%
-% (c) The GRASP/AQUA Project, Glasgow University, 1993-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
%
\section[SaLib]{Basic datatypes, functions for the strictness analyser}
See also: the ``library'' for the ``back end'' (@SaBackLib@).
\begin{code}
-#include "HsVersions.h"
+#ifndef OLD_STRICTNESS
+module SaLib () where
+#else
module SaLib (
AbsVal(..),
AnalysisKind(..),
- AbsValEnv{-abstract-}, StrictEnv(..), AbsenceEnv(..),
- StrAnalFlags(..), getStrAnalFlags,
+ AbsValEnv{-abstract-}, StrictEnv, AbsenceEnv,
+ mkAbsApproxFun,
nullAbsValEnv, addOneToAbsValEnv, growAbsValEnvList,
lookupAbsValEnv,
- absValFromStrictness,
-
- -- and to make the interface self-sufficient...
- CoreExpr, Id, IdEnv(..), UniqFM, Unique,
- Demand, PlainCoreExpr(..)
+ absValFromStrictness
) where
-import IdEnv
-import IdInfo
---import FiniteMap -- debugging only
+#include "HsVersions.h"
+
+import Type ( Type )
+import VarEnv
+import IdInfo ( StrictnessInfo(..) )
+import Demand ( Demand )
import Outputable
-import PlainCore
-import Pretty
-import Util -- for pragmas only
\end{code}
%************************************************************************
data AnalysisKind
= StrAnal -- We're doing strictness analysis
| AbsAnal -- We're doing absence analysis
- deriving Text
+ deriving Show
\end{code}
@AbsVal@ is the data type of HNF abstract values.
| AbsBot -- An expression whose abstract value is
-- AbsBot is sure to fail to terminate.
-- AbsBot represents the abstract
- -- *function* bottom too.
+ -- *function* bottom too.
| AbsProd [AbsVal] -- (Lifted) product of abstract values
-- "Lifted" means that AbsBot is *different* from
-- AbsProd [AbsBot, ..., AbsBot]
| AbsFun -- An abstract function, with the given:
- [Id] -- arguments
- PlainCoreExpr -- body
- AbsValEnv -- and environment
+ Type -- Type of the *argument* to the function
+ (AbsVal -> AbsVal) -- The function
| AbsApproxFun -- This is used to represent a coarse
[Demand] -- approximation to a function value. It's an
- -- abstract function which is strict in its i'th
- -- argument if the i'th element of the Demand
- -- list so indicates.
- -- The list of arguments is always non-empty.
- -- In effect, AbsApproxFun [] = AbsTop
+ AbsVal -- abstract function which is strict in its
+ -- arguments if the Demand so indicates.
+ -- INVARIANT: the [Demand] is non-empty
+
+ -- AbsApproxFun has to take a *list* of demands, no just one,
+ -- because function spaces are now lifted. Hence, (f bot top)
+ -- might be bot, but the partial application (f bot) is a *function*,
+ -- not bot.
+
+mkAbsApproxFun :: Demand -> AbsVal -> AbsVal
+mkAbsApproxFun d (AbsApproxFun ds val) = AbsApproxFun (d:ds) val
+mkAbsApproxFun d val = AbsApproxFun [d] val
instance Outputable AbsVal where
- ppr sty AbsTop = ppStr "AbsTop"
- ppr sty AbsBot = ppStr "AbsBot"
- ppr sty (AbsProd prod) = ppCat [ppStr "AbsProd", ppr sty prod]
- ppr sty (AbsFun args body env)
- = ppCat [ppStr "AbsFun{", ppr sty args,
- ppStr "???", -- ppStr "}{env:", ppr sty (keysFM env `zip` eltsFM env),
- ppStr "}" ]
- ppr sty (AbsApproxFun demands)
- = ppCat [ppStr "AbsApprox{", ppr sty demands, ppStr "}" ]
+ ppr AbsTop = ptext SLIT("AbsTop")
+ ppr AbsBot = ptext SLIT("AbsBot")
+ ppr (AbsProd prod) = hsep [ptext SLIT("AbsProd"), ppr prod]
+ ppr (AbsFun bndr_ty body) = ptext SLIT("AbsFun")
+ ppr (AbsApproxFun demands val)
+ = ptext SLIT("AbsApprox") <+> brackets (interpp'SP demands) <+> ppr val
\end{code}
%-----------
An @AbsValEnv@ maps @Ids@ to @AbsVals@. Any unbound @Ids@ are
implicitly bound to @AbsTop@, the completely uninformative,
-pessimistic value---see @absEval@ of a @CoVar@.
+pessimistic value---see @absEval@ of a @Var@.
\begin{code}
-data AbsValEnv = AbsValEnv StrAnalFlags (IdEnv AbsVal)
-
-type StrAnalFlags
- = (Bool, -- True <=> AllStrict flag is set
- Bool) -- True <=> NumbersStrict flag is set
+newtype AbsValEnv = AbsValEnv (IdEnv AbsVal)
type StrictEnv = AbsValEnv -- Environment for strictness analysis
type AbsenceEnv = AbsValEnv -- Environment for absence analysis
-nullAbsValEnv flags -- this is the one and only way to create AbsValEnvs
- = AbsValEnv flags nullIdEnv
-
-addOneToAbsValEnv (AbsValEnv x idenv) y z = AbsValEnv x (addOneToIdEnv idenv y z)
-growAbsValEnvList (AbsValEnv x idenv) ys = AbsValEnv x (growIdEnvList idenv ys)
+nullAbsValEnv -- this is the one and only way to create AbsValEnvs
+ = AbsValEnv emptyVarEnv
-lookupAbsValEnv (AbsValEnv _ idenv) y
- = lookupIdEnv idenv y
+addOneToAbsValEnv (AbsValEnv idenv) y z = AbsValEnv (extendVarEnv idenv y z)
+growAbsValEnvList (AbsValEnv idenv) ys = AbsValEnv (extendVarEnvList idenv ys)
-getStrAnalFlags (AbsValEnv flags _) = flags
+lookupAbsValEnv (AbsValEnv idenv) y
+ = lookupVarEnv idenv y
\end{code}
\begin{code}
absValFromStrictness :: AnalysisKind -> StrictnessInfo -> AbsVal
-absValFromStrictness anal NoStrictnessInfo = AbsTop
+absValFromStrictness anal NoStrictnessInfo = AbsTop
+absValFromStrictness anal (StrictnessInfo args_info bot_result)
+ = case args_info of -- Check the invariant that the arg list on
+ [] -> res -- AbsApproxFun is non-empty
+ _ -> AbsApproxFun args_info res
+ where
+ res | not bot_result = AbsTop
+ | otherwise = case anal of
+ StrAnal -> AbsBot
+ AbsAnal -> AbsTop
+\end{code}
-absValFromStrictness StrAnal BottomGuaranteed = AbsBot -- Guaranteed bottom
-absValFromStrictness AbsAnal BottomGuaranteed = AbsTop -- Check for poison in
- -- arguments (if any)
-absValFromStrictness anal (StrictnessInfo [] _) = AbsTop
-absValFromStrictness anal (StrictnessInfo args_info _) = AbsApproxFun args_info
+\begin{code}
+#endif /* OLD_STRICTNESS */
\end{code}
projects / ghc-hetmet.git / blobdiff