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, mkTemplateLocalsNum, 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,
29 isSpecPragmaId, isRecordSelector,
30 isPrimOpId, isPrimOpId_maybe,
31 isDataConId, isDataConId_maybe, isDataConWrapId,
32 isDataConWrapId_maybe,
34 isExportedId, isLocalId,
37 -- Inline pragma stuff
38 idInlinePragma, setInlinePragma, modifyInlinePragma,
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,
84 import Type ( Type, typePrimRep, addFreeTyVars,
85 usOnce, seqType, splitTyConApp_maybe )
89 import Demand ( Demand )
90 import Name ( Name, OccName,
91 mkSysLocalName, mkLocalName,
95 import OccName ( UserFS )
96 import PrimRep ( PrimRep )
97 import TysPrim ( statePrimTyCon )
98 import FieldLabel ( FieldLabel )
99 import SrcLoc ( SrcLoc )
100 import Unique ( Unique, mkBuiltinUnique, getBuiltinUniques,
101 getNumBuiltinUniques )
104 infixl 1 `setIdUnfolding`,
110 `setIdSpecialisation`,
115 -- infixl so you can say (id `set` a `set` b)
120 %************************************************************************
122 \subsection{Simple Id construction}
124 %************************************************************************
126 Absolutely all Ids are made by mkId. It
127 a) Pins free-tyvar-info onto the Id's type,
128 where it can easily be found.
129 b) Ensures that exported Ids are
132 mkId :: Name -> Type -> IdInfo -> Id
133 mkId name ty info = mkIdVar name (addFreeTyVars ty) info
137 mkVanillaId :: Name -> Type -> Id
138 mkVanillaId name ty = mkId name ty vanillaIdInfo
140 -- SysLocal: for an Id being created by the compiler out of thin air...
141 -- UserLocal: an Id with a name the user might recognize...
142 mkUserLocal :: OccName -> Unique -> Type -> SrcLoc -> Id
143 mkSysLocal :: UserFS -> Unique -> Type -> Id
145 mkSysLocal fs uniq ty = mkVanillaId (mkSysLocalName uniq fs) ty
146 mkUserLocal occ uniq ty loc = mkVanillaId (mkLocalName uniq occ loc) ty
149 Make some local @Ids@ for a template @CoreExpr@. These have bogus
150 @Uniques@, but that's OK because the templates are supposed to be
151 instantiated before use.
154 -- "Wild Id" typically used when you need a binder that you don't expect to use
155 mkWildId :: Type -> Id
156 mkWildId ty = mkSysLocal SLIT("wild") (mkBuiltinUnique 1) ty
158 -- "Template locals" typically used in unfoldings
159 mkTemplateLocals :: [Type] -> [Id]
160 mkTemplateLocals tys = zipWith (mkSysLocal SLIT("tpl"))
161 (getBuiltinUniques (length tys))
164 mkTemplateLocalsNum :: Int -> [Type] -> [Id]
165 mkTemplateLocalsNum n tys = zipWith (mkSysLocal SLIT("tpl"))
166 (getNumBuiltinUniques n (length tys))
169 mkTemplateLocal :: Int -> Type -> Id
170 mkTemplateLocal i ty = mkSysLocal SLIT("tpl") (mkBuiltinUnique i) ty
174 %************************************************************************
176 \subsection[Id-general-funs]{General @Id@-related functions}
178 %************************************************************************
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 hasNoBinding id = case idFlavour id of
244 -- hasNoBinding 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 -- Don't drop a binding for an exported Id,
249 -- if it otherwise looks dead.
250 -- Perhaps a better name would be isDiscardableId
251 isExportedId :: Id -> Bool
252 isExportedId id = case idFlavour id of
256 isLocalId :: Id -> Bool
257 -- True of Ids that are locally defined, but are not constants
258 -- like data constructors, record selectors, and the like.
259 -- See comments with CoreFVs.isLocalVar
260 isLocalId id = case idFlavour id of
268 omitIfaceSigForId tells whether an Id's info is implied by other declarations,
269 so we don't need to put its signature in an interface file, even if it's mentioned
270 in some other interface unfolding.
273 omitIfaceSigForId :: Id -> Bool
275 = ASSERT2( not (omit && nameIsLocallyDefined (idName id)
276 && idTyGenInfo id /= TyGenNever),
278 -- mustn't omit type signature for a name whose type might change!
281 omit = omitIfaceSigForId' id
283 omitIfaceSigForId' id
284 = case idFlavour id of
285 RecordSelId _ -> True -- Includes dictionary selectors
288 DataConWrapId _ -> True
289 -- These are are implied by their type or class decl;
290 -- remember that all type and class decls appear in the interface file.
291 -- The dfun id must *not* be omitted, because it carries version info for
294 other -> False -- Don't omit!
296 -- Certain names must be exported with their original occ names, because
297 -- these names are bound by either a class declaration or a data declaration
298 -- or an explicit user export.
299 exportWithOrigOccName :: Id -> Bool
300 exportWithOrigOccName id = omitIfaceSigForId id || isExportedId id
304 isDeadBinder :: Id -> Bool
305 isDeadBinder bndr | isId bndr = isDeadOcc (idOccInfo bndr)
306 | otherwise = False -- TyVars count as not dead
308 isIP id = isIPOcc (getOccName id)
312 %************************************************************************
314 \subsection{IdInfo stuff}
316 %************************************************************************
319 ---------------------------------
321 idArityInfo :: Id -> ArityInfo
322 idArityInfo id = arityInfo (idInfo id)
324 idArity :: Id -> Arity
325 idArity id = arityLowerBound (idArityInfo id)
327 setIdArityInfo :: Id -> ArityInfo -> Id
328 setIdArityInfo id arity = modifyIdInfo (`setArityInfo` arity) id
330 ---------------------------------
332 idStrictness :: Id -> StrictnessInfo
333 idStrictness id = strictnessInfo (idInfo id)
335 setIdStrictness :: Id -> StrictnessInfo -> Id
336 setIdStrictness id strict_info = modifyIdInfo (`setStrictnessInfo` strict_info) id
338 -- isBottomingId returns true if an application to n args would diverge
339 isBottomingId :: Id -> Bool
340 isBottomingId id = isBottomingStrictness (idStrictness id)
342 ---------------------------------
343 -- TYPE GENERALISATION
344 idTyGenInfo :: Id -> TyGenInfo
345 idTyGenInfo id = tyGenInfo (idInfo id)
347 setIdTyGenInfo :: Id -> TyGenInfo -> Id
348 setIdTyGenInfo id tygen_info = modifyIdInfo (`setTyGenInfo` tygen_info) id
350 ---------------------------------
352 idWorkerInfo :: Id -> WorkerInfo
353 idWorkerInfo id = workerInfo (idInfo id)
355 setIdWorkerInfo :: Id -> WorkerInfo -> Id
356 setIdWorkerInfo id work_info = modifyIdInfo (`setWorkerInfo` work_info) id
358 ---------------------------------
360 idUnfolding :: Id -> Unfolding
361 idUnfolding id = unfoldingInfo (idInfo id)
363 setIdUnfolding :: Id -> Unfolding -> Id
364 setIdUnfolding id unfolding = modifyIdInfo (`setUnfoldingInfo` unfolding) id
366 ---------------------------------
368 idDemandInfo :: Id -> Demand
369 idDemandInfo id = demandInfo (idInfo id)
371 setIdDemandInfo :: Id -> Demand -> Id
372 setIdDemandInfo id demand_info = modifyIdInfo (`setDemandInfo` demand_info) id
374 ---------------------------------
376 idSpecialisation :: Id -> CoreRules
377 idSpecialisation id = specInfo (idInfo id)
379 setIdSpecialisation :: Id -> CoreRules -> Id
380 setIdSpecialisation id spec_info = modifyIdInfo (`setSpecInfo` spec_info) id
382 ---------------------------------
384 idCafInfo :: Id -> CafInfo
385 idCafInfo id = cafInfo (idInfo id)
387 setIdCafInfo :: Id -> CafInfo -> Id
388 setIdCafInfo id caf_info = modifyIdInfo (`setCafInfo` caf_info) id
390 ---------------------------------
392 idCprInfo :: Id -> CprInfo
393 idCprInfo id = cprInfo (idInfo id)
395 setIdCprInfo :: Id -> CprInfo -> Id
396 setIdCprInfo id cpr_info = modifyIdInfo (`setCprInfo` cpr_info) id
398 ---------------------------------
400 idOccInfo :: Id -> OccInfo
401 idOccInfo id = occInfo (idInfo id)
403 setIdOccInfo :: Id -> OccInfo -> Id
404 setIdOccInfo id occ_info = modifyIdInfo (`setOccInfo` occ_info) id
408 ---------------------------------
410 The inline pragma tells us to be very keen to inline this Id, but it's still
411 OK not to if optimisation is switched off.
414 idInlinePragma :: Id -> InlinePragInfo
415 idInlinePragma id = inlinePragInfo (idInfo id)
417 setInlinePragma :: Id -> InlinePragInfo -> Id
418 setInlinePragma id prag = modifyIdInfo (`setInlinePragInfo` prag) id
420 modifyInlinePragma :: Id -> (InlinePragInfo -> InlinePragInfo) -> Id
421 modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn (inlinePragInfo info))) id
425 ---------------------------------
428 idLBVarInfo :: Id -> LBVarInfo
429 idLBVarInfo id = lbvarInfo (idInfo id)
431 isOneShotLambda :: Id -> Bool
432 isOneShotLambda id = analysis || hack
433 where analysis = case idLBVarInfo id of
434 LBVarInfo u | u == usOnce -> True
436 hack = case splitTyConApp_maybe (idType id) of
437 Just (tycon,_) | tycon == statePrimTyCon -> True
440 -- The last clause is a gross hack. It claims that
441 -- every function over realWorldStatePrimTy is a one-shot
442 -- function. This is pretty true in practice, and makes a big
443 -- difference. For example, consider
444 -- a `thenST` \ r -> ...E...
445 -- The early full laziness pass, if it doesn't know that r is one-shot
446 -- will pull out E (let's say it doesn't mention r) to give
447 -- let lvl = E in a `thenST` \ r -> ...lvl...
448 -- When `thenST` gets inlined, we end up with
449 -- let lvl = E in \s -> case a s of (r, s') -> ...lvl...
450 -- and we don't re-inline E.
452 -- It would be better to spot that r was one-shot to start with, but
453 -- I don't want to rely on that.
455 -- Another good example is in fill_in in PrelPack.lhs. We should be able to
456 -- spot that fill_in has arity 2 (and when Keith is done, we will) but we can't yet.
458 setOneShotLambda :: Id -> Id
459 setOneShotLambda id = modifyIdInfo (`setLBVarInfo` LBVarInfo usOnce) id
461 clearOneShotLambda :: Id -> Id
462 clearOneShotLambda id
463 | isOneShotLambda id = modifyIdInfo (`setLBVarInfo` NoLBVarInfo) id
466 -- But watch out: this may change the type of something else
468 -- If we change the one-shot-ness of x, f's type changes
472 zapFragileIdInfo :: Id -> Id
473 zapFragileIdInfo id = maybeModifyIdInfo zapFragileInfo id
475 zapLamIdInfo :: Id -> Id
476 zapLamIdInfo id = maybeModifyIdInfo zapLamInfo id