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.
14 import CmmBuildInfoTables
15 import CmmCommonBlockElimZ
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 protoCmmCPSZ :: HscEnv -- Compilation env including
49 -- dynamic flags: -dcmm-lint -ddump-cps-cmm
50 -> (TopSRT, [CmmZ]) -- SRT table and accumulating list of compiled procs
51 -> CmmZ -- Input C-- with Procedures
52 -> IO (TopSRT, [CmmZ]) -- Output CPS transformed C--
53 protoCmmCPSZ 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 -- (topSRT, tops) <- foldM (\ z f -> f topCAFEnv z) (topSRT, []) toTops
60 let cmms = Cmm (reverse (concat tops))
61 dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
62 return (topSRT, cmms : rst)
66 The identity and the last pass are stored in
67 mutable reference cells in an 'HscEnv' and are
68 global to one compiler session.
71 cpsTop :: HscEnv -> CmmTopZ ->
72 IO ([(CLabel, CAFSet)],
73 [(CAFSet, CmmTopForInfoTables)])
74 cpsTop _ p@(CmmData {}) = return ([], [(emptyFM, NoInfoTable p)])
75 cpsTop hsc_env (CmmProc h l args (stackInfo@(entry_off, _), g)) =
77 dump Opt_D_dump_cmmz "Pre Proc Points Added" g
78 let callPPs = callProcPoints g
79 -- Why bother doing it this early?
80 -- g <- dual_rewrite Opt_D_dump_cmmz "spills and reloads"
81 -- (dualLivenessWithInsertion callPPs) g
82 -- g <- run $ insertLateReloads g -- Duplicate reloads just before uses
83 -- g <- dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
84 -- (removeDeadAssignmentsAndReloads callPPs) g
85 dump Opt_D_dump_cmmz "Pre common block elimination" g
86 g <- return $ elimCommonBlocks g
87 dump Opt_D_dump_cmmz "Post common block elimination" g
89 ----------- Proc points -------------------
90 procPoints <- run $ minimalProcPointSet callPPs g
91 g <- run $ addProcPointProtocols callPPs procPoints g
92 dump Opt_D_dump_cmmz "Post Proc Points Added" g
94 ----------- Spills and reloads -------------------
96 -- pprTrace "pre Spills" (ppr g) $
97 dual_rewrite Opt_D_dump_cmmz "spills and reloads"
98 (dualLivenessWithInsertion procPoints) g
99 -- Insert spills at defns; reloads at return points
101 -- pprTrace "pre insertLateReloads" (ppr g) $
102 run $ insertLateReloads g -- Duplicate reloads just before uses
103 dump Opt_D_dump_cmmz "Post late reloads" g
105 -- pprTrace "post insertLateReloads" (ppr g) $
106 dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
107 (removeDeadAssignmentsAndReloads procPoints) g
108 -- Remove redundant reloads (and any other redundant asst)
110 ----------- Debug only: add code to put zero in dead stack slots----
111 -- Debugging: stubbing slots on death can cause crashes early
113 -- trace "post dead-assign elim" $
114 if opt_StubDeadValues then run $ stubSlotsOnDeath g else return g
117 --------------- Stack layout ----------------
118 slotEnv <- run $ liveSlotAnal g
119 mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
120 -- cafEnv <- -- trace "post liveSlotAnal" $ run $ cafAnal g
121 -- (cafEnv, slotEnv) <-
122 -- -- trace "post print cafAnal" $
123 -- return $ extendEnvsForSafeForeignCalls cafEnv slotEnv g
124 slotEnv <- return $ extendEnvWithSafeForeignCalls liveSlotTransfers slotEnv g
125 mbpprTrace "slotEnv extended for safe foreign calls: " (ppr slotEnv) $ return ()
126 let areaMap = layout procPoints slotEnv entry_off g
127 mbpprTrace "areaMap" (ppr areaMap) $ return ()
129 ------------ Manifest the the stack pointer --------
130 g <- run $ manifestSP areaMap entry_off g
131 dump Opt_D_dump_cmmz "after manifestSP" g
132 -- UGH... manifestSP can require updates to the procPointMap.
133 -- We can probably do something quicker here for the update...
135 ------------- Split into separate procedures ------------
136 procPointMap <- run $ procPointAnalysis procPoints g
137 dump Opt_D_dump_cmmz "procpoint map" procPointMap
138 gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
139 (CmmProc h l args (stackInfo, g))
140 mapM_ (dump Opt_D_dump_cmmz "after splitting") gs
142 ------------- More CAFs and foreign calls ------------
143 cafEnv <- run $ cafAnal g
144 cafEnv <- return $ extendEnvWithSafeForeignCalls cafTransfers cafEnv g
145 let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
146 mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
148 gs <- liftM concat $ run $ foldM lowerSafeForeignCalls [] gs
149 mapM_ (dump Opt_D_dump_cmmz "after lowerSafeForeignCalls") gs
151 -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
152 let gs' = map (setInfoTableStackMap slotEnv areaMap) gs
153 mapM_ (dump Opt_D_dump_cmmz "after setInfoTableStackMap") gs'
154 let gs'' = map (bundleCAFs cafEnv) gs'
155 mapM_ (dump Opt_D_dump_cmmz "after bundleCAFs") gs''
156 return (localCAFs, gs'')
157 where dflags = hsc_dflags hsc_env
158 mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
159 dump f txt g = dumpIfSet_dyn dflags f txt (ppr g)
161 run :: FuelMonad a -> IO a
162 run = runFuelIO (hsc_OptFuel hsc_env)
164 dual_rewrite flag txt pass g =
165 do dump flag ("Pre " ++ txt) g
167 dump flag ("Post " ++ txt) $ g
170 -- This probably belongs in CmmBuildInfoTables?
171 -- We're just finishing the job here: once we know what CAFs are defined
172 -- in non-static closures, we can build the SRTs.
173 toTops :: HscEnv -> FiniteMap CLabel CAFSet -> (TopSRT, [[CmmTopZ]])
174 -> [(CAFSet, CmmTopForInfoTables)] -> IO (TopSRT, [[CmmTopZ]])
176 toTops hsc_env topCAFEnv (topSRT, tops) gs =
177 do let setSRT (topSRT, rst) g =
178 do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
179 return (topSRT, gs : rst)
180 (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
181 gs' <- mapM finishInfoTables (concat gs')
182 return (topSRT, concat gs' : tops)