-module CmmCPS (cmmCPS) where
+{-# OPTIONS_GHC -XNoMonoLocalBinds #-}
+-- Norman likes local bindings
+-- If this module lives on I'd like to get rid of this flag in due course
-#include "HsVersions.h"
+module CmmCPS (
+ -- | Converts C-- with full proceedures and parameters
+ -- to a CPS transformed C-- with the stack made manifest.
+ -- Well, sort of.
+ protoCmmCPS
+) where
-import Cmm
-import CmmLint
-import PprCmm
-
-import Dataflow (cmmLivenessComment, cmmLiveness, CmmLive)
-
-import MachOp
-import ForeignCall
import CLabel
+import Cmm
+import CmmDecl
+import CmmBuildInfoTables
+import CmmCommonBlockElim
+import CmmProcPoint
+import CmmSpillReload
+import CmmStackLayout
+import OptimizationFuel
import DynFlags
import ErrUtils
-import Maybes
+import HscTypes
+import Data.Maybe
+import Control.Monad
+import Data.Map (Map)
+import qualified Data.Map as Map
import Outputable
-import UniqSupply
-import UniqFM
-import UniqSet
-import Unique
-
-import Monad
-import IO
-
---------------------------------------------------------------------------------
--- Monad for the CPSer
--- Contains:
--- * State for the uniqSupply
-
-data CPSState = CPSState { cps_uniqs :: UniqSupply }
-
-data CPS a = CPS { runCPS :: CPSState -> (CPSState, a) }
-
-instance Monad CPS where
- return a = CPS $ \s -> (s, a)
- (CPS m) >>= f = CPS $ \s ->
- let (s', m') = m s
- in runCPS (f m') s'
-
---------------------------------------------------------------------------------
--- Utility functions
-
-getState = CPS $ \s -> (s, s)
-putState s = CPS $ \_ -> (s, ())
-
-newLabelCPS = do
- state <- getState
- let (us1, us2) = splitUniqSupply (cps_uniqs state)
- putState $ state { cps_uniqs = us1 }
- return $ BlockId (uniqFromSupply us2)
-
-mapMCmmTop :: (Monad m) => (CmmTop -> m [CmmTop]) -> Cmm -> m Cmm
-mapMCmmTop f (Cmm xs) = liftM Cmm $ liftM concat $ mapM f xs
-
---------------------------------------------------------------------------------
-
--- 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 CPSBlockInfo
- = ControlBlock -- Consider whether a proc-point might want arguments on stack
- | ContinuationBlock [(CmmReg,MachHint)] {- params -}
-
-type ContinuationFormat = [Maybe LocalReg] -- TODO: consider params as part of format
-
--- 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
-
-type CmmParam = [(CmmReg,MachHint)]
-
--- For now just select the continuation orders in the order they are in the set with no gaps
-selectContinuationFormat :: UniqFM {-BlockId-} CmmParam -> UniqFM {-BlockId-} CmmLive -> UniqFM {-BlockId-} ContinuationFormat
-selectContinuationFormat param live = mapUFM (map Just . uniqSetToList) live
-
-transformReturn block_infos formats (BasicBlock ident stmts) =
- case last $ init stmts of
- CmmReturn arguments ->
- BasicBlock ident $ (init $ init stmts) ++
- [CmmJump (CmmReg spReg) arguments]
- -- TODO: tail calls
- -- TODO: return direct at the end of a block
- _ -> BasicBlock ident stmts
-
-destructContinuation :: UniqFM {-BlockId-} CPSBlockInfo -> UniqFM {-BlockId-} ContinuationFormat -> CmmBasicBlock -> CmmBasicBlock
-destructContinuation block_infos formats (BasicBlock ident stmts) =
- case info of
- ControlBlock -> BasicBlock ident stmts
- ContinuationBlock _ -> BasicBlock ident (unpack_continuation ++ stmts)
- where
- info = lookupWithDefaultUFM block_infos (panic $ "info: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident
- format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique ident)) ident
- unpack_continuation = CmmAssign spReg (CmmRegOff spReg frame_size) :
- [CmmAssign (CmmLocal reg) (CmmLoad (CmmRegOff spReg (i*stack_slot_size)) (localRegRep reg))
- | (i, Just reg) <- zip [1..] format]
- frame_size = stack_header_size + stack_slot_size * (length format)
- stack_header_size = stack_slot_size -- TODO: check if this could be different than stack_slot_size
- stack_slot_size = 4 -- TODO: find actual variables to be used instead of this
-
-constructContinuation :: UniqFM {-BlockId-} CPSBlockInfo -> UniqFM {-BlockId-} ContinuationFormat -> CmmBasicBlock -> CmmBasicBlock
-constructContinuation block_infos formats (BasicBlock ident stmts) =
- case last $ init stmts of
- -- TODO: global_saves
- --CmmCall (CmmForeignCall target CmmCallConv) results arguments (Just []) -> --TODO: handle globals
- CmmCall (CmmForeignCall target CmmCallConv) results arguments _ ->
- BasicBlock ident $
- init (init stmts) ++
- pack_continuation ++
- [CmmJump target arguments]
- CmmCall target results arguments _ -> panic "unimplemented CmmCall"
- _ -> BasicBlock ident $ (init stmts) ++ build_block_branch
- where
- info = lookupWithDefaultUFM block_infos (panic $ "info: unknown block " ++ (showSDoc $ ppr $ getUnique next_block)) next_block
- format = lookupWithDefaultUFM formats (panic $ "format: unknown block " ++ (showSDoc $ ppr $ getUnique next_block)) next_block
- next_block = case last stmts of
- CmmBranch next -> next
- -- TODO: blocks with jump at end
- -- TODO: blocks with return at end
- _ -> panic "basic block without a branch at the end (unimplemented)"
- next_block_as_proc_expr = CmmLit $ CmmLabel $ mkReturnPtLabel $ getUnique next_block
- pack_continuation = CmmAssign spReg (CmmRegOff spReg (-frame_size)) :
- CmmStore (CmmReg spReg) next_block_as_proc_expr :
- [CmmStore (CmmRegOff spReg (i*stack_slot_size)) (CmmReg $ CmmLocal reg)
- | (i, Just reg) <- zip [1..] format]
- frame_size = stack_header_size + stack_slot_size * (length format)
- stack_header_size = stack_slot_size -- TODO: check if this could be different than stack_slot_size (e.g. fixedHdrSize depends on PAR and GRAN)
- stack_slot_size = 4 -- TODO: find actual variables to be used instead of this (e.g. cgRepSizeW)
- block_needs_call = True -- TODO: use a table (i.e. proc-point)
- build_block_branch =
- if block_needs_call
- then [CmmJump next_block_as_proc_expr [] {- TODO: pass live -}] {- NOTE: a block can never be both a continuation and a controll block -}
- else [CmmBranch next_block]
-
--- TODO: TBD when to adjust the stack
-
-cpsProc :: CmmTop -> CPS [CmmTop]
-cpsProc x@(CmmData _ _) = return [x]
-cpsProc x@(CmmProc info_table ident params blocks) = do
- broken_blocks <- liftM concat $ mapM breakBlock blocks
- let live = cmmLiveness (map snd broken_blocks)
- let blocks_with_live = map (cmmLivenessComment live . snd) broken_blocks
- let formats = selectContinuationFormat (undefined {-TODO-}) live
- let block_infos = listToUFM $ map (\(info, block) -> (blockId block, info)) broken_blocks
- let blocks_with_live' = map (constructContinuation block_infos formats) blocks_with_live
- let blocks_with_live'' = map (destructContinuation block_infos formats) blocks_with_live'
- let blocks_with_live''' = map (transformReturn block_infos formats) blocks_with_live''
-
- return $ [CmmProc info_table ident params blocks_with_live''']
-
---------------------------------------------------------------------------------
--- 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.
-
-cmmBlockifyCalls :: [CmmBasicBlock] -> CPS [(CPSBlockInfo, CmmBasicBlock)]
-cmmBlockifyCalls blocks = liftM concat $ mapM breakBlock blocks
-
--- [(CmmReg,MachHint)] is the results from the previous block that are expected as parameters
---breakBlock :: CmmBasicBlock -> CPS [(Maybe BlockId, CmmBasicBlock)]
-breakBlock :: CmmBasicBlock -> CPS [(CPSBlockInfo, CmmBasicBlock)]
-breakBlock (BasicBlock ident stmts) = breakBlock' ident ControlBlock [] stmts
-
-breakBlock' current_id block_info accum_stmts [] =
- return [(block_info, BasicBlock current_id accum_stmts)]
--- TODO: notice a call just before a branch, jump, call, etc.
-breakBlock' current_id block_info accum_stmts (stmt@(CmmCall _ results _ _):stmts) = do
- new_id <- newLabelCPS
- let new_block = (block_info, BasicBlock current_id (accum_stmts ++ [stmt, CmmBranch new_id]))
- rest <- breakBlock' new_id (ContinuationBlock results) [] stmts
- return $ (new_block:rest)
-breakBlock' current_id arguments accum_stmts (stmt:stmts) =
- breakBlock' current_id arguments (accum_stmts ++ [stmt]) stmts
-
---------------------------------------------------------------------------------
-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 (_, continuationC) = runCPS (mapM (mapMCmmTop cpsProc) abstractC) (CPSState uniqSupply)
-
- dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "CPS Cmm" (pprCmms continuationC)
- -- TODO: add option to dump Cmm to file
- return continuationC
+import StaticFlags
+
+-----------------------------------------------------------------------------
+-- |Top level driver for the CPS pass
+-----------------------------------------------------------------------------
+-- 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.
+-}
+
+-- EZY: It might be helpful to have an easy way of dumping the "pre"
+-- input for any given phase, besides just turning it all on with
+-- -ddump-cmmz
+
+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 these early: dualLivenessWithInsertion,
+ -- insertLateReloads, rewriteAssignments?
+
+ ----------- Eliminate common blocks -------------------
+ g <- return $ elimCommonBlocks g
+ dump Opt_D_dump_cmmz_cbe "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_proc "Post Proc Points Added" g
+
+ ----------- Spills and reloads -------------------
+ g <- run $ dualLivenessWithInsertion procPoints g
+ dump Opt_D_dump_cmmz_spills "Post spills and reloads" g
+
+ ----------- Sink and inline assignments -------------------
+ g <- runOptimization $ rewriteAssignments g
+ dump Opt_D_dump_cmmz_rewrite "Post rewrite assignments" g
+
+ ----------- Eliminate dead assignments -------------------
+ -- Remove redundant reloads (and any other redundant asst)
+ g <- runOptimization $ removeDeadAssignmentsAndReloads procPoints g
+ dump Opt_D_dump_cmmz_dead "Post Dead Assignment Elimination" g
+
+ ----------- Zero dead stack slots (Debug only) ---------------
+ -- Debugging: stubbing slots on death can cause crashes early
+ g <- if opt_StubDeadValues
+ then run $ stubSlotsOnDeath g
+ else return g
+ dump Opt_D_dump_cmmz_stub "Post stub dead stack slots" 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_sp "Post 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_procmap "procpoint map" procPointMap
+ gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
+ (CmmProc h l g)
+ mapM_ (dump Opt_D_dump_cmmz_split "Post 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_lower "Post lowerSafeForeignCalls") gs
+
+ -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
+ gs <- return $ map (setInfoTableStackMap slotEnv areaMap) gs
+ mapM_ (dump Opt_D_dump_cmmz_info "after setInfoTableStackMap") gs
+ gs <- return $ map (bundleCAFs cafEnv) gs
+ mapM_ (dump Opt_D_dump_cmmz_cafs "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 = do
+ -- ToDo: No easy way of say "dump all the cmmz, *and* split
+ -- them into files." Also, -ddump-cmmz doesn't play nicely
+ -- with -ddump-to-file, since the headers get omitted.
+ dumpIfSet_dyn dflags f txt (ppr g)
+ when (not (dopt f dflags)) $
+ dumpIfSet_dyn dflags Opt_D_dump_cmmz 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)
+
+-- 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)
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