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 | not (dopt Opt_TryNewCodeGen (hsc_dflags hsc_env))
51 = return (topSRT, Cmm tops : rst) -- Only if -fnew-codegen
53 = do let dflags = hsc_dflags hsc_env
54 showPass dflags "CPSZ"
55 (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
56 let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
57 (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
58 -- (topSRT, tops) <- foldM (\ z f -> f topCAFEnv z) (topSRT, []) toTops
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 -> CmmTopZ ->
71 IO ([(CLabel, CAFSet)],
72 [(CAFSet, CmmTopForInfoTables)])
73 cpsTop _ p@(CmmData {}) = return ([], [(emptyFM, NoInfoTable p)])
74 cpsTop hsc_env (CmmProc h l args (stackInfo@(entry_off, _), g)) =
76 dump Opt_D_dump_cmmz "Pre Proc Points Added" g
77 let callPPs = callProcPoints g
78 -- Why bother doing it this early?
79 -- g <- dual_rewrite Opt_D_dump_cmmz "spills and reloads"
80 -- (dualLivenessWithInsertion callPPs) g
81 -- g <- run $ insertLateReloads g -- Duplicate reloads just before uses
82 -- g <- dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
83 -- (removeDeadAssignmentsAndReloads callPPs) g
84 dump Opt_D_dump_cmmz "Pre common block elimination" g
85 g <- return $ elimCommonBlocks g
86 dump Opt_D_dump_cmmz "Post common block elimination" g
88 ----------- Proc points -------------------
89 procPoints <- run $ minimalProcPointSet callPPs g
90 g <- run $ addProcPointProtocols callPPs procPoints g
91 dump Opt_D_dump_cmmz "Post Proc Points Added" g
93 ----------- Spills and reloads -------------------
95 -- pprTrace "pre Spills" (ppr g) $
96 dual_rewrite Opt_D_dump_cmmz "spills and reloads"
97 (dualLivenessWithInsertion procPoints) g
98 -- Insert spills at defns; reloads at return points
100 -- pprTrace "pre insertLateReloads" (ppr g) $
101 run $ insertLateReloads g -- Duplicate reloads just before uses
102 dump Opt_D_dump_cmmz "Post late reloads" g
104 -- pprTrace "post insertLateReloads" (ppr g) $
105 dual_rewrite Opt_D_dump_cmmz "Dead Assignment Elimination"
106 (removeDeadAssignmentsAndReloads procPoints) g
107 -- Remove redundant reloads (and any other redundant asst)
109 ----------- Debug only: add code to put zero in dead stack slots----
110 -- Debugging: stubbing slots on death can cause crashes early
112 -- trace "post dead-assign elim" $
113 if opt_StubDeadValues then run $ stubSlotsOnDeath g else return g
116 --------------- Stack layout ----------------
117 slotEnv <- run $ liveSlotAnal g
118 mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
120 -- trace "post liveSlotAnal" $
123 -- trace "post print cafAnal" $
124 return $ extendEnvsForSafeForeignCalls cafEnv 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 let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
144 mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
145 gs <- liftM concat $ run $ foldM lowerSafeForeignCalls [] gs
146 mapM_ (dump Opt_D_dump_cmmz "after lowerSafeForeignCalls") gs
148 -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
149 let gs' = map (setInfoTableStackMap slotEnv areaMap) gs
150 mapM_ (dump Opt_D_dump_cmmz "after setInfoTableStackMap") gs'
151 let gs'' = map (bundleCAFs cafEnv) gs'
152 mapM_ (dump Opt_D_dump_cmmz "after bundleCAFs") gs''
153 return (localCAFs, gs'')
154 where dflags = hsc_dflags hsc_env
155 mbpprTrace x y z = if dopt Opt_D_dump_cmmz dflags then pprTrace x y z else z
156 dump f txt g = dumpIfSet_dyn dflags f txt (ppr g)
157 run = runFuelIO (hsc_OptFuel hsc_env)
158 dual_rewrite 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 -> FiniteMap CLabel CAFSet -> (TopSRT, [[CmmTopZ]])
168 -> [(CAFSet, CmmTopForInfoTables)] -> IO (TopSRT, [[CmmTopZ]])
170 toTops hsc_env topCAFEnv (topSRT, tops) gs =
171 do let setSRT (topSRT, rst) g =
172 do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
173 return (topSRT, gs : rst)
174 (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
175 gs' <- mapM finishInfoTables (concat gs')
176 return (topSRT, concat gs' : tops)