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 PackageConfig ( PackageId )
33 import StaticFlags ( opt_AutoSccsOnIndividualCafs )
34 import CostCentre -- lots of things
36 import Module ( Module )
37 import UniqSupply ( splitUniqSupply, UniqSupply )
39 import UniqSupply ( uniqFromSupply )
41 import Unique ( Unique )
43 import ListSetOps ( removeDups )
46 infixr 9 `thenMM`, `thenMM_`
50 stgMassageForProfiling
52 -> Module -- module name
53 -> UniqSupply -- unique supply
54 -> [StgBinding] -- input
55 -> (CollectedCCs, [StgBinding])
57 stgMassageForProfiling this_pkg mod_name us stg_binds
59 ((local_ccs, extern_ccs, cc_stacks),
61 = initMM mod_name us (do_top_bindings stg_binds)
63 (fixed_ccs, fixed_cc_stacks)
64 = if opt_AutoSccsOnIndividualCafs
65 then ([],[]) -- don't need "all CAFs" CC
66 -- (for Prelude, we use PreludeCC)
67 else ([all_cafs_cc], [all_cafs_ccs])
69 local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
70 extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
72 ((fixed_ccs ++ local_ccs_no_dups,
74 fixed_cc_stacks ++ cc_stacks), stg_binds2)
77 all_cafs_cc = mkAllCafsCC mod_name
78 all_cafs_ccs = mkSingletonCCS all_cafs_cc
81 do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
83 do_top_bindings [] = returnMM []
85 do_top_bindings (StgNonRec b rhs : bs)
86 = do_top_rhs b rhs `thenMM` \ rhs' ->
88 do_top_bindings bs `thenMM` \bs' ->
89 returnMM (StgNonRec b rhs' : bs')
92 do_top_bindings (StgRec pairs : bs)
93 = addTopLevelIshIds binders (
94 mapMM do_pair pairs `thenMM` \ pairs2 ->
95 do_top_bindings bs `thenMM` \ bs' ->
96 returnMM (StgRec pairs2 : bs')
99 binders = map fst pairs
101 = do_top_rhs b rhs `thenMM` \ rhs2 ->
105 do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
107 do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
108 | not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
109 -- Trivial _scc_ around nothing but static data
110 -- Eliminate _scc_ ... and turn into StgRhsCon
112 -- isDllConApp checks for LitLit args too
113 = returnMM (StgRhsCon dontCareCCS con args)
115 {- Can't do this one with cost-centre stacks: --SDM
116 do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
117 | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
118 && not (isSccCountCostCentre cc)
119 -- Top level CAF without a cost centre attached
120 -- Attach and collect cc of trivial _scc_ in body
121 = collectCC cc `thenMM_`
122 set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
123 returnMM (StgRhsClosure cc bi fv u [] expr')
126 do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
127 | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
128 -- Top level CAF without a cost centre attached
129 -- Attach CAF cc (collect if individual CAF ccs)
130 = (if opt_AutoSccsOnIndividualCafs
131 then let cc = mkAutoCC binder mod_name CafCC
132 ccs = mkSingletonCCS cc
134 collectCC cc `thenMM_`
135 collectCCS ccs `thenMM_`
138 returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
139 set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
140 returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
142 do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
143 -- Top level CAF with cost centre attached
144 -- Should this be a CAF cc ??? Does this ever occur ???
145 = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
147 do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
148 -- Top level function, probably subsumed
149 | noCCSAttached no_ccs
150 = set_lambda_cc (do_expr body) `thenMM` \ body' ->
151 returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
154 = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
156 do_top_rhs binder (StgRhsCon ccs con args)
157 -- Top-level (static) data is not counted in heap
158 -- profiles; nor do we set CCCS from it; so we
159 -- just slam in dontCareCostCentre
160 = returnMM (StgRhsCon dontCareCCS con args)
163 do_expr :: StgExpr -> MassageM StgExpr
165 do_expr (StgLit l) = returnMM (StgLit l)
167 do_expr (StgApp fn args)
168 = boxHigherOrderArgs (StgApp fn) args
170 do_expr (StgConApp con args)
171 = boxHigherOrderArgs (\args -> StgConApp con args) args
173 do_expr (StgOpApp con args res_ty)
174 = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
176 do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
177 = collectCC cc `thenMM_`
178 do_expr expr `thenMM` \ expr' ->
179 returnMM (StgSCC cc expr')
181 do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
182 = do_expr expr `thenMM` \ expr' ->
183 mapMM do_alt alts `thenMM` \ alts' ->
184 returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
186 do_alt (id, bs, use_mask, e)
187 = do_expr e `thenMM` \ e' ->
188 returnMM (id, bs, use_mask, e')
191 = do_let b e `thenMM` \ (b,e) ->
192 returnMM (StgLet b e)
194 do_expr (StgLetNoEscape lvs1 lvs2 b e)
195 = do_let b e `thenMM` \ (b,e) ->
196 returnMM (StgLetNoEscape lvs1 lvs2 b e)
198 do_expr (StgTick m n expr)
199 = do_expr expr `thenMM` \ expr' ->
200 returnMM (StgTick m n expr')
203 do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
206 ----------------------------------
208 do_let (StgNonRec b rhs) e
209 = do_rhs rhs `thenMM` \ rhs' ->
211 do_expr e `thenMM` \ e' ->
212 returnMM (StgNonRec b rhs',e')
215 do_let (StgRec pairs) e
216 = addTopLevelIshIds binders (
217 mapMM do_pair pairs `thenMM` \ pairs' ->
218 do_expr e `thenMM` \ e' ->
219 returnMM (StgRec pairs', e')
222 binders = map fst pairs
224 = do_rhs rhs `thenMM` \ rhs2 ->
227 ----------------------------------
228 do_rhs :: StgRhs -> MassageM StgRhs
229 -- We play much the same game as we did in do_top_rhs above;
230 -- but we don't have to worry about cafs etc.
233 do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
234 | not (isSccCountCostCentre cc)
235 = collectCC cc `thenMM_`
236 returnMM (StgRhsCon cc con args)
239 do_rhs (StgRhsClosure _ bi fv u srt args expr)
240 = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
241 do_expr expr' `thenMM` \ expr'' ->
242 returnMM (StgRhsClosure ccs bi fv u srt args expr'')
244 slurpSCCs ccs (StgSCC cc e)
245 = collectCC cc `thenMM_`
246 slurpSCCs (cc `pushCCOnCCS` ccs) e
250 do_rhs (StgRhsCon cc con args)
251 = returnMM (StgRhsCon currentCCS con args)
254 %************************************************************************
256 \subsection{Boxing higher-order args}
258 %************************************************************************
260 Boxing is *turned off* at the moment, until we can figure out how to
261 do it properly in general.
265 :: ([StgArg] -> StgExpr)
266 -- An application lacking its arguments
267 -> [StgArg] -- arguments which we might box
270 #ifndef PROF_DO_BOXING
271 boxHigherOrderArgs almost_expr args
272 = returnMM (almost_expr args)
274 boxHigherOrderArgs almost_expr args
275 = getTopLevelIshIds `thenMM` \ ids ->
276 mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
277 returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
281 do_arg ids bindings arg@(StgVarArg old_var)
282 | (not (isLocalVar old_var) || elemVarSet old_var ids)
283 && isFunTy (dropForAlls var_type)
284 = -- make a trivial let-binding for the top-level function
285 getUniqueMM `thenMM` \ uniq ->
287 new_var = mkSysLocal FSLIT("sf") uniq var_type
289 returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
291 var_type = idType old_var
293 do_arg ids bindings arg = returnMM (bindings, arg)
296 mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
298 mk_stg_let cc (new_var, old_var) body
300 rhs_body = StgApp old_var [{-args-}]
301 rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
303 StgLet (StgNonRec new_var rhs_closure) body
305 bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
309 %************************************************************************
311 \subsection{Boring monad stuff for this}
313 %************************************************************************
317 = Module -- module name
318 -> CostCentreStack -- prevailing CostCentre
319 -- if none, subsumedCosts at top-level
320 -- currentCostCentre at nested levels
322 -> VarSet -- toplevel-ish Ids for boxing
324 -> (CollectedCCs, result)
326 -- the initMM function also returns the final CollectedCCs
328 initMM :: Module -- module name, which we may consult
333 initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
335 thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
336 thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
338 thenMM expr cont mod scope_cc us ids ccs
339 = case splitUniqSupply us of { (s1, s2) ->
340 case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
341 cont result mod scope_cc s2 ids ccs2 }}
343 thenMM_ expr cont mod scope_cc us ids ccs
344 = case splitUniqSupply us of { (s1, s2) ->
345 case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
346 cont mod scope_cc s2 ids ccs2 }}
348 returnMM :: a -> MassageM a
349 returnMM result mod scope_cc us ids ccs = (ccs, result)
352 nopMM mod scope_cc us ids ccs = (ccs, ())
354 mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
355 mapMM f [] = returnMM []
357 = f m `thenMM` \ r ->
358 mapMM f ms `thenMM` \ rs ->
361 mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
362 mapAccumMM f b [] = returnMM (b, [])
363 mapAccumMM f b (m:ms)
364 = f b m `thenMM` \ (b2, r) ->
365 mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
368 #ifdef PROF_DO_BOXING
369 getUniqueMM :: MassageM Unique
370 getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
373 addTopLevelIshId :: Id -> MassageM a -> MassageM a
374 addTopLevelIshId id scope mod scope_cc us ids ccs
375 | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
376 | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
378 addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
379 addTopLevelIshIds [] cont = cont
380 addTopLevelIshIds (id:ids) cont
381 = addTopLevelIshId id (addTopLevelIshIds ids cont)
383 getTopLevelIshIds :: MassageM VarSet
384 getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
387 The prevailing CCS is used to tell whether we're in a top-levelish
388 position, where top-levelish is defined as "not inside a lambda".
389 Prevailing CCs used to be used for something much more complicated,
393 set_lambda_cc :: MassageM a -> MassageM a
394 set_lambda_cc action mod scope_cc us ids ccs
395 = action mod currentCCS us ids ccs
397 set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
398 set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
399 = action mod cc_to_set_to us ids ccs
401 get_prevailing_cc :: MassageM CostCentreStack
402 get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
406 collectCC :: CostCentre -> MassageM ()
408 collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
409 = ASSERT(not (noCCAttached cc))
410 if (cc `ccFromThisModule` mod_name) then
411 ((cc : local_ccs, extern_ccs, ccss), ())
412 else -- must declare it "extern"
413 ((local_ccs, cc : extern_ccs, ccss), ())
415 collectCCS :: CostCentreStack -> MassageM ()
417 collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
418 = ASSERT(not (noCCSAttached ccs))
419 ((local_ccs, extern_ccs, ccs : ccss), ())