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 CmdLineOpts ( DynFlags, opt_AutoSccsOnIndividualCafs )
33 import CostCentre -- lots of things
35 import Module ( Module )
36 import UniqSupply ( uniqFromSupply, splitUniqSupply, UniqSupply )
37 import Unique ( Unique )
39 import ListSetOps ( removeDups )
42 infixr 9 `thenMM`, `thenMM_`
46 stgMassageForProfiling
48 -> Module -- module name
49 -> UniqSupply -- unique supply
50 -> [StgBinding] -- input
51 -> (CollectedCCs, [StgBinding])
53 stgMassageForProfiling dflags mod_name us stg_binds
55 ((local_ccs, extern_ccs, cc_stacks),
57 = initMM mod_name us (do_top_bindings stg_binds)
59 (fixed_ccs, fixed_cc_stacks)
60 = if opt_AutoSccsOnIndividualCafs
61 then ([],[]) -- don't need "all CAFs" CC
62 -- (for Prelude, we use PreludeCC)
63 else ([all_cafs_cc], [all_cafs_ccs])
65 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
66 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
68 ((fixed_ccs ++ local_ccs_no_dups,
70 fixed_cc_stacks ++ cc_stacks), stg_binds2)
73 all_cafs_cc = mkAllCafsCC mod_name
74 all_cafs_ccs = mkSingletonCCS all_cafs_cc
77 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
79 do_top_bindings [] = returnMM []
81 do_top_bindings (StgNonRec b rhs : bs)
82 = do_top_rhs b rhs `thenMM` \ rhs' ->
84 do_top_bindings bs `thenMM` \bs' ->
85 returnMM (StgNonRec b rhs' : bs')
88 do_top_bindings (StgRec pairs : bs)
89 = addTopLevelIshIds binders (
90 mapMM do_pair pairs `thenMM` \ pairs2 ->
91 do_top_bindings bs `thenMM` \ bs' ->
92 returnMM (StgRec pairs2 : bs')
95 binders = map fst pairs
97 = do_top_rhs b rhs `thenMM` \ rhs2 ->
101 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
103 do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
104 | not (isSccCountCostCentre cc) && not (isDllConApp dflags con args)
105 -- Trivial _scc_ around nothing but static data
106 -- Eliminate _scc_ ... and turn into StgRhsCon
108 -- isDllConApp checks for LitLit args too
109 = returnMM (StgRhsCon dontCareCCS con args)
111 {- Can't do this one with cost-centre stacks: --SDM
112 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
113 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
114 && not (isSccCountCostCentre cc)
115 -- Top level CAF without a cost centre attached
116 -- Attach and collect cc of trivial _scc_ in body
117 = collectCC cc `thenMM_`
118 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
119 returnMM (StgRhsClosure cc bi fv u [] expr')
122 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
123 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
124 -- Top level CAF without a cost centre attached
125 -- Attach CAF cc (collect if individual CAF ccs)
126 = (if opt_AutoSccsOnIndividualCafs
127 then let cc = mkAutoCC binder mod_name CafCC
128 ccs = mkSingletonCCS cc
130 collectCC cc `thenMM_`
131 collectCCS ccs `thenMM_`
134 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
135 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
136 returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
138 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
139 -- Top level CAF with cost centre attached
140 -- Should this be a CAF cc ??? Does this ever occur ???
141 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
143 do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
144 -- Top level function, probably subsumed
145 | noCCSAttached no_ccs
146 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
147 returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
150 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
152 do_top_rhs binder (StgRhsCon ccs con args)
153 -- Top-level (static) data is not counted in heap
154 -- profiles; nor do we set CCCS from it; so we
155 -- just slam in dontCareCostCentre
156 = returnMM (StgRhsCon dontCareCCS con args)
159 do_expr :: StgExpr -> MassageM StgExpr
161 do_expr (StgLit l) = returnMM (StgLit l)
163 do_expr (StgApp fn args)
164 = boxHigherOrderArgs (StgApp fn) args
166 do_expr (StgConApp con args)
167 = boxHigherOrderArgs (\args -> StgConApp con args) args
169 do_expr (StgOpApp con args res_ty)
170 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
172 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
173 = collectCC cc `thenMM_`
174 do_expr expr `thenMM` \ expr' ->
175 returnMM (StgSCC cc expr')
177 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
178 = do_expr expr `thenMM` \ expr' ->
179 mapMM do_alt alts `thenMM` \ alts' ->
180 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
182 do_alt (id, bs, use_mask, e)
183 = do_expr e `thenMM` \ e' ->
184 returnMM (id, bs, use_mask, e')
187 = do_let b e `thenMM` \ (b,e) ->
188 returnMM (StgLet b e)
190 do_expr (StgLetNoEscape lvs1 lvs2 b e)
191 = do_let b e `thenMM` \ (b,e) ->
192 returnMM (StgLetNoEscape lvs1 lvs2 b e)
195 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
198 ----------------------------------
200 do_let (StgNonRec b rhs) e
201 = do_rhs rhs `thenMM` \ rhs' ->
203 do_expr e `thenMM` \ e' ->
204 returnMM (StgNonRec b rhs',e')
207 do_let (StgRec pairs) e
208 = addTopLevelIshIds binders (
209 mapMM do_pair pairs `thenMM` \ pairs' ->
210 do_expr e `thenMM` \ e' ->
211 returnMM (StgRec pairs', e')
214 binders = map fst pairs
216 = do_rhs rhs `thenMM` \ rhs2 ->
219 ----------------------------------
220 do_rhs :: StgRhs -> MassageM StgRhs
221 -- We play much the same game as we did in do_top_rhs above;
222 -- but we don't have to worry about cafs etc.
225 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
226 | not (isSccCountCostCentre cc)
227 = collectCC cc `thenMM_`
228 returnMM (StgRhsCon cc con args)
231 do_rhs (StgRhsClosure _ bi fv u srt args expr)
232 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
233 do_expr expr' `thenMM` \ expr'' ->
234 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
236 slurpSCCs ccs (StgSCC cc e)
237 = collectCC cc `thenMM_`
238 slurpSCCs ccs e `thenMM` \ (e', ccs') ->
239 returnMM (e', pushCCOnCCS cc ccs')
243 do_rhs (StgRhsCon cc con args)
244 = returnMM (StgRhsCon currentCCS con args)
247 %************************************************************************
249 \subsection{Boxing higher-order args}
251 %************************************************************************
253 Boxing is *turned off* at the moment, until we can figure out how to
254 do it properly in general.
258 :: ([StgArg] -> StgExpr)
259 -- An application lacking its arguments
260 -> [StgArg] -- arguments which we might box
263 #ifndef PROF_DO_BOXING
264 boxHigherOrderArgs almost_expr args
265 = returnMM (almost_expr args)
267 boxHigherOrderArgs almost_expr args
268 = getTopLevelIshIds `thenMM` \ ids ->
269 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
270 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
274 do_arg ids bindings arg@(StgVarArg old_var)
275 | (not (isLocalVar old_var) || elemVarSet old_var ids)
276 && isFunTy (dropForAlls var_type)
277 = -- make a trivial let-binding for the top-level function
278 getUniqueMM `thenMM` \ uniq ->
280 new_var = mkSysLocal FSLIT("sf") uniq var_type
282 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
284 var_type = idType old_var
286 do_arg ids bindings arg = returnMM (bindings, arg)
289 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
291 mk_stg_let cc (new_var, old_var) body
293 rhs_body = StgApp old_var [{-args-}]
294 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
296 StgLet (StgNonRec new_var rhs_closure) body
298 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
302 %************************************************************************
304 \subsection{Boring monad stuff for this}
306 %************************************************************************
310 = Module -- module name
311 -> CostCentreStack -- prevailing CostCentre
312 -- if none, subsumedCosts at top-level
313 -- currentCostCentre at nested levels
315 -> VarSet -- toplevel-ish Ids for boxing
317 -> (CollectedCCs, result)
319 -- the initMM function also returns the final CollectedCCs
321 initMM :: Module -- module name, which we may consult
326 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
328 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
329 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
331 thenMM expr cont mod scope_cc us ids ccs
332 = case splitUniqSupply us of { (s1, s2) ->
333 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
334 cont result mod scope_cc s2 ids ccs2 }}
336 thenMM_ expr cont mod scope_cc us ids ccs
337 = case splitUniqSupply us of { (s1, s2) ->
338 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
339 cont mod scope_cc s2 ids ccs2 }}
341 returnMM :: a -> MassageM a
342 returnMM result mod scope_cc us ids ccs = (ccs, result)
345 nopMM mod scope_cc us ids ccs = (ccs, ())
347 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
348 mapMM f [] = returnMM []
350 = f m `thenMM` \ r ->
351 mapMM f ms `thenMM` \ rs ->
354 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
355 mapAccumMM f b [] = returnMM (b, [])
356 mapAccumMM f b (m:ms)
357 = f b m `thenMM` \ (b2, r) ->
358 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
361 getUniqueMM :: MassageM Unique
362 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
364 addTopLevelIshId :: Id -> MassageM a -> MassageM a
365 addTopLevelIshId id scope mod scope_cc us ids ccs
366 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
367 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
369 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
370 addTopLevelIshIds [] cont = cont
371 addTopLevelIshIds (id:ids) cont
372 = addTopLevelIshId id (addTopLevelIshIds ids cont)
374 getTopLevelIshIds :: MassageM VarSet
375 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
378 The prevailing CCS is used to tell whether we're in a top-levelish
379 position, where top-levelish is defined as "not inside a lambda".
380 Prevailing CCs used to be used for something much more complicated,
384 set_lambda_cc :: MassageM a -> MassageM a
385 set_lambda_cc action mod scope_cc us ids ccs
386 = action mod currentCCS us ids ccs
388 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
389 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
390 = action mod cc_to_set_to us ids ccs
392 get_prevailing_cc :: MassageM CostCentreStack
393 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
397 collectCC :: CostCentre -> MassageM ()
399 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
400 = ASSERT(not (noCCAttached cc))
401 if (cc `ccFromThisModule` mod_name) then
402 ((cc : local_ccs, extern_ccs, ccss), ())
403 else -- must declare it "extern"
404 ((local_ccs, cc : extern_ccs, ccss), ())
406 collectCCS :: CostCentreStack -> MassageM ()
408 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
409 = ASSERT(not (noCCSAttached ccs))
410 ((local_ccs, extern_ccs, ccs : ccss), ())