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 stgMassageForProfiling
47 :: Module -- module name
48 -> UniqSupply -- unique supply
49 -> [StgBinding] -- input
50 -> (CollectedCCs, [StgBinding])
52 stgMassageForProfiling mod_name us stg_binds
54 ((local_ccs, extern_ccs, cc_stacks),
56 = initMM mod_name us (do_top_bindings stg_binds)
58 (fixed_ccs, fixed_cc_stacks)
59 = if opt_AutoSccsOnIndividualCafs
60 then ([],[]) -- don't need "all CAFs" CC
61 -- (for Prelude, we use PreludeCC)
62 else ([all_cafs_cc], [all_cafs_ccs])
64 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
65 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
67 ((fixed_ccs ++ local_ccs_no_dups,
69 fixed_cc_stacks ++ cc_stacks), stg_binds2)
72 all_cafs_cc = mkAllCafsCC mod_name
73 all_cafs_ccs = mkSingletonCCS all_cafs_cc
76 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
78 do_top_bindings [] = returnMM []
80 do_top_bindings (StgNonRec srt b rhs : bs)
81 = do_top_rhs b rhs `thenMM` \ rhs' ->
83 do_top_bindings bs `thenMM` \bs' ->
84 returnMM (StgNonRec srt b rhs' : bs')
87 do_top_bindings (StgRec srt pairs : bs)
88 = addTopLevelIshIds binders (
89 mapMM do_pair pairs `thenMM` \ pairs2 ->
90 do_top_bindings bs `thenMM` \ bs' ->
91 returnMM (StgRec srt pairs2 : bs')
94 binders = map fst pairs
96 = do_top_rhs b rhs `thenMM` \ rhs2 ->
100 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
102 do_top_rhs binder (StgRhsClosure _ bi fv u [] (StgSCC cc (StgConApp con args)))
103 | not (isSccCountCostCentre cc) && not (isDllConApp con args)
104 -- Trivial _scc_ around nothing but static data
105 -- Eliminate _scc_ ... and turn into StgRhsCon
107 -- isDllConApp checks for LitLit args too
108 = returnMM (StgRhsCon dontCareCCS con args)
110 {- Can't do this one with cost-centre stacks: --SDM
111 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
112 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
113 && not (isSccCountCostCentre cc)
114 -- Top level CAF without a cost centre attached
115 -- Attach and collect cc of trivial _scc_ in body
116 = collectCC cc `thenMM_`
117 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
118 returnMM (StgRhsClosure cc bi fv u [] expr')
121 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] body)
122 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
123 -- Top level CAF without a cost centre attached
124 -- Attach CAF cc (collect if individual CAF ccs)
125 = (if opt_AutoSccsOnIndividualCafs
126 then let cc = mkAutoCC binder mod_name CafCC
127 ccs = mkSingletonCCS cc
129 collectCC cc `thenMM_`
130 collectCCS ccs `thenMM_`
133 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
134 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
135 returnMM (StgRhsClosure caf_ccs bi fv u [] body')
137 do_top_rhs binder (StgRhsClosure cc bi fv u [] body)
138 -- Top level CAF with cost centre attached
139 -- Should this be a CAF cc ??? Does this ever occur ???
140 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
142 do_top_rhs binder (StgRhsClosure no_ccs bi fv u args body)
143 -- Top level function, probably subsumed
144 | noCCSAttached no_ccs
145 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
146 returnMM (StgRhsClosure subsumedCCS bi fv u args body')
149 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
151 do_top_rhs binder (StgRhsCon ccs con args)
152 -- Top-level (static) data is not counted in heap
153 -- profiles; nor do we set CCCS from it; so we
154 -- just slam in dontCareCostCentre
155 = returnMM (StgRhsCon dontCareCCS con args)
158 do_expr :: StgExpr -> MassageM StgExpr
160 do_expr (StgLit l) = returnMM (StgLit l)
162 do_expr (StgApp fn args)
163 = boxHigherOrderArgs (StgApp fn) args
165 do_expr (StgConApp con args)
166 = boxHigherOrderArgs (\args -> StgConApp con args) args
168 do_expr (StgOpApp con args res_ty)
169 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
171 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
172 = collectCC cc `thenMM_`
173 do_expr expr `thenMM` \ expr' ->
174 returnMM (StgSCC cc expr')
176 do_expr (StgCase expr fv1 fv2 bndr srt alts)
177 = do_expr expr `thenMM` \ expr' ->
178 do_alts alts `thenMM` \ alts' ->
179 returnMM (StgCase expr' fv1 fv2 bndr srt alts')
181 do_alts (StgAlgAlts tycon alts def)
182 = mapMM do_alt alts `thenMM` \ alts' ->
183 do_deflt def `thenMM` \ def' ->
184 returnMM (StgAlgAlts tycon alts' def')
186 do_alt (id, bs, use_mask, e)
187 = do_expr e `thenMM` \ e' ->
188 returnMM (id, bs, use_mask, e')
190 do_alts (StgPrimAlts tycon alts def)
191 = mapMM do_alt alts `thenMM` \ alts' ->
192 do_deflt def `thenMM` \ def' ->
193 returnMM (StgPrimAlts tycon alts' def')
196 = do_expr e `thenMM` \ e' ->
199 do_deflt StgNoDefault = returnMM StgNoDefault
200 do_deflt (StgBindDefault e)
201 = do_expr e `thenMM` \ e' ->
202 returnMM (StgBindDefault e')
205 = do_let b e `thenMM` \ (b,e) ->
206 returnMM (StgLet b e)
208 do_expr (StgLetNoEscape lvs1 lvs2 b e)
209 = do_let b e `thenMM` \ (b,e) ->
210 returnMM (StgLetNoEscape lvs1 lvs2 b e)
213 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
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)
249 do_rhs (StgRhsClosure _ bi fv u args expr)
250 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
251 do_expr expr' `thenMM` \ expr'' ->
252 returnMM (StgRhsClosure ccs bi fv u args expr'')
254 slurpSCCs ccs (StgSCC cc e)
255 = collectCC cc `thenMM_`
256 slurpSCCs ccs e `thenMM` \ (e', ccs') ->
257 returnMM (e', pushCCOnCCS cc ccs')
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 [{-args-}] rhs_body
314 StgLet (StgNonRec NoSRT{-eeek!!!-} 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 getUniqueMM :: MassageM Unique
380 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
382 addTopLevelIshId :: Id -> MassageM a -> MassageM a
383 addTopLevelIshId id scope mod scope_cc us ids ccs
384 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
385 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
387 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
388 addTopLevelIshIds [] cont = cont
389 addTopLevelIshIds (id:ids) cont
390 = addTopLevelIshId id (addTopLevelIshIds ids cont)
392 getTopLevelIshIds :: MassageM VarSet
393 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
396 The prevailing CCS is used to tell whether we're in a top-levelish
397 position, where top-levelish is defined as "not inside a lambda".
398 Prevailing CCs used to be used for something much more complicated,
402 set_lambda_cc :: MassageM a -> MassageM a
403 set_lambda_cc action mod scope_cc us ids ccs
404 = action mod currentCCS us ids ccs
406 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
407 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
408 = action mod cc_to_set_to us ids ccs
410 get_prevailing_cc :: MassageM CostCentreStack
411 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
415 collectCC :: CostCentre -> MassageM ()
417 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
418 = ASSERT(not (noCCAttached cc))
419 if (cc `ccFromThisModule` mod_name) then
420 ((cc : local_ccs, extern_ccs, ccss), ())
421 else -- must declare it "extern"
422 ((local_ccs, cc : extern_ccs, ccss), ())
424 collectCCS :: CostCentreStack -> MassageM ()
426 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
427 = ASSERT(not (noCCSAttached ccs))
428 ((local_ccs, extern_ccs, ccs : ccss), ())