2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[Id]{@Ids@: Value and constructor identifiers}
10 -- Simple construction
11 mkGlobalId, mkLocalId, mkSpecPragmaId, mkLocalIdWithInfo,
12 mkSysLocal, mkUserLocal, mkVanillaGlobal,
13 mkTemplateLocals, mkTemplateLocalsNum, mkWildId, mkTemplateLocal,
17 idName, idType, idUnique, idInfo,
18 idPrimRep, isId, globalIdDetails,
19 recordSelectorFieldLabel,
22 setIdName, setIdUnique, setIdType, setIdLocalExported, setGlobalIdDetails,
23 setIdInfo, lazySetIdInfo, modifyIdInfo, maybeModifyIdInfo,
24 zapLamIdInfo, zapDemandIdInfo,
27 isImplicitId, isDeadBinder,
28 isSpecPragmaId, isExportedId, isLocalId, isGlobalId,
30 isPrimOpId, isPrimOpId_maybe,
31 isFCallId, isFCallId_maybe,
32 isDataConId, isDataConId_maybe,
33 isDataConWrapId, isDataConWrapId_maybe,
37 -- Inline pragma stuff
38 idInlinePragma, setInlinePragma, modifyInlinePragma,
41 -- One shot lambda stuff
42 isOneShotLambda, setOneShotLambda, clearOneShotLambda,
47 setIdDemandInfo, setIdNewDemandInfo,
48 setIdStrictness, setIdNewStrictness, zapIdNewStrictness,
57 idDemandInfo, idNewDemandInfo,
58 idStrictness, idNewStrictness, idNewStrictness_maybe, getNewStrictness,
69 newStrictnessFromOld -- Temporary
73 #include "HsVersions.h"
76 import CoreSyn ( Unfolding, CoreRules )
77 import BasicTypes ( Arity )
78 import Var ( Id, DictId,
79 isId, isExportedId, isSpecPragmaId, isLocalId,
80 idName, idType, idUnique, idInfo, isGlobalId,
81 setIdName, setVarType, setIdUnique, setIdLocalExported,
82 setIdInfo, lazySetIdInfo, modifyIdInfo,
84 globalIdDetails, setGlobalIdDetails
86 import qualified Var ( mkLocalId, mkGlobalId, mkSpecPragmaId )
87 import Type ( Type, typePrimRep, addFreeTyVars,
88 usOnce, eqUsage, seqType, splitTyConApp_maybe )
92 import qualified Demand ( Demand )
93 import NewDemand ( Demand, DmdResult(..), StrictSig, topSig, isBotRes,
94 isBottomingSig, splitStrictSig, strictSigResInfo
96 import Name ( Name, OccName,
97 mkSysLocalName, mkLocalName,
100 import OccName ( UserFS, mkWorkerOcc )
101 import PrimRep ( PrimRep )
102 import TysPrim ( statePrimTyCon )
103 import FieldLabel ( FieldLabel )
104 import Maybes ( orElse )
105 import SrcLoc ( SrcLoc )
107 import Unique ( Unique, mkBuiltinUnique )
109 infixl 1 `setIdUnfolding`,
113 `setIdNewDemandInfo`,
114 `setIdNewStrictness`,
117 `setIdSpecialisation`,
122 -- infixl so you can say (id `set` a `set` b)
127 %************************************************************************
129 \subsection{Simple Id construction}
131 %************************************************************************
133 Absolutely all Ids are made by mkId. It is just like Var.mkId,
134 but in addition it pins free-tyvar-info onto the Id's type,
135 where it can easily be found.
138 mkLocalIdWithInfo :: Name -> Type -> IdInfo -> Id
139 mkLocalIdWithInfo name ty info = Var.mkLocalId name (addFreeTyVars ty) info
141 mkSpecPragmaId :: OccName -> Unique -> Type -> SrcLoc -> Id
142 mkSpecPragmaId occ uniq ty loc = Var.mkSpecPragmaId (mkLocalName uniq occ loc)
146 mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
147 mkGlobalId details name ty info = Var.mkGlobalId details name (addFreeTyVars ty) info
151 mkLocalId :: Name -> Type -> Id
152 mkLocalId name ty = mkLocalIdWithInfo name ty vanillaIdInfo
154 -- SysLocal: for an Id being created by the compiler out of thin air...
155 -- UserLocal: an Id with a name the user might recognize...
156 mkUserLocal :: OccName -> Unique -> Type -> SrcLoc -> Id
157 mkSysLocal :: UserFS -> Unique -> Type -> Id
158 mkVanillaGlobal :: Name -> Type -> IdInfo -> Id
160 mkSysLocal fs uniq ty = mkLocalId (mkSysLocalName uniq fs) ty
161 mkUserLocal occ uniq ty loc = mkLocalId (mkLocalName uniq occ loc) ty
162 mkVanillaGlobal = mkGlobalId VanillaGlobal
165 Make some local @Ids@ for a template @CoreExpr@. These have bogus
166 @Uniques@, but that's OK because the templates are supposed to be
167 instantiated before use.
170 -- "Wild Id" typically used when you need a binder that you don't expect to use
171 mkWildId :: Type -> Id
172 mkWildId ty = mkSysLocal SLIT("wild") (mkBuiltinUnique 1) ty
174 mkWorkerId :: Unique -> Id -> Type -> Id
175 -- A worker gets a local name. CoreTidy will globalise it if necessary.
176 mkWorkerId uniq unwrkr ty
177 = mkLocalId wkr_name ty
179 wkr_name = mkLocalName uniq (mkWorkerOcc (getOccName unwrkr)) (getSrcLoc unwrkr)
181 -- "Template locals" typically used in unfoldings
182 mkTemplateLocals :: [Type] -> [Id]
183 mkTemplateLocals tys = zipWith mkTemplateLocal [1..] tys
185 mkTemplateLocalsNum :: Int -> [Type] -> [Id]
186 -- The Int gives the starting point for unique allocation
187 mkTemplateLocalsNum n tys = zipWith mkTemplateLocal [n..] tys
189 mkTemplateLocal :: Int -> Type -> Id
190 mkTemplateLocal i ty = mkSysLocal SLIT("tpl") (mkBuiltinUnique i) ty
194 %************************************************************************
196 \subsection[Id-general-funs]{General @Id@-related functions}
198 %************************************************************************
201 setIdType :: Id -> Type -> Id
202 -- Add free tyvar info to the type
203 setIdType id ty = seqType ty `seq` setVarType id (addFreeTyVars ty)
205 idPrimRep :: Id -> PrimRep
206 idPrimRep id = typePrimRep (idType id)
210 %************************************************************************
212 \subsection{Special Ids}
214 %************************************************************************
216 The @SpecPragmaId@ exists only to make Ids that are
217 on the *LHS* of bindings created by SPECIALISE pragmas;
219 The SpecPragmaId is never itself mentioned; it
220 exists solely so that the specialiser will find
221 the call to f, and make specialised version of it.
222 The SpecPragmaId binding is discarded by the specialiser
223 when it gathers up overloaded calls.
224 Meanwhile, it is not discarded as dead code.
228 recordSelectorFieldLabel :: Id -> FieldLabel
229 recordSelectorFieldLabel id = case globalIdDetails id of
230 RecordSelId lbl -> lbl
232 isRecordSelector id = case globalIdDetails id of
233 RecordSelId lbl -> True
236 isPrimOpId id = case globalIdDetails id of
240 isPrimOpId_maybe id = case globalIdDetails id of
241 PrimOpId op -> Just op
244 isFCallId id = case globalIdDetails id of
248 isFCallId_maybe id = case globalIdDetails id of
249 FCallId call -> Just call
252 isDataConId id = case globalIdDetails id of
256 isDataConId_maybe id = case globalIdDetails id of
257 DataConId con -> Just con
260 isDataConWrapId_maybe id = case globalIdDetails id of
261 DataConWrapId con -> Just con
264 isDataConWrapId id = case globalIdDetails id of
265 DataConWrapId con -> True
268 -- hasNoBinding returns True of an Id which may not have a
269 -- binding, even though it is defined in this module.
270 -- Data constructor workers used to be things of this kind, but
271 -- they aren't any more. Instead, we inject a binding for
272 -- them at the CorePrep stage.
273 hasNoBinding id = case globalIdDetails id of
278 isImplicitId :: Id -> Bool
279 -- isImplicitId tells whether an Id's info is implied by other
280 -- declarations, so we don't need to put its signature in an interface
281 -- file, even if it's mentioned in some other interface unfolding.
283 = case globalIdDetails id of
284 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
297 isDeadBinder :: Id -> Bool
298 isDeadBinder bndr | isId bndr = isDeadOcc (idOccInfo bndr)
299 | otherwise = False -- TyVars count as not dead
303 %************************************************************************
305 \subsection{IdInfo stuff}
307 %************************************************************************
310 ---------------------------------
312 idArity :: Id -> Arity
313 idArity id = arityInfo (idInfo id)
315 setIdArity :: Id -> Arity -> Id
316 setIdArity id arity = modifyIdInfo (`setArityInfo` arity) id
318 ---------------------------------
320 idStrictness :: Id -> StrictnessInfo
321 idStrictness id = case strictnessInfo (idInfo id) of
322 NoStrictnessInfo -> case idNewStrictness_maybe id of
323 Just sig -> oldStrictnessFromNew sig
324 Nothing -> NoStrictnessInfo
325 strictness -> strictness
327 setIdStrictness :: Id -> StrictnessInfo -> Id
328 setIdStrictness id strict_info = modifyIdInfo (`setStrictnessInfo` strict_info) id
330 -- isBottomingId returns true if an application to n args would diverge
331 isBottomingId :: Id -> Bool
332 isBottomingId id = isBottomingSig (idNewStrictness id)
334 idNewStrictness_maybe :: Id -> Maybe StrictSig
335 idNewStrictness :: Id -> StrictSig
337 idNewStrictness_maybe id = newStrictnessInfo (idInfo id)
338 idNewStrictness id = idNewStrictness_maybe id `orElse` topSig
340 getNewStrictness :: Id -> StrictSig
341 -- First tries the "new-strictness" field, and then
342 -- reverts to the old one. This is just until we have
343 -- cross-module info for new strictness
344 getNewStrictness id = idNewStrictness_maybe id `orElse` newStrictnessFromOld id
346 newStrictnessFromOld :: Id -> StrictSig
347 newStrictnessFromOld id = mkNewStrictnessInfo id (idArity id) (idStrictness id) (idCprInfo id)
349 oldStrictnessFromNew :: StrictSig -> StrictnessInfo
350 oldStrictnessFromNew sig = mkStrictnessInfo (map oldDemand dmds, isBotRes res_info)
352 (dmds, res_info) = splitStrictSig sig
354 setIdNewStrictness :: Id -> StrictSig -> Id
355 setIdNewStrictness id sig = modifyIdInfo (`setNewStrictnessInfo` Just sig) id
357 zapIdNewStrictness :: Id -> Id
358 zapIdNewStrictness id = modifyIdInfo (`setNewStrictnessInfo` Nothing) id
360 ---------------------------------
361 -- TYPE GENERALISATION
362 idTyGenInfo :: Id -> TyGenInfo
363 idTyGenInfo id = tyGenInfo (idInfo id)
365 setIdTyGenInfo :: Id -> TyGenInfo -> Id
366 setIdTyGenInfo id tygen_info = modifyIdInfo (`setTyGenInfo` tygen_info) id
368 ---------------------------------
370 idWorkerInfo :: Id -> WorkerInfo
371 idWorkerInfo id = workerInfo (idInfo id)
373 setIdWorkerInfo :: Id -> WorkerInfo -> Id
374 setIdWorkerInfo id work_info = modifyIdInfo (`setWorkerInfo` work_info) id
376 ---------------------------------
378 idUnfolding :: Id -> Unfolding
379 idUnfolding id = unfoldingInfo (idInfo id)
381 setIdUnfolding :: Id -> Unfolding -> Id
382 setIdUnfolding id unfolding = modifyIdInfo (`setUnfoldingInfo` unfolding) id
384 ---------------------------------
386 idDemandInfo :: Id -> Demand.Demand
387 idDemandInfo id = demandInfo (idInfo id)
389 setIdDemandInfo :: Id -> Demand.Demand -> Id
390 setIdDemandInfo id demand_info = modifyIdInfo (`setDemandInfo` demand_info) id
392 idNewDemandInfo :: Id -> NewDemand.Demand
393 idNewDemandInfo id = newDemandInfo (idInfo id)
395 setIdNewDemandInfo :: Id -> NewDemand.Demand -> Id
396 setIdNewDemandInfo id dmd = modifyIdInfo (`setNewDemandInfo` dmd) id
398 ---------------------------------
400 idSpecialisation :: Id -> CoreRules
401 idSpecialisation id = specInfo (idInfo id)
403 setIdSpecialisation :: Id -> CoreRules -> Id
404 setIdSpecialisation id spec_info = modifyIdInfo (`setSpecInfo` spec_info) id
406 ---------------------------------
408 idCgInfo :: Id -> CgInfo
410 idCgInfo id = case cgInfo (idInfo id) of
411 NoCgInfo -> pprPanic "idCgInfo" (ppr id)
414 idCgInfo id = cgInfo (idInfo id)
417 setIdCgInfo :: Id -> CgInfo -> Id
418 setIdCgInfo id cg_info = modifyIdInfo (`setCgInfo` cg_info) id
420 ---------------------------------
422 idCafInfo :: Id -> CafInfo
424 idCafInfo id = case cgInfo (idInfo id) of
425 NoCgInfo -> pprPanic "idCafInfo" (ppr id)
426 info -> cgCafInfo info
428 idCafInfo id = cgCafInfo (idCgInfo id)
431 ---------------------------------
433 idCprInfo :: Id -> CprInfo
434 idCprInfo id = case cprInfo (idInfo id) of
435 NoCPRInfo -> case strictSigResInfo (idNewStrictness id) of
438 ReturnsCPR -> ReturnsCPR
440 setIdCprInfo :: Id -> CprInfo -> Id
441 setIdCprInfo id cpr_info = modifyIdInfo (`setCprInfo` cpr_info) id
443 ---------------------------------
445 idOccInfo :: Id -> OccInfo
446 idOccInfo id = occInfo (idInfo id)
448 setIdOccInfo :: Id -> OccInfo -> Id
449 setIdOccInfo id occ_info = modifyIdInfo (`setOccInfo` occ_info) id
453 ---------------------------------
455 The inline pragma tells us to be very keen to inline this Id, but it's still
456 OK not to if optimisation is switched off.
459 idInlinePragma :: Id -> InlinePragInfo
460 idInlinePragma id = inlinePragInfo (idInfo id)
462 setInlinePragma :: Id -> InlinePragInfo -> Id
463 setInlinePragma id prag = modifyIdInfo (`setInlinePragInfo` prag) id
465 modifyInlinePragma :: Id -> (InlinePragInfo -> InlinePragInfo) -> Id
466 modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn (inlinePragInfo info))) id
470 ---------------------------------
473 idLBVarInfo :: Id -> LBVarInfo
474 idLBVarInfo id = lbvarInfo (idInfo id)
476 isOneShotLambda :: Id -> Bool
477 isOneShotLambda id = analysis || hack
478 where analysis = case idLBVarInfo id of
479 LBVarInfo u | u `eqUsage` usOnce -> True
481 hack = case splitTyConApp_maybe (idType id) of
482 Just (tycon,_) | tycon == statePrimTyCon -> True
485 -- The last clause is a gross hack. It claims that
486 -- every function over realWorldStatePrimTy is a one-shot
487 -- function. This is pretty true in practice, and makes a big
488 -- difference. For example, consider
489 -- a `thenST` \ r -> ...E...
490 -- The early full laziness pass, if it doesn't know that r is one-shot
491 -- will pull out E (let's say it doesn't mention r) to give
492 -- let lvl = E in a `thenST` \ r -> ...lvl...
493 -- When `thenST` gets inlined, we end up with
494 -- let lvl = E in \s -> case a s of (r, s') -> ...lvl...
495 -- and we don't re-inline E.
497 -- It would be better to spot that r was one-shot to start with, but
498 -- I don't want to rely on that.
500 -- Another good example is in fill_in in PrelPack.lhs. We should be able to
501 -- spot that fill_in has arity 2 (and when Keith is done, we will) but we can't yet.
503 setOneShotLambda :: Id -> Id
504 setOneShotLambda id = modifyIdInfo (`setLBVarInfo` LBVarInfo usOnce) id
506 clearOneShotLambda :: Id -> Id
507 clearOneShotLambda id
508 | isOneShotLambda id = modifyIdInfo (`setLBVarInfo` NoLBVarInfo) id
511 -- But watch out: this may change the type of something else
513 -- If we change the one-shot-ness of x, f's type changes
517 zapLamIdInfo :: Id -> Id
518 zapLamIdInfo id = maybeModifyIdInfo zapLamInfo id
520 zapDemandIdInfo id = maybeModifyIdInfo zapDemandInfo id