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 b rhs : bs)
81 = do_top_rhs b rhs `thenMM` \ rhs' ->
83 do_top_bindings bs `thenMM` \bs' ->
84 returnMM (StgNonRec b rhs' : bs')
87 do_top_bindings (StgRec pairs : bs)
88 = addTopLevelIshIds binders (
89 mapMM do_pair pairs `thenMM` \ pairs2 ->
90 do_top_bindings bs `thenMM` \ bs' ->
91 returnMM (StgRec 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 srt [] (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 srt [] 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 srt [] body')
137 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] 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 srt 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 srt 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 alt_type alts)
177 = do_expr expr `thenMM` \ expr' ->
178 mapMM do_alt alts `thenMM` \ alts' ->
179 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
181 do_alt (id, bs, use_mask, e)
182 = do_expr e `thenMM` \ e' ->
183 returnMM (id, bs, use_mask, e')
186 = do_let b e `thenMM` \ (b,e) ->
187 returnMM (StgLet b e)
189 do_expr (StgLetNoEscape lvs1 lvs2 b e)
190 = do_let b e `thenMM` \ (b,e) ->
191 returnMM (StgLetNoEscape lvs1 lvs2 b e)
194 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
197 ----------------------------------
199 do_let (StgNonRec b rhs) e
200 = do_rhs rhs `thenMM` \ rhs' ->
202 do_expr e `thenMM` \ e' ->
203 returnMM (StgNonRec b rhs',e')
206 do_let (StgRec pairs) e
207 = addTopLevelIshIds binders (
208 mapMM do_pair pairs `thenMM` \ pairs' ->
209 do_expr e `thenMM` \ e' ->
210 returnMM (StgRec pairs', e')
213 binders = map fst pairs
215 = do_rhs rhs `thenMM` \ rhs2 ->
218 ----------------------------------
219 do_rhs :: StgRhs -> MassageM StgRhs
220 -- We play much the same game as we did in do_top_rhs above;
221 -- but we don't have to worry about cafs etc.
224 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
225 | not (isSccCountCostCentre cc)
226 = collectCC cc `thenMM_`
227 returnMM (StgRhsCon cc con args)
230 do_rhs (StgRhsClosure _ bi fv u srt args expr)
231 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
232 do_expr expr' `thenMM` \ expr'' ->
233 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
235 slurpSCCs ccs (StgSCC cc e)
236 = collectCC cc `thenMM_`
237 slurpSCCs ccs e `thenMM` \ (e', ccs') ->
238 returnMM (e', pushCCOnCCS cc ccs')
242 do_rhs (StgRhsCon cc con args)
243 = returnMM (StgRhsCon currentCCS con args)
246 %************************************************************************
248 \subsection{Boxing higher-order args}
250 %************************************************************************
252 Boxing is *turned off* at the moment, until we can figure out how to
253 do it properly in general.
257 :: ([StgArg] -> StgExpr)
258 -- An application lacking its arguments
259 -> [StgArg] -- arguments which we might box
262 #ifndef PROF_DO_BOXING
263 boxHigherOrderArgs almost_expr args
264 = returnMM (almost_expr args)
266 boxHigherOrderArgs almost_expr args
267 = getTopLevelIshIds `thenMM` \ ids ->
268 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
269 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
273 do_arg ids bindings arg@(StgVarArg old_var)
274 | (not (isLocalVar old_var) || elemVarSet old_var ids)
275 && isFunTy (dropForAlls var_type)
276 = -- make a trivial let-binding for the top-level function
277 getUniqueMM `thenMM` \ uniq ->
279 new_var = mkSysLocal FSLIT("sf") uniq var_type
281 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
283 var_type = idType old_var
285 do_arg ids bindings arg = returnMM (bindings, arg)
288 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
290 mk_stg_let cc (new_var, old_var) body
292 rhs_body = StgApp old_var [{-args-}]
293 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
295 StgLet (StgNonRec new_var rhs_closure) body
297 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
301 %************************************************************************
303 \subsection{Boring monad stuff for this}
305 %************************************************************************
309 = Module -- module name
310 -> CostCentreStack -- prevailing CostCentre
311 -- if none, subsumedCosts at top-level
312 -- currentCostCentre at nested levels
314 -> VarSet -- toplevel-ish Ids for boxing
316 -> (CollectedCCs, result)
318 -- the initMM function also returns the final CollectedCCs
320 initMM :: Module -- module name, which we may consult
325 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
327 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
328 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
330 thenMM expr cont mod scope_cc us ids ccs
331 = case splitUniqSupply us of { (s1, s2) ->
332 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
333 cont result mod scope_cc s2 ids ccs2 }}
335 thenMM_ expr cont mod scope_cc us ids ccs
336 = case splitUniqSupply us of { (s1, s2) ->
337 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
338 cont mod scope_cc s2 ids ccs2 }}
340 returnMM :: a -> MassageM a
341 returnMM result mod scope_cc us ids ccs = (ccs, result)
344 nopMM mod scope_cc us ids ccs = (ccs, ())
346 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
347 mapMM f [] = returnMM []
349 = f m `thenMM` \ r ->
350 mapMM f ms `thenMM` \ rs ->
353 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
354 mapAccumMM f b [] = returnMM (b, [])
355 mapAccumMM f b (m:ms)
356 = f b m `thenMM` \ (b2, r) ->
357 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
360 getUniqueMM :: MassageM Unique
361 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
363 addTopLevelIshId :: Id -> MassageM a -> MassageM a
364 addTopLevelIshId id scope mod scope_cc us ids ccs
365 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
366 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
368 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
369 addTopLevelIshIds [] cont = cont
370 addTopLevelIshIds (id:ids) cont
371 = addTopLevelIshId id (addTopLevelIshIds ids cont)
373 getTopLevelIshIds :: MassageM VarSet
374 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
377 The prevailing CCS is used to tell whether we're in a top-levelish
378 position, where top-levelish is defined as "not inside a lambda".
379 Prevailing CCs used to be used for something much more complicated,
383 set_lambda_cc :: MassageM a -> MassageM a
384 set_lambda_cc action mod scope_cc us ids ccs
385 = action mod currentCCS us ids ccs
387 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
388 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
389 = action mod cc_to_set_to us ids ccs
391 get_prevailing_cc :: MassageM CostCentreStack
392 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
396 collectCC :: CostCentre -> MassageM ()
398 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
399 = ASSERT(not (noCCAttached cc))
400 if (cc `ccFromThisModule` mod_name) then
401 ((cc : local_ccs, extern_ccs, ccss), ())
402 else -- must declare it "extern"
403 ((local_ccs, cc : extern_ccs, ccss), ())
405 collectCCS :: CostCentreStack -> MassageM ()
407 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
408 = ASSERT(not (noCCSAttached ccs))
409 ((local_ccs, extern_ccs, ccs : ccss), ())