = splitUniqSupply uniqSupply uniques :: [[Unique]] - uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply - (gc_unique:info_uniques):block_uniques = uniques + uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply1 + (gc_unique:stack_use_unique:info_uniques):adaptor_uniques:block_uniques = uniques + proc_uniques = map uniqsFromSupply $ listSplitUniqSupply uniqSupply2 + + stack_use = CmmLocal (LocalReg stack_use_unique (cmmRegRep spReg) KindPtr) - -- Ensure that - forced_gc :: (CmmInfo, [CmmBasicBlock]) - forced_gc = force_gc_block info (BlockId gc_unique) ident params + -- TODO: doc + forced_gc :: (CmmInfo, [CmmBasicBlock], [CmmStmt]) + forced_gc = force_gc_block info stack_use (BlockId gc_unique) ident params + (forced_info, gc_blocks, check_stmts) = forced_gc + + forced_blocks = + case blocks of + (BasicBlock id stmts) : bs -> + (BasicBlock id (check_stmts ++ stmts)) : (bs ++ gc_blocks) + [] -> [] -- If there is no code then we don't need a stack check - 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 :: ([(BlockId, ContFormat)], [BrokenBlock]) broken_blocks = - concat $ zipWith3 breakBlock block_uniques forced_blocks - (FunctionEntry forced_info ident params:repeat ControlEntry) + (\x -> (concatMap fst x, concatMap snd x)) $ + zipWith3 (breakBlock [forced_gc_id]) + block_uniques + forced_blocks + (FunctionEntry forced_info ident params : + repeat ControlEntry) + + f' = selectContinuations (fst broken_blocks) + broken_blocks' = map (makeContinuationEntries f') $ + concat $ + zipWith (adaptBlockToFormat f') + adaptor_uniques + (snd broken_blocks) -- Calculate live variables for each broken block. -- @@ -135,22 +163,22 @@ cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs -- 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 + 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 + 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 + 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) + (gatherBlocksIntoContinuation live proc_points block_env) (uniqSetToList proc_points) - (Just forced_gc_id : repeat Nothing) + (Just forced_gc_id : repeat Nothing) {-dead-} -- Select the stack format on entry to each continuation. -- Return the max stack offset and an association list @@ -158,23 +186,24 @@ cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs -- This is an association list instead of a UniqFM because -- CLabel's don't have a 'Uniqueable' instance. formats :: [(CLabel, -- key - (Maybe CLabel, -- label in top slot + (CmmFormals, -- arguments + Maybe CLabel, -- label in top slot [Maybe LocalReg]))] -- slots - formats = selectStackFormat live continuations + formats = selectContinuationFormat 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' :: (WordOff, [(CLabel, ContinuationFormat)]) formats' = processFormats formats continuations -- Update the info table data on the continuations with -- the selected stack formats. continuations' :: [Continuation CmmInfo] - continuations' = map (applyStackFormat (snd formats')) continuations + continuations' = map (applyContinuationFormat (snd formats')) continuations -- Do the actual CPS transform. cps_procs :: [CmmTop] - cps_procs = map (continuationToProc formats') continuations' + cps_procs = zipWith (continuationToProc formats' stack_use) proc_uniques continuations' -- Convert the info tables from CmmInfo to [CmmStatic] -- We might want to put this in another pass eventually @@ -198,13 +227,14 @@ cpsProc uniqSupply (CmmProc info ident params blocks) = info_procs -- and heap memory (not sure if that's usefull at all though, but it may -- be worth exploring the design space). -continuationLabel (Continuation _ l _ _) = l +continuationLabel (Continuation _ l _ _ _) = l data Continuation info = Continuation info -- 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) + Bool -- ^ True <=> GC block so ignore stack size [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 @@ -214,11 +244,12 @@ data Continuation info = -- to a label. To jump to the first block in a Proc, -- use the appropriate CLabel. -data StackFormat - = 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 +data ContinuationFormat + = ContinuationFormat { + continuation_formals :: CmmFormals, + continuation_label :: Maybe CLabel, -- The label occupying the top slot + continuation_frame_size :: WordOff, -- Total frame size in words (not including arguments) + continuation_stack :: [Maybe LocalReg] -- local reg offsets from stack top } -- A block can be a continuation of a call @@ -254,74 +285,90 @@ collectNonProcPointTargets proc_points blocks current_targets new_blocks = -- * Proc points might get some live variables passed as arguments gatherBlocksIntoContinuation :: - UniqSet BlockId -> BlockEnv BrokenBlock + BlockEntryLiveness -> UniqSet BlockId -> BlockEnv BrokenBlock -> BlockId -> Maybe BlockId -> Continuation (Either C_SRT CmmInfo) -gatherBlocksIntoContinuation proc_points blocks start gc = - Continuation info_table clabel params body +gatherBlocksIntoContinuation live proc_points blocks start gc = + Continuation info_table clabel params is_gc_cont body where - start_and_gc = start : maybeToList gc - children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc) + --start_and_gc = [start] -- : maybeToList gc + --children = (collectNonProcPointTargets proc_points blocks (mkUniqSet start_and_gc) start_and_gc) `minusUniqSet` (mkUniqSet start_and_gc) + children = (collectNonProcPointTargets proc_points blocks (unitUniqSet start) [start]) `minusUniqSet` (unitUniqSet start) start_block = lookupWithDefaultUFM blocks (panic "TODO") start - gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) (maybeToList gc) + unknown_block = panic "unknown block in gatherBlocksIntoContinuation" + --gc_block = map (lookupWithDefaultUFM blocks (panic "TODO)")) + -- (maybeToList gc) children_blocks = map (lookupWithDefaultUFM blocks (panic "TODO")) (uniqSetToList children) - body = start_block : gc_block ++ children_blocks + 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 + ContinuationEntry _ srt _ -> Left srt ControlEntry -> Right (CmmNonInfo Nothing) + is_gc_cont = case start_block_entry of + FunctionEntry _ _ _ -> False + ContinuationEntry _ _ gc_cont -> gc_cont + ControlEntry -> False + start_block_entry = brokenBlockEntry start_block 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 + ContinuationEntry args _ _ -> args + ControlEntry -> + uniqSetToList $ + lookupWithDefaultUFM live unknown_block start + -- it's a proc-point, 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 +selectContinuationFormat :: BlockEnv CmmLive -> [Continuation (Either C_SRT CmmInfo)] - -> [(CLabel, (Maybe CLabel, [Maybe LocalReg]))] -selectStackFormat live continuations = - map (\c -> (continuationLabel c, selectStackFormat' c)) continuations + -> [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))] +selectContinuationFormat live continuations = + map (\c -> (continuationLabel c, selectContinuationFormat' c)) continuations where - selectStackFormat' (Continuation + selectContinuationFormat' (Continuation (Right (CmmInfo _ _ _ (ContInfo format srt))) - label _ _) = (Just label, format) - selectStackFormat' (Continuation (Right _) _ _ _) = (Nothing, []) - selectStackFormat' (Continuation (Left srt) label _ blocks) = + label formals _ _) = + (formals, Just label, format) + selectContinuationFormat' (Continuation (Right _) _ formals _ _) = + (formals, Nothing, []) + -- CPS generated continuations + selectContinuationFormat' (Continuation (Left srt) 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 (Just label, + in (formals, + Just label, map Just $ uniqSetToList $ lookupWithDefaultUFM live unknown_block ident) - unknown_block = panic "unknown BlockId in selectStackFormat" + unknown_block = panic "unknown BlockId in selectContinuationFormat" -processFormats :: [(CLabel, (Maybe CLabel, [Maybe LocalReg]))] +processFormats :: [(CLabel, (CmmFormals, Maybe CLabel, [Maybe LocalReg]))] -> [Continuation (Either C_SRT CmmInfo)] - -> (WordOff, [(CLabel, StackFormat)]) + -> (WordOff, [(CLabel, ContinuationFormat)]) processFormats formats continuations = (max_size, formats') where max_size = maximum $ 0 : map (continuationMaxStack formats') continuations formats' = map make_format formats - make_format (label, format) = + make_format (label, (formals, top, stack)) = (label, - StackFormat { - stack_label = fst format, - stack_frame_size = stack_size (snd format) + - if isJust (fst format) + ContinuationFormat { + continuation_formals = formals, + continuation_label = top, + continuation_frame_size = stack_size stack + + if isJust top then label_size else 0, - stack_live = snd format }) + continuation_stack = stack }) -- TODO: get rid of "+ 1" etc. label_size = 1 :: WordOff @@ -333,11 +380,12 @@ processFormats formats continuations = (max_size, formats') width = machRepByteWidth (localRegRep reg) `quot` wORD_SIZE -- TODO: it would be better if we had a machRepWordWidth -continuationMaxStack :: [(CLabel, StackFormat)] +continuationMaxStack :: [(CLabel, ContinuationFormat)] -> Continuation a -> WordOff -continuationMaxStack formats (Continuation _ label _ blocks) = - max_arg_size + stack_frame_size stack_format +continuationMaxStack _ (Continuation _ _ _ True _) = 0 +continuationMaxStack formats (Continuation _ label _ False blocks) = + max_arg_size + continuation_frame_size stack_format where stack_format = maybe unknown_format id $ lookup label formats unknown_format = panic "Unknown format in continuationMaxStack" @@ -352,11 +400,12 @@ continuationMaxStack formats (Continuation _ label _ blocks) = argumentsSize (cmmExprRep . fst) args final_arg_size (FinalJump _ args) = argumentsSize (cmmExprRep . fst) args - final_arg_size (FinalCall next _ _ args) = + final_arg_size (FinalCall next _ _ args _ True) = 0 + final_arg_size (FinalCall next _ _ args _ False) = -- We have to account for the stack used when we build a frame -- for the *next* continuation from *this* continuation argumentsSize (cmmExprRep . fst) args + - stack_frame_size next_format + continuation_frame_size next_format where next_format = maybe unknown_format id $ lookup next' formats next' = mkReturnPtLabel $ getUnique next @@ -372,28 +421,30 @@ continuationMaxStack formats (Continuation _ label _ blocks) = stmt_arg_size _ = 0 ----------------------------------------------------------------------------- -applyStackFormat :: [(CLabel, StackFormat)] +applyContinuationFormat :: [(CLabel, ContinuationFormat)] -> Continuation (Either C_SRT CmmInfo) -> Continuation CmmInfo -- User written continuations -applyStackFormat formats (Continuation +applyContinuationFormat formats (Continuation (Right (CmmInfo prof gc tag (ContInfo _ srt))) - label formals blocks) = + label formals is_gc blocks) = Continuation (CmmInfo prof gc tag (ContInfo format srt)) - label formals blocks + label formals is_gc blocks where - format = stack_live $ maybe unknown_block id $ lookup label formats - unknown_block = panic "unknown BlockId in applyStackFormat" + format = continuation_stack $ maybe unknown_block id $ lookup label formats + unknown_block = panic "unknown BlockId in applyContinuationFormat" -- User written non-continuation code -applyStackFormat formats (Continuation (Right info) label formals blocks) = - Continuation info label formals blocks +applyContinuationFormat formats (Continuation + (Right info) label formals is_gc blocks) = + Continuation info label formals is_gc 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 +applyContinuationFormat formats (Continuation + (Left srt) label formals is_gc blocks) = + Continuation (CmmInfo prof gc tag (ContInfo (continuation_stack $ format) srt)) + label formals is_gc blocks where gc = Nothing -- Generated continuations never need a stack check -- TODO prof: this is the same as the current implementation @@ -401,40 +452,69 @@ applyStackFormat formats (Continuation (Left srt) label formals blocks) = prof = ProfilingInfo zeroCLit zeroCLit tag = rET_SMALL -- cmmToRawCmm may convert it to rET_BIG format = maybe unknown_block id $ lookup label formats - unknown_block = panic "unknown BlockId in applyStackFormat" + unknown_block = panic "unknown BlockId in applyContinuationFormat" ----------------------------------------------------------------------------- -continuationToProc :: (WordOff, [(CLabel, StackFormat)]) +continuationToProc :: (WordOff, [(CLabel, ContinuationFormat)]) + -> CmmReg + -> [Unique] -> Continuation CmmInfo -> CmmTop -continuationToProc (max_stack, formats) - (Continuation info label formals blocks) = - CmmProc info label formals (map continuationToProc' blocks) +continuationToProc (max_stack, formats) stack_use uniques + (Continuation info label formals _ blocks) = + CmmProc info label formals (concat $ zipWith3 continuationToProc' uniques blocks (True : repeat False)) where curr_format = maybe unknown_block id $ lookup label formats unknown_block = panic "unknown BlockId in continuationToProc" - curr_stack = stack_frame_size curr_format - - continuationToProc' :: BrokenBlock -> CmmBasicBlock - continuationToProc' (BrokenBlock ident entry stmts _ exit) = - BasicBlock ident (prefix++stmts++postfix) + curr_stack = continuation_frame_size curr_format + arg_stack = argumentsSize localRegRep formals + + param_stmts :: [CmmStmt] + param_stmts = function_entry curr_format + + gc_stmts :: [CmmStmt] + gc_stmts = + case info of + CmmInfo _ (Just gc_block) _ _ -> + gc_stack_check' stack_use arg_stack (max_stack - curr_stack) + CmmInfo _ Nothing _ _ -> + panic "continuationToProc: missing GC block" + CmmNonInfo (Just gc_block) -> + gc_stack_check' stack_use arg_stack (max_stack - curr_stack) + CmmNonInfo Nothing -> + panic "continuationToProc: missing non-info GC block" + + continuationToProc' :: Unique -> BrokenBlock -> Bool -> [CmmBasicBlock] + continuationToProc' unique (BrokenBlock ident entry stmts _ exit) is_entry = + case gc_prefix ++ param_prefix of + [] -> [main_block] + stmts -> [BasicBlock prefix_id (gc_prefix ++ param_prefix ++ [CmmBranch ident]), + main_block] where - prefix = case entry of + main_block = BasicBlock ident (stmts ++ postfix) + prefix_id = BlockId unique + gc_prefix = case entry of + FunctionEntry _ _ _ -> gc_stmts ControlEntry -> [] - FunctionEntry (CmmInfo _ (Just gc_block) _ _) _ formals -> - gc_stack_check gc_block (max_stack - curr_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 - curr_stack) ++ - function_entry formals curr_format - FunctionEntry (CmmNonInfo Nothing) _ formals -> - panic "continuationToProc: missing non-info GC block" - ContinuationEntry formals _ -> - function_entry formals curr_format + ContinuationEntry _ _ _ -> [] + param_prefix = if is_entry + then param_stmts + else [] postfix = case exit of - FinalBranch next -> [CmmBranch next] + FinalBranch next -> + if (mkReturnPtLabel $ getUnique next) == label + then [CmmBranch next] + else case lookup (mkReturnPtLabel $ getUnique next) formats of + Nothing -> [CmmBranch next] + Just cont_format -> + pack_continuation False curr_format cont_format ++ + tail_call (curr_stack - cont_stack) + (CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique next) + arguments + where + cont_stack = continuation_frame_size cont_format + arguments = map formal_to_actual (continuation_formals cont_format) + formal_to_actual reg = (CmmReg (CmmLocal reg), NoHint) FinalSwitch expr targets -> [CmmSwitch expr targets] FinalReturn arguments -> tail_call curr_stack @@ -443,15 +523,15 @@ continuationToProc (max_stack, formats) FinalJump target arguments -> tail_call curr_stack target arguments FinalCall next (CmmForeignCall target CmmCallConv) - results arguments -> - pack_continuation curr_format cont_format ++ + results arguments _ _ -> + pack_continuation True curr_format cont_format ++ tail_call (curr_stack - cont_stack) target arguments where cont_format = maybe unknown_block id $ lookup (mkReturnPtLabel $ getUnique next) formats - cont_stack = stack_frame_size cont_format - FinalCall next _ results arguments -> panic "unimplemented CmmCall" + cont_stack = continuation_frame_size cont_format + FinalCall next _ results arguments _ _ -> panic "unimplemented CmmCall" ----------------------------------------------------------------------------- -- Functions that generate CmmStmt sequences @@ -474,6 +554,12 @@ tail_call spRel target arguments argument_formats = assignArguments (cmmExprRep . fst) arguments +gc_stack_check' stack_use arg_stack max_frame_size = + if max_frame_size > arg_stack + then [CmmAssign stack_use (CmmRegOff spReg (-max_frame_size*wORD_SIZE))] + else [CmmAssign stack_use (CmmReg spLimReg)] + -- Trick the optimizer into eliminating the branch for us + gc_stack_check :: BlockId -> WordOff -> [CmmStmt] gc_stack_check gc_block max_frame_size = check_stack_limit where @@ -484,11 +570,13 @@ gc_stack_check gc_block max_frame_size CmmReg spLimReg]) gc_block] + -- 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 _) - (StackFormat cont_id cont_frame_size live_regs) +pack_continuation :: Bool -> ContinuationFormat -> ContinuationFormat -> [CmmStmt] +pack_continuation allow_header_set + (ContinuationFormat _ curr_id curr_frame_size _) + (ContinuationFormat _ cont_id cont_frame_size live_regs) = store_live_values ++ set_stack_header where -- TODO: only save variables when actually needed -- (may be handled by latter pass) @@ -496,7 +584,7 @@ pack_continuation (StackFormat curr_id curr_frame_size _) [stack_put spRel (CmmReg (CmmLocal reg)) offset | (reg, offset) <- cont_offsets] set_stack_header = - if needs_header_set + if needs_header_set && allow_header_set then [stack_put spRel continuation_function 0] else [] @@ -523,8 +611,8 @@ pack_continuation (StackFormat curr_id curr_frame_size _) -- that could branch to eachother (i.e. control blocks) -- have the same stack format (this causes a problem -- only for proc-point). -function_entry :: CmmFormals -> StackFormat -> [CmmStmt] -function_entry formals (StackFormat _ _ live_regs) +function_entry :: ContinuationFormat -> [CmmStmt] +function_entry (ContinuationFormat formals _ _ live_regs) = load_live_values ++ load_args where -- TODO: only save variables when actually needed -- (may be handled by latter pass) diff --git a/compiler/cmm/CmmProcPoint.hs b/compiler/cmm/CmmProcPoint.hs index 5a159a6..36c02ff 100644 --- a/compiler/cmm/CmmProcPoint.hs +++ b/compiler/cmm/CmmProcPoint.hs @@ -46,7 +46,7 @@ calculateProcPoints blocks = always_proc_point BrokenBlock { brokenBlockEntry = FunctionEntry _ _ _ } = True always_proc_point BrokenBlock { - brokenBlockEntry = ContinuationEntry _ _ } = True + brokenBlockEntry = ContinuationEntry _ _ _ } = True always_proc_point _ = False calculateProcPoints' :: UniqSet BlockId -> [BrokenBlock] -> UniqSet BlockId diff --git a/compiler/codeGen/ClosureInfo.lhs b/compiler/codeGen/ClosureInfo.lhs index db46368..d0d2ed9 100644 --- a/compiler/codeGen/ClosureInfo.lhs +++ b/compiler/codeGen/ClosureInfo.lhs @@ -124,6 +124,7 @@ data ClosureInfo data C_SRT = NoC_SRT | C_SRT !CLabel !WordOff !StgHalfWord {-bitmap or escape-} + deriving (Eq) needsSRT :: C_SRT -> Bool needsSRT NoC_SRT = False -- 1.7.10.4