%
-% (c) The GRASP/AQUA Project, Glasgow University, 1993-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
%
\section[StrictAnal]{``Simple'' Mycroft-style strictness analyser}
Semantique analyser) was written by Andy Gill.
\begin{code}
-#include "HsVersions.h"
-
-module StrictAnal ( saWwTopBinds, saTopBinds ) where
+module StrictAnal ( saWwTopBinds ) where
-import Ubiq{-uitous-}
+#include "HsVersions.h"
-import CmdLineOpts ( opt_AllStrict, opt_NumbersStrict,
- opt_D_dump_stranal, opt_D_simplifier_stats
- )
+import CmdLineOpts ( opt_D_dump_stranal, opt_D_simplifier_stats, opt_D_verbose_core2core )
import CoreSyn
-import Id ( idType, addIdStrictness,
- getIdDemandInfo, addIdDemandInfo,
- GenId{-instance Outputable-}
- )
-import IdInfo ( mkStrictnessInfo, mkBottomStrictnessInfo,
- mkDemandInfo, willBeDemanded, DemandInfo
+import Id ( idType, setIdStrictness,
+ getIdDemandInfo, setIdDemandInfo,
+ Id
)
-import PprCore ( pprCoreBinding, pprBigCoreBinder )
-import PprStyle ( PprStyle(..) )
-import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-} )
-import Pretty ( ppBesides, ppStr, ppInt, ppChar, ppAboves )
+import IdInfo ( mkStrictnessInfo )
+import CoreLint ( beginPass, endPass )
+import ErrUtils ( dumpIfSet )
import SaAbsInt
import SaLib
-import TyVar ( GenTyVar{-instance Eq-} )
+import Demand ( isStrict )
import WorkWrap -- "back-end" of strictness analyser
-import Unique ( Unique{-instance Eq -} )
-import Util ( zipWith4Equal, pprTrace, panic{-ToDo:rm-} )
-
-isWrapperId = panic "StrictAnal.isWrapperId (ToDo)"
+import UniqSupply ( UniqSupply )
+import Util ( zipWith4Equal )
+import Outputable
\end{code}
-
%************************************************************************
%* *
\subsection[Thoughts]{Random thoughts}
\begin{code}
saWwTopBinds :: UniqSupply
- -> [CoreBinding]
- -> [CoreBinding]
+ -> [CoreBind]
+ -> IO [CoreBind]
saWwTopBinds us binds
- = let
- strflags = (opt_AllStrict, opt_NumbersStrict)
+ = do {
+ beginPass "Strictness analysis";
- -- mark each binder with its strictness
-#ifndef OMIT_STRANAL_STATS
- (binds_w_strictness, sa_stats)
- = sa_top_binds strflags binds nullSaStats
-#else
- binds_w_strictness
- = sa_top_binds strflags binds
-#endif
- in
- -- possibly show what we decided about strictness...
- (if opt_D_dump_stranal
- then pprTrace "Strictness:\n" (ppAboves (
- map (pprCoreBinding PprDebug) binds_w_strictness))
- else id
- )
- -- possibly show how many things we marked as demanded...
- ((if opt_D_simplifier_stats
+ -- Mark each binder with its strictness
#ifndef OMIT_STRANAL_STATS
- then pp_stats sa_stats
+ let { (binds_w_strictness, sa_stats) = saTopBinds binds nullSaStats };
+ dumpIfSet opt_D_simplifier_stats "Strictness analysis statistics"
+ (pp_stats sa_stats);
#else
- then id
-#endif
- else id
- )
- -- create worker/wrappers, and mark binders with their
- -- "strictness info" [which encodes their
- -- worker/wrapper-ness]
- (workersAndWrappers binds_w_strictness us))
-#ifndef OMIT_STRANAL_STATS
- where
- pp_stats (SaStats tlam dlam tc dc tlet dlet)
- = pprTrace "Binders marked demanded: "
- (ppBesides [ppStr "Lambda vars: ", ppInt IBOX(dlam), ppChar '/', ppInt IBOX(tlam),
- ppStr "; Case vars: ", ppInt IBOX(dc), ppChar '/', ppInt IBOX(tc),
- ppStr "; Let vars: ", ppInt IBOX(dlet), ppChar '/', ppInt IBOX(tlet)
- ])
+ let { binds_w_strictness = saTopBindsBinds binds };
#endif
+
+ -- Create worker/wrappers, and mark binders with their
+ -- "strictness info" [which encodes their worker/wrapper-ness]
+ let { binds' = workersAndWrappers us binds_w_strictness };
+
+ endPass "Strictness analysis" (opt_D_dump_stranal || opt_D_verbose_core2core) binds'
+ }
\end{code}
%************************************************************************
@AbsValEnv@ maps an @Id@ to its @AbsVal@).
\begin{code}
-saTopBinds :: StrAnalFlags -> [CoreBinding] -> [CoreBinding] -- exported
-sa_top_binds :: StrAnalFlags -> [CoreBinding] -> SaM [CoreBinding] -- not exported
+saTopBinds :: [CoreBind] -> SaM [CoreBind] -- not exported
-saTopBinds strflags binds
-#ifndef OMIT_STRANAL_STATS
- = fst (sa_top_binds strflags binds nullSaStats)
-#else
- = sa_top_binds strflags binds
-#endif
-
-sa_top_binds strflags binds
+saTopBinds binds
= let
- starting_abs_env = nullAbsValEnv strflags
+ starting_abs_env = nullAbsValEnv
in
do_it starting_abs_env starting_abs_env binds
where
\begin{code}
saTopBind :: StrictEnv -> AbsenceEnv
- -> CoreBinding
- -> SaM (StrictEnv, AbsenceEnv, CoreBinding)
+ -> CoreBind
+ -> SaM (StrictEnv, AbsenceEnv, CoreBind)
saTopBind str_env abs_env (NonRec binder rhs)
= saExpr str_env abs_env rhs `thenSa` \ new_rhs ->
let
- strflags = getStrAnalFlags str_env
-
str_rhs = absEval StrAnal rhs str_env
abs_rhs = absEval AbsAnal rhs abs_env
new_binder
= addStrictnessInfoToId
- strflags
widened_str_rhs widened_abs_rhs
binder
rhs
saTopBind str_env abs_env (Rec pairs)
= let
- strflags = getStrAnalFlags str_env
(binders,rhss) = unzip pairs
str_rhss = fixpoint StrAnal binders rhss str_env
abs_rhss = fixpoint AbsAnal binders rhss abs_env
-- fixpoint returns widened values
new_str_env = growAbsValEnvList str_env (binders `zip` str_rhss)
new_abs_env = growAbsValEnvList abs_env (binders `zip` abs_rhss)
- new_binders = zipWith4Equal "saTopBind" (addStrictnessInfoToId strflags)
+ new_binders = zipWith4Equal "saTopBind" addStrictnessInfoToId
str_rhss abs_rhss binders rhss
in
mapSa (saExpr new_str_env new_abs_env) rhss `thenSa` \ new_rhss ->
saExpr :: StrictEnv -> AbsenceEnv -> CoreExpr -> SaM CoreExpr
saExpr _ _ e@(Var _) = returnSa e
-saExpr _ _ e@(Lit _) = returnSa e
saExpr _ _ e@(Con _ _) = returnSa e
-saExpr _ _ e@(Prim _ _) = returnSa e
+saExpr _ _ e@(Type _) = returnSa e
-saExpr str_env abs_env (Lam (ValBinder arg) body)
- = saExpr str_env abs_env body `thenSa` \ new_body ->
- let
- new_arg = addDemandInfoToId str_env abs_env body arg
- in
- tickLambda new_arg `thenSa_` -- stats
- returnSa (Lam (ValBinder new_arg) new_body)
-
-saExpr str_env abs_env (Lam other_binder expr)
- = saExpr str_env abs_env expr `thenSa` \ new_expr ->
- returnSa (Lam other_binder new_expr)
+saExpr str_env abs_env (Lam bndr body)
+ = -- Don't bother to set the demand-info on a lambda binder
+ -- We do that only for let(rec)-bound functions
+ saExpr str_env abs_env body `thenSa` \ new_body ->
+ returnSa (Lam bndr new_body)
saExpr str_env abs_env (App fun arg)
= saExpr str_env abs_env fun `thenSa` \ new_fun ->
- returnSa (App new_fun arg)
+ saExpr str_env abs_env arg `thenSa` \ new_arg ->
+ returnSa (App new_fun new_arg)
-saExpr str_env abs_env (SCC cc expr)
+saExpr str_env abs_env (Note note expr)
= saExpr str_env abs_env expr `thenSa` \ new_expr ->
- returnSa (SCC cc new_expr)
+ returnSa (Note note new_expr)
-saExpr str_env abs_env (Coerce c ty expr)
- = saExpr str_env abs_env expr `thenSa` \ new_expr ->
- returnSa (Coerce c ty new_expr)
-
-saExpr str_env abs_env (Case expr (AlgAlts alts deflt))
- = saExpr str_env abs_env expr `thenSa` \ new_expr ->
- saDefault str_env abs_env deflt `thenSa` \ new_deflt ->
- mapSa sa_alt alts `thenSa` \ new_alts ->
- returnSa (Case new_expr (AlgAlts new_alts new_deflt))
+saExpr str_env abs_env (Case expr case_bndr alts)
+ = saExpr str_env abs_env expr `thenSa` \ new_expr ->
+ mapSa sa_alt alts `thenSa` \ new_alts ->
+ let
+ new_case_bndr = addDemandInfoToCaseBndr str_env abs_env alts case_bndr
+ in
+ returnSa (Case new_expr new_case_bndr new_alts)
where
sa_alt (con, binders, rhs)
= saExpr str_env abs_env rhs `thenSa` \ new_rhs ->
let
- new_binders = addDemandInfoToIds str_env abs_env rhs binders
+ new_binders = map add_demand_info binders
+ add_demand_info bndr | isTyVar bndr = bndr
+ | otherwise = addDemandInfoToId str_env abs_env rhs bndr
in
tickCases new_binders `thenSa_` -- stats
returnSa (con, new_binders, new_rhs)
-saExpr str_env abs_env (Case expr (PrimAlts alts deflt))
- = saExpr str_env abs_env expr `thenSa` \ new_expr ->
- saDefault str_env abs_env deflt `thenSa` \ new_deflt ->
- mapSa sa_alt alts `thenSa` \ new_alts ->
- returnSa (Case new_expr (PrimAlts new_alts new_deflt))
- where
- sa_alt (lit, rhs)
- = saExpr str_env abs_env rhs `thenSa` \ new_rhs ->
- returnSa (lit, new_rhs)
-
saExpr str_env abs_env (Let (NonRec binder rhs) body)
= -- Analyse the RHS in the environment at hand
saExpr str_env abs_env rhs `thenSa` \ new_rhs ->
let
- strflags = getStrAnalFlags str_env
-
-- Bind this binder to the abstract value of the RHS; analyse
-- the body of the `let' in the extended environment.
str_rhs_val = absEval StrAnal rhs str_env
-- Now determine the strictness of this binder; use that info
-- to record DemandInfo/StrictnessInfo in the binder.
- new_binder = addStrictnessInfoToId strflags
+ new_binder = addStrictnessInfoToId
widened_str_rhs widened_abs_rhs
(addDemandInfoToId str_env abs_env body binder)
rhs
saExpr str_env abs_env (Let (Rec pairs) body)
= let
- strflags = getStrAnalFlags str_env
(binders,rhss) = unzip pairs
str_vals = fixpoint StrAnal binders rhss str_env
abs_vals = fixpoint AbsAnal binders rhss abs_env
-- deciding that y is absent, which is plain wrong!
-- It's much easier simply not to do this.
- improved_binders = zipWith4Equal "saExpr" (addStrictnessInfoToId strflags)
+ improved_binders = zipWith4Equal "saExpr" addStrictnessInfoToId
str_vals abs_vals binders rhss
- whiter_than_white_binders = launder improved_binders
-
- new_pairs = whiter_than_white_binders `zip` new_rhss
+ new_pairs = improved_binders `zip` new_rhss
in
returnSa (Let (Rec new_pairs) new_body)
- where
- launder me = {-still-} me
-\end{code}
-
-\begin{code}
-saDefault str_env abs_env NoDefault = returnSa NoDefault
-
-saDefault str_env abs_env (BindDefault bdr rhs)
- = saExpr str_env abs_env rhs `thenSa` \ new_rhs ->
- let
- new_bdr = addDemandInfoToId str_env abs_env rhs bdr
- in
- tickCases [new_bdr] `thenSa_` -- stats
- returnSa (BindDefault new_bdr new_rhs)
\end{code}
\begin{code}
addStrictnessInfoToId
- :: StrAnalFlags
- -> AbsVal -- Abstract strictness value
+ :: AbsVal -- Abstract strictness value
-> AbsVal -- Ditto absence
-> Id -- The id
-> CoreExpr -- Its RHS
-> Id -- Augmented with strictness
-addStrictnessInfoToId strflags str_val abs_val binder body
- = if isWrapperId binder then
- binder -- Avoid clobbering existing strictness info
- -- (and, more importantly, worker info).
- -- Deeply suspicious (SLPJ)
- else
- if (isBot str_val) then
- binder `addIdStrictness` mkBottomStrictnessInfo
- else
- case (collectBinders body) of { (_, _, lambda_bounds, rhs) ->
- let
- tys = map idType lambda_bounds
- strictness = findStrictness strflags tys str_val abs_val
- in
- binder `addIdStrictness` mkStrictnessInfo strictness Nothing
- }
+addStrictnessInfoToId str_val abs_val binder body
+ = case (collectTyAndValBinders body) of
+ (_, lambda_bounds, rhs) -> binder `setIdStrictness`
+ mkStrictnessInfo strictness False
+ where
+ tys = map idType lambda_bounds
+ strictness = findStrictness tys str_val abs_val
\end{code}
\begin{code}
-> Id -- Id augmented with Demand info
addDemandInfoToId str_env abs_env expr binder
- = binder `addIdDemandInfo` (mkDemandInfo (findDemand str_env abs_env expr binder))
+ = binder `setIdDemandInfo` (findDemand str_env abs_env expr binder)
+
+addDemandInfoToCaseBndr str_env abs_env alts binder
+ = binder `setIdDemandInfo` (findDemandAlts str_env abs_env alts binder)
addDemandInfoToIds :: StrictEnv -> AbsenceEnv -> CoreExpr -> [Id] -> [Id]
{-# INLINE returnSa #-}
tickLambda :: Id -> SaM ()
-tickCases :: [Id] -> SaM ()
+tickCases :: [CoreBndr] -> SaM ()
tickLet :: Id -> SaM ()
#ifndef OMIT_STRANAL_STATS
((), SaStats tlam dlam tc dc (tlet _ADD_ tot) (dlet _ADD_ demanded)) }
tick_demanded var (tot, demanded)
+ | isTyVar var = (tot, demanded)
+ | otherwise
= (tot + 1,
- if (willBeDemanded (getIdDemandInfo var))
+ if (isStrict (getIdDemandInfo var))
then demanded + 1
else demanded)
+pp_stats (SaStats tlam dlam tc dc tlet dlet)
+ = hcat [ptext SLIT("Lambda vars: "), int IBOX(dlam), char '/', int IBOX(tlam),
+ ptext SLIT("; Case vars: "), int IBOX(dc), char '/', int IBOX(tc),
+ ptext SLIT("; Let vars: "), int IBOX(dlet), char '/', int IBOX(tlet)
+ ]
+
#else {-OMIT_STRANAL_STATS-}
-- identity monad
type SaM a = a
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