--- /dev/null
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+%
+\section[SCCfinal]{Modify and collect code generation for final STG program}
+
+This is now a sort-of-normal STG-to-STG pass (WDP 94/06), run by stg2stg.
+
+* Traverses the STG program collecting the cost centres. These are
+ required to declare the cost centres at the start of code
+ generation.
+
+ Note: because of cross-module unfolding, some of these cost centres
+ may be from other modules. But will still have to give them
+ "extern" declarations.
+
+* Puts on CAF cost-centres if the user has asked for individual CAF
+ cost-centres.
+
+* Ditto for individual DICT cost-centres.
+
+* Boxes top-level inherited functions passed as arguments.
+
+* "Distributes" given cost-centres to all as-yet-unmarked RHSs.
+
+\begin{code}
+module SCCfinal ( stgMassageForProfiling ) where
+
+#include "HsVersions.h"
+
+import StgSyn
+
+import Packages ( HomeModules )
+import StaticFlags ( opt_AutoSccsOnIndividualCafs )
+import CostCentre -- lots of things
+import Id ( Id )
+import Module ( Module )
+import UniqSupply ( uniqFromSupply, splitUniqSupply, UniqSupply )
+import Unique ( Unique )
+import VarSet
+import ListSetOps ( removeDups )
+import Outputable
+
+infixr 9 `thenMM`, `thenMM_`
+\end{code}
+
+\begin{code}
+stgMassageForProfiling
+ :: HomeModules
+ -> Module -- module name
+ -> UniqSupply -- unique supply
+ -> [StgBinding] -- input
+ -> (CollectedCCs, [StgBinding])
+
+stgMassageForProfiling pdeps mod_name us stg_binds
+ = let
+ ((local_ccs, extern_ccs, cc_stacks),
+ stg_binds2)
+ = initMM mod_name us (do_top_bindings stg_binds)
+
+ (fixed_ccs, fixed_cc_stacks)
+ = if opt_AutoSccsOnIndividualCafs
+ then ([],[]) -- don't need "all CAFs" CC
+ -- (for Prelude, we use PreludeCC)
+ else ([all_cafs_cc], [all_cafs_ccs])
+
+ local_ccs_no_dups = fst (removeDups cmpCostCentre local_ccs)
+ extern_ccs_no_dups = fst (removeDups cmpCostCentre extern_ccs)
+ in
+ ((fixed_ccs ++ local_ccs_no_dups,
+ extern_ccs_no_dups,
+ fixed_cc_stacks ++ cc_stacks), stg_binds2)
+ where
+
+ all_cafs_cc = mkAllCafsCC mod_name
+ all_cafs_ccs = mkSingletonCCS all_cafs_cc
+
+ ----------
+ do_top_bindings :: [StgBinding] -> MassageM [StgBinding]
+
+ do_top_bindings [] = returnMM []
+
+ do_top_bindings (StgNonRec b rhs : bs)
+ = do_top_rhs b rhs `thenMM` \ rhs' ->
+ addTopLevelIshId b (
+ do_top_bindings bs `thenMM` \bs' ->
+ returnMM (StgNonRec b rhs' : bs')
+ )
+
+ do_top_bindings (StgRec pairs : bs)
+ = addTopLevelIshIds binders (
+ mapMM do_pair pairs `thenMM` \ pairs2 ->
+ do_top_bindings bs `thenMM` \ bs' ->
+ returnMM (StgRec pairs2 : bs')
+ )
+ where
+ binders = map fst pairs
+ do_pair (b, rhs)
+ = do_top_rhs b rhs `thenMM` \ rhs2 ->
+ returnMM (b, rhs2)
+
+ ----------
+ do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
+
+ do_top_rhs binder (StgRhsClosure _ bi fv u srt [] (StgSCC cc (StgConApp con args)))
+ | not (isSccCountCostCentre cc) && not (isDllConApp pdeps con args)
+ -- Trivial _scc_ around nothing but static data
+ -- Eliminate _scc_ ... and turn into StgRhsCon
+
+ -- isDllConApp checks for LitLit args too
+ = returnMM (StgRhsCon dontCareCCS con args)
+
+{- Can't do this one with cost-centre stacks: --SDM
+ do_top_rhs binder (StgRhsClosure no_cc bi fv u [] (StgSCC ty cc expr))
+ | (noCCSAttached no_cc || currentOrSubsumedCCS no_cc)
+ && not (isSccCountCostCentre cc)
+ -- Top level CAF without a cost centre attached
+ -- Attach and collect cc of trivial _scc_ in body
+ = collectCC cc `thenMM_`
+ set_prevailing_cc cc (do_expr expr) `thenMM` \ expr' ->
+ returnMM (StgRhsClosure cc bi fv u [] expr')
+-}
+
+ do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
+ | noCCSAttached no_cc || currentOrSubsumedCCS no_cc
+ -- Top level CAF without a cost centre attached
+ -- Attach CAF cc (collect if individual CAF ccs)
+ = (if opt_AutoSccsOnIndividualCafs
+ then let cc = mkAutoCC binder mod_name CafCC
+ ccs = mkSingletonCCS cc
+ in
+ collectCC cc `thenMM_`
+ collectCCS ccs `thenMM_`
+ returnMM ccs
+ else
+ returnMM all_cafs_ccs) `thenMM` \ caf_ccs ->
+ set_prevailing_cc caf_ccs (do_expr body) `thenMM` \ body' ->
+ returnMM (StgRhsClosure caf_ccs bi fv u srt [] body')
+
+ do_top_rhs binder (StgRhsClosure cc bi fv u srt [] body)
+ -- Top level CAF with cost centre attached
+ -- Should this be a CAF cc ??? Does this ever occur ???
+ = pprPanic "SCCfinal: CAF with cc:" (ppr cc)
+
+ do_top_rhs binder (StgRhsClosure no_ccs bi fv u srt args body)
+ -- Top level function, probably subsumed
+ | noCCSAttached no_ccs
+ = set_lambda_cc (do_expr body) `thenMM` \ body' ->
+ returnMM (StgRhsClosure subsumedCCS bi fv u srt args body')
+
+ | otherwise
+ = pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
+
+ do_top_rhs binder (StgRhsCon ccs con args)
+ -- Top-level (static) data is not counted in heap
+ -- profiles; nor do we set CCCS from it; so we
+ -- just slam in dontCareCostCentre
+ = returnMM (StgRhsCon dontCareCCS con args)
+
+ ------
+ do_expr :: StgExpr -> MassageM StgExpr
+
+ do_expr (StgLit l) = returnMM (StgLit l)
+
+ do_expr (StgApp fn args)
+ = boxHigherOrderArgs (StgApp fn) args
+
+ do_expr (StgConApp con args)
+ = boxHigherOrderArgs (\args -> StgConApp con args) args
+
+ do_expr (StgOpApp con args res_ty)
+ = boxHigherOrderArgs (\args -> StgOpApp con args res_ty) args
+
+ do_expr (StgSCC cc expr) -- Ha, we found a cost centre!
+ = collectCC cc `thenMM_`
+ do_expr expr `thenMM` \ expr' ->
+ returnMM (StgSCC cc expr')
+
+ do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts)
+ = do_expr expr `thenMM` \ expr' ->
+ mapMM do_alt alts `thenMM` \ alts' ->
+ returnMM (StgCase expr' fv1 fv2 bndr srt alt_type alts')
+ where
+ do_alt (id, bs, use_mask, e)
+ = do_expr e `thenMM` \ e' ->
+ returnMM (id, bs, use_mask, e')
+
+ do_expr (StgLet b e)
+ = do_let b e `thenMM` \ (b,e) ->
+ returnMM (StgLet b e)
+
+ do_expr (StgLetNoEscape lvs1 lvs2 b e)
+ = do_let b e `thenMM` \ (b,e) ->
+ returnMM (StgLetNoEscape lvs1 lvs2 b e)
+
+#ifdef DEBUG
+ do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
+#endif
+
+ ----------------------------------
+
+ do_let (StgNonRec b rhs) e
+ = do_rhs rhs `thenMM` \ rhs' ->
+ addTopLevelIshId b (
+ do_expr e `thenMM` \ e' ->
+ returnMM (StgNonRec b rhs',e')
+ )
+
+ do_let (StgRec pairs) e
+ = addTopLevelIshIds binders (
+ mapMM do_pair pairs `thenMM` \ pairs' ->
+ do_expr e `thenMM` \ e' ->
+ returnMM (StgRec pairs', e')
+ )
+ where
+ binders = map fst pairs
+ do_pair (b, rhs)
+ = do_rhs rhs `thenMM` \ rhs2 ->
+ returnMM (b, rhs2)
+
+ ----------------------------------
+ do_rhs :: StgRhs -> MassageM StgRhs
+ -- We play much the same game as we did in do_top_rhs above;
+ -- but we don't have to worry about cafs etc.
+
+{-
+ do_rhs (StgRhsClosure closure_cc bi fv u [] (StgSCC ty cc (StgCon (DataCon con) args _)))
+ | not (isSccCountCostCentre cc)
+ = collectCC cc `thenMM_`
+ returnMM (StgRhsCon cc con args)
+-}
+
+ do_rhs (StgRhsClosure _ bi fv u srt args expr)
+ = slurpSCCs currentCCS expr `thenMM` \ (expr', ccs) ->
+ do_expr expr' `thenMM` \ expr'' ->
+ returnMM (StgRhsClosure ccs bi fv u srt args expr'')
+ where
+ slurpSCCs ccs (StgSCC cc e)
+ = collectCC cc `thenMM_`
+ slurpSCCs (cc `pushCCOnCCS` ccs) e
+ slurpSCCs ccs e
+ = returnMM (e, ccs)
+
+ do_rhs (StgRhsCon cc con args)
+ = returnMM (StgRhsCon currentCCS con args)
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Boxing higher-order args}
+%* *
+%************************************************************************
+
+Boxing is *turned off* at the moment, until we can figure out how to
+do it properly in general.
+
+\begin{code}
+boxHigherOrderArgs
+ :: ([StgArg] -> StgExpr)
+ -- An application lacking its arguments
+ -> [StgArg] -- arguments which we might box
+ -> MassageM StgExpr
+
+#ifndef PROF_DO_BOXING
+boxHigherOrderArgs almost_expr args
+ = returnMM (almost_expr args)
+#else
+boxHigherOrderArgs almost_expr args
+ = getTopLevelIshIds `thenMM` \ ids ->
+ mapAccumMM (do_arg ids) [] args `thenMM` \ (let_bindings, new_args) ->
+ returnMM (foldr (mk_stg_let currentCCS) (almost_expr new_args) let_bindings)
+ where
+ ---------------
+
+ do_arg ids bindings arg@(StgVarArg old_var)
+ | (not (isLocalVar old_var) || elemVarSet old_var ids)
+ && isFunTy (dropForAlls var_type)
+ = -- make a trivial let-binding for the top-level function
+ getUniqueMM `thenMM` \ uniq ->
+ let
+ new_var = mkSysLocal FSLIT("sf") uniq var_type
+ in
+ returnMM ( (new_var, old_var) : bindings, StgVarArg new_var )
+ where
+ var_type = idType old_var
+
+ do_arg ids bindings arg = returnMM (bindings, arg)
+
+ ---------------
+ mk_stg_let :: CostCentreStack -> (Id, Id) -> StgExpr -> StgExpr
+
+ mk_stg_let cc (new_var, old_var) body
+ = let
+ rhs_body = StgApp old_var [{-args-}]
+ rhs_closure = StgRhsClosure cc stgArgOcc [{-fvs-}] ReEntrant NoSRT{-eeek!!!-} [{-args-}] rhs_body
+ in
+ StgLet (StgNonRec new_var rhs_closure) body
+ where
+ bOGUS_LVs = emptyUniqSet -- easier to print than: panic "mk_stg_let: LVs"
+#endif
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Boring monad stuff for this}
+%* *
+%************************************************************************
+
+\begin{code}
+type MassageM result
+ = Module -- module name
+ -> CostCentreStack -- prevailing CostCentre
+ -- if none, subsumedCosts at top-level
+ -- currentCostCentre at nested levels
+ -> UniqSupply
+ -> VarSet -- toplevel-ish Ids for boxing
+ -> CollectedCCs
+ -> (CollectedCCs, result)
+
+-- the initMM function also returns the final CollectedCCs
+
+initMM :: Module -- module name, which we may consult
+ -> UniqSupply
+ -> MassageM a
+ -> (CollectedCCs, a)
+
+initMM mod_name init_us m = m mod_name noCCS init_us emptyVarSet ([],[],[])
+
+thenMM :: MassageM a -> (a -> MassageM b) -> MassageM b
+thenMM_ :: MassageM a -> (MassageM b) -> MassageM b
+
+thenMM expr cont mod scope_cc us ids ccs
+ = case splitUniqSupply us of { (s1, s2) ->
+ case (expr mod scope_cc s1 ids ccs) of { (ccs2, result) ->
+ cont result mod scope_cc s2 ids ccs2 }}
+
+thenMM_ expr cont mod scope_cc us ids ccs
+ = case splitUniqSupply us of { (s1, s2) ->
+ case (expr mod scope_cc s1 ids ccs) of { (ccs2, _) ->
+ cont mod scope_cc s2 ids ccs2 }}
+
+returnMM :: a -> MassageM a
+returnMM result mod scope_cc us ids ccs = (ccs, result)
+
+nopMM :: MassageM ()
+nopMM mod scope_cc us ids ccs = (ccs, ())
+
+mapMM :: (a -> MassageM b) -> [a] -> MassageM [b]
+mapMM f [] = returnMM []
+mapMM f (m:ms)
+ = f m `thenMM` \ r ->
+ mapMM f ms `thenMM` \ rs ->
+ returnMM (r:rs)
+
+mapAccumMM :: (acc -> x -> MassageM (acc, y)) -> acc -> [x] -> MassageM (acc, [y])
+mapAccumMM f b [] = returnMM (b, [])
+mapAccumMM f b (m:ms)
+ = f b m `thenMM` \ (b2, r) ->
+ mapAccumMM f b2 ms `thenMM` \ (b3, rs) ->
+ returnMM (b3, r:rs)
+
+getUniqueMM :: MassageM Unique
+getUniqueMM mod scope_cc us ids ccs = (ccs, uniqFromSupply us)
+
+addTopLevelIshId :: Id -> MassageM a -> MassageM a
+addTopLevelIshId id scope mod scope_cc us ids ccs
+ | isCurrentCCS scope_cc = scope mod scope_cc us ids ccs
+ | otherwise = scope mod scope_cc us (extendVarSet ids id) ccs
+
+addTopLevelIshIds :: [Id] -> MassageM a -> MassageM a
+addTopLevelIshIds [] cont = cont
+addTopLevelIshIds (id:ids) cont
+ = addTopLevelIshId id (addTopLevelIshIds ids cont)
+
+getTopLevelIshIds :: MassageM VarSet
+getTopLevelIshIds mod scope_cc us ids ccs = (ccs, ids)
+\end{code}
+
+The prevailing CCS is used to tell whether we're in a top-levelish
+position, where top-levelish is defined as "not inside a lambda".
+Prevailing CCs used to be used for something much more complicated,
+I'm sure --SDM
+
+\begin{code}
+set_lambda_cc :: MassageM a -> MassageM a
+set_lambda_cc action mod scope_cc us ids ccs
+ = action mod currentCCS us ids ccs
+
+set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
+set_prevailing_cc cc_to_set_to action mod scope_cc us ids ccs
+ = action mod cc_to_set_to us ids ccs
+
+get_prevailing_cc :: MassageM CostCentreStack
+get_prevailing_cc mod scope_cc us ids ccs = (ccs, scope_cc)
+\end{code}
+
+\begin{code}
+collectCC :: CostCentre -> MassageM ()
+
+collectCC cc mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
+ = ASSERT(not (noCCAttached cc))
+ if (cc `ccFromThisModule` mod_name) then
+ ((cc : local_ccs, extern_ccs, ccss), ())
+ else -- must declare it "extern"
+ ((local_ccs, cc : extern_ccs, ccss), ())
+
+collectCCS :: CostCentreStack -> MassageM ()
+
+collectCCS ccs mod_name scope_cc us ids (local_ccs, extern_ccs, ccss)
+ = ASSERT(not (noCCSAttached ccs))
+ ((local_ccs, extern_ccs, ccs : ccss), ())
+\end{code}
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