-[A BIT DATED [WDP]]
-
-The @Id@ datatype describes {\em values}. The basic things we want to
-know: (1)~a value's {\em type} (@idType@ is a very common
-operation in the compiler); and (2)~what ``flavour'' of value it might
-be---for example, it can be terribly useful to know that a value is a
-class method.
-
-\begin{description}
-%----------------------------------------------------------------------
-\item[@DataConId@:] For the data constructors declared by a @data@
-declaration. Their type is kept in {\em two} forms---as a regular
-@Type@ (in the usual place), and also in its constituent pieces (in
-the ``details''). We are frequently interested in those pieces.
-
-%----------------------------------------------------------------------
-\item[@TupleConId@:] This is just a special shorthand for @DataCons@ for
-the infinite family of tuples.
-
-%----------------------------------------------------------------------
-\item[@ImportedId@:] These are values defined outside this module.
-{\em Everything} we want to know about them must be stored here (or in
-their @IdInfo@).
-
-%----------------------------------------------------------------------
-\item[@PreludeId@:] ToDo
-
-%----------------------------------------------------------------------
-\item[@TopLevId@:] These are values defined at the top-level in this
-module; i.e., those which {\em might} be exported (hence, a
-@Name@). It does {\em not} include those which are moved to the
-top-level through program transformations.
-
-We also guarantee that @TopLevIds@ will {\em stay} at top-level.
-Theoretically, they could be floated inwards, but there's no known
-advantage in doing so. This way, we can keep them with the same
-@Unique@ throughout (no cloning), and, in general, we don't have to be
-so paranoid about them.
-
-In particular, we had the following problem generating an interface:
-We have to ``stitch together'' info (1)~from the typechecker-produced
-global-values list (GVE) and (2)~from the STG code [which @Ids@ have
-what arities]. If the @Uniques@ on the @TopLevIds@ can {\em change}
-between (1) and (2), you're sunk!
-
-%----------------------------------------------------------------------
-\item[@MethodSelId@:] A selector from a dictionary; it may select either
-a method or a dictionary for one of the class's superclasses.
-
-%----------------------------------------------------------------------
-\item[@DictFunId@:]
-
-@mkDictFunId [a,b..] theta C T@ is the function derived from the
-instance declaration
-
- instance theta => C (T a b ..) where
- ...
-
-It builds function @Id@ which maps dictionaries for theta,
-to a dictionary for C (T a b ..).
-
-*Note* that with the ``Mark Jones optimisation'', the theta may
-include dictionaries for the immediate superclasses of C at the type
-(T a b ..).
-
-%----------------------------------------------------------------------
-\item[@InstId@:]
-
-%----------------------------------------------------------------------
-\item[@SpecId@:]
-
-%----------------------------------------------------------------------
-\item[@WorkerId@:]
-
-%----------------------------------------------------------------------
-\item[@LocalId@:] A purely-local value, e.g., a function argument,
-something defined in a @where@ clauses, ... --- but which appears in
-the original program text.
-
-%----------------------------------------------------------------------
-\item[@SysLocalId@:] Same as a @LocalId@, except does {\em not} appear in
-the original program text; these are introduced by the compiler in
-doing its thing.
-
-%----------------------------------------------------------------------
-\item[@SpecPragmaId@:] Introduced by the compiler to record
-Specialisation pragmas. It is dead code which MUST NOT be removed
-before specialisation.
-\end{description}
-
-Further remarks:
-\begin{enumerate}
-%----------------------------------------------------------------------
-\item
-
-@DataCons@ @TupleCons@, @Importeds@, @TopLevIds@, @SuperDictSelIds@,
-@MethodSelIds@, @DictFunIds@, and @DefaultMethodIds@ have the following
-properties:
-\begin{itemize}
-\item
-They have no free type variables, so if you are making a
-type-variable substitution you don't need to look inside them.
-\item
-They are constants, so they are not free variables. (When the STG
-machine makes a closure, it puts all the free variables in the
-closure; the above are not required.)
-\end{itemize}
-Note that @InstIds@, @Locals@ and @SysLocals@ {\em may} have the above
-properties, but they may not.
-\end{enumerate}
-
-%************************************************************************
-%* *
-\subsection[Id-general-funs]{General @Id@-related functions}
-%* *
-%************************************************************************
-
-\begin{code}
-unsafeGenId2Id :: GenId ty -> Id
-unsafeGenId2Id (Id u n ty d p i) = Id u n (panic "unsafeGenId2Id:ty") d p i
-
-isDataCon id = is_data (unsafeGenId2Id id)
- where
- is_data (Id _ _ _ (DataConId _ _ _ _ _ _ _) _ _) = True
- is_data (Id _ _ _ (TupleConId _) _ _) = True
- is_data (Id _ _ _ (SpecId unspec _ _) _ _) = is_data unspec
- is_data other = False
-
-
-isTupleCon id = is_tuple (unsafeGenId2Id id)
- where
- is_tuple (Id _ _ _ (TupleConId _) _ _) = True
- is_tuple (Id _ _ _ (SpecId unspec _ _) _ _) = is_tuple unspec
- is_tuple other = False
-
-{-LATER:
-isSpecId_maybe (Id _ _ _ (SpecId unspec ty_maybes _) _ _)
- = ASSERT(not (maybeToBool (isSpecId_maybe unspec)))
- Just (unspec, ty_maybes)
-isSpecId_maybe other_id
- = Nothing
-
-isSpecPragmaId_maybe (Id _ _ _ (SpecPragmaId specid _) _ _)
- = Just specid
-isSpecPragmaId_maybe other_id
- = Nothing
--}
-\end{code}
-
-@toplevelishId@ tells whether an @Id@ {\em may} be defined in a nested
-@let(rec)@ (returns @False@), or whether it is {\em sure} to be
-defined at top level (returns @True@). This is used to decide whether
-the @Id@ is a candidate free variable. NB: you are only {\em sure}
-about something if it returns @True@!
-
-\begin{code}
-toplevelishId :: Id -> Bool
-idHasNoFreeTyVars :: Id -> Bool
-
-toplevelishId (Id _ _ _ details _ _)
- = chk details
- where
- chk (DataConId _ _ _ _ _ _ _) = True
- chk (TupleConId _) = True
- chk (RecordSelId _) = True
- chk ImportedId = True
- chk PreludeId = True
- chk TopLevId = True -- NB: see notes
- chk (SuperDictSelId _ _) = True
- chk (MethodSelId _ _) = True
- chk (DefaultMethodId _ _ _) = True
- chk (DictFunId _ _ _) = True
- chk (ConstMethodId _ _ _ _) = True
- chk (SpecId unspec _ _) = toplevelishId unspec
- -- depends what the unspecialised thing is
- chk (WorkerId unwrkr) = toplevelishId unwrkr
- chk (InstId _) = False -- these are local
- chk (LocalId _) = False
- chk (SysLocalId _) = False
- chk (SpecPragmaId _ _) = False
-
-idHasNoFreeTyVars (Id _ _ _ details _ info)
- = chk details
- where
- chk (DataConId _ _ _ _ _ _ _) = True
- chk (TupleConId _) = True
- chk (RecordSelId _) = True
- chk ImportedId = True
- chk PreludeId = True
- chk TopLevId = True
- chk (SuperDictSelId _ _) = True
- chk (MethodSelId _ _) = True
- chk (DefaultMethodId _ _ _) = True
- chk (DictFunId _ _ _) = True
- chk (ConstMethodId _ _ _ _) = True
- chk (WorkerId unwrkr) = idHasNoFreeTyVars unwrkr
- chk (SpecId _ _ no_free_tvs) = no_free_tvs
- chk (InstId no_free_tvs) = no_free_tvs
- chk (LocalId no_free_tvs) = no_free_tvs
- chk (SysLocalId no_free_tvs) = no_free_tvs
- chk (SpecPragmaId _ no_free_tvs) = no_free_tvs
-\end{code}
-
-\begin{code}
-isTopLevId (Id _ _ _ TopLevId _ _) = True
-isTopLevId other = False
-
-isImportedId (Id _ _ _ ImportedId _ _) = True
-isImportedId other = False
-
-isBottomingId (Id _ _ _ _ _ info) = bottomIsGuaranteed (getInfo info)
-
-isSysLocalId (Id _ _ _ (SysLocalId _) _ _) = True
-isSysLocalId other = False
-
-isSpecPragmaId (Id _ _ _ (SpecPragmaId _ _) _ _) = True
-isSpecPragmaId other = False
-
-isMethodSelId (Id _ _ _ (MethodSelId _ _) _ _) = True
-isMethodSelId _ = False
-
-isDefaultMethodId (Id _ _ _ (DefaultMethodId _ _ _) _ _) = True
-isDefaultMethodId other = False
-
-isDefaultMethodId_maybe (Id _ _ _ (DefaultMethodId cls clsop err) _ _)
- = Just (cls, clsop, err)
-isDefaultMethodId_maybe other = Nothing
-
-isDictFunId (Id _ _ _ (DictFunId _ _ _) _ _) = True
-isDictFunId other = False
-
-isConstMethodId (Id _ _ _ (ConstMethodId _ _ _ _) _ _) = True
-isConstMethodId other = False
-
-isConstMethodId_maybe (Id _ _ _ (ConstMethodId cls ty clsop _) _ _)
- = Just (cls, ty, clsop)
-isConstMethodId_maybe other = Nothing
-
-isSuperDictSelId_maybe (Id _ _ _ (SuperDictSelId c sc) _ _) = Just (c, sc)
-isSuperDictSelId_maybe other_id = Nothing
-
-isWorkerId (Id _ _ _ (WorkerId _) _ _) = True
-isWorkerId other = False
-
-{-LATER:
-isWrapperId id = workerExists (getIdStrictness id)
--}
-\end{code}
-
-\begin{code}
-{-LATER:
-pprIdInUnfolding :: IdSet -> Id -> Pretty
-
-pprIdInUnfolding in_scopes v
- = let
- v_ty = idType v
- in
- -- local vars first:
- if v `elementOfUniqSet` in_scopes then
- pprUnique (idUnique v)
-
- -- ubiquitous Ids with special syntax:
- else if v == nilDataCon then
- ppPStr SLIT("_NIL_")
- else if isTupleCon v then
- ppBeside (ppPStr SLIT("_TUP_")) (ppInt (dataConArity v))
-
- -- ones to think about:
- else
- let
- (Id _ _ _ v_details _ _) = v
- in
- case v_details of
- -- these ones must have been exported by their original module
- ImportedId -> pp_full_name
- PreludeId -> pp_full_name
-
- -- these ones' exportedness checked later...
- TopLevId -> pp_full_name
- DataConId _ _ _ _ _ _ _ -> pp_full_name
-
- RecordSelId lbl -> ppr sty lbl
-
- -- class-ish things: class already recorded as "mentioned"
- SuperDictSelId c sc
- -> ppCat [ppPStr SLIT("_SDSEL_"), pp_class c, pp_class sc]
- MethodSelId c o
- -> ppCat [ppPStr SLIT("_METH_"), pp_class c, pp_class_op o]
- DefaultMethodId c o _
- -> ppCat [ppPStr SLIT("_DEFM_"), pp_class c, pp_class_op o]
-
- -- instance-ish things: should we try to figure out
- -- *exactly* which extra instances have to be exported? (ToDo)
- DictFunId c t _
- -> ppCat [ppPStr SLIT("_DFUN_"), pp_class c, pp_type t]
- ConstMethodId c t o _
- -> ppCat [ppPStr SLIT("_CONSTM_"), pp_class c, pp_class_op o, pp_type t]
-
- -- specialisations and workers
- SpecId unspec ty_maybes _
- -> let
- pp = pprIdInUnfolding in_scopes unspec
- in
- ppCat [ppPStr SLIT("_SPEC_"), pp, ppLbrack,
- ppIntersperse pp'SP{-'-} (map pp_ty_maybe ty_maybes),
- ppRbrack]
-
- WorkerId unwrkr
- -> let
- pp = pprIdInUnfolding in_scopes unwrkr
- in
- ppBeside (ppPStr SLIT("_WRKR_ ")) pp
-
- -- anything else? we're nae interested
- other_id -> panic "pprIdInUnfolding:mystery Id"
- where
- ppr_Unfolding = PprUnfolding (panic "Id:ppr_Unfolding")
-
- pp_full_name
- = let
- (m_str, n_str) = moduleNamePair v
-
- pp_n =
- if isLexSym n_str && not (isLexSpecialSym n_str) then
- ppBesides [ppLparen, ppPStr n_str, ppRparen]
- else
- ppPStr n_str
- in
- if isPreludeDefined v then
- pp_n
- else
- ppCat [ppPStr SLIT("_ORIG_"), ppPStr m_str, pp_n]
-
- pp_class :: Class -> Pretty
- pp_class_op :: ClassOp -> Pretty
- pp_type :: Type -> Pretty
- pp_ty_maybe :: Maybe Type -> Pretty
-
- pp_class clas = ppr ppr_Unfolding clas
- pp_class_op op = ppr ppr_Unfolding op
-
- pp_type t = ppBesides [ppLparen, ppr ppr_Unfolding t, ppRparen]
-
- pp_ty_maybe Nothing = ppPStr SLIT("_N_")
- pp_ty_maybe (Just t) = pp_type t
--}
-\end{code}
-
-@whatsMentionedInId@ ferrets out the types/classes/instances on which
-this @Id@ depends. If this Id is to appear in an interface, then
-those entities had Jolly Well be in scope. Someone else up the
-call-tree decides that.
-
-\begin{code}
-{-LATER:
-whatsMentionedInId
- :: IdSet -- Ids known to be in scope
- -> Id -- Id being processed
- -> (Bag Id, Bag TyCon, Bag Class) -- mentioned Ids/TyCons/etc.
-
-whatsMentionedInId in_scopes v
- = let
- v_ty = idType v
-
- (tycons, clss)
- = getMentionedTyConsAndClassesFromType v_ty
-
- result0 id_bag = (id_bag, tycons, clss)
-
- result1 ids tcs cs
- = (ids `unionBags` unitBag v, -- we add v to "mentioned"...
- tcs `unionBags` tycons,
- cs `unionBags` clss)
- in
- -- local vars first:
- if v `elementOfUniqSet` in_scopes then
- result0 emptyBag -- v not added to "mentioned"
-
- -- ones to think about:
- else
- let
- (Id _ _ _ v_details _ _) = v
- in
- case v_details of
- -- specialisations and workers
- SpecId unspec ty_maybes _
- -> let
- (ids2, tcs2, cs2) = whatsMentionedInId in_scopes unspec
- in
- result1 ids2 tcs2 cs2
-
- WorkerId unwrkr
- -> let
- (ids2, tcs2, cs2) = whatsMentionedInId in_scopes unwrkr
- in
- result1 ids2 tcs2 cs2
-
- anything_else -> result0 (unitBag v) -- v is added to "mentioned"
--}
-\end{code}
-
-Tell them who my wrapper function is.
-\begin{code}
-{-LATER:
-myWrapperMaybe :: Id -> Maybe Id
-
-myWrapperMaybe (Id _ _ _ (WorkerId my_wrapper) _ _) = Just my_wrapper
-myWrapperMaybe other_id = Nothing
--}
-\end{code}
-
-\begin{code}
-unfoldingUnfriendlyId -- return True iff it is definitely a bad
- :: Id -- idea to export an unfolding that
- -> Bool -- mentions this Id. Reason: it cannot
- -- possibly be seen in another module.
-
-unfoldingUnfriendlyId id = panic "Id.unfoldingUnfriendlyId"
-{-LATER:
-
-unfoldingUnfriendlyId id
- | not (externallyVisibleId id) -- that settles that...
- = True
-
-unfoldingUnfriendlyId (Id _ _ _ (WorkerId wrapper) _ _)
- = class_thing wrapper
- where
- -- "class thing": If we're going to use this worker Id in
- -- an interface, we *have* to be able to untangle the wrapper's
- -- strictness when reading it back in. At the moment, this
- -- is not always possible: in precisely those cases where
- -- we pass tcGenPragmas a "Nothing" for its "ty_maybe".
-
- class_thing (Id _ _ _ (SuperDictSelId _ _) _ _) = True
- class_thing (Id _ _ _ (MethodSelId _ _) _ _) = True
- class_thing (Id _ _ _ (DefaultMethodId _ _ _) _ _) = True
- class_thing other = False
-
-unfoldingUnfriendlyId (Id _ _ _ (SpecId d@(Id _ _ _ dfun@(DictFunId _ t _)) _ _) _ _)
- -- a SPEC of a DictFunId can end up w/ gratuitous
- -- TyVar(Templates) in the i/face; only a problem
- -- if -fshow-pragma-name-errs; but we can do without the pain.
- -- A HACK in any case (WDP 94/05/02)
- = naughty_DictFunId dfun
-
-unfoldingUnfriendlyId d@(Id _ _ _ dfun@(DictFunId _ t _) _ _)
- = naughty_DictFunId dfun -- similar deal...
-
-unfoldingUnfriendlyId other_id = False -- is friendly in all other cases
-
-naughty_DictFunId :: IdDetails -> Bool
- -- True <=> has a TyVar(Template) in the "type" part of its "name"
-
-naughty_DictFunId (DictFunId _ _ _) = panic "False" -- came from outside; must be OK
-naughty_DictFunId (DictFunId _ ty _)
- = not (isGroundTy ty)
--}
-\end{code}
-
-@externallyVisibleId@: is it true that another module might be
-able to ``see'' this Id?
-
-We need the @toplevelishId@ check as well as @isExported@ for when we
-compile instance declarations in the prelude. @DictFunIds@ are
-``exported'' if either their class or tycon is exported, but, in
-compiling the prelude, the compiler may not recognise that as true.