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 #include "HsVersions.h"
32 import PackageConfig ( PackageId )
33 import StaticFlags ( opt_AutoSccsOnIndividualCafs )
34 import CostCentre -- lots of things
37 import Module ( Module )
38 import UniqSupply ( splitUniqSupply, UniqSupply )
40 import UniqSupply ( uniqFromSupply )
42 import Unique ( Unique )
44 import ListSetOps ( removeDups )
47 infixr 9 `thenMM`, `thenMM_`
51 stgMassageForProfiling
53 -> Module -- module name
54 -> UniqSupply -- unique supply
55 -> [StgBinding] -- input
56 -> (CollectedCCs, [StgBinding])
58 stgMassageForProfiling this_pkg mod_name us stg_binds
60 ((local_ccs, extern_ccs, cc_stacks),
62 = initMM mod_name us (do_top_bindings stg_binds)
64 (fixed_ccs, fixed_cc_stacks)
65 = if opt_AutoSccsOnIndividualCafs
66 then ([],[]) -- don't need "all CAFs" CC
67 -- (for Prelude, we use PreludeCC)
68 else ([all_cafs_cc], [all_cafs_ccs])
70 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
71 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
73 ((fixed_ccs ++ local_ccs_no_dups,
75 fixed_cc_stacks ++ cc_stacks), stg_binds2)
78 all_cafs_cc = mkAllCafsCC mod_name
79 all_cafs_ccs = mkSingletonCCS all_cafs_cc
82 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
84 do_top_bindings [] = returnMM []
86 do_top_bindings (StgNonRec b rhs : bs)
87 = do_top_rhs b rhs `thenMM` \ rhs' ->
89 do_top_bindings bs `thenMM` \bs' ->
90 returnMM (StgNonRec b rhs' : bs')
93 do_top_bindings (StgRec pairs : bs)
94 = addTopLevelIshIds binders (
95 mapMM do_pair pairs `thenMM` \ pairs2 ->
96 do_top_bindings bs `thenMM` \ bs' ->
97 returnMM (StgRec pairs2 : bs')
100 binders = map fst pairs
102 = do_top_rhs b rhs `thenMM` \ rhs2 ->
106 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
108 do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
109 | not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
110 -- Trivial _scc_ around nothing but static data
111 -- Eliminate _scc_ ... and turn into StgRhsCon
113 -- isDllConApp checks for LitLit args too
114 = returnMM (StgRhsCon dontCareCCS con args)
116 {- Can't do this one with cost-centre stacks: --SDM
117 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
118 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
119 && not (isSccCountCostCentre cc)
120 -- Top level CAF without a cost centre attached
121 -- Attach and collect cc of trivial _scc_ in body
122 = collectCC cc `thenMM_`
123 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
124 returnMM (StgRhsClosure cc bi fv u [] expr')
127 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
128 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
129 -- Top level CAF without a cost centre attached
130 -- Attach CAF cc (collect if individual CAF ccs)
131 = (if opt_AutoSccsOnIndividualCafs
132 then let cc = mkAutoCC binder modl CafCC
133 ccs = mkSingletonCCS cc
134 -- careful: the binder might be :Main.main,
135 -- which doesn't belong to module mod_name.
136 -- bug #249, tests prof001, prof002
137 modl | Just m <- nameModule_maybe (idName binder) = m
138 | otherwise = mod_name
140 collectCC cc `thenMM_`
141 collectCCS ccs `thenMM_`
144 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
145 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
146 returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
148 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
149 -- Top level CAF with cost centre attached
150 -- Should this be a CAF cc ??? Does this ever occur ???
151 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
153 do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
154 -- Top level function, probably subsumed
155 | noCCSAttached no_ccs
156 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
157 returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
160 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
162 do_top_rhs binder (StgRhsCon ccs con args)
163 -- Top-level (static) data is not counted in heap
164 -- profiles; nor do we set CCCS from it; so we
165 -- just slam in dontCareCostCentre
166 = returnMM (StgRhsCon dontCareCCS con args)
169 do_expr :: StgExpr -> MassageM StgExpr
171 do_expr (StgLit l) = returnMM (StgLit l)
173 do_expr (StgApp fn args)
174 = boxHigherOrderArgs (StgApp fn) args
176 do_expr (StgConApp con args)
177 = boxHigherOrderArgs (\args -> StgConApp con args) args
179 do_expr (StgOpApp con args res_ty)
180 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
182 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
183 = collectCC cc `thenMM_`
184 do_expr expr `thenMM` \ expr' ->
185 returnMM (StgSCC cc expr')
187 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
188 = do_expr expr `thenMM` \ expr' ->
189 mapMM do_alt alts `thenMM` \ alts' ->
190 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
192 do_alt (id, bs, use_mask, e)
193 = do_expr e `thenMM` \ e' ->
194 returnMM (id, bs, use_mask, e')
197 = do_let b e `thenMM` \ (b,e) ->
198 returnMM (StgLet b e)
200 do_expr (StgLetNoEscape lvs1 lvs2 b e)
201 = do_let b e `thenMM` \ (b,e) ->
202 returnMM (StgLetNoEscape lvs1 lvs2 b e)
204 do_expr (StgTick m n expr)
205 = do_expr expr `thenMM` \ expr' ->
206 returnMM (StgTick m n expr')
209 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
212 ----------------------------------
214 do_let (StgNonRec b rhs) e
215 = do_rhs rhs `thenMM` \ rhs' ->
217 do_expr e `thenMM` \ e' ->
218 returnMM (StgNonRec b rhs',e')
221 do_let (StgRec pairs) e
222 = addTopLevelIshIds binders (
223 mapMM do_pair pairs `thenMM` \ pairs' ->
224 do_expr e `thenMM` \ e' ->
225 returnMM (StgRec pairs', e')
228 binders = map fst pairs
230 = do_rhs rhs `thenMM` \ rhs2 ->
233 ----------------------------------
234 do_rhs :: StgRhs -> MassageM StgRhs
235 -- We play much the same game as we did in do_top_rhs above;
236 -- but we don't have to worry about cafs etc.
239 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
240 | not (isSccCountCostCentre cc)
241 = collectCC cc `thenMM_`
242 returnMM (StgRhsCon cc con args)
245 do_rhs (StgRhsClosure _ bi fv u srt args expr)
246 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
247 do_expr expr' `thenMM` \ expr'' ->
248 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
250 slurpSCCs ccs (StgSCC cc e)
251 = collectCC cc `thenMM_`
252 slurpSCCs (cc `pushCCOnCCS` ccs) e
256 do_rhs (StgRhsCon cc con args)
257 = returnMM (StgRhsCon currentCCS con args)
260 %************************************************************************
262 \subsection{Boxing higher-order args}
264 %************************************************************************
266 Boxing is *turned off* at the moment, until we can figure out how to
267 do it properly in general.
271 :: ([StgArg] -> StgExpr)
272 -- An application lacking its arguments
273 -> [StgArg] -- arguments which we might box
276 #ifndef PROF_DO_BOXING
277 boxHigherOrderArgs almost_expr args
278 = returnMM (almost_expr args)
280 boxHigherOrderArgs almost_expr args
281 = getTopLevelIshIds `thenMM` \ ids ->
282 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
283 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
287 do_arg ids bindings arg@(StgVarArg old_var)
288 | (not (isLocalVar old_var) || elemVarSet old_var ids)
289 && isFunTy (dropForAlls var_type)
290 = -- make a trivial let-binding for the top-level function
291 getUniqueMM `thenMM` \ uniq ->
293 new_var = mkSysLocal FSLIT("sf") uniq var_type
295 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
297 var_type = idType old_var
299 do_arg ids bindings arg = returnMM (bindings, arg)
302 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
304 mk_stg_let cc (new_var, old_var) body
306 rhs_body = StgApp old_var [{-args-}]
307 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
309 StgLet (StgNonRec new_var rhs_closure) body
311 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
315 %************************************************************************
317 \subsection{Boring monad stuff for this}
319 %************************************************************************
323 = Module -- module name
324 -> CostCentreStack -- prevailing CostCentre
325 -- if none, subsumedCosts at top-level
326 -- currentCostCentre at nested levels
328 -> VarSet -- toplevel-ish Ids for boxing
330 -> (CollectedCCs, result)
332 -- the initMM function also returns the final CollectedCCs
334 initMM :: Module -- module name, which we may consult
339 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
341 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
342 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
344 thenMM expr cont mod scope_cc us ids ccs
345 = case splitUniqSupply us of { (s1, s2) ->
346 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
347 cont result mod scope_cc s2 ids ccs2 }}
349 thenMM_ expr cont mod scope_cc us ids ccs
350 = case splitUniqSupply us of { (s1, s2) ->
351 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
352 cont mod scope_cc s2 ids ccs2 }}
354 returnMM :: a -> MassageM a
355 returnMM result mod scope_cc us ids ccs = (ccs, result)
358 nopMM mod scope_cc us ids ccs = (ccs, ())
360 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
361 mapMM f [] = returnMM []
363 = f m `thenMM` \ r ->
364 mapMM f ms `thenMM` \ rs ->
367 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
368 mapAccumMM f b [] = returnMM (b, [])
369 mapAccumMM f b (m:ms)
370 = f b m `thenMM` \ (b2, r) ->
371 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
374 #ifdef PROF_DO_BOXING
375 getUniqueMM :: MassageM Unique
376 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
379 addTopLevelIshId :: Id -> MassageM a -> MassageM a
380 addTopLevelIshId id scope mod scope_cc us ids ccs
381 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
382 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
384 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
385 addTopLevelIshIds [] cont = cont
386 addTopLevelIshIds (id:ids) cont
387 = addTopLevelIshId id (addTopLevelIshIds ids cont)
389 getTopLevelIshIds :: MassageM VarSet
390 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
393 The prevailing CCS is used to tell whether we're in a top-levelish
394 position, where top-levelish is defined as "not inside a lambda".
395 Prevailing CCs used to be used for something much more complicated,
399 set_lambda_cc :: MassageM a -> MassageM a
400 set_lambda_cc action mod scope_cc us ids ccs
401 = action mod currentCCS us ids ccs
403 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
404 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
405 = action mod cc_to_set_to us ids ccs
407 get_prevailing_cc :: MassageM CostCentreStack
408 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
412 collectCC :: CostCentre -> MassageM ()
414 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
415 = ASSERT(not (noCCAttached cc))
416 if (cc `ccFromThisModule` mod_name) then
417 ((cc : local_ccs, extern_ccs, ccss), ())
418 else -- must declare it "extern"
419 ((local_ccs, cc : extern_ccs, ccss), ())
421 collectCCS :: CostCentreStack -> MassageM ()
423 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
424 = ASSERT(not (noCCSAttached ccs))
425 ((local_ccs, extern_ccs, ccs : ccss), ())