2 -- | Converts C-- with full proceedures and parameters
3 -- to a CPS transformed C-- with the stack made manifest.
10 import CmmBuildInfoTables
11 import CmmCommonBlockElimZ
28 -----------------------------------------------------------------------------
29 -- |Top level driver for the CPS pass
30 -----------------------------------------------------------------------------
31 -- There are two complications here:
32 -- 1. We need to compile the procedures in two stages because we need
33 -- an analysis of the procedures to tell us what CAFs they use.
34 -- The first stage returns a map from procedure labels to CAFs,
35 -- along with a closure that will compute SRTs and attach them to
36 -- the compiled procedures.
37 -- The second stage is to combine the CAF information into a top-level
38 -- CAF environment mapping non-static closures to the CAFs they keep live,
39 -- then pass that environment to the closures returned in the first
40 -- stage of compilation.
41 -- 2. We need to thread the module's SRT around when the SRT tables
42 -- are computed for each procedure.
43 -- The SRT needs to be threaded because it is grown lazily.
44 protoCmmCPSZ :: HscEnv -- Compilation env including
45 -- dynamic flags: -dcmm-lint -ddump-cps-cmm
46 -> (TopSRT, [CmmZ]) -- SRT table and accumulating list of compiled procs
47 -> CmmZ -- Input C-- with Procedures
48 -> IO (TopSRT, [CmmZ]) -- Output CPS transformed C--
49 protoCmmCPSZ hsc_env (topSRT, rst) (Cmm tops) =
50 do let dflags = hsc_dflags hsc_env
51 showPass dflags "CPSZ"
52 (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
53 let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
54 (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
55 -- (topSRT, tops) <- foldM (\ z f -> f topCAFEnv z) (topSRT, []) toTops
56 let cmms = Cmm (reverse (concat tops))
57 dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
58 return (topSRT, cmms : rst)
62 The identity and the last pass are stored in
63 mutable reference cells in an 'HscEnv' and are
64 global to one compiler session.
67 cpsTop :: HscEnv -> CmmTopZ ->
68 IO ([(CLabel, CAFSet)],
69 [(CAFSet, CmmTopForInfoTables)])
70 cpsTop _ p@(CmmData {}) = return ([], [(emptyFM, NoInfoTable p)])
71 cpsTop hsc_env (CmmProc h l args (stackInfo@(entry_off, _), g)) =
73 dump Opt_D_dump_cmmz "Pre Proc Points Added" g
74 let callPPs = callProcPoints g
75 -- Why bother doing it this early?
76 -- g <- dual_rewrite Opt_D_dump_cmmz "spills and reloads"
77 -- (dualLivenessWithInsertion callPPs) g
78 -- g <- run $ insertLateReloads g -- Duplicate reloads just before uses
79 -- g <- dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
80 -- (removeDeadAssignmentsAndReloads callPPs) g
81 dump Opt_D_dump_cmmz "Pre common block elimination" g
82 g <- return $ elimCommonBlocks g
83 dump Opt_D_dump_cmmz "Post common block elimination" g
85 ----------- Proc points -------------------
86 procPoints <- run $ minimalProcPointSet callPPs g
87 g <- run $ addProcPointProtocols callPPs procPoints g
88 dump Opt_D_dump_cmmz "Post Proc Points Added" g
90 ----------- Spills and reloads -------------------
92 -- pprTrace "pre Spills" (ppr g) $
93 dual_rewrite Opt_D_dump_cmmz "spills and reloads"
94 (dualLivenessWithInsertion procPoints) g
95 -- Insert spills at defns; reloads at return points
97 -- pprTrace "pre insertLateReloads" (ppr g) $
98 run $ insertLateReloads g -- Duplicate reloads just before uses
99 dump Opt_D_dump_cmmz "Post late reloads" g
101 -- pprTrace "post insertLateReloads" (ppr g) $
102 dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
103 (removeDeadAssignmentsAndReloads procPoints) g
104 -- Remove redundant reloads (and any other redundant asst)
106 ----------- Debug only: add code to put zero in dead stack slots----
107 -- Debugging: stubbing slots on death can cause crashes early
109 -- trace "post dead-assign elim" $
110 if opt_StubDeadValues then run $ stubSlotsOnDeath g else return g
113 --------------- Stack layout ----------------
114 slotEnv <- run $ liveSlotAnal g
115 mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
116 -- cafEnv <- -- trace "post liveSlotAnal" $ run $ cafAnal g
117 -- (cafEnv, slotEnv) <-
118 -- -- trace "post print cafAnal" $
119 -- return $ extendEnvsForSafeForeignCalls cafEnv slotEnv g
120 slotEnv <- return $ extendEnvWithSafeForeignCalls liveSlotTransfers slotEnv g
121 mbpprTrace "slotEnv extended for safe foreign calls: " (ppr slotEnv) $ return ()
122 let areaMap = layout procPoints slotEnv entry_off g
123 mbpprTrace "areaMap" (ppr areaMap) $ return ()
125 ------------ Manifest the the stack pointer --------
126 g <- run $ manifestSP areaMap entry_off g
127 dump Opt_D_dump_cmmz "after manifestSP" g
128 -- UGH... manifestSP can require updates to the procPointMap.
129 -- We can probably do something quicker here for the update...
131 ------------- Split into separate procedures ------------
132 procPointMap <- run $ procPointAnalysis procPoints g
133 dump Opt_D_dump_cmmz "procpoint map" procPointMap
134 gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
135 (CmmProc h l args (stackInfo, g))
136 mapM_ (dump Opt_D_dump_cmmz "after splitting") gs
138 ------------- More CAFs and foreign calls ------------
139 cafEnv <- run $ cafAnal g
140 cafEnv <- return $ extendEnvWithSafeForeignCalls cafTransfers cafEnv g
141 let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
142 mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
144 gs <- liftM concat $ run $ foldM lowerSafeForeignCalls [] gs
145 mapM_ (dump Opt_D_dump_cmmz "after lowerSafeForeignCalls") gs
147 -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
148 let gs' = map (setInfoTableStackMap slotEnv areaMap) gs
149 mapM_ (dump Opt_D_dump_cmmz "after setInfoTableStackMap") gs'
150 let gs'' = map (bundleCAFs cafEnv) gs'
151 mapM_ (dump Opt_D_dump_cmmz "after bundleCAFs") gs''
152 return (localCAFs, gs'')
153 where dflags = hsc_dflags hsc_env
154 mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
155 dump f txt g = dumpIfSet_dyn dflags f txt (ppr g)
156 run = runFuelIO (hsc_OptFuel hsc_env)
157 dual_rewrite flag txt pass g =
158 do dump flag ("Pre " ++ txt) g
160 dump flag ("Post " ++ txt) $ g
163 -- This probably belongs in CmmBuildInfoTables?
164 -- We're just finishing the job here: once we know what CAFs are defined
165 -- in non-static closures, we can build the SRTs.
166 toTops :: HscEnv -> FiniteMap CLabel CAFSet -> (TopSRT, [[CmmTopZ]])
167 -> [(CAFSet, CmmTopForInfoTables)] -> IO (TopSRT, [[CmmTopZ]])
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 gs' <- mapM finishInfoTables (concat gs')
175 return (topSRT, concat gs' : tops)