--- 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
+-- There are two complications here:
+-- 1. We need to compile the procedures in two stages because we need
+-- an analysis of the procedures to tell us what CAFs they use.
+-- The first stage returns a map from procedure labels to CAFs,
+-- along with a closure that will compute SRTs and attach them to
+-- the compiled procedures.
+-- The second stage is to combine the CAF information into a top-level
+-- CAF environment mapping non-static closures to the CAFs they keep live,
+-- then pass that environment to the closures returned in the first
+-- stage of compilation.
+-- 2. We need to thread the module's SRT around when the SRT tables
+-- are computed for each procedure.
+-- The SRT needs to be threaded because it is grown lazily.
+protoCmmCPS :: HscEnv -- Compilation env including
+ -- dynamic flags: -dcmm-lint -ddump-cps-cmm
+ -> (TopSRT, [Cmm]) -- SRT table and accumulating list of compiled procs
+ -> Cmm -- Input C-- with Procedures
+ -> IO (TopSRT, [Cmm]) -- Output CPS transformed C--
+protoCmmCPS hsc_env (topSRT, rst) (Cmm tops) =
+ do let dflags = hsc_dflags hsc_env
+ showPass dflags "CPSZ"
+ (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
+ let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
+ (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
+ let cmms = Cmm (reverse (concat tops))
+ dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
+ return (topSRT, cmms : rst)
+
+{- [Note global fuel]
+~~~~~~~~~~~~~~~~~~~~~
+The identity and the last pass are stored in
+mutable reference cells in an 'HscEnv' and are
+global to one compiler session.
+-}
+
+cpsTop :: HscEnv -> CmmTop -> IO ([(CLabel, CAFSet)], [(CAFSet, CmmTop)])
+cpsTop _ p@(CmmData {}) = return ([], [(Map.empty, p)])
+cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}}) l g) =
+ do
+ -- Why bother doing it this early?
+ -- g <- dual_rewrite run Opt_D_dump_cmmz "spills and reloads"
+ -- (dualLivenessWithInsertion callPPs) g
+ -- g <- run $ insertLateReloads g -- Duplicate reloads just before uses
+ -- g <- dual_rewrite runOptimization Opt_D_dump_cmmz "Dead Assignment Elimination"
+ -- (removeDeadAssignmentsAndReloads callPPs) g
+ dump Opt_D_dump_cmmz "Pre common block elimination" g
+ g <- return $ elimCommonBlocks g
+ dump Opt_D_dump_cmmz "Post common block elimination" g
+
+ -- Any work storing block Labels must be performed _after_ elimCommonBlocks
+
+ ----------- Proc points -------------------
+ let callPPs = callProcPoints g
+ procPoints <- run $ minimalProcPointSet callPPs g
+ g <- run $ addProcPointProtocols callPPs procPoints g
+ dump Opt_D_dump_cmmz "Post Proc Points Added" g
+
+ ----------- Spills and reloads -------------------
+ g <-
+ -- pprTrace "pre Spills" (ppr g) $
+ dual_rewrite run Opt_D_dump_cmmz "spills and reloads"
+ (dualLivenessWithInsertion procPoints) g
+ -- Insert spills at defns; reloads at return points
+ g <-
+ -- pprTrace "pre insertLateReloads" (ppr g) $
+ runOptimization $ insertLateReloads g -- Duplicate reloads just before uses
+ dump Opt_D_dump_cmmz "Post late reloads" g
+ g <-
+ -- pprTrace "post insertLateReloads" (ppr g) $
+ dual_rewrite runOptimization Opt_D_dump_cmmz "Dead Assignment Elimination"
+ (removeDeadAssignmentsAndReloads procPoints) g
+ -- Remove redundant reloads (and any other redundant asst)
+
+ ----------- Debug only: add code to put zero in dead stack slots----
+ -- Debugging: stubbing slots on death can cause crashes early
+ g <- -- trace "post dead-assign elim" $
+ if opt_StubDeadValues then run $ stubSlotsOnDeath g else return g
+
+
+ --------------- Stack layout ----------------
+ slotEnv <- run $ liveSlotAnal g
+ let spEntryMap = getSpEntryMap entry_off g
+ mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
+ let areaMap = layout procPoints spEntryMap slotEnv entry_off g
+ mbpprTrace "areaMap" (ppr areaMap) $ return ()
+
+ ------------ Manifest the stack pointer --------
+ g <- run $ manifestSP spEntryMap areaMap entry_off g
+ dump Opt_D_dump_cmmz "after manifestSP" g
+ -- UGH... manifestSP can require updates to the procPointMap.
+ -- We can probably do something quicker here for the update...
+
+ ------------- Split into separate procedures ------------
+ procPointMap <- run $ procPointAnalysis procPoints g
+ dump Opt_D_dump_cmmz "procpoint map" procPointMap
+ gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
+ (CmmProc h l g)
+ mapM_ (dump Opt_D_dump_cmmz "after splitting") gs
+
+ ------------- More CAFs and foreign calls ------------
+ cafEnv <- run $ cafAnal g
+ let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
+ mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
+
+ gs <- run $ mapM (lowerSafeForeignCalls areaMap) gs
+ mapM_ (dump Opt_D_dump_cmmz "after lowerSafeForeignCalls") gs
+
+ -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
+ let gs' = map (setInfoTableStackMap slotEnv areaMap) gs
+ mapM_ (dump Opt_D_dump_cmmz "after setInfoTableStackMap") gs'
+ let gs'' = map (bundleCAFs cafEnv) gs'
+ mapM_ (dump Opt_D_dump_cmmz "after bundleCAFs") gs''
+ return (localCAFs, gs'')
+ where dflags = hsc_dflags hsc_env
+ mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
+ dump f txt g = dumpIfSet_dyn dflags f txt (ppr g)
+ -- Runs a required transformation/analysis
+ run = runInfiniteFuelIO (hsc_OptFuel hsc_env)
+ -- Runs an optional transformation/analysis (and should
+ -- thus be subject to optimization fuel)
+ runOptimization = runFuelIO (hsc_OptFuel hsc_env)
+
+ -- pass 'run' or 'runOptimization' for 'r'
+ dual_rewrite r flag txt pass g =
+ do dump flag ("Pre " ++ txt) g
+ g <- r $ pass g
+ dump flag ("Post " ++ txt) $ g
+ return g
+
+-- This probably belongs in CmmBuildInfoTables?
+-- We're just finishing the job here: once we know what CAFs are defined
+-- in non-static closures, we can build the SRTs.
+toTops :: HscEnv -> Map CLabel CAFSet -> (TopSRT, [[CmmTop]])
+ -> [(CAFSet, CmmTop)] -> IO (TopSRT, [[CmmTop]])
+toTops hsc_env topCAFEnv (topSRT, tops) gs =
+ do let setSRT (topSRT, rst) g =
+ do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
+ return (topSRT, gs : rst)
+ (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
+ return (topSRT, concat gs' : tops)