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 )
43 import ListSetOps ( removeDups )
46 infixr 9 `thenMM`, `thenMM_`
50 stgMassageForProfiling
52 -> Module -- module name
53 -> UniqSupply -- unique supply
54 -> [StgBinding] -- input
55 -> (CollectedCCs, [StgBinding])
57 stgMassageForProfiling this_pkg mod_name us stg_binds
59 ((local_ccs, extern_ccs, cc_stacks),
61 = initMM mod_name us (do_top_bindings stg_binds)
63 (fixed_ccs, fixed_cc_stacks)
64 = if opt_AutoSccsOnIndividualCafs
65 then ([],[]) -- don't need "all CAFs" CC
66 -- (for Prelude, we use PreludeCC)
67 else ([all_cafs_cc], [all_cafs_ccs])
69 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
70 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
72 ((fixed_ccs ++ local_ccs_no_dups,
74 fixed_cc_stacks ++ cc_stacks), stg_binds2)
77 all_cafs_cc = mkAllCafsCC mod_name
78 all_cafs_ccs = mkSingletonCCS all_cafs_cc
81 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
83 do_top_bindings [] = returnMM []
85 do_top_bindings (StgNonRec b rhs : bs)
86 = do_top_rhs b rhs `thenMM` \ rhs' ->
88 do_top_bindings bs `thenMM` \bs' ->
89 returnMM (StgNonRec b rhs' : bs')
92 do_top_bindings (StgRec pairs : bs)
93 = addTopLevelIshIds binders (
94 mapMM do_pair pairs `thenMM` \ pairs2 ->
95 do_top_bindings bs `thenMM` \ bs' ->
96 returnMM (StgRec pairs2 : bs')
99 binders = map fst pairs
101 = do_top_rhs b rhs `thenMM` \ rhs2 ->
105 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
107 do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
108 | not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
109 -- Trivial _scc_ around nothing but static data
110 -- Eliminate _scc_ ... and turn into StgRhsCon
112 -- isDllConApp checks for LitLit args too
113 = returnMM (StgRhsCon dontCareCCS con args)
115 {- Can't do this one with cost-centre stacks: --SDM
116 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
117 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
118 && not (isSccCountCostCentre cc)
119 -- Top level CAF without a cost centre attached
120 -- Attach and collect cc of trivial _scc_ in body
121 = collectCC cc `thenMM_`
122 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
123 returnMM (StgRhsClosure cc bi fv u [] expr')
126 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
127 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
128 -- Top level CAF without a cost centre attached
129 -- Attach CAF cc (collect if individual CAF ccs)
130 = (if opt_AutoSccsOnIndividualCafs
131 then let cc = mkAutoCC binder modl CafCC
132 ccs = mkSingletonCCS cc
133 -- careful: the binder might be :Main.main,
134 -- which doesn't belong to module mod_name.
135 -- bug #249, tests prof001, prof002
136 modl | Just m <- nameModule_maybe (idName binder) = m
137 | otherwise = mod_name
139 collectCC cc `thenMM_`
140 collectCCS ccs `thenMM_`
143 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
144 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
145 returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
147 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
148 -- Top level CAF with cost centre attached
149 -- Should this be a CAF cc ??? Does this ever occur ???
150 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
152 do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
153 -- Top level function, probably subsumed
154 | noCCSAttached no_ccs
155 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
156 returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
159 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
161 do_top_rhs binder (StgRhsCon ccs con args)
162 -- Top-level (static) data is not counted in heap
163 -- profiles; nor do we set CCCS from it; so we
164 -- just slam in dontCareCostCentre
165 = returnMM (StgRhsCon dontCareCCS con args)
168 do_expr :: StgExpr -> MassageM StgExpr
170 do_expr (StgLit l) = returnMM (StgLit l)
172 do_expr (StgApp fn args)
173 = boxHigherOrderArgs (StgApp fn) args
175 do_expr (StgConApp con args)
176 = boxHigherOrderArgs (\args -> StgConApp con args) args
178 do_expr (StgOpApp con args res_ty)
179 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
181 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
182 = collectCC cc `thenMM_`
183 do_expr expr `thenMM` \ expr' ->
184 returnMM (StgSCC cc expr')
186 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
187 = do_expr expr `thenMM` \ expr' ->
188 mapMM do_alt alts `thenMM` \ alts' ->
189 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
191 do_alt (id, bs, use_mask, e)
192 = do_expr e `thenMM` \ e' ->
193 returnMM (id, bs, use_mask, e')
196 = do_let b e `thenMM` \ (b,e) ->
197 returnMM (StgLet b e)
199 do_expr (StgLetNoEscape lvs1 lvs2 b e)
200 = do_let b e `thenMM` \ (b,e) ->
201 returnMM (StgLetNoEscape lvs1 lvs2 b e)
203 do_expr (StgTick m n expr)
204 = do_expr expr `thenMM` \ expr' ->
205 returnMM (StgTick m n expr')
208 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
211 ----------------------------------
213 do_let (StgNonRec b rhs) e
214 = do_rhs rhs `thenMM` \ rhs' ->
216 do_expr e `thenMM` \ e' ->
217 returnMM (StgNonRec b rhs',e')
220 do_let (StgRec pairs) e
221 = addTopLevelIshIds binders (
222 mapMM do_pair pairs `thenMM` \ pairs' ->
223 do_expr e `thenMM` \ e' ->
224 returnMM (StgRec pairs', e')
227 binders = map fst pairs
229 = do_rhs rhs `thenMM` \ rhs2 ->
232 ----------------------------------
233 do_rhs :: StgRhs -> MassageM StgRhs
234 -- We play much the same game as we did in do_top_rhs above;
235 -- but we don't have to worry about cafs etc.
238 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
239 | not (isSccCountCostCentre cc)
240 = collectCC cc `thenMM_`
241 returnMM (StgRhsCon cc con args)
244 do_rhs (StgRhsClosure _ bi fv u srt args expr)
245 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
246 do_expr expr' `thenMM` \ expr'' ->
247 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
249 slurpSCCs ccs (StgSCC cc e)
250 = collectCC cc `thenMM_`
251 slurpSCCs (cc `pushCCOnCCS` ccs) e
255 do_rhs (StgRhsCon cc con args)
256 = returnMM (StgRhsCon currentCCS con args)
259 %************************************************************************
261 \subsection{Boxing higher-order args}
263 %************************************************************************
265 Boxing is *turned off* at the moment, until we can figure out how to
266 do it properly in general.
270 :: ([StgArg] -> StgExpr)
271 -- An application lacking its arguments
272 -> [StgArg] -- arguments which we might box
275 #ifndef PROF_DO_BOXING
276 boxHigherOrderArgs almost_expr args
277 = returnMM (almost_expr args)
279 boxHigherOrderArgs almost_expr args
280 = getTopLevelIshIds `thenMM` \ ids ->
281 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
282 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
286 do_arg ids bindings arg@(StgVarArg old_var)
287 | (not (isLocalVar old_var) || elemVarSet old_var ids)
288 && isFunTy (dropForAlls var_type)
289 = -- make a trivial let-binding for the top-level function
290 getUniqueMM `thenMM` \ uniq ->
292 new_var = mkSysLocal FSLIT("sf") uniq var_type
294 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
296 var_type = idType old_var
298 do_arg ids bindings arg = returnMM (bindings, arg)
301 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
303 mk_stg_let cc (new_var, old_var) body
305 rhs_body = StgApp old_var [{-args-}]
306 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
308 StgLet (StgNonRec new_var rhs_closure) body
310 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
314 %************************************************************************
316 \subsection{Boring monad stuff for this}
318 %************************************************************************
322 = Module -- module name
323 -> CostCentreStack -- prevailing CostCentre
324 -- if none, subsumedCosts at top-level
325 -- currentCostCentre at nested levels
327 -> VarSet -- toplevel-ish Ids for boxing
329 -> (CollectedCCs, result)
331 -- the initMM function also returns the final CollectedCCs
333 initMM :: Module -- module name, which we may consult
338 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
340 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
341 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
343 thenMM expr cont mod scope_cc us ids ccs
344 = case splitUniqSupply us of { (s1, s2) ->
345 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
346 cont result mod scope_cc s2 ids ccs2 }}
348 thenMM_ expr cont mod scope_cc us ids ccs
349 = case splitUniqSupply us of { (s1, s2) ->
350 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
351 cont mod scope_cc s2 ids ccs2 }}
353 returnMM :: a -> MassageM a
354 returnMM result mod scope_cc us ids ccs = (ccs, result)
357 nopMM mod scope_cc us ids ccs = (ccs, ())
359 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
360 mapMM f [] = returnMM []
362 = f m `thenMM` \ r ->
363 mapMM f ms `thenMM` \ rs ->
366 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
367 mapAccumMM f b [] = returnMM (b, [])
368 mapAccumMM f b (m:ms)
369 = f b m `thenMM` \ (b2, r) ->
370 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
373 #ifdef PROF_DO_BOXING
374 getUniqueMM :: MassageM Unique
375 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
378 addTopLevelIshId :: Id -> MassageM a -> MassageM a
379 addTopLevelIshId id scope mod scope_cc us ids ccs
380 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
381 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
383 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
384 addTopLevelIshIds [] cont = cont
385 addTopLevelIshIds (id:ids) cont
386 = addTopLevelIshId id (addTopLevelIshIds ids cont)
388 getTopLevelIshIds :: MassageM VarSet
389 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
392 The prevailing CCS is used to tell whether we're in a top-levelish
393 position, where top-levelish is defined as "not inside a lambda".
394 Prevailing CCs used to be used for something much more complicated,
398 set_lambda_cc :: MassageM a -> MassageM a
399 set_lambda_cc action mod scope_cc us ids ccs
400 = action mod currentCCS us ids ccs
402 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
403 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
404 = action mod cc_to_set_to us ids ccs
406 get_prevailing_cc :: MassageM CostCentreStack
407 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
411 collectCC :: CostCentre -> MassageM ()
413 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
414 = ASSERT(not (noCCAttached cc))
415 if (cc `ccFromThisModule` mod_name) then
416 ((cc : local_ccs, extern_ccs, ccss), ())
417 else -- must declare it "extern"
418 ((local_ccs, cc : extern_ccs, ccss), ())
420 collectCCS :: CostCentreStack -> MassageM ()
422 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
423 = ASSERT(not (noCCSAttached ccs))
424 ((local_ccs, extern_ccs, ccs : ccss), ())