StrictnessInfo(..),
mkStrictnessInfo, noStrictnessInfo,
ppStrictnessInfo,isBottomingStrictness,
-
strictnessInfo, setStrictnessInfo,
+ -- Usage generalisation
+ TyGenInfo(..),
+ tyGenInfo, setTyGenInfo,
+ noTyGenInfo, isNoTyGenInfo, ppTyGenInfo, tyGenInfoString,
+
-- Worker
WorkerInfo(..), workerExists, wrapperArity, workerId,
workerInfo, setWorkerInfo, ppWorkerInfo,
import CoreSyn
+import Type ( Type, usOnce )
import PrimOp ( PrimOp )
import Var ( Id )
import BasicTypes ( OccInfo(..), isFragileOcc, isDeadOcc, seqOccInfo, isLoopBreaker,
)
import DataCon ( DataCon )
import FieldLabel ( FieldLabel )
+import Type ( usOnce, usMany )
import Demand -- Lots of stuff
import Outputable
+import Util ( seqList )
infixl 1 `setDemandInfo`,
+ `setTyGenInfo`,
`setStrictnessInfo`,
`setSpecInfo`,
`setArityInfo`,
`setUnfoldingInfo`,
`setCprInfo`,
`setWorkerInfo`,
+ `setLBVarInfo`,
`setCafInfo`,
`setOccInfo`
-- infixl so you can say (id `set` a `set` b)
arityInfo :: ArityInfo, -- Its arity
demandInfo :: Demand, -- Whether or not it is definitely demanded
specInfo :: CoreRules, -- Specialisations of this function which exist
+ tyGenInfo :: TyGenInfo, -- Restrictions on usage-generalisation of this Id
strictnessInfo :: StrictnessInfo, -- Strictness properties
workerInfo :: WorkerInfo, -- Pointer to Worker Function
unfoldingInfo :: Unfolding, -- Its unfolding
seqArity (arityInfo info) `seq`
seqDemand (demandInfo info) `seq`
seqRules (specInfo info) `seq`
+ seqTyGenInfo (tyGenInfo info) `seq`
seqStrictnessInfo (strictnessInfo info) `seq`
seqWorker (workerInfo info) `seq`
\begin{code}
setWorkerInfo info wk = wk `seq` info { workerInfo = wk }
setSpecInfo info sp = PSEQ sp (info { specInfo = sp })
+setTyGenInfo info tg = tg `seq` info { tyGenInfo = tg }
setInlinePragInfo info pr = pr `seq` info { inlinePragInfo = pr }
setOccInfo info oc = oc `seq` info { occInfo = oc }
setStrictnessInfo info st = st `seq` info { strictnessInfo = st }
arityInfo = UnknownArity,
demandInfo = wwLazy,
specInfo = emptyCoreRules,
+ tyGenInfo = noTyGenInfo,
workerInfo = NoWorker,
strictnessInfo = NoStrictnessInfo,
unfoldingInfo = noUnfolding,
%************************************************************************
+%* *
+\subsection[TyGen-IdInfo]{Type generalisation info about an @Id@}
+%* *
+%************************************************************************
+
+Certain passes (notably usage inference) may change the type of an
+identifier, modifying all in-scope uses of that identifier
+appropriately to maintain type safety.
+
+However, some identifiers must not have their types changed in this
+way, because their types are conjured up in the front end of the
+compiler rather than being read from the interface file. Default
+methods, dictionary functions, record selectors, and others are in
+this category. (see comment at TcClassDcl.tcClassSig).
+
+To indicate this property, such identifiers are marked TyGenNever.
+
+Furthermore, if the usage inference generates a usage-specialised
+variant of a function, we must NOT re-infer a fully-generalised type
+at the next inference. This finer property is indicated by a
+TyGenUInfo on the identifier.
+
+\begin{code}
+data TyGenInfo
+ = NoTyGenInfo -- no restriction on type generalisation
+
+ | TyGenUInfo [Maybe Type] -- restrict generalisation of this Id to
+ -- preserve specified usage annotations
+
+ | TyGenNever -- never generalise the type of this Id
+
+ deriving ( Eq )
+\end{code}
+
+For TyGenUInfo, the list has one entry for each usage annotation on
+the type of the Id, in left-to-right pre-order (annotations come
+before the type they annotate). Nothing means no restriction; Just
+usOnce or Just usMany forces that annotation to that value. Other
+usage annotations are illegal.
+
+\begin{code}
+seqTyGenInfo :: TyGenInfo -> ()
+seqTyGenInfo NoTyGenInfo = ()
+seqTyGenInfo (TyGenUInfo us) = seqList us ()
+seqTyGenInfo TyGenNever = ()
+
+noTyGenInfo :: TyGenInfo
+noTyGenInfo = NoTyGenInfo
+
+isNoTyGenInfo :: TyGenInfo -> Bool
+isNoTyGenInfo NoTyGenInfo = True
+isNoTyGenInfo _ = False
+
+-- NB: There's probably no need to write this information out to the interface file.
+-- Why? Simply because imported identifiers never get their types re-inferred.
+-- But it's definitely nice to see in dumps, it for debugging purposes.
+
+ppTyGenInfo :: TyGenInfo -> SDoc
+ppTyGenInfo NoTyGenInfo = empty
+ppTyGenInfo (TyGenUInfo us) = ptext SLIT("__G") <+> text (tyGenInfoString us)
+ppTyGenInfo TyGenNever = ptext SLIT("__G N")
+
+tyGenInfoString us = map go us
+ where go Nothing = 'x' -- for legibility, choose
+ go (Just u) | u == usOnce = '1' -- chars with identity
+ | u == usMany = 'M' -- Z-encoding.
+ go other = pprPanic "IdInfo.tyGenInfoString: unexpected annotation" (ppr other)
+
+instance Outputable TyGenInfo where
+ ppr = ppTyGenInfo
+
+instance Show TyGenInfo where
+ showsPrec p c = showsPrecSDoc p (ppr c)
+\end{code}
+
+
+%************************************************************************
%* *
\subsection[worker-IdInfo]{Worker info about an @Id@}
%* *
data LBVarInfo
= NoLBVarInfo
- | IsOneShotLambda -- The lambda that binds this Id is applied
- -- at most once
+ | LBVarInfo Type -- The lambda that binds this Id has this usage
+ -- annotation (i.e., if ==usOnce, then the
+ -- lambda is applied at most once).
+ -- The annotation's kind must be `$'
-- HACK ALERT! placing this info here is a short-term hack,
-- but it minimises changes to the rest of the compiler.
-- Hack agreed by SLPJ/KSW 1999-04.
-- not safe to print or parse LBVarInfo because it is not really a
-- property of the definition, but a property of the context.
pprLBVarInfo NoLBVarInfo = empty
-pprLBVarInfo IsOneShotLambda = getPprStyle $ \ sty ->
- if ifaceStyle sty then empty
- else ptext SLIT("OneShot")
+pprLBVarInfo (LBVarInfo u) | u == usOnce
+ = getPprStyle $ \ sty ->
+ if ifaceStyle sty
+ then empty
+ else ptext SLIT("OneShot")
+ | otherwise
+ = empty
instance Outputable LBVarInfo where
ppr = pprLBVarInfo
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