2 % (c) The University of Glasgow, 2006
4 \section[HscTypes]{Types for the per-module compiler}
8 -- * Sessions and compilation state
9 Session(..), withSession, modifySession,
11 FinderCache, FindResult(..), ModLocationCache,
12 Target(..), TargetId(..), pprTarget, pprTargetId,
15 ModDetails(..), emptyModDetails,
16 ModGuts(..), CgGuts(..), ModImports(..), ForeignStubs(..),
18 ModSummary(..), ms_mod_name, showModMsg, isBootSummary,
19 msHsFilePath, msHiFilePath, msObjFilePath,
21 HscSource(..), isHsBoot, hscSourceString, -- Re-exported from DriverPhases
23 HomePackageTable, HomeModInfo(..), emptyHomePackageTable,
24 hptInstances, hptRules, hptVectInfo,
26 ExternalPackageState(..), EpsStats(..), addEpsInStats,
27 PackageTypeEnv, PackageIfaceTable, emptyPackageIfaceTable,
28 lookupIfaceByModule, emptyModIface,
30 InteractiveContext(..), emptyInteractiveContext,
31 icPrintUnqual, mkPrintUnqualified, extendInteractiveContext,
33 ModIface(..), mkIfaceDepCache, mkIfaceVerCache, mkIfaceFixCache,
36 Deprecs(..), IfaceDeprecs,
38 FixityEnv, FixItem(..), lookupFixity, emptyFixityEnv,
40 implicitTyThings, isImplicitTyThing,
42 TyThing(..), tyThingClass, tyThingTyCon, tyThingDataCon, tyThingId,
43 TypeEnv, lookupType, mkTypeEnv, emptyTypeEnv,
44 extendTypeEnv, extendTypeEnvList, extendTypeEnvWithIds, lookupTypeEnv,
45 typeEnvElts, typeEnvClasses, typeEnvTyCons, typeEnvIds,
48 WhetherHasOrphans, IsBootInterface, Usage(..),
49 Dependencies(..), noDependencies,
50 NameCache(..), OrigNameCache, OrigIParamCache,
51 Avails, availsToNameSet, availsToNameEnv, availName, availNames,
52 GenAvailInfo(..), AvailInfo, RdrAvailInfo,
55 Deprecations, DeprecTxt, plusDeprecs,
57 PackageInstEnv, PackageRuleBase,
60 Linkable(..), isObjectLinkable,
61 Unlinked(..), CompiledByteCode,
62 isObject, nameOfObject, isInterpretable, byteCodeOfObject,
63 HpcInfo(..), noHpcInfo,
66 ModBreaks (..), BreakIndex, emptyModBreaks,
68 -- Vectorisation information
69 VectInfo(..), IfaceVectInfo(..), noVectInfo, plusVectInfo,
73 #include "HsVersions.h"
76 import ByteCodeAsm ( CompiledByteCode )
77 import {-# SOURCE #-} InteractiveEval ( Resume )
80 import RdrName ( GlobalRdrEnv, emptyGlobalRdrEnv, GlobalRdrElt(..),
81 unQualOK, ImpDeclSpec(..), Provenance(..),
82 ImportSpec(..), lookupGlobalRdrEnv )
83 import Name ( Name, NamedThing, getName, nameOccName, nameModule )
86 import OccName ( OccName, OccEnv, lookupOccEnv, mkOccEnv, emptyOccEnv,
89 import InstEnv ( InstEnv, Instance )
90 import FamInstEnv ( FamInstEnv, FamInst )
91 import Rules ( RuleBase )
92 import CoreSyn ( CoreBind )
97 import Type ( TyThing(..) )
99 import Class ( Class, classSelIds, classATs, classTyCon )
101 import DataCon ( DataCon, dataConImplicitIds )
102 import PrelNames ( gHC_PRIM )
103 import Packages ( PackageId )
104 import DynFlags ( DynFlags(..), isOneShot, HscTarget (..) )
105 import DriverPhases ( HscSource(..), isHsBoot, hscSourceString, Phase )
106 import BasicTypes ( Version, initialVersion, IPName,
107 Fixity, defaultFixity, DeprecTxt )
109 import FiniteMap ( FiniteMap )
110 import CoreSyn ( CoreRule )
111 import Maybes ( orElse, expectJust, catMaybes, seqMaybe )
114 import SrcLoc ( SrcSpan, Located )
115 import UniqFM ( lookupUFM, eltsUFM, emptyUFM )
116 import UniqSupply ( UniqSupply )
117 import FastString ( FastString )
119 import StringBuffer ( StringBuffer )
121 import System.Time ( ClockTime )
123 import Data.Array ( Array, array )
127 %************************************************************************
129 \subsection{Compilation environment}
131 %************************************************************************
135 -- | The Session is a handle to the complete state of a compilation
136 -- session. A compilation session consists of a set of modules
137 -- constituting the current program or library, the context for
138 -- interactive evaluation, and various caches.
139 newtype Session = Session (IORef HscEnv)
141 withSession :: Session -> (HscEnv -> IO a) -> IO a
142 withSession (Session ref) f = do h <- readIORef ref; f h
144 modifySession :: Session -> (HscEnv -> HscEnv) -> IO ()
145 modifySession (Session ref) f = do h <- readIORef ref; writeIORef ref $! f h
148 HscEnv is like Session, except that some of the fields are immutable.
149 An HscEnv is used to compile a single module from plain Haskell source
150 code (after preprocessing) to either C, assembly or C--. Things like
151 the module graph don't change during a single compilation.
153 Historical note: "hsc" used to be the name of the compiler binary,
154 when there was a separate driver and compiler. To compile a single
155 module, the driver would invoke hsc on the source code... so nowadays
156 we think of hsc as the layer of the compiler that deals with compiling
162 hsc_dflags :: DynFlags,
163 -- The dynamic flag settings
165 hsc_targets :: [Target],
166 -- The targets (or roots) of the current session
168 hsc_mod_graph :: ModuleGraph,
169 -- The module graph of the current session
171 hsc_IC :: InteractiveContext,
172 -- The context for evaluating interactive statements
174 hsc_HPT :: HomePackageTable,
175 -- The home package table describes already-compiled
176 -- home-packge modules, *excluding* the module we
177 -- are compiling right now.
178 -- (In one-shot mode the current module is the only
179 -- home-package module, so hsc_HPT is empty. All other
180 -- modules count as "external-package" modules.
181 -- However, even in GHCi mode, hi-boot interfaces are
182 -- demand-loadeded into the external-package table.)
184 -- hsc_HPT is not mutable because we only demand-load
185 -- external packages; the home package is eagerly
186 -- loaded, module by module, by the compilation manager.
188 -- The HPT may contain modules compiled earlier by --make
189 -- but not actually below the current module in the dependency
190 -- graph. (This changes a previous invariant: changed Jan 05.)
192 hsc_EPS :: {-# UNPACK #-} !(IORef ExternalPackageState),
193 hsc_NC :: {-# UNPACK #-} !(IORef NameCache),
194 -- These are side-effected by compiling to reflect
195 -- sucking in interface files. They cache the state of
196 -- external interface files, in effect.
198 hsc_FC :: {-# UNPACK #-} !(IORef FinderCache),
199 hsc_MLC :: {-# UNPACK #-} !(IORef ModLocationCache),
200 -- The finder's cache. This caches the location of modules,
201 -- so we don't have to search the filesystem multiple times.
203 hsc_global_rdr_env :: GlobalRdrEnv,
204 hsc_global_type_env :: TypeEnv
207 hscEPS :: HscEnv -> IO ExternalPackageState
208 hscEPS hsc_env = readIORef (hsc_EPS hsc_env)
210 -- | A compilation target.
212 -- A target may be supplied with the actual text of the
213 -- module. If so, use this instead of the file contents (this
214 -- is for use in an IDE where the file hasn't been saved by
216 data Target = Target TargetId (Maybe (StringBuffer,ClockTime))
219 = TargetModule ModuleName
220 -- ^ A module name: search for the file
221 | TargetFile FilePath (Maybe Phase)
222 -- ^ A filename: preprocess & parse it to find the module name.
223 -- If specified, the Phase indicates how to compile this file
224 -- (which phase to start from). Nothing indicates the starting phase
225 -- should be determined from the suffix of the filename.
228 pprTarget :: Target -> SDoc
229 pprTarget (Target id _) = pprTargetId id
231 instance Outputable Target where
234 pprTargetId (TargetModule m) = ppr m
235 pprTargetId (TargetFile f _) = text f
237 instance Outputable TargetId where
240 type HomePackageTable = ModuleNameEnv HomeModInfo
241 -- Domain = modules in the home package
242 -- "home" package name cached here for convenience
243 type PackageIfaceTable = ModuleEnv ModIface
244 -- Domain = modules in the imported packages
246 emptyHomePackageTable = emptyUFM
247 emptyPackageIfaceTable = emptyModuleEnv
250 = HomeModInfo { hm_iface :: !ModIface,
251 hm_details :: !ModDetails,
252 hm_linkable :: !(Maybe Linkable) }
253 -- hm_linkable might be Nothing if:
254 -- a) this is an .hs-boot module
255 -- b) temporarily during compilation if we pruned away
256 -- the old linkable because it was out of date.
257 -- after a complete compilation (GHC.load), all hm_linkable
258 -- fields in the HPT will be Just.
260 -- When re-linking a module (hscNoRecomp), we construct
261 -- the HomModInfo by building a new ModDetails from the
262 -- old ModIface (only).
264 -- | Find the 'ModIface' for a 'Module'
271 lookupIfaceByModule dflags hpt pit mod
272 | modulePackageId mod == thisPackage dflags
273 = -- The module comes from the home package, so look first
274 -- in the HPT. If it's not from the home package it's wrong to look
275 -- in the HPT, because the HPT is indexed by *ModuleName* not Module
276 fmap hm_iface (lookupUFM hpt (moduleName mod))
277 `seqMaybe` lookupModuleEnv pit mod
279 | otherwise = lookupModuleEnv pit mod -- Look in PIT only
281 -- If the module does come from the home package, why do we look in the PIT as well?
282 -- (a) In OneShot mode, even home-package modules accumulate in the PIT
283 -- (b) Even in Batch (--make) mode, there is *one* case where a home-package
284 -- module is in the PIT, namely GHC.Prim when compiling the base package.
285 -- We could eliminate (b) if we wanted, by making GHC.Prim belong to a packake
286 -- of its own, but it doesn't seem worth the bother.
291 hptInstances :: HscEnv -> (ModuleName -> Bool) -> ([Instance], [FamInst])
292 -- Find all the instance declarations (of classes and families) that are in
293 -- modules imported by this one, directly or indirectly, and are in the Home
294 -- Package Table. This ensures that we don't see instances from modules --make
295 -- compiled before this one, but which are not below this one.
296 hptInstances hsc_env want_this_module
297 = let (insts, famInsts) = unzip
298 [ (md_insts details, md_fam_insts details)
299 | mod_info <- eltsUFM (hsc_HPT hsc_env)
300 , want_this_module (moduleName (mi_module (hm_iface mod_info)))
301 , let details = hm_details mod_info ]
303 (concat insts, concat famInsts)
305 hptRules :: HscEnv -> [(ModuleName, IsBootInterface)] -> [CoreRule]
306 -- Get rules from modules "below" this one (in the dependency sense)
307 -- C.f Inst.hptInstances
308 hptRules hsc_env deps
309 | isOneShot (ghcMode (hsc_dflags hsc_env)) = []
312 hpt = hsc_HPT hsc_env
315 | -- Find each non-hi-boot module below me
318 -- unsavoury: when compiling the base package with --make, we
319 -- sometimes try to look up RULES for GHC.Prim. GHC.Prim won't
320 -- be in the HPT, because we never compile it; it's in the EPT
321 -- instead. ToDo: clean up, and remove this slightly bogus
323 , mod /= moduleName gHC_PRIM
325 -- Look it up in the HPT
326 , let rules = case lookupUFM hpt mod of
327 Just info -> md_rules (hm_details info)
328 Nothing -> pprTrace "WARNING in hptRules" msg []
329 msg = vcat [ptext SLIT("missing module") <+> ppr mod,
330 ptext SLIT("Probable cause: out-of-date interface files")]
331 -- This really shouldn't happen, but see Trac #962
336 hptVectInfo :: HscEnv -> VectInfo
337 -- Get the combined VectInfo of all modules in the home package table. In
338 -- contrast to instances and rules, we don't care whether the modules are
339 -- "below" or us. The VectInfo of those modules not "below" us does not
340 -- affect the compilation of the current module.
342 = foldr plusVectInfo noVectInfo [ md_vect_info (hm_details mod_info)
343 | mod_info <- eltsUFM (hsc_HPT hsc_env)]
346 %************************************************************************
348 \subsection{The Finder cache}
350 %************************************************************************
353 -- | The 'FinderCache' maps home module names to the result of
354 -- searching for that module. It records the results of searching for
355 -- modules along the search path. On @:load@, we flush the entire
356 -- contents of this cache.
358 -- Although the @FinderCache@ range is 'FindResult' for convenience ,
359 -- in fact it will only ever contain 'Found' or 'NotFound' entries.
361 type FinderCache = ModuleNameEnv FindResult
363 -- | The result of searching for an imported module.
365 = Found ModLocation Module
366 -- the module was found
367 | NoPackage PackageId
368 -- the requested package was not found
369 | FoundMultiple [PackageId]
370 -- *error*: both in multiple packages
371 | PackageHidden PackageId
372 -- for an explicit source import: the package containing the module is
374 | ModuleHidden PackageId
375 -- for an explicit source import: the package containing the module is
376 -- exposed, but the module itself is hidden.
377 | NotFound [FilePath] (Maybe PackageId)
378 -- the module was not found, the specified places were searched
379 | NotFoundInPackage PackageId
380 -- the module was not found in this package
382 -- | Cache that remembers where we found a particular module. Contains both
383 -- home modules and package modules. On @:load@, only home modules are
384 -- purged from this cache.
385 type ModLocationCache = ModuleEnv ModLocation
388 %************************************************************************
390 \subsection{Symbol tables and Module details}
392 %************************************************************************
394 A @ModIface@ plus a @ModDetails@ summarises everything we know
395 about a compiled module. The @ModIface@ is the stuff *before* linking,
396 and can be written out to an interface file. (The @ModDetails@ is after
397 linking; it is the "linked" form of the mi_decls field.)
399 When we *read* an interface file, we also construct a @ModIface@ from it,
400 except that the mi_decls part is empty; when reading we consolidate
401 the declarations into a single indexed map in the @PersistentRenamerState@.
406 mi_module :: !Module,
407 mi_mod_vers :: !Version, -- Module version: changes when anything changes
409 mi_orphan :: !WhetherHasOrphans, -- Whether this module has orphans
410 mi_finsts :: !WhetherHasFamInst, -- Whether module has family insts
411 mi_boot :: !IsBootInterface, -- Read from an hi-boot file?
413 mi_deps :: Dependencies,
414 -- This is consulted for directly-imported modules,
415 -- but not for anything else (hence lazy)
417 -- Usages; kept sorted so that it's easy to decide
418 -- whether to write a new iface file (changing usages
419 -- doesn't affect the version of this module)
420 mi_usages :: [Usage],
421 -- NOT STRICT! we read this field lazily from the interface file
422 -- It is *only* consulted by the recompilation checker
425 -- Kept sorted by (mod,occ), to make version comparisons easier
426 mi_exports :: ![IfaceExport],
427 mi_exp_vers :: !Version, -- Version number of export list
430 mi_fixities :: [(OccName,Fixity)],
431 -- NOT STRICT! we read this field lazily from the interface file
434 mi_deprecs :: IfaceDeprecs,
435 -- NOT STRICT! we read this field lazily from the interface file
437 -- Type, class and variable declarations
438 -- The version of an Id changes if its fixity or deprecations change
439 -- (as well as its type of course)
440 -- Ditto data constructors, class operations, except that
441 -- the version of the parent class/tycon changes
442 mi_decls :: [(Version,IfaceDecl)], -- Sorted
444 mi_globals :: !(Maybe GlobalRdrEnv),
445 -- Binds all the things defined at the top level in
446 -- the *original source* code for this module. which
447 -- is NOT the same as mi_exports, nor mi_decls (which
448 -- may contains declarations for things not actually
449 -- defined by the user). Used for GHCi and for inspecting
450 -- the contents of modules via the GHC API only.
452 -- (We need the source file to figure out the
453 -- top-level environment, if we didn't compile this module
454 -- from source then this field contains Nothing).
456 -- Strictly speaking this field should live in the
457 -- HomeModInfo, but that leads to more plumbing.
459 -- Instance declarations and rules
460 mi_insts :: [IfaceInst], -- Sorted
461 mi_fam_insts :: [IfaceFamInst], -- Sorted
462 mi_rules :: [IfaceRule], -- Sorted
463 mi_rule_vers :: !Version, -- Version number for rules and
464 -- instances (for classes and families)
467 -- Vectorisation information
468 mi_vect_info :: !IfaceVectInfo,
470 -- Cached environments for easy lookup
471 -- These are computed (lazily) from other fields
472 -- and are not put into the interface file
473 mi_dep_fn :: Name -> Maybe DeprecTxt, -- Cached lookup for mi_deprecs
474 mi_fix_fn :: OccName -> Fixity, -- Cached lookup for mi_fixities
475 mi_ver_fn :: OccName -> Maybe (OccName, Version)
476 -- Cached lookup for mi_decls
477 -- The Nothing in mi_ver_fn means that the thing
478 -- isn't in decls. It's useful to know that when
479 -- seeing if we are up to date wrt the old interface
480 -- The 'OccName' is the parent of the name, if it has one.
483 -- Should be able to construct ModDetails from mi_decls in ModIface
486 -- The next two fields are created by the typechecker
487 md_exports :: [AvailInfo],
488 md_types :: !TypeEnv,
489 md_insts :: ![Instance], -- Dfun-ids for the instances in this module
490 md_fam_insts :: ![FamInst],
491 md_rules :: ![CoreRule], -- Domain may include Ids from other modules
492 md_modBreaks :: !ModBreaks, -- Breakpoint information for this module
493 md_vect_info :: !VectInfo -- Vectorisation information
496 emptyModDetails = ModDetails { md_types = emptyTypeEnv,
501 md_modBreaks = emptyModBreaks,
502 md_vect_info = noVectInfo
505 -- A ModGuts is carried through the compiler, accumulating stuff as it goes
506 -- There is only one ModGuts at any time, the one for the module
507 -- being compiled right now. Once it is compiled, a ModIface and
508 -- ModDetails are extracted and the ModGuts is dicarded.
512 mg_module :: !Module,
513 mg_boot :: IsBootInterface, -- Whether it's an hs-boot module
514 mg_exports :: ![AvailInfo], -- What it exports
515 mg_deps :: !Dependencies, -- What is below it, directly or
517 mg_dir_imps :: ![Module], -- Directly-imported modules; used to
518 -- generate initialisation code
519 mg_usages :: ![Usage], -- Version info for what it needed
521 mg_rdr_env :: !GlobalRdrEnv, -- Top-level lexical environment
522 mg_fix_env :: !FixityEnv, -- Fixity env, for things declared in
525 mg_fam_inst_env :: FamInstEnv, -- Type-family instance enviroment
526 -- for *home-package* modules (including
527 -- this one). c.f. tcg_fam_inst_env
529 mg_types :: !TypeEnv,
530 mg_insts :: ![Instance], -- Instances
531 mg_fam_insts :: ![FamInst], -- Instances
532 mg_rules :: ![CoreRule], -- Rules from this module
533 mg_binds :: ![CoreBind], -- Bindings for this module
534 mg_foreign :: !ForeignStubs,
535 mg_deprecs :: !Deprecations, -- Deprecations declared in the module
536 mg_hpc_info :: !HpcInfo, -- info about coverage tick boxes
537 mg_modBreaks :: !ModBreaks,
538 mg_vect_info :: !VectInfo -- Pool of vectorised declarations
541 -- The ModGuts takes on several slightly different forms:
543 -- After simplification, the following fields change slightly:
544 -- mg_rules Orphan rules only (local ones now attached to binds)
545 -- mg_binds With rules attached
548 ---------------------------------------------------------
549 -- The Tidy pass forks the information about this module:
550 -- * one lot goes to interface file generation (ModIface)
551 -- and later compilations (ModDetails)
552 -- * the other lot goes to code generation (CgGuts)
555 cg_module :: !Module,
557 cg_tycons :: [TyCon],
558 -- Algebraic data types (including ones that started
559 -- life as classes); generate constructors and info
560 -- tables Includes newtypes, just for the benefit of
563 cg_binds :: [CoreBind],
564 -- The tidied main bindings, including
565 -- previously-implicit bindings for record and class
566 -- selectors, and data construtor wrappers. But *not*
567 -- data constructor workers; reason: we we regard them
568 -- as part of the code-gen of tycons
570 cg_dir_imps :: ![Module],
571 -- Directly-imported modules; used to generate
572 -- initialisation code
574 cg_foreign :: !ForeignStubs,
575 cg_dep_pkgs :: ![PackageId], -- Used to generate #includes for C code gen
576 cg_hpc_info :: !HpcInfo -- info about coverage tick boxes
579 -----------------------------------
582 imp_direct :: ![(Module,Bool)], -- Explicitly-imported modules
583 -- Boolean is true if we imported the whole
584 -- module (apart, perhaps, from hiding some)
585 imp_pkg_mods :: !ModuleSet, -- Non-home-package modules on which we depend,
586 -- directly or indirectly
587 imp_home_names :: !NameSet -- Home package things on which we depend,
588 -- directly or indirectly
591 -----------------------------------
592 data ForeignStubs = NoStubs
594 SDoc -- Header file prototypes for
595 -- "foreign exported" functions
596 SDoc -- C stubs to use when calling
597 -- "foreign exported" functions
598 [FastString] -- Headers that need to be included
599 -- into C code generated for this module
600 [Id] -- Foreign-exported binders
601 -- we have to generate code to register these
606 emptyModIface :: Module -> ModIface
608 = ModIface { mi_module = mod,
609 mi_mod_vers = initialVersion,
613 mi_deps = noDependencies,
616 mi_exp_vers = initialVersion,
618 mi_deprecs = NoDeprecs,
623 mi_globals = Nothing,
624 mi_rule_vers = initialVersion,
625 mi_vect_info = noIfaceVectInfo,
626 mi_dep_fn = emptyIfaceDepCache,
627 mi_fix_fn = emptyIfaceFixCache,
628 mi_ver_fn = emptyIfaceVerCache
633 %************************************************************************
635 \subsection{The interactive context}
637 %************************************************************************
640 data InteractiveContext
641 = InteractiveContext {
642 ic_toplev_scope :: [Module], -- Include the "top-level" scope of
645 ic_exports :: [Module], -- Include just the exports of these
648 ic_rn_gbl_env :: GlobalRdrEnv, -- The cached GlobalRdrEnv, built from
649 -- ic_toplev_scope and ic_exports
651 ic_tmp_ids :: [Id], -- Names bound during interaction.
653 -- earlier ones with the same OccName.
655 ic_tyvars :: TyVarSet -- skolem type variables free in
656 -- ic_tmp_ids. These arise at
657 -- breakpoints in a polymorphic
658 -- context, where we have only partial
662 , ic_resume :: [Resume] -- the stack of breakpoint contexts
667 emptyInteractiveContext
668 = InteractiveContext { ic_toplev_scope = [],
670 ic_rn_gbl_env = emptyGlobalRdrEnv,
672 ic_tyvars = emptyVarSet
678 icPrintUnqual :: InteractiveContext -> PrintUnqualified
679 icPrintUnqual ictxt = mkPrintUnqualified (ic_rn_gbl_env ictxt)
682 extendInteractiveContext
683 :: InteractiveContext
686 -> InteractiveContext
687 extendInteractiveContext ictxt ids tyvars
688 = ictxt { ic_tmp_ids = ic_tmp_ids ictxt ++ ids,
689 -- NB. must be this way around, because we want
690 -- new ids to shadow existing bindings.
691 ic_tyvars = ic_tyvars ictxt `unionVarSet` tyvars }
694 %************************************************************************
696 Building a PrintUnqualified
698 %************************************************************************
701 mkPrintUnqualified :: GlobalRdrEnv -> PrintUnqualified
702 mkPrintUnqualified env = (qual_name, qual_mod)
705 | null gres = Just (moduleName mod)
706 -- it isn't in scope at all, this probably shouldn't happen,
707 -- but we'll qualify it by the original module anyway.
708 | any unQualOK gres = Nothing
709 | (Imported is : _) <- map gre_prov gres, (idecl : _) <- is
710 = Just (is_as (is_decl idecl))
711 | otherwise = panic "mkPrintUnqualified"
713 gres = [ gre | gre <- lookupGlobalRdrEnv env occ,
714 nameModule (gre_name gre) == mod ]
716 qual_mod mod = Nothing -- For now...
720 %************************************************************************
724 %************************************************************************
727 implicitTyThings :: TyThing -> [TyThing]
728 -- If you change this, make sure you change LoadIface.ifaceDeclSubBndrs in sync
730 implicitTyThings (AnId id) = []
732 -- For type constructors, add the data cons (and their extras),
733 -- and the selectors and generic-programming Ids too
735 -- Newtypes don't have a worker Id, so don't generate that?
736 implicitTyThings (ATyCon tc) = implicitCoTyCon tc ++
737 map AnId (tyConSelIds tc) ++
738 concatMap (extras_plus . ADataCon)
741 -- For classes, add the class selector Ids, and assoicated TyCons
742 -- and the class TyCon too (and its extras)
743 implicitTyThings (AClass cl)
744 = map AnId (classSelIds cl) ++
745 map ATyCon (classATs cl) ++
746 -- No extras_plus for the classATs, because they
747 -- are only the family decls; they have no implicit things
748 extras_plus (ATyCon (classTyCon cl))
750 -- For data cons add the worker and wrapper (if any)
751 implicitTyThings (ADataCon dc) = map AnId (dataConImplicitIds dc)
753 -- | returns 'True' if there should be no interface-file declaration
754 -- for this thing on its own: either it is built-in, or it is part
755 -- of some other declaration, or it is generated implicitly by some
756 -- other declaration.
757 isImplicitTyThing :: TyThing -> Bool
758 isImplicitTyThing (ADataCon _) = True
759 isImplicitTyThing (AnId id) = isImplicitId id
760 isImplicitTyThing (AClass _) = False
761 isImplicitTyThing (ATyCon tc) = isImplicitTyCon tc
763 -- For newtypes and indexed data types, add the implicit coercion tycon
765 = map ATyCon . catMaybes $ [newTyConCo_maybe tc,
766 tyConFamilyCoercion_maybe tc]
768 extras_plus thing = thing : implicitTyThings thing
770 extendTypeEnvWithIds :: TypeEnv -> [Id] -> TypeEnv
771 extendTypeEnvWithIds env ids
772 = extendNameEnvList env [(getName id, AnId id) | id <- ids]
775 %************************************************************************
779 %************************************************************************
782 type TypeEnv = NameEnv TyThing
784 emptyTypeEnv :: TypeEnv
785 typeEnvElts :: TypeEnv -> [TyThing]
786 typeEnvClasses :: TypeEnv -> [Class]
787 typeEnvTyCons :: TypeEnv -> [TyCon]
788 typeEnvIds :: TypeEnv -> [Id]
789 typeEnvDataCons :: TypeEnv -> [DataCon]
790 lookupTypeEnv :: TypeEnv -> Name -> Maybe TyThing
792 emptyTypeEnv = emptyNameEnv
793 typeEnvElts env = nameEnvElts env
794 typeEnvClasses env = [cl | AClass cl <- typeEnvElts env]
795 typeEnvTyCons env = [tc | ATyCon tc <- typeEnvElts env]
796 typeEnvIds env = [id | AnId id <- typeEnvElts env]
797 typeEnvDataCons env = [dc | ADataCon dc <- typeEnvElts env]
799 mkTypeEnv :: [TyThing] -> TypeEnv
800 mkTypeEnv things = extendTypeEnvList emptyTypeEnv things
802 lookupTypeEnv = lookupNameEnv
804 -- Extend the type environment
805 extendTypeEnv :: TypeEnv -> TyThing -> TypeEnv
806 extendTypeEnv env thing = extendNameEnv env (getName thing) thing
808 extendTypeEnvList :: TypeEnv -> [TyThing] -> TypeEnv
809 extendTypeEnvList env things = foldl extendTypeEnv env things
813 lookupType :: DynFlags
819 lookupType dflags hpt pte name
820 -- in one-shot, we don't use the HPT
821 | not (isOneShot (ghcMode dflags)) && modulePackageId mod == this_pkg
822 = do hm <- lookupUFM hpt (moduleName mod) -- Maybe monad
823 lookupNameEnv (md_types (hm_details hm)) name
825 = lookupNameEnv pte name
826 where mod = nameModule name
827 this_pkg = thisPackage dflags
831 tyThingTyCon (ATyCon tc) = tc
832 tyThingTyCon other = pprPanic "tyThingTyCon" (ppr other)
834 tyThingClass (AClass cls) = cls
835 tyThingClass other = pprPanic "tyThingClass" (ppr other)
837 tyThingDataCon (ADataCon dc) = dc
838 tyThingDataCon other = pprPanic "tyThingDataCon" (ppr other)
840 tyThingId (AnId id) = id
841 tyThingId other = pprPanic "tyThingId" (ppr other)
844 %************************************************************************
846 \subsection{Auxiliary types}
848 %************************************************************************
850 These types are defined here because they are mentioned in ModDetails,
851 but they are mostly elaborated elsewhere
854 mkIfaceVerCache :: [(Version,IfaceDecl)]
855 -> (OccName -> Maybe (OccName, Version))
856 mkIfaceVerCache pairs
857 = \occ -> lookupOccEnv env occ
859 env = foldr add_decl emptyOccEnv pairs
860 add_decl (v,d) env0 = foldr add_imp env1 (ifaceDeclSubBndrs d)
863 env1 = extendOccEnv env0 decl_name (decl_name, v)
864 add_imp bndr env = extendOccEnv env bndr (decl_name, v)
866 emptyIfaceVerCache :: OccName -> Maybe (OccName, Version)
867 emptyIfaceVerCache occ = Nothing
869 ------------------ Deprecations -------------------------
872 | DeprecAll DeprecTxt -- Whole module deprecated
873 | DeprecSome a -- Some specific things deprecated
876 type IfaceDeprecs = Deprecs [(OccName,DeprecTxt)]
877 type Deprecations = Deprecs (NameEnv (OccName,DeprecTxt))
878 -- Keep the OccName so we can flatten the NameEnv to
879 -- get an IfaceDeprecs from a Deprecations
880 -- Only an OccName is needed, because a deprecation always
881 -- applies to things defined in the module in which the
882 -- deprecation appears.
884 mkIfaceDepCache:: IfaceDeprecs -> Name -> Maybe DeprecTxt
885 mkIfaceDepCache NoDeprecs = \n -> Nothing
886 mkIfaceDepCache (DeprecAll t) = \n -> Just t
887 mkIfaceDepCache (DeprecSome pairs) = lookupOccEnv (mkOccEnv pairs) . nameOccName
889 emptyIfaceDepCache :: Name -> Maybe DeprecTxt
890 emptyIfaceDepCache n = Nothing
892 plusDeprecs :: Deprecations -> Deprecations -> Deprecations
893 plusDeprecs d NoDeprecs = d
894 plusDeprecs NoDeprecs d = d
895 plusDeprecs d (DeprecAll t) = DeprecAll t
896 plusDeprecs (DeprecAll t) d = DeprecAll t
897 plusDeprecs (DeprecSome v1) (DeprecSome v2) = DeprecSome (v1 `plusNameEnv` v2)
902 type Avails = [AvailInfo]
903 type AvailInfo = GenAvailInfo Name
904 type RdrAvailInfo = GenAvailInfo OccName
906 data GenAvailInfo name = Avail name -- An ordinary identifier
907 | AvailTC name -- The name of the type or class
908 [name] -- The available pieces of type/class.
909 -- NB: If the type or class is itself
910 -- to be in scope, it must be in this list.
911 -- Thus, typically: AvailTC Eq [Eq, ==, /=]
913 -- Equality used when deciding if the interface has changed
915 type IfaceExport = (Module, [GenAvailInfo OccName])
917 availsToNameSet :: [AvailInfo] -> NameSet
918 availsToNameSet avails = foldr add emptyNameSet avails
919 where add avail set = addListToNameSet set (availNames avail)
921 availsToNameEnv :: [AvailInfo] -> NameEnv AvailInfo
922 availsToNameEnv avails = foldr add emptyNameEnv avails
923 where add avail env = extendNameEnvList env
924 (zip (availNames avail) (repeat avail))
926 availName :: GenAvailInfo name -> name
927 availName (Avail n) = n
928 availName (AvailTC n _) = n
930 availNames :: GenAvailInfo name -> [name]
931 availNames (Avail n) = [n]
932 availNames (AvailTC n ns) = ns
934 instance Outputable n => Outputable (GenAvailInfo n) where
937 pprAvail :: Outputable n => GenAvailInfo n -> SDoc
938 pprAvail (Avail n) = ppr n
939 pprAvail (AvailTC n ns) = ppr n <> braces (hsep (punctuate comma (map ppr ns)))
943 mkIfaceFixCache :: [(OccName, Fixity)] -> OccName -> Fixity
944 mkIfaceFixCache pairs
945 = \n -> lookupOccEnv env n `orElse` defaultFixity
949 emptyIfaceFixCache :: OccName -> Fixity
950 emptyIfaceFixCache n = defaultFixity
952 -- This fixity environment is for source code only
953 type FixityEnv = NameEnv FixItem
955 -- We keep the OccName in the range so that we can generate an interface from it
956 data FixItem = FixItem OccName Fixity SrcSpan
958 instance Outputable FixItem where
959 ppr (FixItem occ fix loc) = ppr fix <+> ppr occ <+> parens (ppr loc)
961 emptyFixityEnv :: FixityEnv
962 emptyFixityEnv = emptyNameEnv
964 lookupFixity :: FixityEnv -> Name -> Fixity
965 lookupFixity env n = case lookupNameEnv env n of
966 Just (FixItem _ fix _) -> fix
967 Nothing -> defaultFixity
971 %************************************************************************
973 \subsection{WhatsImported}
975 %************************************************************************
978 type WhetherHasOrphans = Bool
980 -- * an instance decl in a module other than the defn module for
981 -- one of the tycons or classes in the instance head
982 -- * a transformation rule in a module other than the one defining
983 -- the function in the head of the rule.
985 type WhetherHasFamInst = Bool -- This module defines family instances?
987 type IsBootInterface = Bool
989 -- Dependency info about modules and packages below this one
990 -- in the import hierarchy. See TcRnTypes.ImportAvails for details.
991 -- The orphan modules in `dep_orphs' do *not* include family instance orphans,
992 -- as they are anyway included in `dep_finsts'.
994 -- Invariant: the dependencies of a module M never includes M
995 -- Invariant: the lists are unordered, with no duplicates
997 = Deps { dep_mods :: [(ModuleName, -- Home-package module dependencies
999 , dep_pkgs :: [PackageId] -- External package dependencies
1000 , dep_orphs :: [Module] -- Orphan modules (whether home or
1002 , dep_finsts :: [Module] -- Modules that contain family
1003 -- instances (whether home or
1007 -- Equality used only for old/new comparison in MkIface.addVersionInfo
1009 noDependencies :: Dependencies
1010 noDependencies = Deps [] [] [] []
1013 = Usage { usg_name :: ModuleName, -- Name of the module
1014 usg_mod :: Version, -- Module version
1015 usg_entities :: [(OccName,Version)], -- Sorted by occurrence name
1016 -- NB. usages are for parent names only, eg. tycon but not constructors.
1017 usg_exports :: Maybe Version, -- Export-list version, if we depend on it
1018 usg_rules :: Version -- Orphan-rules version (for non-orphan
1019 -- modules this will always be initialVersion)
1021 -- This type doesn't let you say "I imported f but none of the rules in
1022 -- the module". If you use anything in the module you get its rule version
1023 -- So if the rules change, you'll recompile, even if you don't use them.
1024 -- This is easy to implement, and it's safer: you might not have used the rules last
1025 -- time round, but if someone has added a new rule you might need it this time
1027 -- The export list field is (Just v) if we depend on the export list:
1028 -- i.e. we imported the module directly, whether or not we
1029 -- enumerated the things we imported, or just imported everything
1030 -- We need to recompile if M's exports change, because
1031 -- if the import was import M, we might now have a name clash in the
1032 -- importing module.
1033 -- if the import was import M(x) M might no longer export x
1034 -- The only way we don't depend on the export list is if we have
1036 -- And of course, for modules that aren't imported directly we don't
1037 -- depend on their export lists
1041 %************************************************************************
1043 The External Package State
1045 %************************************************************************
1048 type PackageTypeEnv = TypeEnv
1049 type PackageRuleBase = RuleBase
1050 type PackageInstEnv = InstEnv
1051 type PackageFamInstEnv = FamInstEnv
1052 type PackageVectInfo = VectInfo
1054 data ExternalPackageState
1056 eps_is_boot :: !(ModuleNameEnv (ModuleName, IsBootInterface)),
1057 -- In OneShot mode (only), home-package modules
1058 -- accumulate in the external package state, and are
1059 -- sucked in lazily. For these home-pkg modules
1060 -- (only) we need to record which are boot modules.
1061 -- We set this field after loading all the
1062 -- explicitly-imported interfaces, but before doing
1065 -- The ModuleName part is not necessary, but it's useful for
1066 -- debug prints, and it's convenient because this field comes
1067 -- direct from TcRnTypes.ImportAvails.imp_dep_mods
1069 eps_PIT :: !PackageIfaceTable,
1070 -- The ModuleIFaces for modules in external packages
1071 -- whose interfaces we have opened
1072 -- The declarations in these interface files are held in
1073 -- eps_decls, eps_inst_env, eps_fam_inst_env, eps_rules
1074 -- (below), not in the mi_decls fields of the iPIT.
1075 -- What _is_ in the iPIT is:
1082 eps_PTE :: !PackageTypeEnv, -- Domain = external-package modules
1084 eps_inst_env :: !PackageInstEnv, -- The total InstEnv accumulated
1085 -- from all the external-package
1087 eps_fam_inst_env :: !PackageFamInstEnv,-- Ditto FamInstEnv
1088 eps_rule_base :: !PackageRuleBase, -- Ditto RuleEnv
1089 eps_vect_info :: !PackageVectInfo, -- Ditto VectInfo
1091 eps_mod_fam_inst_env :: !(ModuleEnv FamInstEnv), -- identifies family
1092 -- instances of each mod
1093 eps_stats :: !EpsStats
1096 -- "In" means read from iface files
1097 -- "Out" means actually sucked in and type-checked
1098 data EpsStats = EpsStats { n_ifaces_in
1099 , n_decls_in, n_decls_out
1100 , n_rules_in, n_rules_out
1101 , n_insts_in, n_insts_out :: !Int }
1103 addEpsInStats :: EpsStats -> Int -> Int -> Int -> EpsStats
1104 -- Add stats for one newly-read interface
1105 addEpsInStats stats n_decls n_insts n_rules
1106 = stats { n_ifaces_in = n_ifaces_in stats + 1
1107 , n_decls_in = n_decls_in stats + n_decls
1108 , n_insts_in = n_insts_in stats + n_insts
1109 , n_rules_in = n_rules_in stats + n_rules }
1112 The NameCache makes sure that there is just one Unique assigned for
1113 each original name; i.e. (module-name, occ-name) pair. The Name is
1114 always stored as a Global, and has the SrcLoc of its binding location.
1115 Actually that's not quite right. When we first encounter the original
1116 name, we might not be at its binding site (e.g. we are reading an
1117 interface file); so we give it 'noSrcLoc' then. Later, when we find
1118 its binding site, we fix it up.
1122 = NameCache { nsUniqs :: UniqSupply,
1123 -- Supply of uniques
1124 nsNames :: OrigNameCache,
1125 -- Ensures that one original name gets one unique
1126 nsIPs :: OrigIParamCache
1127 -- Ensures that one implicit parameter name gets one unique
1130 type OrigNameCache = ModuleEnv (OccEnv Name)
1131 type OrigIParamCache = FiniteMap (IPName OccName) (IPName Name)
1136 %************************************************************************
1138 The module graph and ModSummary type
1139 A ModSummary is a node in the compilation manager's
1140 dependency graph, and it's also passed to hscMain
1142 %************************************************************************
1144 A ModuleGraph contains all the nodes from the home package (only).
1145 There will be a node for each source module, plus a node for each hi-boot
1149 type ModuleGraph = [ModSummary] -- The module graph,
1150 -- NOT NECESSARILY IN TOPOLOGICAL ORDER
1152 emptyMG :: ModuleGraph
1155 -- The nodes of the module graph are
1156 -- EITHER a regular Haskell source module
1157 -- OR a hi-boot source module
1161 ms_mod :: Module, -- Identity of the module
1162 ms_hsc_src :: HscSource, -- Source is Haskell, hs-boot, external core
1163 ms_location :: ModLocation, -- Location
1164 ms_hs_date :: ClockTime, -- Timestamp of source file
1165 ms_obj_date :: Maybe ClockTime, -- Timestamp of object, maybe
1166 ms_srcimps :: [Located ModuleName], -- Source imports
1167 ms_imps :: [Located ModuleName], -- Non-source imports
1168 ms_hspp_file :: FilePath, -- Filename of preprocessed source.
1169 ms_hspp_opts :: DynFlags, -- Cached flags from OPTIONS, INCLUDE
1170 -- and LANGUAGE pragmas.
1171 ms_hspp_buf :: Maybe StringBuffer -- The actual preprocessed source, maybe.
1174 ms_mod_name :: ModSummary -> ModuleName
1175 ms_mod_name = moduleName . ms_mod
1177 -- The ModLocation contains both the original source filename and the
1178 -- filename of the cleaned-up source file after all preprocessing has been
1179 -- done. The point is that the summariser will have to cpp/unlit/whatever
1180 -- all files anyway, and there's no point in doing this twice -- just
1181 -- park the result in a temp file, put the name of it in the location,
1182 -- and let @compile@ read from that file on the way back up.
1184 -- The ModLocation is stable over successive up-sweeps in GHCi, wheres
1185 -- the ms_hs_date and imports can, of course, change
1187 msHsFilePath, msHiFilePath, msObjFilePath :: ModSummary -> FilePath
1188 msHsFilePath ms = expectJust "msHsFilePath" (ml_hs_file (ms_location ms))
1189 msHiFilePath ms = ml_hi_file (ms_location ms)
1190 msObjFilePath ms = ml_obj_file (ms_location ms)
1192 isBootSummary :: ModSummary -> Bool
1193 isBootSummary ms = isHsBoot (ms_hsc_src ms)
1195 instance Outputable ModSummary where
1197 = sep [text "ModSummary {",
1198 nest 3 (sep [text "ms_hs_date = " <> text (show (ms_hs_date ms)),
1199 text "ms_mod =" <+> ppr (ms_mod ms)
1200 <> text (hscSourceString (ms_hsc_src ms)) <> comma,
1201 text "ms_imps =" <+> ppr (ms_imps ms),
1202 text "ms_srcimps =" <+> ppr (ms_srcimps ms)]),
1206 showModMsg :: HscTarget -> Bool -> ModSummary -> String
1207 showModMsg target recomp mod_summary
1208 = showSDoc (hsep [text (mod_str ++ replicate (max 0 (16 - length mod_str)) ' '),
1209 char '(', text (msHsFilePath mod_summary) <> comma,
1211 HscInterpreted | recomp
1212 -> text "interpreted"
1213 HscNothing -> text "nothing"
1214 _other -> text (msObjFilePath mod_summary),
1217 mod = moduleName (ms_mod mod_summary)
1218 mod_str = showSDoc (ppr mod) ++ hscSourceString (ms_hsc_src mod_summary)
1222 %************************************************************************
1224 \subsection{Hpc Support}
1226 %************************************************************************
1229 data HpcInfo = HpcInfo
1230 { hpcInfoTickCount :: Int
1231 , hpcInfoHash :: Int
1235 noHpcInfo :: HpcInfo
1236 noHpcInfo = NoHpcInfo
1239 %************************************************************************
1241 \subsection{Vectorisation Support}
1243 %************************************************************************
1245 The following information is generated and consumed by the vectorisation
1246 subsystem. It communicates the vectorisation status of declarations from one
1249 Why do we need both f and f_CC in the ModGuts/ModDetails/EPS version VectInfo
1250 below? We need to know `f' when converting to IfaceVectInfo. However, during
1251 closure conversion, we need to know `f_CC', whose `Var' we cannot lookup based
1252 on just the OccName easily in a Core pass.
1255 -- ModGuts/ModDetails/EPS version
1258 vectInfoCCVar :: VarEnv (Var , Var ), -- (f, f_CC) keyed on f
1259 vectInfoCCTyCon :: NameEnv (TyCon , TyCon), -- (T, T_CC) keyed on T
1260 vectInfoCCDataCon :: NameEnv (DataCon, DataCon), -- (C, C_CC) keyed on C
1261 vectInfoCCIso :: NameEnv (TyCon , Var) -- (T, isoT) keyed on T
1263 -- all of this is always tidy, even in ModGuts
1268 ifaceVectInfoCCVar :: [Name],
1269 -- all variables in here have a closure-converted variant;
1270 -- the name of the CC'ed variant is determined by `mkCloOcc'
1271 ifaceVectInfoCCTyCon :: [Name],
1272 -- all tycons in here have a closure-converted variant;
1273 -- the name of the CC'ed variant and those of its data constructors are
1274 -- determined by `mkCloTyConOcc' and `mkCloDataConOcc'; the names of
1275 -- the isomorphisms is determined by `mkCloIsoOcc'
1276 ifaceVectInfoCCTyConReuse :: [Name]
1277 -- the closure-converted form of all the tycons in here coincids with
1278 -- the unconverted from; the names of the isomorphisms is determined
1282 noVectInfo :: VectInfo
1283 noVectInfo = VectInfo emptyVarEnv emptyNameEnv emptyNameEnv emptyNameEnv
1285 plusVectInfo :: VectInfo -> VectInfo -> VectInfo
1286 plusVectInfo vi1 vi2 =
1287 VectInfo (vectInfoCCVar vi1 `plusVarEnv` vectInfoCCVar vi2)
1288 (vectInfoCCTyCon vi1 `plusNameEnv` vectInfoCCTyCon vi2)
1289 (vectInfoCCDataCon vi1 `plusNameEnv` vectInfoCCDataCon vi2)
1290 (vectInfoCCIso vi1 `plusNameEnv` vectInfoCCIso vi2)
1292 noIfaceVectInfo :: IfaceVectInfo
1293 noIfaceVectInfo = IfaceVectInfo [] [] []
1296 %************************************************************************
1298 \subsection{Linkable stuff}
1300 %************************************************************************
1302 This stuff is in here, rather than (say) in Linker.lhs, because the Linker.lhs
1303 stuff is the *dynamic* linker, and isn't present in a stage-1 compiler
1306 data Linkable = LM {
1307 linkableTime :: ClockTime, -- Time at which this linkable was built
1308 -- (i.e. when the bytecodes were produced,
1309 -- or the mod date on the files)
1310 linkableModule :: Module, -- Should be Module, but see below
1311 linkableUnlinked :: [Unlinked]
1314 isObjectLinkable :: Linkable -> Bool
1315 isObjectLinkable l = not (null unlinked) && all isObject unlinked
1316 where unlinked = linkableUnlinked l
1317 -- A linkable with no Unlinked's is treated as a BCO. We can
1318 -- generate a linkable with no Unlinked's as a result of
1319 -- compiling a module in HscNothing mode, and this choice
1320 -- happens to work well with checkStability in module GHC.
1322 instance Outputable Linkable where
1323 ppr (LM when_made mod unlinkeds)
1324 = (text "LinkableM" <+> parens (text (show when_made)) <+> ppr mod)
1325 $$ nest 3 (ppr unlinkeds)
1327 -------------------------------------------
1332 | BCOs CompiledByteCode
1335 data CompiledByteCode = NoByteCode
1338 instance Outputable Unlinked where
1339 ppr (DotO path) = text "DotO" <+> text path
1340 ppr (DotA path) = text "DotA" <+> text path
1341 ppr (DotDLL path) = text "DotDLL" <+> text path
1343 ppr (BCOs bcos) = text "BCOs" <+> ppr bcos
1345 ppr (BCOs bcos) = text "No byte code"
1348 isObject (DotO _) = True
1349 isObject (DotA _) = True
1350 isObject (DotDLL _) = True
1353 isInterpretable = not . isObject
1355 nameOfObject (DotO fn) = fn
1356 nameOfObject (DotA fn) = fn
1357 nameOfObject (DotDLL fn) = fn
1358 nameOfObject other = pprPanic "nameOfObject" (ppr other)
1360 byteCodeOfObject (BCOs bc) = bc
1361 byteCodeOfObject other = pprPanic "byteCodeOfObject" (ppr other)
1364 %************************************************************************
1366 \subsection{Breakpoint Support}
1368 %************************************************************************
1371 type BreakIndex = Int
1373 -- | all the information about the breakpoints for a given module
1376 { modBreaks_flags :: BreakArray
1377 -- The array of flags, one per breakpoint,
1378 -- indicating which breakpoints are enabled.
1379 , modBreaks_locs :: !(Array BreakIndex SrcSpan)
1380 -- An array giving the source span of each breakpoint.
1381 , modBreaks_vars :: !(Array BreakIndex [OccName])
1382 -- An array giving the names of the free variables at each breakpoint.
1385 emptyModBreaks :: ModBreaks
1386 emptyModBreaks = ModBreaks
1387 { modBreaks_flags = error "ModBreaks.modBreaks_array not initialised"
1388 -- Todo: can we avoid this?
1389 , modBreaks_locs = array (0,-1) []
1390 , modBreaks_vars = array (0,-1) []