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.
27 -- The above warning supression flag is a temporary kludge.
28 -- While working on this module you are encouraged to remove it and fix
29 -- any warnings in the module. See
30 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
33 module SCCfinal ( stgMassageForProfiling ) where
35 #include "HsVersions.h"
39 import StaticFlags ( opt_AutoSccsOnIndividualCafs )
40 import CostCentre -- lots of things
44 import UniqSupply ( splitUniqSupply, UniqSupply )
46 import UniqSupply ( uniqFromSupply )
49 import ListSetOps ( removeDups )
52 infixr 9 `thenMM`, `thenMM_`
56 stgMassageForProfiling
58 -> Module -- module name
59 -> UniqSupply -- unique supply
60 -> [StgBinding] -- input
61 -> (CollectedCCs, [StgBinding])
63 stgMassageForProfiling this_pkg mod_name us stg_binds
65 ((local_ccs, extern_ccs, cc_stacks),
67 = initMM mod_name us (do_top_bindings stg_binds)
69 (fixed_ccs, fixed_cc_stacks)
70 = if opt_AutoSccsOnIndividualCafs
71 then ([],[]) -- don't need "all CAFs" CC
72 -- (for Prelude, we use PreludeCC)
73 else ([all_cafs_cc], [all_cafs_ccs])
75 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
76 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
78 ((fixed_ccs ++ local_ccs_no_dups,
80 fixed_cc_stacks ++ cc_stacks), stg_binds2)
83 all_cafs_cc = mkAllCafsCC mod_name
84 all_cafs_ccs = mkSingletonCCS all_cafs_cc
87 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
89 do_top_bindings [] = returnMM []
91 do_top_bindings (StgNonRec b rhs : bs)
92 = do_top_rhs b rhs `thenMM` \ rhs' ->
94 do_top_bindings bs `thenMM` \bs' ->
95 returnMM (StgNonRec b rhs' : bs')
98 do_top_bindings (StgRec pairs : bs)
99 = addTopLevelIshIds binders (
100 mapMM do_pair pairs `thenMM` \ pairs2 ->
101 do_top_bindings bs `thenMM` \ bs' ->
102 returnMM (StgRec pairs2 : bs')
105 binders = map fst pairs
107 = do_top_rhs b rhs `thenMM` \ rhs2 ->
111 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
113 do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
114 | not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
115 -- Trivial _scc_ around nothing but static data
116 -- Eliminate _scc_ ... and turn into StgRhsCon
118 -- isDllConApp checks for LitLit args too
119 = returnMM (StgRhsCon dontCareCCS con args)
121 {- Can't do this one with cost-centre stacks: --SDM
122 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
123 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
124 && not (isSccCountCostCentre cc)
125 -- Top level CAF without a cost centre attached
126 -- Attach and collect cc of trivial _scc_ in body
127 = collectCC cc `thenMM_`
128 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
129 returnMM (StgRhsClosure cc bi fv u [] expr')
132 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
133 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
134 -- Top level CAF without a cost centre attached
135 -- Attach CAF cc (collect if individual CAF ccs)
136 = (if opt_AutoSccsOnIndividualCafs
137 then let cc = mkAutoCC binder modl CafCC
138 ccs = mkSingletonCCS cc
139 -- careful: the binder might be :Main.main,
140 -- which doesn't belong to module mod_name.
141 -- bug #249, tests prof001, prof002
142 modl | Just m <- nameModule_maybe (idName binder) = m
143 | otherwise = mod_name
145 collectNewCC cc `thenMM_`
146 collectCCS ccs `thenMM_`
149 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
150 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
151 returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
153 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
154 -- Top level CAF with cost centre attached
155 -- Should this be a CAF cc ??? Does this ever occur ???
156 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
158 do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
159 -- Top level function, probably subsumed
160 | noCCSAttached no_ccs
161 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
162 returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
165 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
167 do_top_rhs binder (StgRhsCon ccs con args)
168 -- Top-level (static) data is not counted in heap
169 -- profiles; nor do we set CCCS from it; so we
170 -- just slam in dontCareCostCentre
171 = returnMM (StgRhsCon dontCareCCS con args)
174 do_expr :: StgExpr -> MassageM StgExpr
176 do_expr (StgLit l) = returnMM (StgLit l)
178 do_expr (StgApp fn args)
179 = boxHigherOrderArgs (StgApp fn) args
181 do_expr (StgConApp con args)
182 = boxHigherOrderArgs (\args -> StgConApp con args) args
184 do_expr (StgOpApp con args res_ty)
185 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
187 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
188 = collectCC cc `thenMM_`
189 do_expr expr `thenMM` \ expr' ->
190 returnMM (StgSCC cc expr')
192 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
193 = do_expr expr `thenMM` \ expr' ->
194 mapMM do_alt alts `thenMM` \ alts' ->
195 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
197 do_alt (id, bs, use_mask, e)
198 = do_expr e `thenMM` \ e' ->
199 returnMM (id, bs, use_mask, e')
202 = do_let b e `thenMM` \ (b,e) ->
203 returnMM (StgLet b e)
205 do_expr (StgLetNoEscape lvs1 lvs2 b e)
206 = do_let b e `thenMM` \ (b,e) ->
207 returnMM (StgLetNoEscape lvs1 lvs2 b e)
209 do_expr (StgTick m n expr)
210 = do_expr expr `thenMM` \ expr' ->
211 returnMM (StgTick m n expr')
214 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
217 ----------------------------------
219 do_let (StgNonRec b rhs) e
220 = do_rhs rhs `thenMM` \ rhs' ->
222 do_expr e `thenMM` \ e' ->
223 returnMM (StgNonRec b rhs',e')
226 do_let (StgRec pairs) e
227 = addTopLevelIshIds binders (
228 mapMM do_pair pairs `thenMM` \ pairs' ->
229 do_expr e `thenMM` \ e' ->
230 returnMM (StgRec pairs', e')
233 binders = map fst pairs
235 = do_rhs rhs `thenMM` \ rhs2 ->
238 ----------------------------------
239 do_rhs :: StgRhs -> MassageM StgRhs
240 -- We play much the same game as we did in do_top_rhs above;
241 -- but we don't have to worry about cafs etc.
244 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
245 | not (isSccCountCostCentre cc)
246 = collectCC cc `thenMM_`
247 returnMM (StgRhsCon cc con args)
250 do_rhs (StgRhsClosure _ bi fv u srt args expr)
251 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
252 do_expr expr' `thenMM` \ expr'' ->
253 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
255 slurpSCCs ccs (StgSCC cc e)
256 = collectCC cc `thenMM_`
257 slurpSCCs (cc `pushCCOnCCS` ccs) e
261 do_rhs (StgRhsCon cc con args)
262 = returnMM (StgRhsCon currentCCS con args)
265 %************************************************************************
267 \subsection{Boxing higher-order args}
269 %************************************************************************
271 Boxing is *turned off* at the moment, until we can figure out how to
272 do it properly in general.
276 :: ([StgArg] -> StgExpr)
277 -- An application lacking its arguments
278 -> [StgArg] -- arguments which we might box
281 #ifndef PROF_DO_BOXING
282 boxHigherOrderArgs almost_expr args
283 = returnMM (almost_expr args)
285 boxHigherOrderArgs almost_expr args
286 = getTopLevelIshIds `thenMM` \ ids ->
287 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
288 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
292 do_arg ids bindings arg@(StgVarArg old_var)
293 | (not (isLocalVar old_var) || elemVarSet old_var ids)
294 && isFunTy (dropForAlls var_type)
295 = -- make a trivial let-binding for the top-level function
296 getUniqueMM `thenMM` \ uniq ->
298 new_var = mkSysLocal FSLIT("sf") uniq var_type
300 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
302 var_type = idType old_var
304 do_arg ids bindings arg = returnMM (bindings, arg)
307 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
309 mk_stg_let cc (new_var, old_var) body
311 rhs_body = StgApp old_var [{-args-}]
312 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
314 StgLet (StgNonRec new_var rhs_closure) body
316 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
320 %************************************************************************
322 \subsection{Boring monad stuff for this}
324 %************************************************************************
328 = Module -- module name
329 -> CostCentreStack -- prevailing CostCentre
330 -- if none, subsumedCosts at top-level
331 -- currentCostCentre at nested levels
333 -> VarSet -- toplevel-ish Ids for boxing
335 -> (CollectedCCs, result)
337 -- the initMM function also returns the final CollectedCCs
339 initMM :: Module -- module name, which we may consult
344 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
346 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
347 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
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, result) ->
352 cont result mod scope_cc s2 ids ccs2 }}
354 thenMM_ expr cont mod scope_cc us ids ccs
355 = case splitUniqSupply us of { (s1, s2) ->
356 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
357 cont mod scope_cc s2 ids ccs2 }}
359 returnMM :: a -> MassageM a
360 returnMM result mod scope_cc us ids ccs = (ccs, result)
363 nopMM mod scope_cc us ids ccs = (ccs, ())
365 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
366 mapMM f [] = returnMM []
368 = f m `thenMM` \ r ->
369 mapMM f ms `thenMM` \ rs ->
372 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
373 mapAccumMM f b [] = returnMM (b, [])
374 mapAccumMM f b (m:ms)
375 = f b m `thenMM` \ (b2, r) ->
376 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
379 #ifdef PROF_DO_BOXING
380 getUniqueMM :: MassageM Unique
381 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
384 addTopLevelIshId :: Id -> MassageM a -> MassageM a
385 addTopLevelIshId id scope mod scope_cc us ids ccs
386 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
387 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
389 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
390 addTopLevelIshIds [] cont = cont
391 addTopLevelIshIds (id:ids) cont
392 = addTopLevelIshId id (addTopLevelIshIds ids cont)
394 getTopLevelIshIds :: MassageM VarSet
395 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
398 The prevailing CCS is used to tell whether we're in a top-levelish
399 position, where top-levelish is defined as "not inside a lambda".
400 Prevailing CCs used to be used for something much more complicated,
404 set_lambda_cc :: MassageM a -> MassageM a
405 set_lambda_cc action mod scope_cc us ids ccs
406 = action mod currentCCS us ids ccs
408 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
409 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
410 = action mod cc_to_set_to us ids ccs
412 get_prevailing_cc :: MassageM CostCentreStack
413 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
417 collectCC :: CostCentre -> MassageM ()
419 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
420 = ASSERT(not (noCCAttached cc))
421 if (cc `ccFromThisModule` mod_name) then
422 ((cc : local_ccs, extern_ccs, ccss), ())
423 else -- must declare it "extern"
424 ((local_ccs, cc : extern_ccs, ccss), ())
426 -- Version of collectCC used when we definitely want to declare this
427 -- CC as local, even if its module name is not the same as the current
428 -- module name (eg. the special :Main module) see bug #249, #1472,
429 -- test prof001,prof002.
430 collectNewCC :: CostCentre -> MassageM ()
431 collectNewCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
432 = ((cc : local_ccs, extern_ccs, ccss), ())
434 collectCCS :: CostCentreStack -> MassageM ()
436 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
437 = ASSERT(not (noCCSAttached ccs))
438 ((local_ccs, extern_ccs, ccs : ccss), ())