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 an implicit stack and native C-- calls into
7 -- optimized, CPS converted and native-call-less C--. The latter
8 -- C-- can be used to generate assembly.
15 import CmmBuildInfoTables
16 import CmmCommonBlockElim
21 import OptimizationFuel
29 import qualified Data.Map as Map
33 -----------------------------------------------------------------------------
34 -- | Top level driver for C-- pipeline
35 -----------------------------------------------------------------------------
36 -- There are two complications here:
37 -- 1. We need to compile the procedures in two stages because we need
38 -- an analysis of the procedures to tell us what CAFs they use.
39 -- The first stage returns a map from procedure labels to CAFs,
40 -- along with a closure that will compute SRTs and attach them to
41 -- the compiled procedures.
42 -- The second stage is to combine the CAF information into a top-level
43 -- CAF environment mapping non-static closures to the CAFs they keep live,
44 -- then pass that environment to the closures returned in the first
45 -- stage of compilation.
46 -- 2. We need to thread the module's SRT around when the SRT tables
47 -- are computed for each procedure.
48 -- The SRT needs to be threaded because it is grown lazily.
49 -- 3. We run control flow optimizations twice, once before any pipeline
50 -- work is done, and once again at the very end on all of the
51 -- resulting C-- blocks. EZY: It's unclear whether or not whether
52 -- we actually need to do the initial pass.
53 cmmPipeline :: HscEnv -- Compilation env including
54 -- dynamic flags: -dcmm-lint -ddump-cps-cmm
55 -> (TopSRT, [Cmm]) -- SRT table and accumulating list of compiled procs
56 -> Cmm -- Input C-- with Procedures
57 -> IO (TopSRT, [Cmm]) -- Output CPS transformed C--
58 cmmPipeline hsc_env (topSRT, rst) prog =
59 do let dflags = hsc_dflags hsc_env
60 (Cmm tops) = runCmmContFlowOpts prog
61 showPass dflags "CPSZ"
62 (cafEnvs, tops) <- liftM unzip $ mapM (cpsTop hsc_env) tops
63 let topCAFEnv = mkTopCAFInfo (concat cafEnvs)
64 (topSRT, tops) <- foldM (toTops hsc_env topCAFEnv) (topSRT, []) tops
65 let cmms = Cmm (reverse (concat tops))
66 dumpIfSet_dyn dflags Opt_D_dump_cps_cmm "Post CPS Cmm" (ppr cmms)
67 -- SRT is not affected by control flow optimization pass
68 let prog' = map runCmmContFlowOpts (cmms : rst)
69 return (topSRT, prog')
73 The identity and the last pass are stored in
74 mutable reference cells in an 'HscEnv' and are
75 global to one compiler session.
78 -- EZY: It might be helpful to have an easy way of dumping the "pre"
79 -- input for any given phase, besides just turning it all on with
82 cpsTop :: HscEnv -> CmmTop -> IO ([(CLabel, CAFSet)], [(CAFSet, CmmTop)])
83 cpsTop _ p@(CmmData {}) = return ([], [(Map.empty, p)])
84 cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}}) l g) =
86 -- Why bother doing these early: dualLivenessWithInsertion,
87 -- insertLateReloads, rewriteAssignments?
89 ----------- Eliminate common blocks -------------------
90 g <- return $ elimCommonBlocks g
91 dump Opt_D_dump_cmmz_cbe "Post common block elimination" g
92 -- Any work storing block Labels must be performed _after_ elimCommonBlocks
94 ----------- Proc points -------------------
95 let callPPs = callProcPoints g
96 procPoints <- run $ minimalProcPointSet callPPs g
97 g <- run $ addProcPointProtocols callPPs procPoints g
98 dump Opt_D_dump_cmmz_proc "Post Proc Points Added" g
100 ----------- Spills and reloads -------------------
101 g <- run $ dualLivenessWithInsertion procPoints g
102 dump Opt_D_dump_cmmz_spills "Post spills and reloads" g
104 ----------- Sink and inline assignments -------------------
105 g <- runOptimization $ rewriteAssignments g
106 dump Opt_D_dump_cmmz_rewrite "Post rewrite assignments" g
108 ----------- Eliminate dead assignments -------------------
109 -- Remove redundant reloads (and any other redundant asst)
110 g <- runOptimization $ removeDeadAssignmentsAndReloads procPoints g
111 dump Opt_D_dump_cmmz_dead "Post Dead Assignment Elimination" g
113 ----------- Zero dead stack slots (Debug only) ---------------
114 -- Debugging: stubbing slots on death can cause crashes early
115 g <- if opt_StubDeadValues
116 then run $ stubSlotsOnDeath g
118 dump Opt_D_dump_cmmz_stub "Post stub dead stack slots" g
120 --------------- Stack layout ----------------
121 slotEnv <- run $ liveSlotAnal g
122 let spEntryMap = getSpEntryMap entry_off g
123 mbpprTrace "live slot analysis results: " (ppr slotEnv) $ return ()
124 let areaMap = layout procPoints spEntryMap slotEnv entry_off g
125 mbpprTrace "areaMap" (ppr areaMap) $ return ()
127 ------------ Manifest the stack pointer --------
128 g <- run $ manifestSP spEntryMap areaMap entry_off g
129 dump Opt_D_dump_cmmz_sp "Post manifestSP" g
130 -- UGH... manifestSP can require updates to the procPointMap.
131 -- We can probably do something quicker here for the update...
133 ------------- Split into separate procedures ------------
134 procPointMap <- run $ procPointAnalysis procPoints g
135 dump Opt_D_dump_cmmz_procmap "procpoint map" procPointMap
136 gs <- run $ splitAtProcPoints l callPPs procPoints procPointMap
138 mapM_ (dump Opt_D_dump_cmmz_split "Post splitting") gs
140 ------------- More CAFs and foreign calls ------------
141 cafEnv <- run $ cafAnal g
142 let localCAFs = catMaybes $ map (localCAFInfo cafEnv) gs
143 mbpprTrace "localCAFs" (ppr localCAFs) $ return ()
145 gs <- run $ mapM (lowerSafeForeignCalls areaMap) gs
146 mapM_ (dump Opt_D_dump_cmmz_lower "Post lowerSafeForeignCalls") gs
148 -- NO MORE GRAPH TRANSFORMATION AFTER HERE -- JUST MAKING INFOTABLES
149 gs <- return $ map (setInfoTableStackMap slotEnv areaMap) gs
150 mapM_ (dump Opt_D_dump_cmmz_info "after setInfoTableStackMap") gs
151 gs <- return $ map (bundleCAFs cafEnv) gs
152 mapM_ (dump Opt_D_dump_cmmz_cafs "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
157 -- ToDo: No easy way of say "dump all the cmmz, *and* split
158 -- them into files." Also, -ddump-cmmz doesn't play nicely
159 -- with -ddump-to-file, since the headers get omitted.
160 dumpIfSet_dyn dflags f txt (ppr g)
161 when (not (dopt f dflags)) $
162 dumpIfSet_dyn dflags Opt_D_dump_cmmz txt (ppr g)
163 -- Runs a required transformation/analysis
164 run = runInfiniteFuelIO (hsc_OptFuel hsc_env)
165 -- Runs an optional transformation/analysis (and should
166 -- thus be subject to optimization fuel)
167 runOptimization = runFuelIO (hsc_OptFuel hsc_env)
169 -- This probably belongs in CmmBuildInfoTables?
170 -- We're just finishing the job here: once we know what CAFs are defined
171 -- in non-static closures, we can build the SRTs.
172 toTops :: HscEnv -> Map CLabel CAFSet -> (TopSRT, [[CmmTop]])
173 -> [(CAFSet, CmmTop)] -> IO (TopSRT, [[CmmTop]])
174 toTops hsc_env topCAFEnv (topSRT, tops) gs =
175 do let setSRT (topSRT, rst) g =
176 do (topSRT, gs) <- setInfoTableSRT topCAFEnv topSRT g
177 return (topSRT, gs : rst)
178 (topSRT, gs') <- runFuelIO (hsc_OptFuel hsc_env) $ foldM setSRT (topSRT, []) gs
179 return (topSRT, concat gs' : tops)