[project @ 2000-03-23 17:45:17 by simonpj]

[ghc-hetmet.git] / ghc / compiler / stranal / SaLib.lhs

diff --git a/ghc/compiler/stranal/SaLib.lhs b/ghc/compiler/stranal/SaLib.lhs
index 563ecc6..813410c 100644 (file)
--- a/ghc/compiler/stranal/SaLib.lhs
+++ b/ghc/compiler/stranal/SaLib.lhs
@@ -1,5 +1,5 @@
 %
-% (c) The GRASP/AQUA Project, Glasgow University, 1993-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
 %
 \section[SaLib]{Basic datatypes, functions for the strictness analyser}
 
@@ -10,6 +10,7 @@ module SaLib (
        AbsVal(..),
        AnalysisKind(..),
        AbsValEnv{-abstract-}, StrictEnv, AbsenceEnv,
+       mkAbsApproxFun,
        nullAbsValEnv, addOneToAbsValEnv, growAbsValEnvList,
        lookupAbsValEnv,
        absValFromStrictness
@@ -17,15 +18,13 @@ module SaLib (
 
 #include "HsVersions.h"
 
+import Id              ( Id )
+import Type            ( Type )
 import CoreSyn         ( CoreExpr )
-import Id              ( nullIdEnv, addOneToIdEnv, growIdEnvList,
-                         lookupIdEnv, IdEnv,
-                         GenId{-instance Outputable-}, Id
-                       )
+import VarEnv
 import IdInfo          ( StrictnessInfo(..) )
-import Demand          ( Demand{-instance Outputable-} )
+import Demand          ( Demand, pprDemands )
 import Outputable
-import PprType         ( GenType{-instance Outputable-} )
 \end{code}
 
 %************************************************************************
@@ -60,25 +59,31 @@ data AbsVal
                            --    AbsProd [AbsBot, ..., AbsBot]
 
   | AbsFun                 -- An abstract function, with the given:
-           Id              -- argument
-           CoreExpr        -- 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
+           [Demand]        -- approximation to a function value.  It's an
            AbsVal          -- abstract function which is strict in its
-                           -- argument if the  Demand so indicates.
+                           -- 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 AbsTop = ptext SLIT("AbsTop")
     ppr AbsBot = ptext SLIT("AbsBot")
     ppr (AbsProd prod) = hsep [ptext SLIT("AbsProd"), ppr prod]
-    ppr (AbsFun arg body env)
-      = hsep [ptext SLIT("AbsFun{"), ppr arg,
-              ptext SLIT("???"), -- text "}{env:", ppr (keysFM env `zip` eltsFM env),
-              char '}' ]
-    ppr (AbsApproxFun demand val)
-      = hsep [ptext SLIT("AbsApprox "), ppr demand, ppr val]
+    ppr (AbsFun bndr_ty body) = ptext SLIT("AbsFun")
+    ppr (AbsApproxFun demands val)
+      = ptext SLIT("AbsApprox") <+> brackets (interpp'SP demands) <+> ppr val
 \end{code}
 
 %-----------
@@ -94,22 +99,26 @@ type StrictEnv  = AbsValEnv -- Environment for strictness analysis
 type AbsenceEnv = AbsValEnv    -- Environment for absence analysis
 
 nullAbsValEnv -- this is the one and only way to create AbsValEnvs
-  = AbsValEnv nullIdEnv
+  = AbsValEnv emptyVarEnv
 
-addOneToAbsValEnv (AbsValEnv idenv) y z = AbsValEnv (addOneToIdEnv idenv y z)
-growAbsValEnvList (AbsValEnv idenv) ys  = AbsValEnv (growIdEnvList idenv ys)
+addOneToAbsValEnv (AbsValEnv idenv) y z = AbsValEnv (extendVarEnv idenv y z)
+growAbsValEnvList (AbsValEnv idenv) ys  = AbsValEnv (extendVarEnvList idenv ys)
 
 lookupAbsValEnv (AbsValEnv idenv) y
-  = lookupIdEnv idenv y
+  = lookupVarEnv idenv y
 \end{code}
 
 \begin{code}
 absValFromStrictness :: AnalysisKind -> StrictnessInfo -> AbsVal
 
-absValFromStrictness anal NoStrictnessInfo            = AbsTop
-
-absValFromStrictness StrAnal BottomGuaranteed         = AbsBot -- Guaranteed bottom
-absValFromStrictness AbsAnal BottomGuaranteed         = AbsTop -- Check for poison in
-                                                               -- arguments (if any)
-absValFromStrictness anal (StrictnessInfo args_info _) = foldr AbsApproxFun AbsTop args_info
+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}