1 {-# OPTIONS_GHC -XNoMonoLocalBinds #-}
2 -- Norman likes local bindings
3 -- If this module lives on I'd like to get rid of this flag in due course
6 -- | Converts C-- with full proceedures and parameters
7 -- to a CPS transformed C-- with the stack made manifest.
15 import CmmBuildInfoTables
16 import CmmCommonBlockElim
20 import OptimizationFuel
28 import qualified Data.Map as Map
32 -----------------------------------------------------------------------------
33 -- |Top level driver for the CPS pass
34 -----------------------------------------------------------------------------
35 -- There are two complications here:
36 -- 1. We need to compile the procedures in two stages because we need
37 -- an analysis of the procedures to tell us what CAFs they use.
38 -- The first stage returns a map from procedure labels to CAFs,
39 -- along with a closure that will compute SRTs and attach them to
40 -- the compiled procedures.
41 -- The second stage is to combine the CAF information into a top-level
42 -- CAF environment mapping non-static closures to the CAFs they keep live,
43 -- then pass that environment to the closures returned in the first
44 -- stage of compilation.
45 -- 2. We need to thread the module's SRT around when the SRT tables
46 -- are computed for each procedure.
47 -- The SRT needs to be threaded because it is grown lazily.
48 protoCmmCPS :: HscEnv -- Compilation env including
49 -- dynamic flags: -dcmm-lint -ddump-cps-cmm
50 -> (TopSRT, [Cmm]) -- SRT table and accumulating list of compiled procs
51 -> Cmm -- Input C-- with Procedures
52 -> IO (TopSRT, [Cmm]) -- Output CPS transformed C--
53 protoCmmCPS hsc_env (topSRT, rst) (Cmm tops) =
54 do let dflags = hsc_dflags hsc_env
55 showPass dflags "CPSZ"
56 (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
57 let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
58 (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
59 let cmms = Cmm (reverse (concat tops))
60 dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
61 return (topSRT, cmms : rst)
65 The identity and the last pass are stored in
66 mutable reference cells in an 'HscEnv' and are
67 global to one compiler session.
70 cpsTop :: HscEnv -> CmmTop -> IO ([(CLabel, CAFSet)], [(CAFSet, CmmTop)])
71 cpsTop _ p@(CmmData {}) = return ([], [(Map.empty, p)])
72 cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}}) l g) =
74 -- Why bother doing it this early?
75 -- g <- dual_rewrite run Opt_D_dump_cmmz "spills and reloads"
76 -- (dualLivenessWithInsertion callPPs) g
77 -- g <- run $ insertLateReloads g -- Duplicate reloads just before uses
78 -- g <- dual_rewrite runOptimization Opt_D_dump_cmmz "Dead Assignment Elimination"
79 -- (removeDeadAssignmentsAndReloads callPPs) g
80 dump Opt_D_dump_cmmz "Pre common block elimination" g
81 g <- return $ elimCommonBlocks g
82 dump Opt_D_dump_cmmz "Post common block elimination" g
84 -- Any work storing block Labels must be performed _after_ elimCommonBlocks
86 ----------- Proc points -------------------
87 let callPPs = callProcPoints g
88 procPoints <- run $ minimalProcPointSet callPPs g
89 g <- run $ addProcPointProtocols callPPs procPoints g
90 dump Opt_D_dump_cmmz "Post Proc Points Added" g
92 ----------- Spills and reloads -------------------
94 -- pprTrace "pre Spills" (ppr g) $
95 dual_rewrite run Opt_D_dump_cmmz "spills and reloads"
96 (dualLivenessWithInsertion procPoints) g
97 -- Insert spills at defns; reloads at return points
99 -- pprTrace "pre insertLateReloads" (ppr g) $
100 runOptimization $ insertLateReloads g -- Duplicate reloads just before uses
101 dump Opt_D_dump_cmmz "Post late reloads" g
103 -- pprTrace "post insertLateReloads" (ppr g) $
104 dual_rewrite runOptimization Opt_D_dump_cmmz "Dead Assignment Elimination"
105 (removeDeadAssignmentsAndReloads procPoints) g
106 -- Remove redundant reloads (and any other redundant asst)
108 ----------- Debug only: add code to put zero in dead stack slots----
109 -- Debugging: stubbing slots on death can cause crashes early
110 g <- -- trace "post dead-assign elim" $
111 if opt_StubDeadValues then run $ stubSlotsOnDeath g else return g
114 --------------- Stack layout ----------------
115 slotEnv <- run $ liveSlotAnal g
116 let spEntryMap = getSpEntryMap entry_off g
117 mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
118 let areaMap = layout procPoints spEntryMap slotEnv entry_off g
119 mbpprTrace "areaMap" (ppr areaMap) $ return ()
121 ------------ Manifest the stack pointer --------
122 g <- run $ manifestSP spEntryMap areaMap entry_off g
123 dump Opt_D_dump_cmmz "after manifestSP" g
124 -- UGH... manifestSP can require updates to the procPointMap.
125 -- We can probably do something quicker here for the update...
127 ------------- Split into separate procedures ------------
128 procPointMap <- run $ procPointAnalysis procPoints g
129 dump Opt_D_dump_cmmz "procpoint map" procPointMap
130 gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
132 mapM_ (dump Opt_D_dump_cmmz "after splitting") gs
134 ------------- More CAFs and foreign calls ------------
135 cafEnv <- run $ cafAnal g
136 let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
137 mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
139 gs <- run $ mapM (lowerSafeForeignCalls areaMap) gs
140 mapM_ (dump Opt_D_dump_cmmz "after lowerSafeForeignCalls") gs
142 -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
143 let gs' = map (setInfoTableStackMap slotEnv areaMap) gs
144 mapM_ (dump Opt_D_dump_cmmz "after setInfoTableStackMap") gs'
145 let gs'' = map (bundleCAFs cafEnv) gs'
146 mapM_ (dump Opt_D_dump_cmmz "after bundleCAFs") gs''
147 return (localCAFs, gs'')
148 where dflags = hsc_dflags hsc_env
149 mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
150 dump f txt g = dumpIfSet_dyn dflags f txt (ppr g)
151 -- Runs a required transformation/analysis
152 run = runInfiniteFuelIO (hsc_OptFuel hsc_env)
153 -- Runs an optional transformation/analysis (and should
154 -- thus be subject to optimization fuel)
155 runOptimization = runFuelIO (hsc_OptFuel hsc_env)
157 -- pass 'run' or 'runOptimization' for 'r'
158 dual_rewrite r flag txt pass g =
159 do dump flag ("Pre " ++ txt) g
161 dump flag ("Post " ++ txt) $ g
164 -- This probably belongs in CmmBuildInfoTables?
165 -- We're just finishing the job here: once we know what CAFs are defined
166 -- in non-static closures, we can build the SRTs.
167 toTops :: HscEnv -> Map CLabel CAFSet -> (TopSRT, [[CmmTop]])
168 -> [(CAFSet, CmmTop)] -> IO (TopSRT, [[CmmTop]])
169 toTops hsc_env topCAFEnv (topSRT, tops) gs =
170 do let setSRT (topSRT, rst) g =
171 do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
172 return (topSRT, gs : rst)
173 (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
174 return (topSRT, concat gs' : tops)