%
% (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 CostCentre
import Id
import Name
import Module
import UniqSupply ( splitUniqSupply, UniqSupply )
#ifdef PROF_DO_BOXING
import UniqSupply ( uniqFromSupply )
#endif
import VarSet
import ListSetOps ( removeDups )
import Outputable
import DynFlags
\end{code}
\begin{code}
stgMassageForProfiling
:: DynFlags
-> PackageId
-> Module
-> UniqSupply
-> [StgBinding]
-> (CollectedCCs, [StgBinding])
stgMassageForProfiling dflags this_pkg 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 dopt Opt_AutoSccsOnIndividualCafs dflags
then ([],[])
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 [] = return []
do_top_bindings (StgNonRec b rhs : bs) = do
rhs' <- do_top_rhs b rhs
addTopLevelIshId b $ do
bs' <- do_top_bindings bs
return (StgNonRec b rhs' : bs')
do_top_bindings (StgRec pairs : bs)
= addTopLevelIshIds binders $ do
pairs2 <- mapM do_pair pairs
bs' <- do_top_bindings bs
return (StgRec pairs2 : bs')
where
binders = map fst pairs
do_pair (b, rhs) = do
rhs2 <- do_top_rhs b rhs
return (b, rhs2)
do_top_rhs :: Id -> StgRhs -> MassageM StgRhs
do_top_rhs _ (StgRhsClosure _ _ _ _ _ [] (StgSCC cc (StgConApp con args)))
| not (isSccCountCostCentre cc) && not (isDllConApp this_pkg con args)
= return (StgRhsCon dontCareCCS con args)
do_top_rhs binder (StgRhsClosure no_cc bi fv u srt [] body)
| noCCSAttached no_cc || currentOrSubsumedCCS no_cc = do
caf_ccs <- if dopt Opt_AutoSccsOnIndividualCafs dflags
then let cc = mkAutoCC binder modl CafCC
ccs = mkSingletonCCS cc
modl | Just m <- nameModule_maybe (idName binder) = m
| otherwise = mod_name
in do
collectNewCC cc
collectCCS ccs
return ccs
else
return all_cafs_ccs
body' <- set_prevailing_cc caf_ccs (do_expr body)
return (StgRhsClosure caf_ccs bi fv u srt [] body')
do_top_rhs _ (StgRhsClosure cc _ _ _ _ [] _)
= pprPanic "SCCfinal: CAF with cc:" (ppr cc)
do_top_rhs _ (StgRhsClosure no_ccs bi fv u srt args body)
| noCCSAttached no_ccs
= do body' <- set_lambda_cc (do_expr body)
return (StgRhsClosure subsumedCCS bi fv u srt args body')
| otherwise
= pprPanic "SCCfinal: CAF with cc:" (ppr no_ccs)
do_top_rhs _ (StgRhsCon _ con args)
= return (StgRhsCon dontCareCCS con args)
do_expr :: StgExpr -> MassageM StgExpr
do_expr (StgLit l) = return (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) = do
collectCC cc
expr' <- do_expr expr
return (StgSCC cc expr')
do_expr (StgCase expr fv1 fv2 bndr srt alt_type alts) = do
expr' <- do_expr expr
alts' <- mapM do_alt alts
return (StgCase expr' fv1 fv2 bndr srt alt_type alts')
where
do_alt (id, bs, use_mask, e) = do
e' <- do_expr e
return (id, bs, use_mask, e')
do_expr (StgLet b e) = do
(b,e) <- do_let b e
return (StgLet b e)
do_expr (StgLetNoEscape lvs1 lvs2 b e) = do
(b,e) <- do_let b e
return (StgLetNoEscape lvs1 lvs2 b e)
do_expr (StgTick m n expr) = do
expr' <- do_expr expr
return (StgTick m n expr')
do_expr other = pprPanic "SCCfinal.do_expr" (ppr other)
do_let (StgNonRec b rhs) e = do
rhs' <- do_rhs rhs
addTopLevelIshId b $ do
e' <- do_expr e
return (StgNonRec b rhs',e')
do_let (StgRec pairs) e
= addTopLevelIshIds binders $ do
pairs' <- mapM do_pair pairs
e' <- do_expr e
return (StgRec pairs', e')
where
binders = map fst pairs
do_pair (b, rhs) = do
rhs2 <- do_rhs rhs
return (b, rhs2)
do_rhs :: StgRhs -> MassageM StgRhs
do_rhs (StgRhsClosure _ bi fv u srt args expr) = do
(expr', ccs) <- slurpSCCs currentCCS expr
expr'' <- do_expr expr'
return (StgRhsClosure ccs bi fv u srt args expr'')
where
slurpSCCs ccs (StgSCC cc e)
= do collectCC cc
slurpSCCs (cc `pushCCOnCCS` ccs) e
slurpSCCs ccs e
= return (e, ccs)
do_rhs (StgRhsCon _ con args)
= return (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)
-> [StgArg]
-> MassageM StgExpr
#ifndef PROF_DO_BOXING
boxHigherOrderArgs almost_expr args
= return (almost_expr args)
#else
boxHigherOrderArgs almost_expr args = do
ids <- getTopLevelIshIds
(let_bindings, new_args) <- mapAccumLM (do_arg ids) [] args
return (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)
= do
uniq <- getUniqueMM
let
new_var = mkSysLocal (fsLit "sf") uniq var_type
return ( (new_var, old_var) : bindings, StgVarArg new_var )
where
var_type = idType old_var
do_arg ids bindings arg = return (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 []
rhs_closure = StgRhsClosure cc stgArgOcc [] ReEntrant NoSRT [] rhs_body
in
StgLet (StgNonRec new_var rhs_closure) body
where
bOGUS_LVs = emptyUniqSet
#endif
\end{code}
%************************************************************************
%* *
\subsection{Boring monad stuff for this}
%* *
%************************************************************************
\begin{code}
newtype MassageM result
= MassageM {
unMassageM :: Module
-> CostCentreStack
-> UniqSupply
-> VarSet
-> CollectedCCs
-> (CollectedCCs, result)
}
instance Monad MassageM where
return x = MassageM (\_ _ _ _ ccs -> (ccs, x))
(>>=) = thenMM
(>>) = thenMM_
initMM :: Module
-> UniqSupply
-> MassageM a
-> (CollectedCCs, a)
initMM mod_name init_us (MassageM 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 = MassageM $ \mod scope_cc us ids ccs ->
case splitUniqSupply us of { (s1, s2) ->
case unMassageM expr mod scope_cc s1 ids ccs of { (ccs2, result) ->
unMassageM (cont result) mod scope_cc s2 ids ccs2 }}
thenMM_ expr cont = MassageM $ \mod scope_cc us ids ccs ->
case splitUniqSupply us of { (s1, s2) ->
case unMassageM expr mod scope_cc s1 ids ccs of { (ccs2, _) ->
unMassageM cont mod scope_cc s2 ids ccs2 }}
#ifdef PROF_DO_BOXING
getUniqueMM :: MassageM Unique
getUniqueMM = MassageM \mod scope_cc us ids ccs -> (ccs, uniqFromSupply us)
#endif
addTopLevelIshId :: Id -> MassageM a -> MassageM a
addTopLevelIshId id scope
= MassageM $ \mod scope_cc us ids ccs ->
if isCurrentCCS scope_cc then unMassageM scope mod scope_cc us ids ccs
else unMassageM 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)
#ifdef PROF_DO_BOXING
getTopLevelIshIds :: MassageM VarSet
getTopLevelIshIds = MassageM $ \_mod _scope_cc _us ids ccs -> (ccs, ids)
#endif
\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
= MassageM $ \mod _scope_cc us ids ccs
-> unMassageM action mod currentCCS us ids ccs
set_prevailing_cc :: CostCentreStack -> MassageM a -> MassageM a
set_prevailing_cc cc_to_set_to action
= MassageM $ \mod _scope_cc us ids ccs
-> unMassageM action mod cc_to_set_to us ids ccs
\end{code}
\begin{code}
collectCC :: CostCentre -> MassageM ()
collectCC cc
= MassageM $ \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
((local_ccs, cc : extern_ccs, ccss), ())
collectNewCC :: CostCentre -> MassageM ()
collectNewCC cc
= MassageM $ \_mod_name _scope_cc _us _ids (local_ccs, extern_ccs, ccss)
-> ((cc : local_ccs, extern_ccs, ccss), ())
collectCCS :: CostCentreStack -> MassageM ()
collectCCS ccs
= MassageM $ \_mod_name _scope_cc _us _ids (local_ccs, extern_ccs, ccss)
-> ASSERT(not (noCCSAttached ccs))
((local_ccs, extern_ccs, ccs : ccss), ())
\end{code}