CmmPipeline.hs 8.53 KB
Newer Older
1 2 3
{-# OPTIONS_GHC -XNoMonoLocalBinds #-}
-- Norman likes local bindings
-- If this module lives on I'd like to get rid of this flag in due course
4

Edward Z. Yang's avatar
Edward Z. Yang committed
5
module CmmPipeline (
6 7 8 9
  -- | Converts C-- with an implicit stack and native C-- calls into
  -- optimized, CPS converted and native-call-less C--.  The latter
  -- C-- can be used to generate assembly.
  cmmPipeline
10
) where
11

12
import CLabel
13
import Cmm
14
import CmmLive
15 16
import CmmBuildInfoTables
import CmmCommonBlockElim
17
import CmmProcPoint
18
import CmmSpillReload
19
import CmmRewriteAssignments
20
import CmmStackLayout
21
import CmmContFlowOpt
22
import OptimizationFuel
23 24 25

import DynFlags
import ErrUtils
26 27
import HscTypes
import Data.Maybe
Ian Lynagh's avatar
Ian Lynagh committed
28
import Control.Monad
29 30 31 32
import Data.Map (Map)
import qualified Data.Map as Map
import Outputable
import StaticFlags
33

34
-----------------------------------------------------------------------------
35
-- | Top level driver for C-- pipeline
36
-----------------------------------------------------------------------------
37 38 39 40 41 42 43 44 45 46 47 48 49
-- 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.
50 51 52 53 54
-- 3. We run control flow optimizations twice, once before any pipeline
--    work is done, and once again at the very end on all of the
--    resulting C-- blocks.  EZY: It's unclear whether or not whether
--    we actually need to do the initial pass.
cmmPipeline  :: HscEnv -- Compilation env including
55
                       -- dynamic flags: -dcmm-lint -ddump-cps-cmm
56 57 58
             -> (TopSRT, [CmmPgm])    -- SRT table and accumulating list of compiled procs
             -> CmmPgm             -- Input C-- with Procedures
             -> IO (TopSRT, [CmmPgm]) -- Output CPS transformed C--
59
cmmPipeline hsc_env (topSRT, rst) prog =
60
  do let dflags = hsc_dflags hsc_env
61
     --
62
     showPass dflags "CPSZ"
63 64

     let tops = runCmmContFlowOpts prog
65
     (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
66 67
     -- tops :: [[(CmmTop,CAFSet]]  (one list per group)

68
     let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
69 70

     -- folding over the groups
71
     (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
72 73 74

     let cmms = reverse (concat tops)

75
     dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (pprPlatform (targetPlatform dflags) cmms)
76

77
     -- SRT is not affected by control flow optimization pass
78 79 80
     let prog' = runCmmContFlowOpts cmms

     return (topSRT, prog' : rst)
81 82 83 84 85 86 87 88

{- [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.
-}

89 90 91 92
-- 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

93 94 95 96
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
97 98
       -- Why bother doing these early: dualLivenessWithInsertion,
       -- insertLateReloads, rewriteAssignments?
99

100 101
       ----------- Eliminate common blocks -------------------
       g <- return $ elimCommonBlocks g
102
       dumpPlatform platform Opt_D_dump_cmmz_cbe "Post common block elimination" g
103 104 105 106
       -- Any work storing block Labels must be performed _after_ elimCommonBlocks

       ----------- Proc points -------------------
       let callPPs = callProcPoints g
107
       procPoints <- run $ minimalProcPointSet (targetPlatform dflags) callPPs g
108
       g <- run $ addProcPointProtocols callPPs procPoints g
109
       dumpPlatform platform Opt_D_dump_cmmz_proc "Post Proc Points Added" g
110 111

       ----------- Spills and reloads -------------------
112
       g <- run $ dualLivenessWithInsertion procPoints g
113
       dumpPlatform platform Opt_D_dump_cmmz_spills "Post spills and reloads" g
114

115 116
       ----------- Sink and inline assignments -------------------
       g <- runOptimization $ rewriteAssignments g
117
       dumpPlatform platform Opt_D_dump_cmmz_rewrite "Post rewrite assignments" g
118 119

       ----------- Eliminate dead assignments -------------------
120
       g <- runOptimization $ removeDeadAssignments g
121
       dumpPlatform platform Opt_D_dump_cmmz_dead "Post remove dead assignments" g
122 123 124 125 126 127

       ----------- 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
128
       dumpPlatform platform Opt_D_dump_cmmz_stub "Post stub dead stack slots" g
129 130 131

       --------------- Stack layout ----------------
       slotEnv <- run $ liveSlotAnal g
132
       let spEntryMap = getSpEntryMap entry_off g
133
       mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
134
       let areaMap = layout procPoints spEntryMap slotEnv entry_off g
135 136 137
       mbpprTrace "areaMap" (ppr areaMap) $ return ()

       ------------  Manifest the stack pointer --------
138
       g  <- run $ manifestSP spEntryMap areaMap entry_off g
139
       dumpPlatform platform Opt_D_dump_cmmz_sp "Post manifestSP" g
140 141 142 143 144
       -- 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
145
       dump Opt_D_dump_cmmz_procmap "procpoint map" procPointMap
146 147
       gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
                                       (CmmProc h l g)
148
       mapM_ (dumpPlatform platform Opt_D_dump_cmmz_split "Post splitting") gs
149 150 151 152 153 154 155

       ------------- 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
156
       mapM_ (dumpPlatform platform Opt_D_dump_cmmz_lower "Post lowerSafeForeignCalls") gs
157 158

       -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
159
       gs <- return $ map (setInfoTableStackMap slotEnv areaMap) gs
160
       mapM_ (dumpPlatform platform Opt_D_dump_cmmz_info "after setInfoTableStackMap") gs
161
       gs <- return $ map (bundleCAFs cafEnv) gs
162
       mapM_ (dumpPlatform platform Opt_D_dump_cmmz_cafs "after bundleCAFs") gs
163
       return (localCAFs, gs)
164 165 166 167

              -- gs        :: [ (CAFSet, CmmTop) ]
              -- localCAFs :: [ (CLabel, CAFSet) ] -- statics filtered out(?)

168
  where dflags = hsc_dflags hsc_env
169
        platform = targetPlatform dflags
170
        mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
171 172 173
        dump f = dumpWith ppr f
        dumpPlatform platform = dumpWith (pprPlatform platform)
        dumpWith pprFun f txt g = do
174 175 176
            -- 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.
177
            dumpIfSet_dyn dflags f txt (pprFun g)
178
            when (not (dopt f dflags)) $
179
                dumpIfSet_dyn dflags Opt_D_dump_cmmz txt (pprFun g)
180 181 182 183 184 185
        -- 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)

186 187 188 189 190 191 192 193 194 195 196
-- 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)