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 ( 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 type CollectedCCs = ([CostCentre], -- locally defined ones
47 [CostCentre], -- ones needing "extern" decls
48 [CostCentreStack]) -- singleton stacks (for CAFs)
50 stgMassageForProfiling
51 :: Module -- module name
52 -> UniqSupply -- unique supply
53 -> [StgBinding] -- input
54 -> (CollectedCCs, [StgBinding])
56 stgMassageForProfiling 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 [] = returnMM []
84 do_top_bindings (StgNonRec srt b rhs : bs)
85 = do_top_rhs b rhs `thenMM` \ rhs' ->
87 do_top_bindings bs `thenMM` \bs' ->
88 returnMM (StgNonRec srt b rhs' : bs')
91 do_top_bindings (StgRec srt pairs : bs)
92 = addTopLevelIshIds binders (
93 mapMM do_pair pairs `thenMM` \ pairs2 ->
94 do_top_bindings bs `thenMM` \ bs' ->
95 returnMM (StgRec srt pairs2 : bs')
98 binders = map fst pairs
100 = do_top_rhs b rhs `thenMM` \ rhs2 ->
104 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
106 do_top_rhs binder (StgRhsClosure _ bi fv u [] (StgSCC cc (StgConApp con args)))
107 | not (isSccCountCostCentre cc) && not (isDllConApp con args)
108 -- Trivial _scc_ around nothing but static data
109 -- Eliminate _scc_ ... and turn into StgRhsCon
111 -- isDllConApp checks for LitLit args too
112 = returnMM (StgRhsCon dontCareCCS con args)
114 {- Can't do this one with cost-centre stacks: --SDM
115 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
116 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
117 && not (isSccCountCostCentre cc)
118 -- Top level CAF without a cost centre attached
119 -- Attach and collect cc of trivial _scc_ in body
120 = collectCC cc `thenMM_`
121 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
122 returnMM (StgRhsClosure cc bi fv u [] expr')
125 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] body)
126 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
127 -- Top level CAF without a cost centre attached
128 -- Attach CAF cc (collect if individual CAF ccs)
129 = (if opt_AutoSccsOnIndividualCafs
130 then let cc = mkAutoCC binder mod_name CafCC
131 ccs = mkSingletonCCS cc
133 collectCC cc `thenMM_`
134 collectCCS ccs `thenMM_`
137 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
138 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
139 returnMM (StgRhsClosure caf_ccs bi fv u [] body')
141 do_top_rhs binder (StgRhsClosure cc bi fv u [] body)
142 -- Top level CAF with cost centre attached
143 -- Should this be a CAF cc ??? Does this ever occur ???
144 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
146 do_top_rhs binder (StgRhsClosure no_ccs bi fv u args body)
147 -- Top level function, probably subsumed
148 | noCCSAttached no_ccs
149 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
150 returnMM (StgRhsClosure subsumedCCS bi fv u args body')
153 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
155 do_top_rhs binder (StgRhsCon ccs con args)
156 -- Top-level (static) data is not counted in heap
157 -- profiles; nor do we set CCCS from it; so we
158 -- just slam in dontCareCostCentre
159 = returnMM (StgRhsCon dontCareCCS con args)
162 do_expr :: StgExpr -> MassageM StgExpr
164 do_expr (StgLit l) = returnMM (StgLit l)
166 do_expr (StgApp fn args)
167 = boxHigherOrderArgs (StgApp fn) args
169 do_expr (StgConApp con args)
170 = boxHigherOrderArgs (\args -> StgConApp con args) args
172 do_expr (StgOpApp con args res_ty)
173 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
175 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
176 = collectCC cc `thenMM_`
177 do_expr expr `thenMM` \ expr' ->
178 returnMM (StgSCC cc expr')
180 do_expr (StgCase expr fv1 fv2 bndr srt alts)
181 = do_expr expr `thenMM` \ expr' ->
182 do_alts alts `thenMM` \ alts' ->
183 returnMM (StgCase expr' fv1 fv2 bndr srt alts')
185 do_alts (StgAlgAlts tycon alts def)
186 = mapMM do_alt alts `thenMM` \ alts' ->
187 do_deflt def `thenMM` \ def' ->
188 returnMM (StgAlgAlts tycon alts' def')
190 do_alt (id, bs, use_mask, e)
191 = do_expr e `thenMM` \ e' ->
192 returnMM (id, bs, use_mask, e')
194 do_alts (StgPrimAlts tycon alts def)
195 = mapMM do_alt alts `thenMM` \ alts' ->
196 do_deflt def `thenMM` \ def' ->
197 returnMM (StgPrimAlts tycon alts' def')
200 = do_expr e `thenMM` \ e' ->
203 do_deflt StgNoDefault = returnMM StgNoDefault
204 do_deflt (StgBindDefault e)
205 = do_expr e `thenMM` \ e' ->
206 returnMM (StgBindDefault e')
209 = do_let b e `thenMM` \ (b,e) ->
210 returnMM (StgLet b e)
212 do_expr (StgLetNoEscape lvs1 lvs2 b e)
213 = do_let b e `thenMM` \ (b,e) ->
214 returnMM (StgLetNoEscape lvs1 lvs2 b e)
216 ----------------------------------
218 do_let (StgNonRec srt b rhs) e
219 = do_rhs rhs `thenMM` \ rhs' ->
221 do_expr e `thenMM` \ e' ->
222 returnMM (StgNonRec srt b rhs',e')
225 do_let (StgRec srt pairs) e
226 = addTopLevelIshIds binders (
227 mapMM do_pair pairs `thenMM` \ pairs' ->
228 do_expr e `thenMM` \ e' ->
229 returnMM (StgRec srt pairs', e')
232 binders = map fst pairs
234 = do_rhs rhs `thenMM` \ rhs2 ->
237 ----------------------------------
238 do_rhs :: StgRhs -> MassageM StgRhs
239 -- We play much the same game as we did in do_top_rhs above;
240 -- but we don't have to worry about cafs etc.
243 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
244 | not (isSccCountCostCentre cc)
245 = collectCC cc `thenMM_`
246 returnMM (StgRhsCon cc con args)
250 do_rhs (StgRhsClosure _ bi fv u args (StgSCC ty cc expr))
251 | not (isSccCountCostCentre cc)
252 = collectCC cc `thenMM_`
253 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
254 returnMM (StgRhsClosure cc bi fv u args expr')
257 do_rhs (StgRhsClosure cc bi fv u [] body)
258 = do_expr body `thenMM` \ body' ->
259 returnMM (StgRhsClosure currentCCS bi fv u [] body')
261 do_rhs (StgRhsClosure cc bi fv u args body)
262 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
263 get_prevailing_cc `thenMM` \ prev_ccs ->
264 returnMM (StgRhsClosure currentCCS bi fv u args body')
266 do_rhs (StgRhsCon cc con args)
267 = returnMM (StgRhsCon currentCCS con args)
270 %************************************************************************
272 \subsection{Boxing higher-order args}
274 %************************************************************************
276 Boxing is *turned off* at the moment, until we can figure out how to
277 do it properly in general.
281 :: ([StgArg] -> StgExpr)
282 -- An application lacking its arguments
283 -> [StgArg] -- arguments which we might box
286 #ifndef PROF_DO_BOXING
287 boxHigherOrderArgs almost_expr args
288 = returnMM (almost_expr args)
290 boxHigherOrderArgs almost_expr args
291 = getTopLevelIshIds `thenMM` \ ids ->
292 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
293 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
297 do_arg ids bindings arg@(StgVarArg old_var)
298 | (not (isLocalVar old_var) || elemVarSet old_var ids)
299 && isFunType var_type
300 = -- make a trivial let-binding for the top-level function
301 getUniqueMM `thenMM` \ uniq ->
303 new_var = mkSysLocal SLIT("sf") uniq var_type
305 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
307 var_type = idType old_var
309 do_arg ids bindings arg = returnMM (bindings, arg)
312 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
314 mk_stg_let cc (new_var, old_var) body
316 rhs_body = StgApp old_var [{-args-}]
317 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant [{-args-}] rhs_body
319 StgLet (StgNonRec NoSRT{-eeek!!!-} new_var rhs_closure) body
321 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
324 = case splitForAllTys var_type of
325 (_, ty) -> maybeToBool (splitFunTy_Maybe ty)
329 %************************************************************************
331 \subsection{Boring monad stuff for this}
333 %************************************************************************
337 = Module -- module name
338 -> CostCentreStack -- prevailing CostCentre
339 -- if none, subsumedCosts at top-level
340 -- useCurrentCostCentre at nested levels
342 -> VarSet -- toplevel-ish Ids for boxing
344 -> (CollectedCCs, result)
346 -- the initMM function also returns the final CollectedCCs
348 initMM :: Module -- module name, which we may consult
353 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
355 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
356 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
358 thenMM expr cont mod scope_cc us ids ccs
359 = case splitUniqSupply us of { (s1, s2) ->
360 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
361 cont result mod scope_cc s2 ids ccs2 }}
363 thenMM_ expr cont mod scope_cc us ids ccs
364 = case splitUniqSupply us of { (s1, s2) ->
365 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
366 cont mod scope_cc s2 ids ccs2 }}
368 returnMM :: a -> MassageM a
369 returnMM result mod scope_cc us ids ccs = (ccs, result)
372 nopMM mod scope_cc us ids ccs = (ccs, ())
374 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
375 mapMM f [] = returnMM []
377 = f m `thenMM` \ r ->
378 mapMM f ms `thenMM` \ rs ->
381 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
382 mapAccumMM f b [] = returnMM (b, [])
383 mapAccumMM f b (m:ms)
384 = f b m `thenMM` \ (b2, r) ->
385 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
388 getUniqueMM :: MassageM Unique
389 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
391 addTopLevelIshId :: Id -> MassageM a -> MassageM a
392 addTopLevelIshId id scope mod scope_cc us ids ccs
393 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
394 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
396 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
397 addTopLevelIshIds [] cont = cont
398 addTopLevelIshIds (id:ids) cont
399 = addTopLevelIshId id (addTopLevelIshIds ids cont)
401 getTopLevelIshIds :: MassageM VarSet
402 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
405 The prevailing CCS is used to tell whether we're in a top-levelish
406 position, where top-levelish is defined as "not inside a lambda".
407 Prevailing CCs used to be used for something much more complicated,
411 set_lambda_cc :: MassageM a -> MassageM a
412 set_lambda_cc action mod scope_cc us ids ccs
413 = action mod currentCCS us ids ccs
415 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
416 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
417 = action mod cc_to_set_to us ids ccs
419 get_prevailing_cc :: MassageM CostCentreStack
420 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
424 collectCC :: CostCentre -> MassageM ()
426 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
427 = ASSERT(not (noCCAttached cc))
428 if (cc `ccFromThisModule` mod_name) then
429 ((cc : local_ccs, extern_ccs, ccss), ())
430 else -- must declare it "extern"
431 ((local_ccs, cc : extern_ccs, ccss), ())
433 collectCCS :: CostCentreStack -> MassageM ()
435 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
436 = ASSERT(not (noCCSAttached ccs))
437 ((local_ccs, extern_ccs, ccs : ccss), ())