2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[Name]{@Name@: to transmit name info from renamer to typechecker}
8 -- Re-export the OccName stuff
13 mkLocalName, mkImportedLocalName, mkSysLocalName,
15 mkDerivedName, mkGlobalName, mkKnownKeyGlobal,
16 mkWiredInIdName, mkWiredInTyConName,
17 maybeWiredInIdName, maybeWiredInTyConName,
18 isWiredInName, hashName,
20 nameUnique, setNameUnique, setNameProvenance, getNameProvenance, setNameImportReason,
22 nameOccName, nameModule, setNameOcc, nameRdrName, setNameModule,
24 isUserExportedName, isUserImportedExplicitlyName, nameSrcLoc,
27 isSystemName, isLocalName, isGlobalName, isExternallyVisibleName,
31 Provenance(..), ImportReason(..), pprProvenance,
32 ExportFlag(..), PrintUnqualified,
33 pprNameProvenance, hasBetterProv,
35 -- Class NamedThing and overloaded friends
37 getSrcLoc, isLocallyDefined, getOccString
40 #include "HsVersions.h"
42 import {-# SOURCE #-} Var ( Id, setIdName )
43 import {-# SOURCE #-} TyCon ( TyCon, setTyConName )
45 import OccName -- All of it
46 import Module ( Module, moduleName, pprModule, mkVanillaModule )
47 import RdrName ( RdrName, mkRdrQual, mkRdrUnqual, rdrNameOcc, rdrNameModule )
48 import CmdLineOpts ( opt_PprStyle_NoPrags, opt_OmitInterfacePragmas, opt_EnsureSplittableC )
50 import SrcLoc ( noSrcLoc, mkBuiltinSrcLoc, SrcLoc )
51 import Unique ( pprUnique, Unique, Uniquable(..), u2i )
57 %************************************************************************
59 \subsection[Name-datatype]{The @Name@ datatype, and name construction}
61 %************************************************************************
65 n_sort :: NameSort, -- What sort of name it is
67 n_occ :: OccName, -- Its occurrence name
68 n_prov :: Provenance -- How it was made
75 | WiredInTyCon Module TyCon
78 Things with a @Global@ name are given C static labels, so they finally
79 appear in the .o file's symbol table. They appear in the symbol table
80 in the form M.n. If originally-local things have this property they
81 must be made @Global@ first.
84 mkLocalName :: Unique -> OccName -> SrcLoc -> Name
85 mkLocalName uniq occ loc = Name { n_uniq = uniq, n_sort = Local, n_occ = occ,
86 n_prov = LocalDef loc NotExported }
87 -- NB: You might worry that after lots of huffing and
88 -- puffing we might end up with two local names with distinct
89 -- uniques, but the same OccName. Indeed we can, but that's ok
90 -- * the insides of the compiler don't care: they use the Unique
91 -- * when printing for -ddump-xxx you can switch on -dppr-debug to get the
92 -- uniques if you get confused
93 -- * for interface files we tidyCore first, which puts the uniques
94 -- into the print name (see setNameVisibility below)
96 mkImportedLocalName :: Unique -> OccName -> SrcLoc -> Name
97 -- Just the same as mkLocalName, except the provenance is different
98 -- Reason: this flags the name as one that came in from an interface file.
99 -- This is useful when trying to decide which of two type variables
100 -- should 'win' when unifying them.
101 -- NB: this is only for non-top-level names, so we use ImplicitImport
102 mkImportedLocalName uniq occ loc = Name { n_uniq = uniq, n_sort = Local, n_occ = occ,
103 n_prov = NonLocalDef ImplicitImport True }
106 mkGlobalName :: Unique -> Module -> OccName -> Provenance -> Name
107 mkGlobalName uniq mod occ prov = Name { n_uniq = uniq, n_sort = Global mod,
108 n_occ = occ, n_prov = prov }
111 mkKnownKeyGlobal :: (RdrName, Unique) -> Name
112 mkKnownKeyGlobal (rdr_name, uniq)
113 = mkGlobalName uniq (mkVanillaModule (rdrNameModule rdr_name))
114 (rdrNameOcc rdr_name)
117 mkSysLocalName :: Unique -> UserFS -> Name
118 mkSysLocalName uniq fs = Name { n_uniq = uniq, n_sort = Local,
119 n_occ = mkSrcVarOcc fs, n_prov = systemProvenance }
121 mkTopName :: Unique -> Module -> FAST_STRING -> Name
122 -- Make a top-level name; make it Global if top-level
123 -- things should be externally visible; Local otherwise
124 -- This chap is only used *after* the tidyCore phase
125 -- Notably, it is used during STG lambda lifting
127 -- We have to make sure that the name is globally unique
128 -- and we don't have tidyCore to help us. So we append
129 -- the unique. Hack! Hack!
130 mkTopName uniq mod fs
131 = Name { n_uniq = uniq,
132 n_sort = mk_top_sort mod,
133 n_occ = mkSrcVarOcc (_PK_ ((_UNPK_ fs) ++ show uniq)),
134 n_prov = LocalDef noSrcLoc NotExported }
136 mkIPName :: Unique -> OccName -> Name
138 = Name { n_uniq = uniq,
141 -- ZZ is this an appropriate provinence?
142 n_prov = SystemProv }
144 ------------------------- Wired in names -------------------------
146 mkWiredInIdName :: Unique -> Module -> OccName -> Id -> Name
147 mkWiredInIdName uniq mod occ id = Name { n_uniq = uniq, n_sort = WiredInId mod id,
148 n_occ = occ, n_prov = SystemProv }
150 -- mkWiredInTyConName takes a FAST_STRING instead of
151 -- an OccName, which is a bit yukky but that's what the
152 -- clients find easiest.
153 mkWiredInTyConName :: Unique -> Module -> FAST_STRING -> TyCon -> Name
154 mkWiredInTyConName uniq mod fs tycon
155 = Name { n_uniq = uniq, n_sort = WiredInTyCon mod tycon,
156 n_occ = mkSrcOccFS tcName fs, n_prov = SystemProv }
159 ---------------------------------------------------------------------
160 mkDerivedName :: (OccName -> OccName)
162 -> Unique -- New unique
163 -> Name -- Result is always a value name
165 mkDerivedName f name uniq = name {n_uniq = uniq, n_occ = f (n_occ name)}
167 -- When we renumber/rename things, we need to be
168 -- able to change a Name's Unique to match the cached
169 -- one in the thing it's the name of. If you know what I mean.
170 setNameUnique name uniq = name {n_uniq = uniq}
172 setNameOcc :: Name -> OccName -> Name
173 -- Give the thing a new OccName, *and*
174 -- record that it's no longer a sys-local
175 -- This is used by the tidy-up pass
176 setNameOcc name occ = name {n_occ = occ}
178 setNameModule :: Name -> Module -> Name
179 setNameModule name mod = name {n_sort = set (n_sort name)}
181 set (Global _) = Global mod
182 set (WiredInId _ id) = WiredInId mod id
183 set (WiredInTyCon _ tycon) = WiredInTyCon mod tycon
187 %************************************************************************
189 \subsection{Setting provenance and visibility
191 %************************************************************************
193 tidyTopName is applied to top-level names in the final program
195 For top-level things, it globalises Local names
196 (if all top-level things should be visible)
197 and localises non-exported Global names
198 (if only exported things should be visible)
200 In all cases except an exported global, it gives it a new occurrence name.
202 The "visibility" here concerns whether the .o file's symbol table
203 mentions the thing; if so, it needs a module name in its symbol.
204 The Global things are "visible" and the Local ones are not
206 Why should things be "visible"? Certainly they must be if they
207 are exported. But also:
209 (a) In certain (prelude only) modules we split up the .hc file into
210 lots of separate little files, which are separately compiled by the C
211 compiler. That gives lots of little .o files. The idea is that if
212 you happen to mention one of them you don't necessarily pull them all
213 in. (Pulling in a piece you don't need can be v bad, because it may
214 mention other pieces you don't need either, and so on.)
216 Sadly, splitting up .hc files means that local names (like s234) are
217 now globally visible, which can lead to clashes between two .hc
218 files. So unlocaliseWhatnot goes through making all the local things
219 into global things, essentially by giving them full names so when they
220 are printed they'll have their module name too. Pretty revolting
223 (b) When optimisation is on we want to make all the internal
224 top-level defns externally visible
227 tidyTopName :: Module -> TidyOccEnv -> Name -> (TidyOccEnv, Name)
228 tidyTopName mod env name
231 (env', occ') = tidyOccName env (n_occ name)
233 name' = Name { n_uniq = n_uniq name, n_sort = mk_top_sort mod,
234 n_occ = occ', n_prov = LocalDef noSrcLoc NotExported }
236 mk_top_sort mod | all_toplev_ids_visible = Global mod
239 all_toplev_ids_visible =
240 not opt_OmitInterfacePragmas || -- Pragmas can make them visible
241 opt_EnsureSplittableC -- Splitting requires visiblilty
246 setNameProvenance :: Name -> Provenance -> Name
247 -- setNameProvenance used to only change the provenance of
248 -- Implicit-provenance things, but that gives bad error messages
249 -- for names defined twice in the same module, so I changed it to
250 -- set the provenance of *any* global (SLPJ Jun 97)
251 setNameProvenance name prov = name {n_prov = prov}
253 getNameProvenance :: Name -> Provenance
254 getNameProvenance name = n_prov name
256 setNameImportReason :: Name -> ImportReason -> Name
257 setNameImportReason name reason
258 = name { n_prov = new_prov }
260 -- It's important that we don't do the pattern matching
261 -- in the top-level clause, else we get a black hole in
262 -- the renamer. Rather a yukky constraint. There's only
263 -- one call, in RnNames
264 old_prov = n_prov name
265 new_prov = case old_prov of
266 NonLocalDef _ omit -> NonLocalDef reason omit
271 %************************************************************************
273 \subsection{Provenance and export info}
275 %************************************************************************
279 = LocalDef -- Defined locally
281 ExportFlag -- Whether it's exported
283 | NonLocalDef -- Defined non-locally
287 | SystemProv -- Either (a) a system-generated local with
288 -- a v short name OccName
289 -- or (b) a known-key global which should have a proper
290 -- provenance attached by the renamer
293 Sys-provs are only used internally. When the compiler generates (say)
294 a fresh desguar variable it always calls it "ds", and of course it gets
295 a fresh unique. But when printing -ddump-xx dumps, we must print it with
296 its unique, because there'll be a lot of "ds" variables.
298 Names with SystemProv differ in the following ways:
299 a) locals have unique attached when printing dumps
300 b) unifier eliminates sys tyvars in favour of user provs where possible
301 c) renamer replaces SystemProv with a better one
303 Before anything gets printed in interface files or output code, it's
304 fed through a 'tidy' processor, which zaps the OccNames to have
305 unique names; and converts all sys-locals to user locals
306 If any desugarer sys-locals have survived that far, they get changed to
311 = UserImport Module SrcLoc Bool -- Imported from module M on line L
312 -- Note the M may well not be the defining module
314 -- The Bool is true iff the thing was named *explicitly* in the import spec,
315 -- rather than being imported as part of a group; e.g.
318 -- Here, everything imported by B, and the constructors of T
319 -- are not named explicitly; only T is named explicitly.
320 -- This info is used when warning of unused names.
322 | ImplicitImport -- Imported implicitly for some other reason
325 type PrintUnqualified = Bool -- True <=> the unqualified name of this thing is
326 -- in scope in this module, so print it
327 -- unqualified in error messages
329 data ExportFlag = Exported | NotExported
332 Something is "Exported" if it may be mentioned by another module without
333 warning. The crucial thing about Exported things is that they must
334 never be dropped as dead code, even if they aren't used in this module.
335 Furthermore, being Exported means that we can't see all call sites of the thing.
337 Exported things include:
339 - explicitly exported Ids, including data constructors,
340 class method selectors
342 - dfuns from instance decls
344 Being Exported is *not* the same as finally appearing in the .o file's
345 symbol table. For example, a local Id may be mentioned in an Exported
346 Id's unfolding in the interface file, in which case the local Id goes
351 systemProvenance :: Provenance
352 systemProvenance = SystemProv
354 -- pprNameProvenance is used in error messages to say where a name came from
355 pprNameProvenance :: Name -> SDoc
356 pprNameProvenance name = pprProvenance (getNameProvenance name)
358 pprProvenance :: Provenance -> SDoc
359 pprProvenance SystemProv = ptext SLIT("System")
360 pprProvenance (LocalDef loc _) = ptext SLIT("defined at") <+> ppr loc
361 pprProvenance (NonLocalDef ImplicitImport _)
362 = ptext SLIT("implicitly imported")
363 pprProvenance (NonLocalDef (UserImport mod loc _) _)
364 = ptext SLIT("imported from") <+> ppr mod <+> ptext SLIT("at") <+> ppr loc
368 %************************************************************************
370 \subsection{Predicates and selectors}
372 %************************************************************************
375 nameUnique :: Name -> Unique
376 nameOccName :: Name -> OccName
377 nameModule :: Name -> Module
378 nameSrcLoc :: Name -> SrcLoc
379 isLocallyDefinedName :: Name -> Bool
380 isUserExportedName :: Name -> Bool
381 isWiredInName :: Name -> Bool
382 isLocalName :: Name -> Bool
383 isGlobalName :: Name -> Bool
384 isExternallyVisibleName :: Name -> Bool
388 hashName :: Name -> Int
389 hashName name = IBOX( u2i (nameUnique name) )
391 nameUnique name = n_uniq name
392 nameOccName name = n_occ name
396 Local -> pprPanic "nameModule" (ppr name)
397 x -> nameSortModule x
399 nameSortModule (Global mod) = mod
400 nameSortModule (WiredInId mod _) = mod
401 nameSortModule (WiredInTyCon mod _) = mod
403 nameRdrName :: Name -> RdrName
404 nameRdrName (Name { n_sort = Local, n_occ = occ }) = mkRdrUnqual occ
405 nameRdrName (Name { n_sort = sort, n_occ = occ }) = mkRdrQual (moduleName (nameSortModule sort)) occ
407 isUserExportedName (Name { n_prov = LocalDef _ Exported }) = True
408 isUserExportedName other = False
410 isUserImportedExplicitlyName (Name { n_prov = NonLocalDef (UserImport _ _ explicit) _ }) = explicit
411 isUserImportedExplicitlyName other = False
413 nameSrcLoc name = provSrcLoc (n_prov name)
415 provSrcLoc (LocalDef loc _) = loc
416 provSrcLoc (NonLocalDef (UserImport _ loc _) _) = loc
417 provSrcLoc other = noSrcLoc
419 isLocallyDefinedName (Name {n_sort = Local}) = True -- Local (might have SystemProv)
420 isLocallyDefinedName (Name {n_prov = LocalDef _ _}) = True -- Global, but defined here
421 isLocallyDefinedName other = False -- Other
423 -- Things the compiler "knows about" are in some sense
424 -- "imported". When we are compiling the module where
425 -- the entities are defined, we need to be able to pick
426 -- them out, often in combination with isLocallyDefined.
427 isWiredInName (Name {n_sort = WiredInTyCon _ _}) = True
428 isWiredInName (Name {n_sort = WiredInId _ _}) = True
429 isWiredInName _ = False
431 maybeWiredInIdName :: Name -> Maybe Id
432 maybeWiredInIdName (Name {n_sort = WiredInId _ id}) = Just id
433 maybeWiredInIdName other = Nothing
435 maybeWiredInTyConName :: Name -> Maybe TyCon
436 maybeWiredInTyConName (Name {n_sort = WiredInTyCon _ tc}) = Just tc
437 maybeWiredInTyConName other = Nothing
440 isLocalName (Name {n_sort = Local}) = True
441 isLocalName _ = False
443 isGlobalName (Name {n_sort = Local}) = False
444 isGlobalName other = True
446 -- Global names are by definition those that are visible
447 -- outside the module, *as seen by the linker*. Externally visible
448 -- does not mean visible at the source level (that's isExported).
449 isExternallyVisibleName name = isGlobalName name
451 hasBetterProv :: Name -> Name -> Bool
452 hasBetterProv name1 name2
453 = case n_prov name1 of
456 NonLocalDef _ _ -> case n_prov name2 of
457 LocalDef _ _ -> False
460 isSystemName (Name {n_prov = SystemProv}) = True
461 isSystemName other = False
465 %************************************************************************
467 \subsection[Name-instances]{Instance declarations}
469 %************************************************************************
472 cmpName n1 n2 = n_uniq n1 `compare` n_uniq n2
476 instance Eq Name where
477 a == b = case (a `compare` b) of { EQ -> True; _ -> False }
478 a /= b = case (a `compare` b) of { EQ -> False; _ -> True }
480 instance Ord Name where
481 a <= b = case (a `compare` b) of { LT -> True; EQ -> True; GT -> False }
482 a < b = case (a `compare` b) of { LT -> True; EQ -> False; GT -> False }
483 a >= b = case (a `compare` b) of { LT -> False; EQ -> True; GT -> True }
484 a > b = case (a `compare` b) of { LT -> False; EQ -> False; GT -> True }
485 compare a b = cmpName a b
487 instance Uniquable Name where
488 getUnique = nameUnique
490 instance NamedThing Name where
495 %************************************************************************
497 \subsection{Pretty printing}
499 %************************************************************************
502 instance Outputable Name where
503 -- When printing interfaces, all Locals have been given nice print-names
504 ppr name = pprName name
506 pprName (Name {n_sort = Local, n_uniq = uniq, n_occ = occ, n_prov = prov})
508 = getPprStyle $ \ sty ->
509 if codeStyle sty then
510 pprUnique uniq -- When printing in code we required all names to
511 -- be globally unique; for example, we use this identifier
512 -- for the closure name. So we just print the unique alone.
514 pprOccName occ <> pp_local_extra sty uniq
516 sys_local = case prov of
520 pp_local_extra sty uniq
521 | sys_local = underscore <> pprUnique uniq -- Must print uniques for sys_locals
522 | debugStyle sty = text "{-" <> pprUnique uniq <> text "-}"
526 pprName (Name {n_sort = sort, n_uniq = uniq, n_occ = occ, n_prov = prov})
527 -- Globals, and wired in things
528 = getPprStyle $ \ sty ->
529 if codeStyle sty then
530 ppr mod <> underscore <> ppr occ
532 pp_mod_dot sty <> ppr occ <> pp_global_debug sty uniq prov
534 mod = nameSortModule sort
538 SystemProv -> pp_qual mod user_sty
539 -- Hack alert! Omit the qualifier on SystemProv things in user style
540 -- I claim such SystemProv things will also be WiredIn things.
541 -- We can't get the omit flag right
542 -- on wired in tycons etc (sigh) so we just leave it out in user style,
543 -- and hope that leaving it out isn't too consfusing.
544 -- (e.g. if the programmer hides Bool and redefines it. If so, use -dppr-debug.)
546 LocalDef _ _ -> pp_qual mod (user_sty || iface_sty)
548 NonLocalDef (UserImport imp_mod _ _) omit
549 | user_sty -> pp_qual imp_mod omit
550 | otherwise -> pp_qual mod False
551 NonLocalDef ImplicitImport omit -> pp_qual mod (user_sty && omit)
553 user_sty = userStyle sty
554 iface_sty = ifaceStyle sty
556 pp_qual mod omit_qual
558 | otherwise = pprModule mod <> dot
560 pp_global_debug sty uniq prov
561 | debugStyle sty = hcat [text "{-", pprUnique uniq, prov_p prov, text "-}"]
564 prov_p prov | opt_PprStyle_NoPrags = empty
565 | otherwise = comma <> pp_prov prov
567 pp_prov (LocalDef _ Exported) = char 'x'
568 pp_prov (LocalDef _ NotExported) = char 'l'
569 pp_prov (NonLocalDef ImplicitImport _) = char 'j'
570 pp_prov (NonLocalDef (UserImport _ _ True ) _) = char 'I' -- Imported by name
571 pp_prov (NonLocalDef (UserImport _ _ False) _) = char 'i' -- Imported by ..
572 pp_prov SystemProv = char 's'
576 %************************************************************************
578 \subsection{Overloaded functions related to Names}
580 %************************************************************************
583 class NamedThing a where
584 getOccName :: a -> OccName
587 getOccName n = nameOccName (getName n) -- Default method
591 getSrcLoc :: NamedThing a => a -> SrcLoc
592 isLocallyDefined :: NamedThing a => a -> Bool
593 getOccString :: NamedThing a => a -> String
595 getSrcLoc = nameSrcLoc . getName
596 isLocallyDefined = isLocallyDefinedName . getName
597 getOccString x = occNameString (getOccName x)
601 {-# SPECIALIZE isLocallyDefined :: Name -> Bool #-}