\section[SaAbsInt]{Abstract interpreter for strictness analysis}
\begin{code}
-#include "HsVersions.h"
-
module SaAbsInt (
findStrictness,
findDemand,
isBot
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
+import CmdLineOpts ( opt_AllStrict, opt_NumbersStrict )
import CoreSyn
-import CoreUnfold ( UnfoldingDetails(..), FormSummary )
+import CoreUnfold ( Unfolding(..), FormSummary )
import CoreUtils ( unTagBinders )
import Id ( idType, getIdStrictness, getIdUnfolding,
- dataConTyCon, dataConArgTys
- )
-import IdInfo ( StrictnessInfo(..), Demand(..),
- wwPrim, wwStrict, wwEnum, wwUnpack
+ dataConTyCon, dataConArgTys, Id
)
+import IdInfo ( StrictnessInfo(..) )
+import Demand ( Demand(..), wwPrim, wwStrict, wwEnum, wwUnpackData, wwUnpackNew )
import MagicUFs ( MagicUnfoldingFun )
import Maybes ( maybeToBool )
-import Outputable ( Outputable(..){-instance * []-} )
-import PprStyle ( PprStyle(..) )
-import Pretty ( ppStr )
import PrimOp ( PrimOp(..) )
import SaLib
-import TyCon ( maybeTyConSingleCon, isEnumerationTyCon,
+import TyCon ( isProductTyCon, isEnumerationTyCon, isNewTyCon,
TyCon{-instance Eq-}
)
-import Type ( maybeAppDataTyConExpandingDicts, isPrimType )
+import BasicTypes ( NewOrData(..) )
+import Type ( splitAlgTyConApp_maybe,
+ isUnpointedType, Type )
import TysWiredIn ( intTyCon, integerTyCon, doubleTyCon,
floatTyCon, wordTyCon, addrTyCon
)
-import Util ( isIn, isn'tIn, nOfThem, zipWithEqual,
- pprTrace, panic, pprPanic, assertPanic
- )
+import Util ( isIn, isn'tIn, nOfThem, zipWithEqual )
+import GlaExts ( trace )
+import Outputable
returnsRealWorld x = False -- ToDo: panic "SaAbsInt.returnsRealWorld (ToDo)"
\end{code}
else
AbsBot
where
- is_fun (AbsFun _ _ _) = True
- is_fun (AbsApproxFun _) = True -- Not used, but the glb works ok
- is_fun other = False
+ is_fun (AbsFun _ _ _) = True
+ is_fun (AbsApproxFun _ _) = True -- Not used, but the glb works ok
+ is_fun other = False
-- The non-functional cases are quite straightforward
tracer = if at_least_one_AbsFun && at_least_one_AbsTop
&& no_AbsBots then
- pprTrace "combineCase:" (ppr PprDebug branches)
+ pprTrace "combineCase:" (ppr branches)
else
id
in
\begin{code}
isBot :: AbsVal -> Bool
-isBot AbsBot = True
-isBot (AbsFun args body env) = isBot (absEval StrAnal body env)
+isBot AbsBot = True
+isBot (AbsFun arg body env) = isBot (absEval StrAnal body env)
-- Don't bother to extend the envt because
-- unbound variables default to AbsTop anyway
-isBot other = False
+isBot other = False
\end{code}
Used only in absence analysis:
anyBot AbsBot = True -- poisoned!
anyBot AbsTop = False
anyBot (AbsProd vals) = any anyBot vals
-anyBot (AbsFun args body env) = anyBot (absEval AbsAnal body env)
-anyBot (AbsApproxFun demands) = False
+anyBot (AbsFun arg body env) = anyBot (absEval AbsAnal body env)
+anyBot (AbsApproxFun _ _) = False
-- AbsApproxFun can only arise in absence analysis from the Demand
-- info of an imported value; whatever it is we're looking for is
\begin{code}
widen :: AnalysisKind -> AbsVal -> AbsVal
-widen StrAnal (AbsFun args body env)
- | isBot (absEval StrAnal body env) = AbsBot
- | otherwise
- = ASSERT (not (null args))
- AbsApproxFun (map (findDemandStrOnly env body) args)
+widen StrAnal (AbsFun arg body env)
+ = AbsApproxFun (findDemandStrOnly env body arg)
+ (widen StrAnal abs_body)
+ where
+ abs_body = absEval StrAnal body env
+{- OLD comment...
+ This stuff is now instead handled neatly by the fact that AbsApproxFun
+ contains an AbsVal inside it. SLPJ Jan 97
+
+ | isBot abs_body = AbsBot
-- It's worth checking for a function which is unconditionally
-- bottom. Consider
--
-- alternative here would be to bind g to its exact abstract
-- value, but that entails lots of potential re-computation, at
-- every application of g.)
+-}
widen StrAnal (AbsProd vals) = AbsProd (map (widen StrAnal) vals)
widen StrAnal other_val = other_val
-widen AbsAnal (AbsFun args body env)
- | anyBot (absEval AbsAnal body env) = AbsBot
+widen AbsAnal (AbsFun arg body env)
+ | anyBot abs_body = AbsBot
-- In the absence-analysis case it's *essential* to check
-- that the function has no poison in its body. If it does,
-- anywhere, then the whole function is poisonous.
| otherwise
- = ASSERT (not (null args))
- AbsApproxFun (map (findDemandAbsOnly env body) args)
+ = AbsApproxFun (findDemandAbsOnly env body arg)
+ (widen AbsAnal abs_body)
+ where
+ abs_body = absEval AbsAnal body env
widen AbsAnal (AbsProd vals) = AbsProd (map (widen AbsAnal) vals)
sameVal (AbsProd _) AbsTop = False
sameVal (AbsProd _) AbsBot = False
-sameVal (AbsApproxFun str1) (AbsApproxFun str2) = str1 == str2
-sameVal (AbsApproxFun _) AbsTop = False
-sameVal (AbsApproxFun _) AbsBot = False
+sameVal (AbsApproxFun str1 v1) (AbsApproxFun str2 v2) = str1 == str2 && sameVal v1 v2
+sameVal (AbsApproxFun _ _) AbsTop = False
+sameVal (AbsApproxFun _ _) AbsBot = False
sameVal val1 val2 = panic "sameVal: type mismatch or AbsFun encountered"
\end{code}
evalStrictness WwStrict val = isBot val
evalStrictness WwEnum val = isBot val
-evalStrictness (WwUnpack demand_info) val
+evalStrictness (WwUnpack NewType _ (demand:_)) val
+ = evalStrictness demand val
+
+evalStrictness (WwUnpack DataType _ demand_info) val
= case val of
AbsTop -> False
AbsBot -> True
other -> -- A primitive value should be defined, never bottom;
-- hence this paranoia check
- pprPanic "evalStrictness: WwPrim:" (ppr PprDebug other)
+ pprPanic "evalStrictness: WwPrim:" (ppr other)
\end{code}
For absence analysis, we're interested in whether "poison" in the
evalAbsence (WwLazy True) _ = False -- Can't possibly hit poison
-- with Absent demand
-evalAbsence (WwUnpack demand_info) val
+evalAbsence (WwUnpack NewType _ (demand:_)) val
+ = evalAbsence demand val
+
+evalAbsence (WwUnpack DataType _ demand_info) val
= case val of
AbsTop -> False -- No poison in here
AbsBot -> True -- Pure poison
(Just abs_val, _, _) ->
abs_val -- Bound in the environment
- (Nothing, NoStrictnessInfo, GenForm _ unfolding _) ->
+ (Nothing, NoStrictnessInfo, CoreUnfolding _ _ unfolding) ->
-- We have an unfolding for the expr
-- Assume the unfolding has no free variables since it
-- came from inside the Id
(Nothing, strictness_info, _) ->
- -- Includes MagicForm, IWantToBeINLINEd, NoUnfoldingDetails
+ -- Includes MagicUnfolding, NoUnfolding
-- Try the strictness info
absValFromStrictness anal strictness_info
in
- -- pprTrace "absId:" (ppBesides [ppr PprDebug var, ppStr "=:", pp_anal anal, ppStr ":=",ppr PprDebug result]) $
+ -- pprTrace "absId:" (hcat [ppr var, ptext SLIT("=:"), pp_anal anal, text SLIT(":="),ppr result]) $
result
where
- pp_anal StrAnal = ppStr "STR"
- pp_anal AbsAnal = ppStr "ABS"
+ pp_anal StrAnal = ptext SLIT("STR")
+ pp_anal AbsAnal = ptext SLIT("ABS")
absEvalAtom anal (VarArg v) env = absId anal v env
absEvalAtom anal (LitArg _) env = AbsTop
-- For absence analysis, we want to see if the poison shows up...
absEval anal (Con con as) env
- | has_single_con
- = AbsProd [absEvalAtom anal a env | a <- as, isValArg a]
+ | isProductTyCon (dataConTyCon con)
+ = --pprTrace "absEval.Con" (cat[ text "con: ", (ppr con), text "args: ", interppSP as]) $
+ AbsProd [absEvalAtom anal a env | a <- as, isValArg a]
| otherwise -- Not single-constructor
= case anal of
if any anyBot [absEvalAtom AbsAnal a env | a <- as, isValArg a]
then AbsBot
else AbsTop
- where
- has_single_con = maybeToBool (maybeTyConSingleCon (dataConTyCon con))
\end{code}
\begin{code}
absEval anal (Lam (ValBinder binder) body) env
- = AbsFun [binder] body env
+ = AbsFun binder body env
absEval anal (Lam other_binder expr) env
= absEval anal expr env
absEval anal (App f a) env | isValArg a
{-
(case anal of
StrAnal -> id
- _ -> pprTrace "absCase:ABS:" (ppAbove (ppCat [ppr PprDebug expr, ppr PprDebug result, ppr PprDebug expr_val, ppr PprDebug abs_deflt, ppr PprDebug abs_alts]) (ppr PprDebug (keysFM env `zip` eltsFM env)))
+ _ -> pprTrace "absCase:ABS:" (($$) (hsep [ppr expr, ppr result, ppr expr_val, ppr abs_deflt, ppr abs_alts]) (ppr (keysFM env `zip` eltsFM env)))
)
-}
result
an augmented environment.
\begin{code}
-absApply anal (AbsFun [binder] body env) arg
+absApply anal (AbsFun binder body env) arg
= absEval anal body (addOneToAbsValEnv env binder arg)
-
-absApply anal (AbsFun (binder:bs) body env) arg
- = AbsFun bs body (addOneToAbsValEnv env binder arg)
\end{code}
\begin{code}
-absApply StrAnal (AbsApproxFun (arg1_demand:ds)) arg
- = if evalStrictness arg1_demand arg
+absApply StrAnal (AbsApproxFun demand val) arg
+ = if evalStrictness demand arg
then AbsBot
- else case ds of
- [] -> AbsTop
- other -> AbsApproxFun ds
+ else val
-absApply AbsAnal (AbsApproxFun (arg1_demand:ds)) arg
- = if evalAbsence arg1_demand arg
+absApply AbsAnal (AbsApproxFun demand val) arg
+ = if evalAbsence demand arg
then AbsBot
- else case ds of
- [] -> AbsTop
- other -> AbsApproxFun ds
+ else val
#ifdef DEBUG
-absApply anal (AbsApproxFun []) arg = panic ("absApply: Duff function: AbsApproxFun." ++ show anal)
-absApply anal (AbsFun [] _ _) arg = panic ("absApply: Duff function: AbsFun." ++ show anal)
-absApply anal (AbsProd _) arg = panic ("absApply: Duff function: AbsProd." ++ show anal)
+absApply anal f@(AbsProd _) arg = pprPanic ("absApply: Duff function: AbsProd." ++ show anal) ((ppr f) <+> (ppr arg))
#endif
\end{code}
See notes on @addStrictnessInfoToId@.
\begin{code}
-findStrictness :: StrAnalFlags
- -> [Type] -- Types of args in which strictness is wanted
+findStrictness :: [Type] -- Types of args in which strictness is wanted
-> AbsVal -- Abstract strictness value of function
-> AbsVal -- Abstract absence value of function
-> [Demand] -- Resulting strictness annotation
-findStrictness strflags [] str_val abs_val = []
+findStrictness [] str_val abs_val = []
-findStrictness strflags (ty:tys) str_val abs_val
+findStrictness (ty:tys) str_val abs_val
= let
- demand = findRecDemand strflags [] str_fn abs_fn ty
+ demand = findRecDemand str_fn abs_fn ty
str_fn val = absApply StrAnal str_val val
abs_fn val = absApply AbsAnal abs_val val
- demands = findStrictness strflags tys
+ demands = findStrictness tys
(absApply StrAnal str_val AbsTop)
(absApply AbsAnal abs_val AbsTop)
in
\begin{code}
findDemandStrOnly str_env expr binder -- Only strictness environment available
- = findRecDemand strflags [] str_fn abs_fn (idType binder)
+ = findRecDemand str_fn abs_fn (idType binder)
where
str_fn val = absEval StrAnal expr (addOneToAbsValEnv str_env binder val)
abs_fn val = AbsBot -- Always says poison; so it looks as if
-- nothing is absent; safe
- strflags = getStrAnalFlags str_env
findDemandAbsOnly abs_env expr binder -- Only absence environment available
- = findRecDemand strflags [] str_fn abs_fn (idType binder)
+ = findRecDemand str_fn abs_fn (idType binder)
where
str_fn val = AbsBot -- Always says non-termination;
-- that'll make findRecDemand peer into the
-- structure of the value.
abs_fn val = absEval AbsAnal expr (addOneToAbsValEnv abs_env binder val)
- strflags = getStrAnalFlags abs_env
findDemand str_env abs_env expr binder
- = findRecDemand strflags [] str_fn abs_fn (idType binder)
+ = findRecDemand str_fn abs_fn (idType binder)
where
str_fn val = absEval StrAnal expr (addOneToAbsValEnv str_env binder val)
abs_fn val = absEval AbsAnal expr (addOneToAbsValEnv abs_env binder val)
- strflags = getStrAnalFlags str_env
\end{code}
@findRecDemand@ is where we finally convert strictness/absence info
Ho hum.
\begin{code}
-findRecDemand :: StrAnalFlags
- -> [TyCon] -- TyCons already seen; used to avoid
- -- zooming into recursive types
- -> (AbsVal -> AbsVal) -- The strictness function
+findRecDemand :: (AbsVal -> AbsVal) -- The strictness function
-> (AbsVal -> AbsVal) -- The absence function
-> Type -- The type of the argument
-> Demand
-findRecDemand strflags seen str_fn abs_fn ty
- = if isPrimType ty then -- It's a primitive type!
+findRecDemand str_fn abs_fn ty
+ = if isUnpointedType ty then -- It's a primitive type!
wwPrim
else if not (anyBot (abs_fn AbsBot)) then -- It's absent
-- We prefer absence over strictness: see NOTE above.
WwLazy True
- else if not (all_strict ||
- (num_strict && is_numeric_type ty) ||
- (isBot (str_fn AbsBot))) then
+ else if not (opt_AllStrict ||
+ (opt_NumbersStrict && is_numeric_type ty) ||
+ (isBot (str_fn AbsBot))) then
WwLazy False -- It's not strict and we're not pretending
else -- It's strict (or we're pretending it is)!
- case (maybeAppDataTyConExpandingDicts ty) of
+ case (splitAlgTyConApp_maybe ty) of
Nothing -> wwStrict
- Just (tycon,tycon_arg_tys,[data_con]) | tycon `not_elem` seen ->
- -- Single constructor case, tycon not already seen higher up
+ Just (tycon,tycon_arg_tys,[data_con]) | isProductTyCon tycon ->
+ -- Non-recursive, single constructor case
let
cmpnt_tys = dataConArgTys data_con tycon_arg_tys
prod_len = length cmpnt_tys
+ in
+
+ if isNewTyCon tycon then -- A newtype!
+ ASSERT( null (tail cmpnt_tys) )
+ let
+ demand = findRecDemand str_fn abs_fn (head cmpnt_tys)
+ in
+ case demand of -- No point in unpacking unless there is more to see inside
+ WwUnpack _ _ _ -> wwUnpackNew demand
+ other -> wwStrict
+ else -- A data type!
+ let
compt_strict_infos
- = [ findRecDemand strflags (tycon:seen)
+ = [ findRecDemand
(\ cmpnt_val ->
str_fn (mkMainlyTopProd prod_len i cmpnt_val)
)
if null compt_strict_infos then
if isEnumerationTyCon tycon then wwEnum else wwStrict
else
- wwUnpack compt_strict_infos
- where
- not_elem = isn'tIn "findRecDemand"
+ wwUnpackData compt_strict_infos
Just (tycon,_,_) ->
-- Multi-constr data types, *or* an abstract data
else
wwStrict
where
- (all_strict, num_strict) = strflags
-
is_numeric_type ty
- = case (maybeAppDataTyConExpandingDicts ty) of -- NB: duplicates stuff done above
+ = case (splitAlgTyConApp_maybe ty) of -- NB: duplicates stuff done above
Nothing -> False
Just (tycon, _, _)
| tycon `is_elem`
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