2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[Id]{@Ids@: Value and constructor identifiers}
10 -- Simple construction
11 mkId, mkVanillaId, mkSysLocal, mkUserLocal,
12 mkTemplateLocals, mkWildId, mkTemplateLocal,
15 idName, idType, idUnique, idInfo,
17 recordSelectorFieldLabel,
20 setIdName, setIdUnique, setIdType, setIdNoDiscard,
21 setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo,
22 zapFragileIdInfo, zapLamIdInfo,
25 omitIfaceSigForId, isDeadBinder,
26 exportWithOrigOccName,
31 -- Inline pragma stuff
32 idInlinePragma, setInlinePragma, modifyInlinePragma,
34 isSpecPragmaId, isRecordSelector,
35 isPrimOpId, isPrimOpId_maybe,
36 isDataConId, isDataConId_maybe, isDataConWrapId, isDataConWrapId_maybe,
38 isExportedId, isUserExportedId,
41 -- One shot lambda stuff
42 isOneShotLambda, setOneShotLambda, clearOneShotLambda,
71 #include "HsVersions.h"
74 import CoreSyn ( Unfolding, CoreRules )
75 import BasicTypes ( Arity )
76 import Var ( Id, DictId,
78 idName, idType, idUnique, idInfo,
79 setIdName, setVarType, setIdUnique,
80 setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo,
84 import Type ( Type, tyVarsOfType, typePrimRep, addFreeTyVars, seqType, splitTyConApp_maybe )
88 import Demand ( Demand, isStrict, wwLazy )
89 import Name ( Name, OccName,
90 mkSysLocalName, mkLocalName,
91 isWiredInName, isUserExportedName,
94 import OccName ( UserFS )
95 import PrimRep ( PrimRep )
96 import PrimOp ( PrimOp, primOpIsCheap )
97 import TysPrim ( statePrimTyCon )
98 import FieldLabel ( FieldLabel(..) )
99 import SrcLoc ( SrcLoc )
100 import Unique ( Unique, mkBuiltinUnique, getBuiltinUniques )
103 infixl 1 `setIdUnfolding`,
108 `setIdSpecialisation`,
114 -- infixl so you can say (id `set` a `set` b)
119 %************************************************************************
121 \subsection{Simple Id construction}
123 %************************************************************************
125 Absolutely all Ids are made by mkId. It
126 a) Pins free-tyvar-info onto the Id's type,
127 where it can easily be found.
128 b) Ensures that exported Ids are
131 mkId :: Name -> Type -> IdInfo -> Id
132 mkId name ty info = mkIdVar name (addFreeTyVars ty) info'
134 info' | isUserExportedName name = setNoDiscardInfo info
139 mkVanillaId :: Name -> Type -> Id
140 mkVanillaId name ty = mkId name ty vanillaIdInfo
142 -- SysLocal: for an Id being created by the compiler out of thin air...
143 -- UserLocal: an Id with a name the user might recognize...
144 mkUserLocal :: OccName -> Unique -> Type -> SrcLoc -> Id
145 mkSysLocal :: UserFS -> Unique -> Type -> Id
147 mkSysLocal fs uniq ty = mkVanillaId (mkSysLocalName uniq fs) ty
148 mkUserLocal occ uniq ty loc = mkVanillaId (mkLocalName uniq occ loc) ty
151 Make some local @Ids@ for a template @CoreExpr@. These have bogus
152 @Uniques@, but that's OK because the templates are supposed to be
153 instantiated before use.
156 -- "Wild Id" typically used when you need a binder that you don't expect to use
157 mkWildId :: Type -> Id
158 mkWildId ty = mkSysLocal SLIT("wild") (mkBuiltinUnique 1) ty
160 -- "Template locals" typically used in unfoldings
161 mkTemplateLocals :: [Type] -> [Id]
162 mkTemplateLocals tys = zipWith (mkSysLocal SLIT("tpl"))
163 (getBuiltinUniques (length tys))
166 mkTemplateLocal :: Int -> Type -> Id
167 mkTemplateLocal i ty = mkSysLocal SLIT("tpl") (mkBuiltinUnique i) ty
171 %************************************************************************
173 \subsection[Id-general-funs]{General @Id@-related functions}
175 %************************************************************************
178 idFreeTyVars :: Id -> TyVarSet
179 idFreeTyVars id = tyVarsOfType (idType id)
181 setIdType :: Id -> Type -> Id
182 -- Add free tyvar info to the type
183 setIdType id ty = seqType ty `seq` setVarType id (addFreeTyVars ty)
185 idPrimRep :: Id -> PrimRep
186 idPrimRep id = typePrimRep (idType id)
190 %************************************************************************
192 \subsection{Special Ids}
194 %************************************************************************
197 idFlavour :: Id -> IdFlavour
198 idFlavour id = flavourInfo (idInfo id)
200 setIdNoDiscard :: Id -> Id
201 setIdNoDiscard id -- Make an Id into a NoDiscardId, unless it is already
202 = modifyIdInfo setNoDiscardInfo id
204 recordSelectorFieldLabel :: Id -> FieldLabel
205 recordSelectorFieldLabel id = case idFlavour id of
206 RecordSelId lbl -> lbl
208 isRecordSelector id = case idFlavour id of
209 RecordSelId lbl -> True
212 isPrimOpId id = case idFlavour id of
216 isPrimOpId_maybe id = case idFlavour id of
217 PrimOpId op -> Just op
220 isDataConId id = case idFlavour id of
224 isDataConId_maybe id = case idFlavour id of
225 DataConId con -> Just con
228 isDataConWrapId_maybe id = case idFlavour id of
229 DataConWrapId con -> Just con
232 isDataConWrapId id = case idFlavour id of
233 DataConWrapId con -> True
236 isSpecPragmaId id = case idFlavour id of
240 mayHaveNoBinding id = case idFlavour id of
244 -- mayHaveNoBinding returns True of an Id which may not have a
245 -- binding, even though it is defined in this module. Notably,
246 -- the constructors of a dictionary are in this situation.
248 -- mayHaveNoBinding returns True of some things that *do* have a local binding,
249 -- so it's only an approximation. That's ok... it's only use for assertions.
251 -- Don't drop a binding for an exported Id,
252 -- if it otherwise looks dead.
253 isExportedId :: Id -> Bool
254 isExportedId id = case idFlavour id of
256 other -> True -- All the others are no-discard
258 -- Say if an Id was exported by the user
259 -- Implies isExportedId (see mkId above)
260 isUserExportedId :: Id -> Bool
261 isUserExportedId id = isUserExportedName (idName id)
265 omitIfaceSigForId tells whether an Id's info is implied by other declarations,
266 so we don't need to put its signature in an interface file, even if it's mentioned
267 in some other interface unfolding.
270 omitIfaceSigForId :: Id -> Bool
272 | isWiredInName (idName id)
276 = case idFlavour id of
277 RecordSelId _ -> True -- Includes dictionary selectors
280 DataConWrapId _ -> True
281 -- These are are implied by their type or class decl;
282 -- remember that all type and class decls appear in the interface file.
283 -- The dfun id must *not* be omitted, because it carries version info for
286 other -> False -- Don't omit!
288 -- Certain names must be exported with their original occ names, because
289 -- these names are bound by either a class declaration or a data declaration
290 -- or an explicit user export.
291 exportWithOrigOccName :: Id -> Bool
292 exportWithOrigOccName id = omitIfaceSigForId id || isUserExportedId id
296 isDeadBinder :: Id -> Bool
297 isDeadBinder bndr | isId bndr = case idOccInfo bndr of
300 | otherwise = False -- TyVars count as not dead
302 isIP id = isIPOcc (getOccName id)
306 %************************************************************************
308 \subsection{IdInfo stuff}
310 %************************************************************************
313 ---------------------------------
315 idArityInfo :: Id -> ArityInfo
316 idArityInfo id = arityInfo (idInfo id)
318 idArity :: Id -> Arity
319 idArity id = arityLowerBound (idArityInfo id)
321 setIdArityInfo :: Id -> ArityInfo -> Id
322 setIdArityInfo id arity = modifyIdInfo (`setArityInfo` arity) id
324 ---------------------------------
326 idStrictness :: Id -> StrictnessInfo
327 idStrictness id = strictnessInfo (idInfo id)
329 setIdStrictness :: Id -> StrictnessInfo -> Id
330 setIdStrictness id strict_info = modifyIdInfo (`setStrictnessInfo` strict_info) id
332 -- isBottomingId returns true if an application to n args would diverge
333 isBottomingId :: Id -> Bool
334 isBottomingId id = isBottomingStrictness (idStrictness id)
336 ---------------------------------
338 idWorkerInfo :: Id -> WorkerInfo
339 idWorkerInfo id = workerInfo (idInfo id)
341 setIdWorkerInfo :: Id -> WorkerInfo -> Id
342 setIdWorkerInfo id work_info = modifyIdInfo (`setWorkerInfo` work_info) id
344 ---------------------------------
346 idUnfolding :: Id -> Unfolding
347 idUnfolding id = unfoldingInfo (idInfo id)
349 setIdUnfolding :: Id -> Unfolding -> Id
350 setIdUnfolding id unfolding = modifyIdInfo (`setUnfoldingInfo` unfolding) id
352 ---------------------------------
354 idDemandInfo :: Id -> Demand
355 idDemandInfo id = demandInfo (idInfo id)
357 setIdDemandInfo :: Id -> Demand -> Id
358 setIdDemandInfo id demand_info = modifyIdInfo (`setDemandInfo` demand_info) id
360 ---------------------------------
362 idUpdateInfo :: Id -> UpdateInfo
363 idUpdateInfo id = updateInfo (idInfo id)
365 setIdUpdateInfo :: Id -> UpdateInfo -> Id
366 setIdUpdateInfo id upd_info = modifyIdInfo (`setUpdateInfo` upd_info) id
368 ---------------------------------
370 idSpecialisation :: Id -> CoreRules
371 idSpecialisation id = specInfo (idInfo id)
373 setIdSpecialisation :: Id -> CoreRules -> Id
374 setIdSpecialisation id spec_info = modifyIdInfo (`setSpecInfo` spec_info) id
376 ---------------------------------
378 idCafInfo :: Id -> CafInfo
379 idCafInfo id = cafInfo (idInfo id)
381 setIdCafInfo :: Id -> CafInfo -> Id
382 setIdCafInfo id caf_info = modifyIdInfo (`setCafInfo` caf_info) id
384 ---------------------------------
386 idCprInfo :: Id -> CprInfo
387 idCprInfo id = cprInfo (idInfo id)
389 setIdCprInfo :: Id -> CprInfo -> Id
390 setIdCprInfo id cpr_info = modifyIdInfo (`setCprInfo` cpr_info) id
392 ---------------------------------
394 idOccInfo :: Id -> OccInfo
395 idOccInfo id = occInfo (idInfo id)
397 setIdOccInfo :: Id -> OccInfo -> Id
398 setIdOccInfo id occ_info = modifyIdInfo (`setOccInfo` occ_info) id
402 ---------------------------------
404 The inline pragma tells us to be very keen to inline this Id, but it's still
405 OK not to if optimisation is switched off.
408 idInlinePragma :: Id -> InlinePragInfo
409 idInlinePragma id = inlinePragInfo (idInfo id)
411 setInlinePragma :: Id -> InlinePragInfo -> Id
412 setInlinePragma id prag = modifyIdInfo (`setInlinePragInfo` prag) id
414 modifyInlinePragma :: Id -> (InlinePragInfo -> InlinePragInfo) -> Id
415 modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn (inlinePragInfo info))) id
419 ---------------------------------
422 idLBVarInfo :: Id -> LBVarInfo
423 idLBVarInfo id = lbvarInfo (idInfo id)
425 isOneShotLambda :: Id -> Bool
426 isOneShotLambda id = case idLBVarInfo id of
427 IsOneShotLambda -> True
428 NoLBVarInfo -> case splitTyConApp_maybe (idType id) of
429 Just (tycon,_) -> tycon == statePrimTyCon
431 -- The last clause is a gross hack. It claims that
432 -- every function over realWorldStatePrimTy is a one-shot
433 -- function. This is pretty true in practice, and makes a big
434 -- difference. For example, consider
435 -- a `thenST` \ r -> ...E...
436 -- The early full laziness pass, if it doesn't know that r is one-shot
437 -- will pull out E (let's say it doesn't mention r) to give
438 -- let lvl = E in a `thenST` \ r -> ...lvl...
439 -- When `thenST` gets inlined, we end up with
440 -- let lvl = E in \s -> case a s of (r, s') -> ...lvl...
441 -- and we don't re-inline E.
443 -- It would be better to spot that r was one-shot to start with, but
444 -- I don't want to rely on that.
446 -- Another good example is in fill_in in PrelPack.lhs. We should be able to
447 -- spot that fill_in has arity 2 (and when Keith is done, we will) but we can't yet.
449 setOneShotLambda :: Id -> Id
450 setOneShotLambda id = modifyIdInfo (`setLBVarInfo` IsOneShotLambda) id
452 clearOneShotLambda :: Id -> Id
453 clearOneShotLambda id
454 | isOneShotLambda id = modifyIdInfo (`setLBVarInfo` NoLBVarInfo) id
457 -- But watch out: this may change the type of something else
459 -- If we change the one-shot-ness of x, f's type changes
463 zapFragileIdInfo :: Id -> Id
464 zapFragileIdInfo id = maybeModifyIdInfo zapFragileInfo id
466 zapLamIdInfo :: Id -> Id
467 zapLamIdInfo id = maybeModifyIdInfo zapLamInfo id