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, setIdNoDiscard, 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,
57 idDemandInfo, idNewDemandInfo,
58 idStrictness, idNewStrictness, idNewStrictness_maybe, getNewStrictness,
70 newStrictnessFromOld -- Temporary
74 #include "HsVersions.h"
77 import CoreSyn ( Unfolding, CoreRules )
78 import BasicTypes ( Arity )
79 import Var ( Id, DictId,
80 isId, isExportedId, isSpecPragmaId, isLocalId,
81 idName, idType, idUnique, idInfo, isGlobalId,
82 setIdName, setVarType, setIdUnique, setIdNoDiscard,
83 setIdInfo, lazySetIdInfo, modifyIdInfo,
85 globalIdDetails, setGlobalIdDetails
87 import qualified Var ( mkLocalId, mkGlobalId, mkSpecPragmaId )
88 import Type ( Type, typePrimRep, addFreeTyVars,
89 usOnce, eqUsage, seqType, splitTyConApp_maybe )
93 import qualified Demand ( Demand )
94 import NewDemand ( Demand, DmdResult(..), StrictSig, topSig, isBotRes,
95 isBottomingSig, splitStrictSig, strictSigResInfo
97 import Name ( Name, OccName,
98 mkSysLocalName, mkLocalName,
101 import OccName ( UserFS, mkWorkerOcc )
102 import PrimRep ( PrimRep )
103 import TysPrim ( statePrimTyCon )
104 import FieldLabel ( FieldLabel )
105 import Maybes ( orElse )
106 import SrcLoc ( SrcLoc )
108 import Unique ( Unique, mkBuiltinUnique )
110 infixl 1 `setIdUnfolding`,
114 `setIdNewDemandInfo`,
115 `setIdNewStrictness`,
118 `setIdSpecialisation`,
123 -- infixl so you can say (id `set` a `set` b)
128 %************************************************************************
130 \subsection{Simple Id construction}
132 %************************************************************************
134 Absolutely all Ids are made by mkId. It is just like Var.mkId,
135 but in addition it pins free-tyvar-info onto the Id's type,
136 where it can easily be found.
139 mkLocalIdWithInfo :: Name -> Type -> IdInfo -> Id
140 mkLocalIdWithInfo name ty info = Var.mkLocalId name (addFreeTyVars ty) info
142 mkSpecPragmaId :: OccName -> Unique -> Type -> SrcLoc -> Id
143 mkSpecPragmaId occ uniq ty loc = Var.mkSpecPragmaId (mkLocalName uniq occ loc)
147 mkGlobalId :: GlobalIdDetails -> Name -> Type -> IdInfo -> Id
148 mkGlobalId details name ty info = Var.mkGlobalId details name (addFreeTyVars ty) info
152 mkLocalId :: Name -> Type -> Id
153 mkLocalId name ty = mkLocalIdWithInfo name ty vanillaIdInfo
155 -- SysLocal: for an Id being created by the compiler out of thin air...
156 -- UserLocal: an Id with a name the user might recognize...
157 mkUserLocal :: OccName -> Unique -> Type -> SrcLoc -> Id
158 mkSysLocal :: UserFS -> Unique -> Type -> Id
159 mkVanillaGlobal :: Name -> Type -> IdInfo -> Id
161 mkSysLocal fs uniq ty = mkLocalId (mkSysLocalName uniq fs) ty
162 mkUserLocal occ uniq ty loc = mkLocalId (mkLocalName uniq occ loc) ty
163 mkVanillaGlobal = mkGlobalId VanillaGlobal
166 Make some local @Ids@ for a template @CoreExpr@. These have bogus
167 @Uniques@, but that's OK because the templates are supposed to be
168 instantiated before use.
171 -- "Wild Id" typically used when you need a binder that you don't expect to use
172 mkWildId :: Type -> Id
173 mkWildId ty = mkSysLocal SLIT("wild") (mkBuiltinUnique 1) ty
175 mkWorkerId :: Unique -> Id -> Type -> Id
176 -- A worker gets a local name. CoreTidy will globalise it if necessary.
177 mkWorkerId uniq unwrkr ty
178 = mkLocalId wkr_name ty
180 wkr_name = mkLocalName uniq (mkWorkerOcc (getOccName unwrkr)) (getSrcLoc unwrkr)
182 -- "Template locals" typically used in unfoldings
183 mkTemplateLocals :: [Type] -> [Id]
184 mkTemplateLocals tys = zipWith mkTemplateLocal [1..] tys
186 mkTemplateLocalsNum :: Int -> [Type] -> [Id]
187 -- The Int gives the starting point for unique allocation
188 mkTemplateLocalsNum n tys = zipWith mkTemplateLocal [n..] tys
190 mkTemplateLocal :: Int -> Type -> Id
191 mkTemplateLocal i ty = mkSysLocal SLIT("tpl") (mkBuiltinUnique i) ty
195 %************************************************************************
197 \subsection[Id-general-funs]{General @Id@-related functions}
199 %************************************************************************
202 setIdType :: Id -> Type -> Id
203 -- Add free tyvar info to the type
204 setIdType id ty = seqType ty `seq` setVarType id (addFreeTyVars ty)
206 idPrimRep :: Id -> PrimRep
207 idPrimRep id = typePrimRep (idType id)
211 %************************************************************************
213 \subsection{Special Ids}
215 %************************************************************************
217 The @SpecPragmaId@ exists only to make Ids that are
218 on the *LHS* of bindings created by SPECIALISE pragmas;
220 The SpecPragmaId is never itself mentioned; it
221 exists solely so that the specialiser will find
222 the call to f, and make specialised version of it.
223 The SpecPragmaId binding is discarded by the specialiser
224 when it gathers up overloaded calls.
225 Meanwhile, it is not discarded as dead code.
229 recordSelectorFieldLabel :: Id -> FieldLabel
230 recordSelectorFieldLabel id = case globalIdDetails id of
231 RecordSelId lbl -> lbl
233 isRecordSelector id = case globalIdDetails id of
234 RecordSelId lbl -> True
237 isPrimOpId id = case globalIdDetails id of
241 isPrimOpId_maybe id = case globalIdDetails id of
242 PrimOpId op -> Just op
245 isFCallId id = case globalIdDetails id of
249 isFCallId_maybe id = case globalIdDetails id of
250 FCallId call -> Just call
253 isDataConId id = case globalIdDetails id of
257 isDataConId_maybe id = case globalIdDetails id of
258 DataConId con -> Just con
261 isDataConWrapId_maybe id = case globalIdDetails id of
262 DataConWrapId con -> Just con
265 isDataConWrapId id = case globalIdDetails id of
266 DataConWrapId con -> True
269 -- hasNoBinding returns True of an Id which may not have a
270 -- binding, even though it is defined in this module. Notably,
271 -- the constructors of a dictionary are in this situation.
272 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 idArityInfo :: Id -> ArityInfo
313 idArityInfo id = arityInfo (idInfo id)
315 idArity :: Id -> Arity
316 idArity id = arityLowerBound (idArityInfo id)
318 setIdArityInfo :: Id -> Arity -> Id
319 setIdArityInfo id arity = modifyIdInfo (`setArityInfo` arity) id
321 ---------------------------------
323 idStrictness :: Id -> StrictnessInfo
324 idStrictness id = case strictnessInfo (idInfo id) of
325 NoStrictnessInfo -> case idNewStrictness_maybe id of
326 Just sig -> oldStrictnessFromNew sig
327 Nothing -> NoStrictnessInfo
328 strictness -> strictness
330 setIdStrictness :: Id -> StrictnessInfo -> Id
331 setIdStrictness id strict_info = modifyIdInfo (`setStrictnessInfo` strict_info) id
333 -- isBottomingId returns true if an application to n args would diverge
334 isBottomingId :: Id -> Bool
335 isBottomingId id = isBottomingSig (idNewStrictness id)
337 idNewStrictness_maybe :: Id -> Maybe StrictSig
338 idNewStrictness :: Id -> StrictSig
340 idNewStrictness_maybe id = newStrictnessInfo (idInfo id)
341 idNewStrictness id = idNewStrictness_maybe id `orElse` topSig
343 getNewStrictness :: Id -> StrictSig
344 -- First tries the "new-strictness" field, and then
345 -- reverts to the old one. This is just until we have
346 -- cross-module info for new strictness
347 getNewStrictness id = idNewStrictness_maybe id `orElse` newStrictnessFromOld id
349 newStrictnessFromOld :: Id -> StrictSig
350 newStrictnessFromOld id = mkNewStrictnessInfo id (idArity id) (idStrictness id) (idCprInfo id)
352 oldStrictnessFromNew :: StrictSig -> StrictnessInfo
353 oldStrictnessFromNew sig = mkStrictnessInfo (map oldDemand dmds, isBotRes res_info)
355 (dmds, res_info) = splitStrictSig sig
357 setIdNewStrictness :: Id -> StrictSig -> Id
358 setIdNewStrictness id sig = modifyIdInfo (`setNewStrictnessInfo` Just sig) 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
423 idCafInfo id = cgCafInfo (idCgInfo id)
425 ---------------------------------
427 idCgArity :: Id -> Arity
428 idCgArity id = cgArity (idCgInfo id)
430 ---------------------------------
432 idCprInfo :: Id -> CprInfo
433 idCprInfo id = case cprInfo (idInfo id) of
434 NoCPRInfo -> case strictSigResInfo (idNewStrictness id) of
437 ReturnsCPR -> ReturnsCPR
439 setIdCprInfo :: Id -> CprInfo -> Id
440 setIdCprInfo id cpr_info = modifyIdInfo (`setCprInfo` cpr_info) id
442 ---------------------------------
444 idOccInfo :: Id -> OccInfo
445 idOccInfo id = occInfo (idInfo id)
447 setIdOccInfo :: Id -> OccInfo -> Id
448 setIdOccInfo id occ_info = modifyIdInfo (`setOccInfo` occ_info) id
452 ---------------------------------
454 The inline pragma tells us to be very keen to inline this Id, but it's still
455 OK not to if optimisation is switched off.
458 idInlinePragma :: Id -> InlinePragInfo
459 idInlinePragma id = inlinePragInfo (idInfo id)
461 setInlinePragma :: Id -> InlinePragInfo -> Id
462 setInlinePragma id prag = modifyIdInfo (`setInlinePragInfo` prag) id
464 modifyInlinePragma :: Id -> (InlinePragInfo -> InlinePragInfo) -> Id
465 modifyInlinePragma id fn = modifyIdInfo (\info -> info `setInlinePragInfo` (fn (inlinePragInfo info))) id
469 ---------------------------------
472 idLBVarInfo :: Id -> LBVarInfo
473 idLBVarInfo id = lbvarInfo (idInfo id)
475 isOneShotLambda :: Id -> Bool
476 isOneShotLambda id = analysis || hack
477 where analysis = case idLBVarInfo id of
478 LBVarInfo u | u `eqUsage` usOnce -> True
480 hack = case splitTyConApp_maybe (idType id) of
481 Just (tycon,_) | tycon == statePrimTyCon -> True
484 -- The last clause is a gross hack. It claims that
485 -- every function over realWorldStatePrimTy is a one-shot
486 -- function. This is pretty true in practice, and makes a big
487 -- difference. For example, consider
488 -- a `thenST` \ r -> ...E...
489 -- The early full laziness pass, if it doesn't know that r is one-shot
490 -- will pull out E (let's say it doesn't mention r) to give
491 -- let lvl = E in a `thenST` \ r -> ...lvl...
492 -- When `thenST` gets inlined, we end up with
493 -- let lvl = E in \s -> case a s of (r, s') -> ...lvl...
494 -- and we don't re-inline E.
496 -- It would be better to spot that r was one-shot to start with, but
497 -- I don't want to rely on that.
499 -- Another good example is in fill_in in PrelPack.lhs. We should be able to
500 -- spot that fill_in has arity 2 (and when Keith is done, we will) but we can't yet.
502 setOneShotLambda :: Id -> Id
503 setOneShotLambda id = modifyIdInfo (`setLBVarInfo` LBVarInfo usOnce) id
505 clearOneShotLambda :: Id -> Id
506 clearOneShotLambda id
507 | isOneShotLambda id = modifyIdInfo (`setLBVarInfo` NoLBVarInfo) id
510 -- But watch out: this may change the type of something else
512 -- If we change the one-shot-ness of x, f's type changes
516 zapLamIdInfo :: Id -> Id
517 zapLamIdInfo id = maybeModifyIdInfo zapLamInfo id
519 zapDemandIdInfo id = maybeModifyIdInfo zapDemandInfo id