2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[SCCfinal]{Modify and collect code generation for final STG program}
6 This is now a sort-of-normal STG-to-STG pass (WDP 94/06), run by stg2stg.
8 * Traverses the STG program collecting the cost centres. These are
9 required to declare the cost centres at the start of code
12 Note: because of cross-module unfolding, some of these cost centres
13 may be from other modules. But will still have to give them
14 "extern" declarations.
16 * Puts on CAF cost-centres if the user has asked for individual CAF
19 * Ditto for individual DICT cost-centres.
21 * Boxes top-level inherited functions passed as arguments.
23 * "Distributes" given cost-centres to all as-yet-unmarked RHSs.
26 module SCCfinal ( stgMassageForProfiling ) where
28 -- XXX This define is a bit of a hack, and should be done more nicely
29 #define FAST_STRING_NOT_NEEDED 1
30 #include "HsVersions.h"
34 import StaticFlags ( opt_AutoSccsOnIndividualCafs )
35 import CostCentre -- lots of things
39 import UniqSupply ( splitUniqSupply, UniqSupply )
41 import UniqSupply ( uniqFromSupply )
44 import ListSetOps ( removeDups )
49 stgMassageForProfiling
51 -> Module -- module name
52 -> UniqSupply -- unique supply
53 -> [StgBinding] -- input
54 -> (CollectedCCs, [StgBinding])
56 stgMassageForProfiling this_pkg mod_name us stg_binds
58 ((local_ccs, extern_ccs, cc_stacks),
60 = initMM mod_name us (do_top_bindings stg_binds)
62 (fixed_ccs, fixed_cc_stacks)
63 = if opt_AutoSccsOnIndividualCafs
64 then ([],[]) -- don't need "all CAFs" CC
65 -- (for Prelude, we use PreludeCC)
66 else ([all_cafs_cc], [all_cafs_ccs])
68 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
69 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
71 ((fixed_ccs ++ local_ccs_no_dups,
73 fixed_cc_stacks ++ cc_stacks), stg_binds2)
76 all_cafs_cc = mkAllCafsCC mod_name
77 all_cafs_ccs = mkSingletonCCS all_cafs_cc
80 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
82 do_top_bindings [] = return []
84 do_top_bindings (StgNonRec b rhs : bs) = do
85 rhs' <- do_top_rhs b rhs
86 addTopLevelIshId b $ do
87 bs' <- do_top_bindings bs
88 return (StgNonRec b rhs' : bs')
90 do_top_bindings (StgRec pairs : bs)
91 = addTopLevelIshIds binders $ do
92 pairs2 <- mapM do_pair pairs
93 bs' <- do_top_bindings bs
94 return (StgRec pairs2 : bs')
96 binders = map fst pairs
98 rhs2 <- do_top_rhs b rhs
102 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
104 do_top_rhs _ (StgRhsClosure _ _ _ _ _ [] (StgSCC cc (StgConApp con args)))
105 | not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
106 -- Trivial _scc_ around nothing but static data
107 -- Eliminate _scc_ ... and turn into StgRhsCon
109 -- isDllConApp checks for LitLit args too
110 = return (StgRhsCon dontCareCCS con args)
112 {- Can't do this one with cost-centre stacks: --SDM
113 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
114 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
115 && not (isSccCountCostCentre cc)
116 -- Top level CAF without a cost centre attached
117 -- Attach and collect cc of trivial _scc_ in body
119 expr' <- set_prevailing_cc cc (do_expr expr)
120 return (StgRhsClosure cc bi fv u [] expr')
123 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
124 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc = do
125 -- Top level CAF without a cost centre attached
126 -- Attach CAF cc (collect if individual CAF ccs)
127 caf_ccs <- if opt_AutoSccsOnIndividualCafs
128 then let cc = mkAutoCC binder modl CafCC
129 ccs = mkSingletonCCS cc
130 -- careful: the binder might be :Main.main,
131 -- which doesn't belong to module mod_name.
132 -- bug #249, tests prof001, prof002
133 modl | Just m <- nameModule_maybe (idName binder) = m
134 | otherwise = mod_name
141 body' <- set_prevailing_cc caf_ccs (do_expr body)
142 return (StgRhsClosure caf_ccs bi fv u srt [] body')
144 do_top_rhs _ (StgRhsClosure cc _ _ _ _ [] _)
145 -- Top level CAF with cost centre attached
146 -- Should this be a CAF cc ??? Does this ever occur ???
147 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
149 do_top_rhs _ (StgRhsClosure no_ccs bi fv u srt args body)
150 -- Top level function, probably subsumed
151 | noCCSAttached no_ccs
152 = do body' <- set_lambda_cc (do_expr body)
153 return (StgRhsClosure subsumedCCS bi fv u srt args body')
156 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
158 do_top_rhs _ (StgRhsCon _ con args)
159 -- Top-level (static) data is not counted in heap
160 -- profiles; nor do we set CCCS from it; so we
161 -- just slam in dontCareCostCentre
162 = return (StgRhsCon dontCareCCS con args)
165 do_expr :: StgExpr -> MassageM StgExpr
167 do_expr (StgLit l) = return (StgLit l)
169 do_expr (StgApp fn args)
170 = boxHigherOrderArgs (StgApp fn) args
172 do_expr (StgConApp con args)
173 = boxHigherOrderArgs (\args -> StgConApp con args) args
175 do_expr (StgOpApp con args res_ty)
176 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
178 do_expr (StgSCC cc expr) = do -- Ha, we found a cost centre!
180 expr' <- do_expr expr
181 return (StgSCC cc expr')
183 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts) = do
184 expr' <- do_expr expr
185 alts' <- mapM do_alt alts
186 return (StgCase expr' fv1 fv2 bndr srt alt_type alts')
188 do_alt (id, bs, use_mask, e) = do
190 return (id, bs, use_mask, e')
192 do_expr (StgLet b e) = do
196 do_expr (StgLetNoEscape lvs1 lvs2 b e) = do
198 return (StgLetNoEscape lvs1 lvs2 b e)
200 do_expr (StgTick m n expr) = do
201 expr' <- do_expr expr
202 return (StgTick m n expr')
204 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
206 ----------------------------------
208 do_let (StgNonRec b rhs) e = do
210 addTopLevelIshId b $ do
212 return (StgNonRec b rhs',e')
214 do_let (StgRec pairs) e
215 = addTopLevelIshIds binders $ do
216 pairs' <- mapM do_pair pairs
218 return (StgRec pairs', e')
220 binders = map fst pairs
221 do_pair (b, rhs) = do
225 ----------------------------------
226 do_rhs :: StgRhs -> MassageM StgRhs
227 -- We play much the same game as we did in do_top_rhs above;
228 -- but we don't have to worry about cafs etc.
231 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
232 | not (isSccCountCostCentre cc)
234 return (StgRhsCon cc con args)
237 do_rhs (StgRhsClosure _ bi fv u srt args expr) = do
238 (expr', ccs) <- slurpSCCs currentCCS expr
239 expr'' <- do_expr expr'
240 return (StgRhsClosure ccs bi fv u srt args expr'')
242 slurpSCCs ccs (StgSCC cc e)
244 slurpSCCs (cc `pushCCOnCCS` ccs) e
248 do_rhs (StgRhsCon _ con args)
249 = return (StgRhsCon currentCCS con args)
252 %************************************************************************
254 \subsection{Boxing higher-order args}
256 %************************************************************************
258 Boxing is *turned off* at the moment, until we can figure out how to
259 do it properly in general.
263 :: ([StgArg] -> StgExpr)
264 -- An application lacking its arguments
265 -> [StgArg] -- arguments which we might box
268 #ifndef PROF_DO_BOXING
269 boxHigherOrderArgs almost_expr args
270 = return (almost_expr args)
272 boxHigherOrderArgs almost_expr args = do
273 ids <- getTopLevelIshIds
274 (let_bindings, new_args) <- mapAccumLM (do_arg ids) [] args
275 return (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
279 do_arg ids bindings arg@(StgVarArg old_var)
280 | (not (isLocalVar old_var) || elemVarSet old_var ids)
281 && isFunTy (dropForAlls var_type)
282 = do -- make a trivial let-binding for the top-level function
285 new_var = mkSysLocal FSLIT("sf") uniq var_type
286 return ( (new_var, old_var) : bindings, StgVarArg new_var )
288 var_type = idType old_var
290 do_arg ids bindings arg = return (bindings, arg)
293 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
295 mk_stg_let cc (new_var, old_var) body
297 rhs_body = StgApp old_var [{-args-}]
298 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
300 StgLet (StgNonRec new_var rhs_closure) body
302 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
306 %************************************************************************
308 \subsection{Boring monad stuff for this}
310 %************************************************************************
313 newtype MassageM result
315 unMassageM :: Module -- module name
316 -> CostCentreStack -- prevailing CostCentre
317 -- if none, subsumedCosts at top-level
318 -- currentCostCentre at nested levels
320 -> VarSet -- toplevel-ish Ids for boxing
322 -> (CollectedCCs, result)
325 instance Monad MassageM where
326 return x = MassageM (\_ _ _ _ ccs -> (ccs, x))
330 -- the initMM function also returns the final CollectedCCs
332 initMM :: Module -- module name, which we may consult
337 initMM mod_name init_us (MassageM m) = m mod_name noCCS init_us emptyVarSet ([],[],[])
339 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
340 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
342 thenMM expr cont = MassageM $ \mod scope_cc us ids ccs ->
343 case splitUniqSupply us of { (s1, s2) ->
344 case unMassageM expr mod scope_cc s1 ids ccs of { (ccs2, result) ->
345 unMassageM (cont result) mod scope_cc s2 ids ccs2 }}
347 thenMM_ expr cont = MassageM $ \mod scope_cc us ids ccs ->
348 case splitUniqSupply us of { (s1, s2) ->
349 case unMassageM expr mod scope_cc s1 ids ccs of { (ccs2, _) ->
350 unMassageM cont mod scope_cc s2 ids ccs2 }}
352 #ifdef PROF_DO_BOXING
353 getUniqueMM :: MassageM Unique
354 getUniqueMM = MassageM \mod scope_cc us ids ccs -> (ccs, uniqFromSupply us)
357 addTopLevelIshId :: Id -> MassageM a -> MassageM a
358 addTopLevelIshId id scope
359 = MassageM $ \mod scope_cc us ids ccs ->
360 if isCurrentCCS scope_cc then unMassageM scope mod scope_cc us ids ccs
361 else unMassageM scope mod scope_cc us (extendVarSet ids id) ccs
363 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
364 addTopLevelIshIds [] cont = cont
365 addTopLevelIshIds (id:ids) cont
366 = addTopLevelIshId id (addTopLevelIshIds ids cont)
368 #ifdef PROF_DO_BOXING
369 getTopLevelIshIds :: MassageM VarSet
370 getTopLevelIshIds = MassageM $ \_mod _scope_cc _us ids ccs -> (ccs, ids)
374 The prevailing CCS is used to tell whether we're in a top-levelish
375 position, where top-levelish is defined as "not inside a lambda".
376 Prevailing CCs used to be used for something much more complicated,
380 set_lambda_cc :: MassageM a -> MassageM a
382 = MassageM $ \mod _scope_cc us ids ccs
383 -> unMassageM action mod currentCCS us ids ccs
385 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
386 set_prevailing_cc cc_to_set_to action
387 = MassageM $ \mod _scope_cc us ids ccs
388 -> unMassageM action mod cc_to_set_to us ids ccs
392 collectCC :: CostCentre -> MassageM ()
394 = MassageM $ \mod_name _scope_cc _us _ids (local_ccs, extern_ccs, ccss)
395 -> ASSERT(not (noCCAttached cc))
396 if (cc `ccFromThisModule` mod_name) then
397 ((cc : local_ccs, extern_ccs, ccss), ())
398 else -- must declare it "extern"
399 ((local_ccs, cc : extern_ccs, ccss), ())
401 -- Version of collectCC used when we definitely want to declare this
402 -- CC as local, even if its module name is not the same as the current
403 -- module name (eg. the special :Main module) see bug #249, #1472,
404 -- test prof001,prof002.
405 collectNewCC :: CostCentre -> MassageM ()
407 = MassageM $ \_mod_name _scope_cc _us _ids (local_ccs, extern_ccs, ccss)
408 -> ((cc : local_ccs, extern_ccs, ccss), ())
410 collectCCS :: CostCentreStack -> MassageM ()
413 = MassageM $ \_mod_name _scope_cc _us _ids (local_ccs, extern_ccs, ccss)
414 -> ASSERT(not (noCCSAttached ccs))
415 ((local_ccs, extern_ccs, ccs : ccss), ())