2 % (c) The University of Glasgow, 2006
4 \section[HscTypes]{Types for the per-module compiler}
7 -- | Types for the per-module compiler
11 FinderCache, FindResult(..), ModLocationCache,
12 Target(..), TargetId(..), pprTarget, pprTargetId,
15 -- * Information about modules
16 ModDetails(..), emptyModDetails,
17 ModGuts(..), CgGuts(..), ForeignStubs(..), appendStubC,
20 ModSummary(..), ms_mod_name, showModMsg, isBootSummary,
21 msHsFilePath, msHiFilePath, msObjFilePath,
23 -- * Information about the module being compiled
24 HscSource(..), isHsBoot, hscSourceString, -- Re-exported from DriverPhases
26 -- * State relating to modules in this package
27 HomePackageTable, HomeModInfo(..), emptyHomePackageTable,
28 hptInstances, hptRules, hptVectInfo,
31 -- * State relating to known packages
32 ExternalPackageState(..), EpsStats(..), addEpsInStats,
33 PackageTypeEnv, PackageIfaceTable, emptyPackageIfaceTable,
34 lookupIfaceByModule, emptyModIface,
36 PackageInstEnv, PackageRuleBase,
42 -- * Interactive context
43 InteractiveContext(..), emptyInteractiveContext,
44 icPrintUnqual, extendInteractiveContext,
45 substInteractiveContext,
46 mkPrintUnqualified, pprModulePrefix,
49 ModIface(..), mkIfaceWarnCache, mkIfaceHashCache, mkIfaceFixCache,
53 FixityEnv, FixItem(..), lookupFixity, emptyFixityEnv,
55 -- * TyThings and type environments
57 tyThingClass, tyThingTyCon, tyThingDataCon, tyThingId, tyThingCoAxiom,
58 implicitTyThings, implicitTyConThings, implicitClassThings, isImplicitTyThing,
60 TypeEnv, lookupType, lookupTypeHscEnv, mkTypeEnv, emptyTypeEnv,
61 extendTypeEnv, extendTypeEnvList, extendTypeEnvWithIds, lookupTypeEnv,
62 typeEnvElts, typeEnvClasses, typeEnvTyCons, typeEnvIds,
63 typeEnvDataCons, typeEnvCoAxioms,
68 -- * Information on imports and exports
69 WhetherHasOrphans, IsBootInterface, Usage(..),
70 Dependencies(..), noDependencies,
71 NameCache(..), OrigNameCache, OrigIParamCache,
72 Avails, availsToNameSet, availsToNameEnv, availName, availNames,
73 GenAvailInfo(..), AvailInfo, RdrAvailInfo,
77 Warnings(..), WarningTxt(..), plusWarns,
80 Linkable(..), isObjectLinkable, linkableObjs,
81 Unlinked(..), CompiledByteCode,
82 isObject, nameOfObject, isInterpretable, byteCodeOfObject,
85 HpcInfo(..), emptyHpcInfo, isHpcUsed, AnyHpcUsage,
88 ModBreaks (..), BreakIndex, emptyModBreaks,
90 -- * Vectorisation information
91 VectInfo(..), IfaceVectInfo(..), noVectInfo, plusVectInfo,
94 -- * Compilation errors and warnings
95 SourceError, GhcApiError, mkSrcErr, srcErrorMessages, mkApiErr,
96 throwOneError, handleSourceError,
97 handleFlagWarnings, printOrThrowWarnings,
100 #include "HsVersions.h"
103 import ByteCodeAsm ( CompiledByteCode )
104 import {-# SOURCE #-} InteractiveEval ( Resume )
113 import InstEnv ( InstEnv, Instance )
114 import FamInstEnv ( FamInstEnv, FamInst )
115 import Rules ( RuleBase )
116 import CoreSyn ( CoreBind )
124 import Class ( Class, classAllSelIds, classATs, classTyCon )
126 import DataCon ( DataCon, dataConImplicitIds, dataConWrapId )
127 import PrelNames ( gHC_PRIM )
128 import Packages hiding ( Version(..) )
129 import DynFlags ( DynFlags(..), isOneShot, HscTarget (..), dopt,
131 import DriverPhases ( HscSource(..), isHsBoot, hscSourceString, Phase )
132 import BasicTypes ( IPName, defaultFixity, WarningTxt(..) )
133 import OptimizationFuel ( OptFuelState )
135 import CoreSyn ( CoreRule, CoreVect )
136 import Maybes ( orElse, expectJust, catMaybes )
139 import SrcLoc ( SrcSpan, Located(..) )
140 import UniqFM ( lookupUFM, eltsUFM, emptyUFM )
141 import UniqSupply ( UniqSupply )
143 import StringBuffer ( StringBuffer )
146 import Data.Dynamic ( Typeable )
147 import qualified Data.Dynamic as Dyn
151 import System.FilePath
152 import System.Time ( ClockTime )
154 import Data.Array ( Array, array )
156 import Data.Map (Map)
157 import Control.Monad ( mplus, guard, liftM, when )
160 -- -----------------------------------------------------------------------------
163 -- When the compiler (HscMain) discovers errors, it throws an
164 -- exception in the IO monad.
166 mkSrcErr :: ErrorMessages -> SourceError
167 srcErrorMessages :: SourceError -> ErrorMessages
168 mkApiErr :: SDoc -> GhcApiError
170 throwOneError :: MonadIO m => ErrMsg -> m ab
171 throwOneError err = liftIO $ throwIO $ mkSrcErr $ unitBag err
173 -- | A source error is an error that is caused by one or more errors in the
174 -- source code. A 'SourceError' is thrown by many functions in the
175 -- compilation pipeline. Inside GHC these errors are merely printed via
176 -- 'log_action', but API clients may treat them differently, for example,
177 -- insert them into a list box. If you want the default behaviour, use the
180 -- > handleSourceError printExceptionAndWarnings $ do
181 -- > ... api calls that may fail ...
183 -- The 'SourceError's error messages can be accessed via 'srcErrorMessages'.
184 -- This list may be empty if the compiler failed due to @-Werror@
185 -- ('Opt_WarnIsError').
187 -- See 'printExceptionAndWarnings' for more information on what to take care
188 -- of when writing a custom error handler.
189 data SourceError = SourceError ErrorMessages
191 instance Show SourceError where
192 show (SourceError msgs) = unlines . map show . bagToList $ msgs
193 -- ToDo: is there some nicer way to print this?
195 sourceErrorTc :: Dyn.TyCon
196 sourceErrorTc = Dyn.mkTyCon "SourceError"
197 {-# NOINLINE sourceErrorTc #-}
198 instance Typeable SourceError where
199 typeOf _ = Dyn.mkTyConApp sourceErrorTc []
201 instance Exception SourceError
203 mkSrcErr = SourceError
205 -- | Perform the given action and call the exception handler if the action
206 -- throws a 'SourceError'. See 'SourceError' for more information.
207 handleSourceError :: (ExceptionMonad m) =>
208 (SourceError -> m a) -- ^ exception handler
209 -> m a -- ^ action to perform
211 handleSourceError handler act =
212 gcatch act (\(e :: SourceError) -> handler e)
214 srcErrorMessages (SourceError msgs) = msgs
216 -- | XXX: what exactly is an API error?
217 data GhcApiError = GhcApiError SDoc
219 instance Show GhcApiError where
220 show (GhcApiError msg) = showSDoc msg
222 ghcApiErrorTc :: Dyn.TyCon
223 ghcApiErrorTc = Dyn.mkTyCon "GhcApiError"
224 {-# NOINLINE ghcApiErrorTc #-}
225 instance Typeable GhcApiError where
226 typeOf _ = Dyn.mkTyConApp ghcApiErrorTc []
228 instance Exception GhcApiError
230 mkApiErr = GhcApiError
232 -- | Given a bag of warnings, turn them into an exception if
233 -- -Werror is enabled, or print them out otherwise.
234 printOrThrowWarnings :: DynFlags -> Bag WarnMsg -> IO ()
235 printOrThrowWarnings dflags warns
236 | dopt Opt_WarnIsError dflags
237 = when (not (isEmptyBag warns)) $ do
238 throwIO $ mkSrcErr $ warns `snocBag` warnIsErrorMsg
240 = printBagOfWarnings dflags warns
242 handleFlagWarnings :: DynFlags -> [Located String] -> IO ()
243 handleFlagWarnings dflags warns
244 = when (dopt Opt_WarnDeprecatedFlags dflags) $ do
245 -- It would be nicer if warns :: [Located Message], but that
246 -- has circular import problems.
247 let bag = listToBag [ mkPlainWarnMsg loc (text warn)
248 | L loc warn <- warns ]
250 printOrThrowWarnings dflags bag
254 -- | Hscenv is like 'Session', except that some of the fields are immutable.
255 -- An HscEnv is used to compile a single module from plain Haskell source
256 -- code (after preprocessing) to either C, assembly or C--. Things like
257 -- the module graph don't change during a single compilation.
259 -- Historical note: \"hsc\" used to be the name of the compiler binary,
260 -- when there was a separate driver and compiler. To compile a single
261 -- module, the driver would invoke hsc on the source code... so nowadays
262 -- we think of hsc as the layer of the compiler that deals with compiling
266 hsc_dflags :: DynFlags,
267 -- ^ The dynamic flag settings
269 hsc_targets :: [Target],
270 -- ^ The targets (or roots) of the current session
272 hsc_mod_graph :: ModuleGraph,
273 -- ^ The module graph of the current session
275 hsc_IC :: InteractiveContext,
276 -- ^ The context for evaluating interactive statements
278 hsc_HPT :: HomePackageTable,
279 -- ^ The home package table describes already-compiled
280 -- home-package modules, /excluding/ the module we
281 -- are compiling right now.
282 -- (In one-shot mode the current module is the only
283 -- home-package module, so hsc_HPT is empty. All other
284 -- modules count as \"external-package\" modules.
285 -- However, even in GHCi mode, hi-boot interfaces are
286 -- demand-loaded into the external-package table.)
288 -- 'hsc_HPT' is not mutable because we only demand-load
289 -- external packages; the home package is eagerly
290 -- loaded, module by module, by the compilation manager.
292 -- The HPT may contain modules compiled earlier by @--make@
293 -- but not actually below the current module in the dependency
296 -- (This changes a previous invariant: changed Jan 05.)
298 hsc_EPS :: {-# UNPACK #-} !(IORef ExternalPackageState),
299 -- ^ Information about the currently loaded external packages.
300 -- This is mutable because packages will be demand-loaded during
301 -- a compilation run as required.
303 hsc_NC :: {-# UNPACK #-} !(IORef NameCache),
304 -- ^ As with 'hsc_EPS', this is side-effected by compiling to
305 -- reflect sucking in interface files. They cache the state of
306 -- external interface files, in effect.
308 hsc_FC :: {-# UNPACK #-} !(IORef FinderCache),
309 -- ^ The cached result of performing finding in the file system
310 hsc_MLC :: {-# UNPACK #-} !(IORef ModLocationCache),
311 -- ^ This caches the location of modules, so we don't have to
312 -- search the filesystem multiple times. See also 'hsc_FC'.
314 hsc_OptFuel :: OptFuelState,
315 -- ^ Settings to control the use of \"optimization fuel\":
316 -- by limiting the number of transformations,
317 -- we can use binary search to help find compiler bugs.
319 hsc_type_env_var :: Maybe (Module, IORef TypeEnv)
320 -- ^ Used for one-shot compilation only, to initialise
321 -- the 'IfGblEnv'. See 'TcRnTypes.tcg_type_env_var' for
322 -- 'TcRunTypes.TcGblEnv'
325 hscEPS :: HscEnv -> IO ExternalPackageState
326 hscEPS hsc_env = readIORef (hsc_EPS hsc_env)
328 -- | A compilation target.
330 -- A target may be supplied with the actual text of the
331 -- module. If so, use this instead of the file contents (this
332 -- is for use in an IDE where the file hasn't been saved by
335 { targetId :: TargetId -- ^ module or filename
336 , targetAllowObjCode :: Bool -- ^ object code allowed?
337 , targetContents :: Maybe (StringBuffer,ClockTime)
338 -- ^ in-memory text buffer?
342 = TargetModule ModuleName
343 -- ^ A module name: search for the file
344 | TargetFile FilePath (Maybe Phase)
345 -- ^ A filename: preprocess & parse it to find the module name.
346 -- If specified, the Phase indicates how to compile this file
347 -- (which phase to start from). Nothing indicates the starting phase
348 -- should be determined from the suffix of the filename.
351 pprTarget :: Target -> SDoc
352 pprTarget (Target id obj _) =
353 (if obj then char '*' else empty) <> pprTargetId id
355 instance Outputable Target where
358 pprTargetId :: TargetId -> SDoc
359 pprTargetId (TargetModule m) = ppr m
360 pprTargetId (TargetFile f _) = text f
362 instance Outputable TargetId where
365 -- | Helps us find information about modules in the home package
366 type HomePackageTable = ModuleNameEnv HomeModInfo
367 -- Domain = modules in the home package that have been fully compiled
368 -- "home" package name cached here for convenience
370 -- | Helps us find information about modules in the imported packages
371 type PackageIfaceTable = ModuleEnv ModIface
372 -- Domain = modules in the imported packages
374 emptyHomePackageTable :: HomePackageTable
375 emptyHomePackageTable = emptyUFM
377 emptyPackageIfaceTable :: PackageIfaceTable
378 emptyPackageIfaceTable = emptyModuleEnv
380 -- | Information about modules in the package being compiled
383 hm_iface :: !ModIface,
384 -- ^ The basic loaded interface file: every loaded module has one of
385 -- these, even if it is imported from another package
386 hm_details :: !ModDetails,
387 -- ^ Extra information that has been created from the 'ModIface' for
388 -- the module, typically during typechecking
389 hm_linkable :: !(Maybe Linkable)
390 -- ^ The actual artifact we would like to link to access things in
393 -- 'hm_linkable' might be Nothing:
395 -- 1. If this is an .hs-boot module
397 -- 2. Temporarily during compilation if we pruned away
398 -- the old linkable because it was out of date.
400 -- After a complete compilation ('GHC.load'), all 'hm_linkable' fields
401 -- in the 'HomePackageTable' will be @Just@.
403 -- When re-linking a module ('HscMain.HscNoRecomp'), we construct the
404 -- 'HomeModInfo' by building a new 'ModDetails' from the old
405 -- 'ModIface' (only).
408 -- | Find the 'ModIface' for a 'Module', searching in both the loaded home
409 -- and external package module information
416 lookupIfaceByModule dflags hpt pit mod
417 | modulePackageId mod == thisPackage dflags
418 = -- The module comes from the home package, so look first
419 -- in the HPT. If it's not from the home package it's wrong to look
420 -- in the HPT, because the HPT is indexed by *ModuleName* not Module
421 fmap hm_iface (lookupUFM hpt (moduleName mod))
422 `mplus` lookupModuleEnv pit mod
424 | otherwise = lookupModuleEnv pit mod -- Look in PIT only
426 -- If the module does come from the home package, why do we look in the PIT as well?
427 -- (a) In OneShot mode, even home-package modules accumulate in the PIT
428 -- (b) Even in Batch (--make) mode, there is *one* case where a home-package
429 -- module is in the PIT, namely GHC.Prim when compiling the base package.
430 -- We could eliminate (b) if we wanted, by making GHC.Prim belong to a package
431 -- of its own, but it doesn't seem worth the bother.
436 hptInstances :: HscEnv -> (ModuleName -> Bool) -> ([Instance], [FamInst])
437 -- ^ Find all the instance declarations (of classes and families) that are in
438 -- modules imported by this one, directly or indirectly, and are in the Home
439 -- Package Table. This ensures that we don't see instances from modules @--make@
440 -- compiled before this one, but which are not below this one.
441 hptInstances hsc_env want_this_module
442 = let (insts, famInsts) = unzip $ flip hptAllThings hsc_env $ \mod_info -> do
443 guard (want_this_module (moduleName (mi_module (hm_iface mod_info))))
444 let details = hm_details mod_info
445 return (md_insts details, md_fam_insts details)
446 in (concat insts, concat famInsts)
448 hptVectInfo :: HscEnv -> VectInfo
449 -- ^ Get the combined VectInfo of all modules in the home package table. In
450 -- contrast to instances and rules, we don't care whether the modules are
451 -- \"below\" us in the dependency sense. The VectInfo of those modules not \"below\"
452 -- us does not affect the compilation of the current module.
453 hptVectInfo = concatVectInfo . hptAllThings ((: []) . md_vect_info . hm_details)
455 hptRules :: HscEnv -> [(ModuleName, IsBootInterface)] -> [CoreRule]
456 -- ^ Get rules from modules \"below\" this one (in the dependency sense)
457 hptRules = hptSomeThingsBelowUs (md_rules . hm_details) False
460 hptAnns :: HscEnv -> Maybe [(ModuleName, IsBootInterface)] -> [Annotation]
461 -- ^ Get annotations from modules \"below\" this one (in the dependency sense)
462 hptAnns hsc_env (Just deps) = hptSomeThingsBelowUs (md_anns . hm_details) False hsc_env deps
463 hptAnns hsc_env Nothing = hptAllThings (md_anns . hm_details) hsc_env
465 hptAllThings :: (HomeModInfo -> [a]) -> HscEnv -> [a]
466 hptAllThings extract hsc_env = concatMap extract (eltsUFM (hsc_HPT hsc_env))
468 hptSomeThingsBelowUs :: (HomeModInfo -> [a]) -> Bool -> HscEnv -> [(ModuleName, IsBootInterface)] -> [a]
469 -- Get things from modules \"below\" this one (in the dependency sense)
470 -- C.f Inst.hptInstances
471 hptSomeThingsBelowUs extract include_hi_boot hsc_env deps
472 | isOneShot (ghcMode (hsc_dflags hsc_env)) = []
475 hpt = hsc_HPT hsc_env
478 | -- Find each non-hi-boot module below me
479 (mod, is_boot_mod) <- deps
480 , include_hi_boot || not is_boot_mod
482 -- unsavoury: when compiling the base package with --make, we
483 -- sometimes try to look up RULES etc for GHC.Prim. GHC.Prim won't
484 -- be in the HPT, because we never compile it; it's in the EPT
485 -- instead. ToDo: clean up, and remove this slightly bogus
487 , mod /= moduleName gHC_PRIM
489 -- Look it up in the HPT
490 , let things = case lookupUFM hpt mod of
491 Just info -> extract info
492 Nothing -> pprTrace "WARNING in hptSomeThingsBelowUs" msg []
493 msg = vcat [ptext (sLit "missing module") <+> ppr mod,
494 ptext (sLit "Probable cause: out-of-date interface files")]
495 -- This really shouldn't happen, but see Trac #962
500 hptObjs :: HomePackageTable -> [FilePath]
501 hptObjs hpt = concat (map (maybe [] linkableObjs . hm_linkable) (eltsUFM hpt))
504 %************************************************************************
506 \subsection{Dealing with Annotations}
508 %************************************************************************
511 prepareAnnotations :: HscEnv -> Maybe ModGuts -> IO AnnEnv
512 -- ^ Deal with gathering annotations in from all possible places
513 -- and combining them into a single 'AnnEnv'
514 prepareAnnotations hsc_env mb_guts
515 = do { eps <- hscEPS hsc_env
516 ; let -- Extract annotations from the module being compiled if supplied one
517 mb_this_module_anns = fmap (mkAnnEnv . mg_anns) mb_guts
518 -- Extract dependencies of the module if we are supplied one,
519 -- otherwise load annotations from all home package table
520 -- entries regardless of dependency ordering.
521 home_pkg_anns = (mkAnnEnv . hptAnns hsc_env) $ fmap (dep_mods . mg_deps) mb_guts
522 other_pkg_anns = eps_ann_env eps
523 ann_env = foldl1' plusAnnEnv $ catMaybes [mb_this_module_anns,
530 %************************************************************************
532 \subsection{The Finder cache}
534 %************************************************************************
537 -- | The 'FinderCache' maps home module names to the result of
538 -- searching for that module. It records the results of searching for
539 -- modules along the search path. On @:load@, we flush the entire
540 -- contents of this cache.
542 -- Although the @FinderCache@ range is 'FindResult' for convenience ,
543 -- in fact it will only ever contain 'Found' or 'NotFound' entries.
545 type FinderCache = ModuleNameEnv FindResult
547 -- | The result of searching for an imported module.
549 = Found ModLocation Module
550 -- ^ The module was found
551 | NoPackage PackageId
552 -- ^ The requested package was not found
553 | FoundMultiple [PackageId]
554 -- ^ _Error_: both in multiple packages
556 | NotFound -- Not found
557 { fr_paths :: [FilePath] -- Places where I looked
559 , fr_pkg :: Maybe PackageId -- Just p => module is in this package's
560 -- manifest, but couldn't find
563 , fr_mods_hidden :: [PackageId] -- Module is in these packages,
564 -- but the *module* is hidden
566 , fr_pkgs_hidden :: [PackageId] -- Module is in these packages,
567 -- but the *package* is hidden
569 , fr_suggestions :: [Module] -- Possible mis-spelled modules
572 -- | Cache that remembers where we found a particular module. Contains both
573 -- home modules and package modules. On @:load@, only home modules are
574 -- purged from this cache.
575 type ModLocationCache = ModuleEnv ModLocation
578 %************************************************************************
580 \subsection{Symbol tables and Module details}
582 %************************************************************************
585 -- | A 'ModIface' plus a 'ModDetails' summarises everything we know
586 -- about a compiled module. The 'ModIface' is the stuff *before* linking,
587 -- and can be written out to an interface file. The 'ModDetails is after
588 -- linking and can be completely recovered from just the 'ModIface'.
590 -- When we read an interface file, we also construct a 'ModIface' from it,
591 -- except that we explicitly make the 'mi_decls' and a few other fields empty;
592 -- as when reading we consolidate the declarations etc. into a number of indexed
593 -- maps and environments in the 'ExternalPackageState'.
596 mi_module :: !Module, -- ^ Name of the module we are for
597 mi_iface_hash :: !Fingerprint, -- ^ Hash of the whole interface
598 mi_mod_hash :: !Fingerprint, -- ^ Hash of the ABI only
600 mi_orphan :: !WhetherHasOrphans, -- ^ Whether this module has orphans
601 mi_finsts :: !WhetherHasFamInst, -- ^ Whether this module has family instances
602 mi_boot :: !IsBootInterface, -- ^ Read from an hi-boot file?
604 mi_deps :: Dependencies,
605 -- ^ The dependencies of the module. This is
606 -- consulted for directly-imported modules, but not
607 -- for anything else (hence lazy)
609 mi_usages :: [Usage],
610 -- ^ Usages; kept sorted so that it's easy to decide
611 -- whether to write a new iface file (changing usages
612 -- doesn't affect the hash of this module)
614 -- NOT STRICT! we read this field lazily from the interface file
615 -- It is *only* consulted by the recompilation checker
618 -- Kept sorted by (mod,occ), to make version comparisons easier
619 mi_exports :: ![IfaceExport],
620 -- ^ Records the modules that are the declaration points for things
621 -- exported by this module, and the 'OccName's of those things
623 mi_exp_hash :: !Fingerprint, -- ^ Hash of export list
625 mi_fixities :: [(OccName,Fixity)],
628 -- NOT STRICT! we read this field lazily from the interface file
630 mi_warns :: Warnings,
633 -- NOT STRICT! we read this field lazily from the interface file
635 mi_anns :: [IfaceAnnotation],
638 -- NOT STRICT! we read this field lazily from the interface file
640 -- Type, class and variable declarations
641 -- The hash of an Id changes if its fixity or deprecations change
642 -- (as well as its type of course)
643 -- Ditto data constructors, class operations, except that
644 -- the hash of the parent class/tycon changes
645 mi_decls :: [(Fingerprint,IfaceDecl)], -- ^ Sorted type, variable, class etc. declarations
647 mi_globals :: !(Maybe GlobalRdrEnv),
648 -- ^ Binds all the things defined at the top level in
649 -- the /original source/ code for this module. which
650 -- is NOT the same as mi_exports, nor mi_decls (which
651 -- may contains declarations for things not actually
652 -- defined by the user). Used for GHCi and for inspecting
653 -- the contents of modules via the GHC API only.
655 -- (We need the source file to figure out the
656 -- top-level environment, if we didn't compile this module
657 -- from source then this field contains @Nothing@).
659 -- Strictly speaking this field should live in the
660 -- 'HomeModInfo', but that leads to more plumbing.
662 -- Instance declarations and rules
663 mi_insts :: [IfaceInst], -- ^ Sorted class instance
664 mi_fam_insts :: [IfaceFamInst], -- ^ Sorted family instances
665 mi_rules :: [IfaceRule], -- ^ Sorted rules
666 mi_orphan_hash :: !Fingerprint, -- ^ Hash for orphan rules and
667 -- class and family instances
670 mi_vect_info :: !IfaceVectInfo, -- ^ Vectorisation information
672 -- Cached environments for easy lookup
673 -- These are computed (lazily) from other fields
674 -- and are not put into the interface file
675 mi_warn_fn :: Name -> Maybe WarningTxt, -- ^ Cached lookup for 'mi_warns'
676 mi_fix_fn :: OccName -> Fixity, -- ^ Cached lookup for 'mi_fixities'
677 mi_hash_fn :: OccName -> Maybe (OccName, Fingerprint),
678 -- ^ Cached lookup for 'mi_decls'.
679 -- The @Nothing@ in 'mi_hash_fn' means that the thing
680 -- isn't in decls. It's useful to know that when
681 -- seeing if we are up to date wrt. the old interface.
682 -- The 'OccName' is the parent of the name, if it has one.
683 mi_hpc :: !AnyHpcUsage
684 -- ^ True if this program uses Hpc at any point in the program.
687 -- | The 'ModDetails' is essentially a cache for information in the 'ModIface'
688 -- for home modules only. Information relating to packages will be loaded into
689 -- global environments in 'ExternalPackageState'.
692 -- The next two fields are created by the typechecker
693 md_exports :: [AvailInfo],
694 md_types :: !TypeEnv, -- ^ Local type environment for this particular module
695 md_insts :: ![Instance], -- ^ 'DFunId's for the instances in this module
696 md_fam_insts :: ![FamInst],
697 md_rules :: ![CoreRule], -- ^ Domain may include 'Id's from other modules
698 md_anns :: ![Annotation], -- ^ Annotations present in this module: currently
699 -- they only annotate things also declared in this module
700 md_vect_info :: !VectInfo -- ^ Module vectorisation information
703 emptyModDetails :: ModDetails
704 emptyModDetails = ModDetails { md_types = emptyTypeEnv,
710 md_vect_info = noVectInfo
713 -- | Records the modules directly imported by a module for extracting e.g. usage information
714 type ImportedMods = ModuleEnv [(ModuleName, Bool, SrcSpan)]
715 -- TODO: we are not actually using the codomain of this type at all, so it can be
716 -- replaced with ModuleEnv ()
718 -- | A ModGuts is carried through the compiler, accumulating stuff as it goes
719 -- There is only one ModGuts at any time, the one for the module
720 -- being compiled right now. Once it is compiled, a 'ModIface' and
721 -- 'ModDetails' are extracted and the ModGuts is discarded.
724 mg_module :: !Module, -- ^ Module being compiled
725 mg_boot :: IsBootInterface, -- ^ Whether it's an hs-boot module
726 mg_exports :: ![AvailInfo], -- ^ What it exports
727 mg_deps :: !Dependencies, -- ^ What it depends on, directly or
729 mg_dir_imps :: !ImportedMods, -- ^ Directly-imported modules; used to
730 -- generate initialisation code
731 mg_used_names:: !NameSet, -- ^ What the module needed (used in 'MkIface.mkIface')
733 mg_rdr_env :: !GlobalRdrEnv, -- ^ Top-level lexical environment
735 -- These fields all describe the things **declared in this module**
736 mg_fix_env :: !FixityEnv, -- ^ Fixities declared in this module
737 -- TODO: I'm unconvinced this is actually used anywhere
738 mg_types :: !TypeEnv, -- ^ Types declared in this module
739 mg_insts :: ![Instance], -- ^ Class instances declared in this module
740 mg_fam_insts :: ![FamInst], -- ^ Family instances declared in this module
741 mg_rules :: ![CoreRule], -- ^ Before the core pipeline starts, contains
742 -- See Note [Overall plumbing for rules] in Rules.lhs
743 mg_binds :: ![CoreBind], -- ^ Bindings for this module
744 mg_foreign :: !ForeignStubs, -- ^ Foreign exports declared in this module
745 mg_warns :: !Warnings, -- ^ Warnings declared in the module
746 mg_anns :: [Annotation], -- ^ Annotations declared in this module
747 mg_hpc_info :: !HpcInfo, -- ^ Coverage tick boxes in the module
748 mg_modBreaks :: !ModBreaks, -- ^ Breakpoints for the module
749 mg_vect_decls:: ![CoreVect], -- ^ Vectorisation declarations in this module
750 -- (produced by desugarer & consumed by vectoriser)
751 mg_vect_info :: !VectInfo, -- ^ Pool of vectorised declarations in the module
753 -- The next two fields are unusual, because they give instance
754 -- environments for *all* modules in the home package, including
755 -- this module, rather than for *just* this module.
756 -- Reason: when looking up an instance we don't want to have to
757 -- look at each module in the home package in turn
758 mg_inst_env :: InstEnv,
759 -- ^ Class instance environment from /home-package/ modules (including
760 -- this one); c.f. 'tcg_inst_env'
761 mg_fam_inst_env :: FamInstEnv
762 -- ^ Type-family instance enviroment for /home-package/ modules
763 -- (including this one); c.f. 'tcg_fam_inst_env'
766 -- The ModGuts takes on several slightly different forms:
768 -- After simplification, the following fields change slightly:
769 -- mg_rules Orphan rules only (local ones now attached to binds)
770 -- mg_binds With rules attached
772 -- The ModGuts takes on several slightly different forms:
774 -- After simplification, the following fields change slightly:
775 -- mg_rules Orphan rules only (local ones now attached to binds)
776 -- mg_binds With rules attached
779 ---------------------------------------------------------
780 -- The Tidy pass forks the information about this module:
781 -- * one lot goes to interface file generation (ModIface)
782 -- and later compilations (ModDetails)
783 -- * the other lot goes to code generation (CgGuts)
785 -- | A restricted form of 'ModGuts' for code generation purposes
788 cg_module :: !Module, -- ^ Module being compiled
790 cg_tycons :: [TyCon],
791 -- ^ Algebraic data types (including ones that started
792 -- life as classes); generate constructors and info
793 -- tables. Includes newtypes, just for the benefit of
796 cg_binds :: [CoreBind],
797 -- ^ The tidied main bindings, including
798 -- previously-implicit bindings for record and class
799 -- selectors, and data construtor wrappers. But *not*
800 -- data constructor workers; reason: we we regard them
801 -- as part of the code-gen of tycons
803 cg_foreign :: !ForeignStubs, -- ^ Foreign export stubs
804 cg_dep_pkgs :: ![PackageId], -- ^ Dependent packages, used to
805 -- generate #includes for C code gen
806 cg_hpc_info :: !HpcInfo, -- ^ Program coverage tick box information
807 cg_modBreaks :: !ModBreaks -- ^ Module breakpoints
810 -----------------------------------
811 -- | Foreign export stubs
812 data ForeignStubs = NoStubs -- ^ We don't have any stubs
816 -- ^ There are some stubs. Parameters:
818 -- 1) Header file prototypes for
819 -- "foreign exported" functions
821 -- 2) C stubs to use when calling
822 -- "foreign exported" functions
824 appendStubC :: ForeignStubs -> SDoc -> ForeignStubs
825 appendStubC NoStubs c_code = ForeignStubs empty c_code
826 appendStubC (ForeignStubs h c) c_code = ForeignStubs h (c $$ c_code)
830 emptyModIface :: Module -> ModIface
832 = ModIface { mi_module = mod,
833 mi_iface_hash = fingerprint0,
834 mi_mod_hash = fingerprint0,
838 mi_deps = noDependencies,
841 mi_exp_hash = fingerprint0,
843 mi_warns = NoWarnings,
849 mi_globals = Nothing,
850 mi_orphan_hash = fingerprint0,
851 mi_vect_info = noIfaceVectInfo,
852 mi_warn_fn = emptyIfaceWarnCache,
853 mi_fix_fn = emptyIfaceFixCache,
854 mi_hash_fn = emptyIfaceHashCache,
860 %************************************************************************
862 \subsection{The interactive context}
864 %************************************************************************
867 -- | Interactive context, recording information about the state of the
868 -- context in which statements are executed in a GHC session.
870 data InteractiveContext
871 = InteractiveContext {
872 -- These two fields are only stored here so that the client
873 -- can retrieve them with GHC.getContext. GHC itself doesn't
874 -- use them, but it does reset them to empty sometimes (such
875 -- as before a GHC.load). The context is set with GHC.setContext.
876 ic_toplev_scope :: [Module],
877 -- ^ The context includes the "top-level" scope of
879 ic_imports :: [ImportDecl RdrName],
880 -- ^ The context is extended with these import declarations
882 ic_rn_gbl_env :: GlobalRdrEnv,
883 -- ^ The contexts' cached 'GlobalRdrEnv', built by
884 -- 'InteractiveEval.setContext'
887 -- ^ Names bound during interaction with the user. Later
888 -- Ids shadow earlier ones with the same OccName
889 -- Expressions are typed with these Ids in the envt For
890 -- runtime-debugging, these Ids may have free TcTyVars of
891 -- RuntimUnkSkol flavour, but no free TyVars (because the
892 -- typechecker doesn't expect that)
895 ic_resume :: [Resume],
896 -- ^ The stack of breakpoint contexts
899 ic_cwd :: Maybe FilePath
900 -- virtual CWD of the program
904 emptyInteractiveContext :: InteractiveContext
905 emptyInteractiveContext
906 = InteractiveContext { ic_toplev_scope = [],
908 ic_rn_gbl_env = emptyGlobalRdrEnv,
916 icPrintUnqual :: DynFlags -> InteractiveContext -> PrintUnqualified
917 icPrintUnqual dflags ictxt = mkPrintUnqualified dflags (ic_rn_gbl_env ictxt)
920 extendInteractiveContext
921 :: InteractiveContext
923 -> InteractiveContext
924 extendInteractiveContext ictxt ids
925 = ictxt { ic_tmp_ids = snub ((ic_tmp_ids ictxt \\ ids) ++ ids)
926 -- NB. must be this way around, because we want
927 -- new ids to shadow existing bindings.
929 where snub = map head . group . sort
931 substInteractiveContext :: InteractiveContext -> TvSubst -> InteractiveContext
932 substInteractiveContext ictxt subst | isEmptyTvSubst subst = ictxt
933 substInteractiveContext ictxt@InteractiveContext{ic_tmp_ids=ids} subst
934 = ictxt { ic_tmp_ids = map subst_ty ids }
936 subst_ty id = id `setIdType` substTy subst (idType id)
939 %************************************************************************
941 Building a PrintUnqualified
943 %************************************************************************
945 Note [Printing original names]
946 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
947 Deciding how to print names is pretty tricky. We are given a name
948 P:M.T, where P is the package name, M is the defining module, and T is
949 the occurrence name, and we have to decide in which form to display
950 the name given a GlobalRdrEnv describing the current scope.
952 Ideally we want to display the name in the form in which it is in
953 scope. However, the name might not be in scope at all, and that's
954 where it gets tricky. Here are the cases:
956 1. T uniquely maps to P:M.T ---> "T" NameUnqual
957 2. There is an X for which X.T
958 uniquely maps to P:M.T ---> "X.T" NameQual X
959 3. There is no binding for "M.T" ---> "M.T" NameNotInScope1
960 4. Otherwise ---> "P:M.T" NameNotInScope2
962 (3) and (4) apply when the entity P:M.T is not in the GlobalRdrEnv at
963 all. In these cases we still want to refer to the name as "M.T", *but*
964 "M.T" might mean something else in the current scope (e.g. if there's
965 an "import X as M"), so to avoid confusion we avoid using "M.T" if
966 there's already a binding for it. Instead we write P:M.T.
968 There's one further subtlety: in case (3), what if there are two
969 things around, P1:M.T and P2:M.T? Then we don't want to print both of
970 them as M.T! However only one of the modules P1:M and P2:M can be
971 exposed (say P2), so we use M.T for that, and P1:M.T for the other one.
972 This is handled by the qual_mod component of PrintUnqualified, inside
973 the (ppr mod) of case (3), in Name.pprModulePrefix
976 -- | Creates some functions that work out the best ways to format
977 -- names for the user according to a set of heuristics
978 mkPrintUnqualified :: DynFlags -> GlobalRdrEnv -> PrintUnqualified
979 mkPrintUnqualified dflags env = (qual_name, qual_mod)
981 qual_name mod occ -- The (mod,occ) pair is the original name of the thing
982 | [gre] <- unqual_gres, right_name gre = NameUnqual
983 -- If there's a unique entity that's in scope unqualified with 'occ'
984 -- AND that entity is the right one, then we can use the unqualified name
986 | [gre] <- qual_gres = NameQual (get_qual_mod (gre_prov gre))
989 if null (lookupGRE_RdrName (mkRdrQual (moduleName mod) occ) env)
993 | otherwise = panic "mkPrintUnqualified"
995 right_name gre = nameModule_maybe (gre_name gre) == Just mod
997 unqual_gres = lookupGRE_RdrName (mkRdrUnqual occ) env
998 qual_gres = filter right_name (lookupGlobalRdrEnv env occ)
1000 get_qual_mod LocalDef = moduleName mod
1001 get_qual_mod (Imported is) = ASSERT( not (null is) ) is_as (is_decl (head is))
1003 -- we can mention a module P:M without the P: qualifier iff
1004 -- "import M" would resolve unambiguously to P:M. (if P is the
1005 -- current package we can just assume it is unqualified).
1008 | modulePackageId mod == thisPackage dflags = False
1010 | [pkgconfig] <- [pkg | (pkg,exposed_module) <- lookup,
1011 exposed pkg && exposed_module],
1012 packageConfigId pkgconfig == modulePackageId mod
1013 -- this says: we are given a module P:M, is there just one exposed package
1014 -- that exposes a module M, and is it package P?
1018 where lookup = lookupModuleInAllPackages dflags (moduleName mod)
1022 %************************************************************************
1026 %************************************************************************
1029 -- | Determine the 'TyThing's brought into scope by another 'TyThing'
1030 -- /other/ than itself. For example, Id's don't have any implicit TyThings
1031 -- as they just bring themselves into scope, but classes bring their
1032 -- dictionary datatype, type constructor and some selector functions into
1033 -- scope, just for a start!
1035 -- N.B. the set of TyThings returned here *must* match the set of
1036 -- names returned by LoadIface.ifaceDeclSubBndrs, in the sense that
1037 -- TyThing.getOccName should define a bijection between the two lists.
1038 -- This invariant is used in LoadIface.loadDecl (see note [Tricky iface loop])
1039 -- The order of the list does not matter.
1040 implicitTyThings :: TyThing -> [TyThing]
1041 implicitTyThings (AnId _) = []
1042 implicitTyThings (ACoAxiom _cc) = []
1043 implicitTyThings (ATyCon tc) = implicitTyConThings tc
1044 implicitTyThings (AClass cl) = implicitClassThings cl
1045 implicitTyThings (ADataCon dc) = map AnId (dataConImplicitIds dc)
1046 -- For data cons add the worker and (possibly) wrapper
1048 implicitClassThings :: Class -> [TyThing]
1049 implicitClassThings cl
1050 = -- Does not include default methods, because those Ids may have
1051 -- their own pragmas, unfoldings etc, not derived from the Class object
1052 -- Dictionary datatype:
1055 -- [recursive call:]
1056 -- (possibly) newtype coercion; definitely no family coercion here
1059 -- (no wrapper by invariant)
1060 extras_plus (ATyCon (classTyCon cl)) ++
1062 -- No extras_plus (recursive call) for the classATs, because they
1063 -- are only the family decls; they have no implicit things
1064 map ATyCon (classATs cl) ++
1065 -- superclass and operation selectors
1066 map AnId (classAllSelIds cl)
1068 implicitTyConThings :: TyCon -> [TyThing]
1069 implicitTyConThings tc
1070 = -- fields (names of selectors)
1071 -- (possibly) implicit coercion and family coercion
1072 -- depending on whether it's a newtype or a family instance or both
1073 implicitCoTyCon tc ++
1074 -- for each data constructor in order,
1075 -- the contructor, worker, and (possibly) wrapper
1076 concatMap (extras_plus . ADataCon) (tyConDataCons tc)
1079 -- add a thing and recursive call
1080 extras_plus :: TyThing -> [TyThing]
1081 extras_plus thing = thing : implicitTyThings thing
1083 -- For newtypes and indexed data types (and both),
1084 -- add the implicit coercion tycon
1085 implicitCoTyCon :: TyCon -> [TyThing]
1087 = map ACoAxiom . catMaybes $ [-- Just if newtype, Nothing if not
1088 newTyConCo_maybe tc,
1089 -- Just if family instance, Nothing if not
1090 tyConFamilyCoercion_maybe tc]
1092 -- sortByOcc = sortBy (\ x -> \ y -> getOccName x < getOccName y)
1095 -- | Returns @True@ if there should be no interface-file declaration
1096 -- for this thing on its own: either it is built-in, or it is part
1097 -- of some other declaration, or it is generated implicitly by some
1098 -- other declaration.
1099 isImplicitTyThing :: TyThing -> Bool
1100 isImplicitTyThing (ADataCon {}) = True
1101 isImplicitTyThing (AnId id) = isImplicitId id
1102 isImplicitTyThing (AClass {}) = False
1103 isImplicitTyThing (ATyCon tc) = isImplicitTyCon tc
1104 isImplicitTyThing (ACoAxiom {}) = True
1106 extendTypeEnvWithIds :: TypeEnv -> [Id] -> TypeEnv
1107 extendTypeEnvWithIds env ids
1108 = extendNameEnvList env [(getName id, AnId id) | id <- ids]
1111 %************************************************************************
1115 %************************************************************************
1118 -- | A map from 'Name's to 'TyThing's, constructed by typechecking
1119 -- local declarations or interface files
1120 type TypeEnv = NameEnv TyThing
1122 emptyTypeEnv :: TypeEnv
1123 typeEnvElts :: TypeEnv -> [TyThing]
1124 typeEnvClasses :: TypeEnv -> [Class]
1125 typeEnvTyCons :: TypeEnv -> [TyCon]
1126 typeEnvCoAxioms :: TypeEnv -> [CoAxiom]
1127 typeEnvIds :: TypeEnv -> [Id]
1128 typeEnvDataCons :: TypeEnv -> [DataCon]
1129 lookupTypeEnv :: TypeEnv -> Name -> Maybe TyThing
1131 emptyTypeEnv = emptyNameEnv
1132 typeEnvElts env = nameEnvElts env
1133 typeEnvClasses env = [cl | AClass cl <- typeEnvElts env]
1134 typeEnvTyCons env = [tc | ATyCon tc <- typeEnvElts env]
1135 typeEnvCoAxioms env = [ax | ACoAxiom ax <- typeEnvElts env]
1136 typeEnvIds env = [id | AnId id <- typeEnvElts env]
1137 typeEnvDataCons env = [dc | ADataCon dc <- typeEnvElts env]
1139 mkTypeEnv :: [TyThing] -> TypeEnv
1140 mkTypeEnv things = extendTypeEnvList emptyTypeEnv things
1142 lookupTypeEnv = lookupNameEnv
1144 -- Extend the type environment
1145 extendTypeEnv :: TypeEnv -> TyThing -> TypeEnv
1146 extendTypeEnv env thing = extendNameEnv env (getName thing) thing
1148 extendTypeEnvList :: TypeEnv -> [TyThing] -> TypeEnv
1149 extendTypeEnvList env things = foldl extendTypeEnv env things
1153 -- | Find the 'TyThing' for the given 'Name' by using all the resources
1154 -- at our disposal: the compiled modules in the 'HomePackageTable' and the
1155 -- compiled modules in other packages that live in 'PackageTypeEnv'. Note
1156 -- that this does NOT look up the 'TyThing' in the module being compiled: you
1157 -- have to do that yourself, if desired
1158 lookupType :: DynFlags
1164 lookupType dflags hpt pte name
1165 -- in one-shot, we don't use the HPT
1166 | not (isOneShot (ghcMode dflags)) && modulePackageId mod == this_pkg
1167 = do hm <- lookupUFM hpt (moduleName mod) -- Maybe monad
1168 lookupNameEnv (md_types (hm_details hm)) name
1170 = lookupNameEnv pte name
1171 where mod = ASSERT( isExternalName name ) nameModule name
1172 this_pkg = thisPackage dflags
1174 -- | As 'lookupType', but with a marginally easier-to-use interface
1175 -- if you have a 'HscEnv'
1176 lookupTypeHscEnv :: HscEnv -> Name -> IO (Maybe TyThing)
1177 lookupTypeHscEnv hsc_env name = do
1178 eps <- readIORef (hsc_EPS hsc_env)
1179 return $! lookupType dflags hpt (eps_PTE eps) name
1181 dflags = hsc_dflags hsc_env
1182 hpt = hsc_HPT hsc_env
1186 -- | Get the 'TyCon' from a 'TyThing' if it is a type constructor thing. Panics otherwise
1187 tyThingTyCon :: TyThing -> TyCon
1188 tyThingTyCon (ATyCon tc) = tc
1189 tyThingTyCon other = pprPanic "tyThingTyCon" (pprTyThing other)
1191 -- | Get the 'CoAxiom' from a 'TyThing' if it is a coercion axiom thing. Panics otherwise
1192 tyThingCoAxiom :: TyThing -> CoAxiom
1193 tyThingCoAxiom (ACoAxiom ax) = ax
1194 tyThingCoAxiom other = pprPanic "tyThingCoAxiom" (pprTyThing other)
1196 -- | Get the 'Class' from a 'TyThing' if it is a class thing. Panics otherwise
1197 tyThingClass :: TyThing -> Class
1198 tyThingClass (AClass cls) = cls
1199 tyThingClass other = pprPanic "tyThingClass" (pprTyThing other)
1201 -- | Get the 'DataCon' from a 'TyThing' if it is a data constructor thing. Panics otherwise
1202 tyThingDataCon :: TyThing -> DataCon
1203 tyThingDataCon (ADataCon dc) = dc
1204 tyThingDataCon other = pprPanic "tyThingDataCon" (pprTyThing other)
1206 -- | Get the 'Id' from a 'TyThing' if it is a id *or* data constructor thing. Panics otherwise
1207 tyThingId :: TyThing -> Id
1208 tyThingId (AnId id) = id
1209 tyThingId (ADataCon dc) = dataConWrapId dc
1210 tyThingId other = pprPanic "tyThingId" (pprTyThing other)
1213 %************************************************************************
1215 \subsection{MonadThings and friends}
1217 %************************************************************************
1220 -- | Class that abstracts out the common ability of the monads in GHC
1221 -- to lookup a 'TyThing' in the monadic environment by 'Name'. Provides
1222 -- a number of related convenience functions for accessing particular
1223 -- kinds of 'TyThing'
1224 class Monad m => MonadThings m where
1225 lookupThing :: Name -> m TyThing
1227 lookupId :: Name -> m Id
1228 lookupId = liftM tyThingId . lookupThing
1230 lookupDataCon :: Name -> m DataCon
1231 lookupDataCon = liftM tyThingDataCon . lookupThing
1233 lookupTyCon :: Name -> m TyCon
1234 lookupTyCon = liftM tyThingTyCon . lookupThing
1236 lookupClass :: Name -> m Class
1237 lookupClass = liftM tyThingClass . lookupThing
1241 -- | Constructs cache for the 'mi_hash_fn' field of a 'ModIface'
1242 mkIfaceHashCache :: [(Fingerprint,IfaceDecl)]
1243 -> (OccName -> Maybe (OccName, Fingerprint))
1244 mkIfaceHashCache pairs
1245 = \occ -> lookupOccEnv env occ
1247 env = foldr add_decl emptyOccEnv pairs
1248 add_decl (v,d) env0 = foldr add_imp env1 (ifaceDeclSubBndrs d)
1250 decl_name = ifName d
1251 env1 = extendOccEnv env0 decl_name (decl_name, v)
1252 add_imp bndr env = extendOccEnv env bndr (decl_name, v)
1254 emptyIfaceHashCache :: OccName -> Maybe (OccName, Fingerprint)
1255 emptyIfaceHashCache _occ = Nothing
1258 %************************************************************************
1260 \subsection{Auxiliary types}
1262 %************************************************************************
1264 These types are defined here because they are mentioned in ModDetails,
1265 but they are mostly elaborated elsewhere
1268 ------------------ Warnings -------------------------
1269 -- | Warning information for a module
1271 = NoWarnings -- ^ Nothing deprecated
1272 | WarnAll WarningTxt -- ^ Whole module deprecated
1273 | WarnSome [(OccName,WarningTxt)] -- ^ Some specific things deprecated
1275 -- Only an OccName is needed because
1276 -- (1) a deprecation always applies to a binding
1277 -- defined in the module in which the deprecation appears.
1278 -- (2) deprecations are only reported outside the defining module.
1279 -- this is important because, otherwise, if we saw something like
1281 -- {-# DEPRECATED f "" #-}
1284 -- g = let f = undefined in f
1286 -- we'd need more information than an OccName to know to say something
1287 -- about the use of f in h but not the use of the locally bound f in g
1289 -- however, because we only report about deprecations from the outside,
1290 -- and a module can only export one value called f,
1291 -- an OccName suffices.
1293 -- this is in contrast with fixity declarations, where we need to map
1294 -- a Name to its fixity declaration.
1297 -- | Constructs the cache for the 'mi_warn_fn' field of a 'ModIface'
1298 mkIfaceWarnCache :: Warnings -> Name -> Maybe WarningTxt
1299 mkIfaceWarnCache NoWarnings = \_ -> Nothing
1300 mkIfaceWarnCache (WarnAll t) = \_ -> Just t
1301 mkIfaceWarnCache (WarnSome pairs) = lookupOccEnv (mkOccEnv pairs) . nameOccName
1303 emptyIfaceWarnCache :: Name -> Maybe WarningTxt
1304 emptyIfaceWarnCache _ = Nothing
1306 plusWarns :: Warnings -> Warnings -> Warnings
1307 plusWarns d NoWarnings = d
1308 plusWarns NoWarnings d = d
1309 plusWarns _ (WarnAll t) = WarnAll t
1310 plusWarns (WarnAll t) _ = WarnAll t
1311 plusWarns (WarnSome v1) (WarnSome v2) = WarnSome (v1 ++ v2)
1314 -- | A collection of 'AvailInfo' - several things that are \"available\"
1315 type Avails = [AvailInfo]
1316 -- | 'Name'd things that are available
1317 type AvailInfo = GenAvailInfo Name
1318 -- | 'RdrName'd things that are available
1319 type RdrAvailInfo = GenAvailInfo OccName
1321 -- | Records what things are "available", i.e. in scope
1322 data GenAvailInfo name = Avail name -- ^ An ordinary identifier in scope
1324 [name] -- ^ A type or class in scope. Parameters:
1326 -- 1) The name of the type or class
1328 -- 2) The available pieces of type or class.
1329 -- NB: If the type or class is itself
1330 -- to be in scope, it must be in this list.
1331 -- Thus, typically: @AvailTC Eq [Eq, ==, \/=]@
1333 -- Equality used when deciding if the interface has changed
1335 -- | The original names declared of a certain module that are exported
1336 type IfaceExport = (Module, [GenAvailInfo OccName])
1338 availsToNameSet :: [AvailInfo] -> NameSet
1339 availsToNameSet avails = foldr add emptyNameSet avails
1340 where add avail set = addListToNameSet set (availNames avail)
1342 availsToNameEnv :: [AvailInfo] -> NameEnv AvailInfo
1343 availsToNameEnv avails = foldr add emptyNameEnv avails
1344 where add avail env = extendNameEnvList env
1345 (zip (availNames avail) (repeat avail))
1347 -- | Just the main name made available, i.e. not the available pieces
1348 -- of type or class brought into scope by the 'GenAvailInfo'
1349 availName :: GenAvailInfo name -> name
1350 availName (Avail n) = n
1351 availName (AvailTC n _) = n
1353 -- | All names made available by the availability information
1354 availNames :: GenAvailInfo name -> [name]
1355 availNames (Avail n) = [n]
1356 availNames (AvailTC _ ns) = ns
1358 instance Outputable n => Outputable (GenAvailInfo n) where
1361 pprAvail :: Outputable n => GenAvailInfo n -> SDoc
1362 pprAvail (Avail n) = ppr n
1363 pprAvail (AvailTC n ns) = ppr n <> braces (hsep (punctuate comma (map ppr ns)))
1367 -- | Creates cached lookup for the 'mi_fix_fn' field of 'ModIface'
1368 mkIfaceFixCache :: [(OccName, Fixity)] -> OccName -> Fixity
1369 mkIfaceFixCache pairs
1370 = \n -> lookupOccEnv env n `orElse` defaultFixity
1372 env = mkOccEnv pairs
1374 emptyIfaceFixCache :: OccName -> Fixity
1375 emptyIfaceFixCache _ = defaultFixity
1377 -- | Fixity environment mapping names to their fixities
1378 type FixityEnv = NameEnv FixItem
1380 -- | Fixity information for an 'Name'. We keep the OccName in the range
1381 -- so that we can generate an interface from it
1382 data FixItem = FixItem OccName Fixity
1384 instance Outputable FixItem where
1385 ppr (FixItem occ fix) = ppr fix <+> ppr occ
1387 emptyFixityEnv :: FixityEnv
1388 emptyFixityEnv = emptyNameEnv
1390 lookupFixity :: FixityEnv -> Name -> Fixity
1391 lookupFixity env n = case lookupNameEnv env n of
1392 Just (FixItem _ fix) -> fix
1393 Nothing -> defaultFixity
1397 %************************************************************************
1399 \subsection{WhatsImported}
1401 %************************************************************************
1404 -- | Records whether a module has orphans. An \"orphan\" is one of:
1406 -- * An instance declaration in a module other than the definition
1407 -- module for one of the type constructors or classes in the instance head
1409 -- * A transformation rule in a module other than the one defining
1410 -- the function in the head of the rule
1411 type WhetherHasOrphans = Bool
1413 -- | Does this module define family instances?
1414 type WhetherHasFamInst = Bool
1416 -- | Did this module originate from a *-boot file?
1417 type IsBootInterface = Bool
1419 -- | Dependency information about modules and packages below this one
1420 -- in the import hierarchy.
1422 -- Invariant: the dependencies of a module @M@ never includes @M@.
1424 -- Invariant: none of the lists contain duplicates.
1426 = Deps { dep_mods :: [(ModuleName, IsBootInterface)]
1427 -- ^ Home-package module dependencies
1428 , dep_pkgs :: [PackageId]
1429 -- ^ External package dependencies
1430 , dep_orphs :: [Module]
1431 -- ^ Orphan modules (whether home or external pkg),
1432 -- *not* including family instance orphans as they
1433 -- are anyway included in 'dep_finsts'
1434 , dep_finsts :: [Module]
1435 -- ^ Modules that contain family instances (whether the
1436 -- instances are from the home or an external package)
1439 -- Equality used only for old/new comparison in MkIface.addVersionInfo
1441 -- See 'TcRnTypes.ImportAvails' for details on dependencies.
1443 noDependencies :: Dependencies
1444 noDependencies = Deps [] [] [] []
1446 -- | Records modules that we depend on by making a direct import from
1448 = UsagePackageModule {
1450 -- ^ External package module depended on
1451 usg_mod_hash :: Fingerprint
1452 } -- ^ Module from another package
1454 usg_mod_name :: ModuleName,
1455 -- ^ Name of the module
1456 usg_mod_hash :: Fingerprint,
1457 -- ^ Cached module fingerprint
1458 usg_entities :: [(OccName,Fingerprint)],
1459 -- ^ Entities we depend on, sorted by occurrence name and fingerprinted.
1460 -- NB: usages are for parent names only, e.g. type constructors
1461 -- but not the associated data constructors.
1462 usg_exports :: Maybe Fingerprint
1463 -- ^ Fingerprint for the export list we used to depend on this module,
1464 -- if we depend on the export list
1465 } -- ^ Module from the current package
1467 -- The export list field is (Just v) if we depend on the export list:
1468 -- i.e. we imported the module directly, whether or not we
1469 -- enumerated the things we imported, or just imported
1471 -- We need to recompile if M's exports change, because
1472 -- if the import was import M, we might now have a name clash
1473 -- in the importing module.
1474 -- if the import was import M(x) M might no longer export x
1475 -- The only way we don't depend on the export list is if we have
1477 -- And of course, for modules that aren't imported directly we don't
1478 -- depend on their export lists
1482 %************************************************************************
1484 The External Package State
1486 %************************************************************************
1489 type PackageTypeEnv = TypeEnv
1490 type PackageRuleBase = RuleBase
1491 type PackageInstEnv = InstEnv
1492 type PackageFamInstEnv = FamInstEnv
1493 type PackageVectInfo = VectInfo
1494 type PackageAnnEnv = AnnEnv
1496 -- | Information about other packages that we have slurped in by reading
1497 -- their interface files
1498 data ExternalPackageState
1500 eps_is_boot :: !(ModuleNameEnv (ModuleName, IsBootInterface)),
1501 -- ^ In OneShot mode (only), home-package modules
1502 -- accumulate in the external package state, and are
1503 -- sucked in lazily. For these home-pkg modules
1504 -- (only) we need to record which are boot modules.
1505 -- We set this field after loading all the
1506 -- explicitly-imported interfaces, but before doing
1509 -- The 'ModuleName' part is not necessary, but it's useful for
1510 -- debug prints, and it's convenient because this field comes
1511 -- direct from 'TcRnTypes.imp_dep_mods'
1513 eps_PIT :: !PackageIfaceTable,
1514 -- ^ The 'ModIface's for modules in external packages
1515 -- whose interfaces we have opened.
1516 -- The declarations in these interface files are held in the
1517 -- 'eps_decls', 'eps_inst_env', 'eps_fam_inst_env' and 'eps_rules'
1518 -- fields of this record, not in the 'mi_decls' fields of the
1519 -- interface we have sucked in.
1521 -- What /is/ in the PIT is:
1525 -- * Fingerprint info
1531 -- * Deprecations and warnings
1533 eps_PTE :: !PackageTypeEnv,
1534 -- ^ Result of typechecking all the external package
1535 -- interface files we have sucked in. The domain of
1536 -- the mapping is external-package modules
1538 eps_inst_env :: !PackageInstEnv, -- ^ The total 'InstEnv' accumulated
1539 -- from all the external-package modules
1540 eps_fam_inst_env :: !PackageFamInstEnv,-- ^ The total 'FamInstEnv' accumulated
1541 -- from all the external-package modules
1542 eps_rule_base :: !PackageRuleBase, -- ^ The total 'RuleEnv' accumulated
1543 -- from all the external-package modules
1544 eps_vect_info :: !PackageVectInfo, -- ^ The total 'VectInfo' accumulated
1545 -- from all the external-package modules
1546 eps_ann_env :: !PackageAnnEnv, -- ^ The total 'AnnEnv' accumulated
1547 -- from all the external-package modules
1549 eps_mod_fam_inst_env :: !(ModuleEnv FamInstEnv), -- ^ The family instances accumulated from external
1550 -- packages, keyed off the module that declared them
1552 eps_stats :: !EpsStats -- ^ Stastics about what was loaded from external packages
1555 -- | Accumulated statistics about what we are putting into the 'ExternalPackageState'.
1556 -- \"In\" means stuff that is just /read/ from interface files,
1557 -- \"Out\" means actually sucked in and type-checked
1558 data EpsStats = EpsStats { n_ifaces_in
1559 , n_decls_in, n_decls_out
1560 , n_rules_in, n_rules_out
1561 , n_insts_in, n_insts_out :: !Int }
1563 addEpsInStats :: EpsStats -> Int -> Int -> Int -> EpsStats
1564 -- ^ Add stats for one newly-read interface
1565 addEpsInStats stats n_decls n_insts n_rules
1566 = stats { n_ifaces_in = n_ifaces_in stats + 1
1567 , n_decls_in = n_decls_in stats + n_decls
1568 , n_insts_in = n_insts_in stats + n_insts
1569 , n_rules_in = n_rules_in stats + n_rules }
1572 Names in a NameCache are always stored as a Global, and have the SrcLoc
1573 of their binding locations.
1575 Actually that's not quite right. When we first encounter the original
1576 name, we might not be at its binding site (e.g. we are reading an
1577 interface file); so we give it 'noSrcLoc' then. Later, when we find
1578 its binding site, we fix it up.
1581 -- | The NameCache makes sure that there is just one Unique assigned for
1582 -- each original name; i.e. (module-name, occ-name) pair and provides
1583 -- something of a lookup mechanism for those names.
1585 = NameCache { nsUniqs :: UniqSupply,
1586 -- ^ Supply of uniques
1587 nsNames :: OrigNameCache,
1588 -- ^ Ensures that one original name gets one unique
1589 nsIPs :: OrigIParamCache
1590 -- ^ Ensures that one implicit parameter name gets one unique
1593 -- | Per-module cache of original 'OccName's given 'Name's
1594 type OrigNameCache = ModuleEnv (OccEnv Name)
1596 -- | Module-local cache of implicit parameter 'OccName's given 'Name's
1597 type OrigIParamCache = Map (IPName OccName) (IPName Name)
1602 %************************************************************************
1604 The module graph and ModSummary type
1605 A ModSummary is a node in the compilation manager's
1606 dependency graph, and it's also passed to hscMain
1608 %************************************************************************
1611 -- | A ModuleGraph contains all the nodes from the home package (only).
1612 -- There will be a node for each source module, plus a node for each hi-boot
1615 -- The graph is not necessarily stored in topologically-sorted order. Use
1616 -- 'GHC.topSortModuleGraph' and 'Digraph.flattenSCC' to achieve this.
1617 type ModuleGraph = [ModSummary]
1619 emptyMG :: ModuleGraph
1622 -- | A single node in a 'ModuleGraph. The nodes of the module graph are one of:
1624 -- * A regular Haskell source module
1626 -- * A hi-boot source module
1628 -- * An external-core source module
1631 ms_mod :: Module, -- ^ Identity of the module
1632 ms_hsc_src :: HscSource, -- ^ The module source either plain Haskell, hs-boot or external core
1633 ms_location :: ModLocation, -- ^ Location of the various files belonging to the module
1634 ms_hs_date :: ClockTime, -- ^ Timestamp of source file
1635 ms_obj_date :: Maybe ClockTime, -- ^ Timestamp of object, if we have one
1636 ms_srcimps :: [Located (ImportDecl RdrName)], -- ^ Source imports of the module
1637 ms_imps :: [Located (ImportDecl RdrName)], -- ^ Non-source imports of the module
1638 ms_hspp_file :: FilePath, -- ^ Filename of preprocessed source file
1639 ms_hspp_opts :: DynFlags, -- ^ Cached flags from @OPTIONS@, @INCLUDE@
1640 -- and @LANGUAGE@ pragmas in the modules source code
1641 ms_hspp_buf :: Maybe StringBuffer -- ^ The actual preprocessed source, if we have it
1644 ms_mod_name :: ModSummary -> ModuleName
1645 ms_mod_name = moduleName . ms_mod
1647 -- The ModLocation contains both the original source filename and the
1648 -- filename of the cleaned-up source file after all preprocessing has been
1649 -- done. The point is that the summariser will have to cpp/unlit/whatever
1650 -- all files anyway, and there's no point in doing this twice -- just
1651 -- park the result in a temp file, put the name of it in the location,
1652 -- and let @compile@ read from that file on the way back up.
1654 -- The ModLocation is stable over successive up-sweeps in GHCi, wheres
1655 -- the ms_hs_date and imports can, of course, change
1657 msHsFilePath, msHiFilePath, msObjFilePath :: ModSummary -> FilePath
1658 msHsFilePath ms = expectJust "msHsFilePath" (ml_hs_file (ms_location ms))
1659 msHiFilePath ms = ml_hi_file (ms_location ms)
1660 msObjFilePath ms = ml_obj_file (ms_location ms)
1662 -- | Did this 'ModSummary' originate from a hs-boot file?
1663 isBootSummary :: ModSummary -> Bool
1664 isBootSummary ms = isHsBoot (ms_hsc_src ms)
1666 instance Outputable ModSummary where
1668 = sep [text "ModSummary {",
1669 nest 3 (sep [text "ms_hs_date = " <> text (show (ms_hs_date ms)),
1670 text "ms_mod =" <+> ppr (ms_mod ms)
1671 <> text (hscSourceString (ms_hsc_src ms)) <> comma,
1672 text "ms_imps =" <+> ppr (ms_imps ms),
1673 text "ms_srcimps =" <+> ppr (ms_srcimps ms)]),
1677 showModMsg :: HscTarget -> Bool -> ModSummary -> String
1678 showModMsg target recomp mod_summary
1680 hsep [text (mod_str ++ replicate (max 0 (16 - length mod_str)) ' '),
1681 char '(', text (normalise $ msHsFilePath mod_summary) <> comma,
1683 HscInterpreted | recomp
1684 -> text "interpreted"
1685 HscNothing -> text "nothing"
1686 _ -> text (normalise $ msObjFilePath mod_summary),
1689 mod = moduleName (ms_mod mod_summary)
1690 mod_str = showSDoc (ppr mod) ++ hscSourceString (ms_hsc_src mod_summary)
1694 %************************************************************************
1696 \subsection{Hpc Support}
1698 %************************************************************************
1701 -- | Information about a modules use of Haskell Program Coverage
1704 { hpcInfoTickCount :: Int
1705 , hpcInfoHash :: Int
1708 { hpcUsed :: AnyHpcUsage -- ^ Is hpc used anywhere on the module \*tree\*?
1711 -- | This is used to signal if one of my imports used HPC instrumentation
1712 -- even if there is no module-local HPC usage
1713 type AnyHpcUsage = Bool
1715 emptyHpcInfo :: AnyHpcUsage -> HpcInfo
1716 emptyHpcInfo = NoHpcInfo
1718 -- | Find out if HPC is used by this module or any of the modules
1720 isHpcUsed :: HpcInfo -> AnyHpcUsage
1721 isHpcUsed (HpcInfo {}) = True
1722 isHpcUsed (NoHpcInfo { hpcUsed = used }) = used
1725 %************************************************************************
1727 \subsection{Vectorisation Support}
1729 %************************************************************************
1731 The following information is generated and consumed by the vectorisation
1732 subsystem. It communicates the vectorisation status of declarations from one
1735 Why do we need both f and f_v in the ModGuts/ModDetails/EPS version VectInfo
1736 below? We need to know `f' when converting to IfaceVectInfo. However, during
1737 vectorisation, we need to know `f_v', whose `Var' we cannot lookup based
1738 on just the OccName easily in a Core pass.
1741 -- |Vectorisation information for 'ModGuts', 'ModDetails' and 'ExternalPackageState'; see also
1742 -- documentation at 'Vectorise.Env.GlobalEnv'.
1745 { vectInfoVar :: VarEnv (Var , Var ) -- ^ @(f, f_v)@ keyed on @f@
1746 , vectInfoTyCon :: NameEnv (TyCon , TyCon) -- ^ @(T, T_v)@ keyed on @T@
1747 , vectInfoDataCon :: NameEnv (DataCon, DataCon) -- ^ @(C, C_v)@ keyed on @C@
1748 , vectInfoPADFun :: NameEnv (TyCon , Var) -- ^ @(T_v, paT)@ keyed on @T_v@
1749 , vectInfoIso :: NameEnv (TyCon , Var) -- ^ @(T, isoT)@ keyed on @T@
1750 , vectInfoScalarVars :: VarSet -- ^ set of purely scalar variables
1751 , vectInfoScalarTyCons :: NameSet -- ^ set of scalar type constructors
1754 -- |Vectorisation information for 'ModIface'; i.e, the vectorisation information propagated
1755 -- across module boundaries.
1759 { ifaceVectInfoVar :: [Name] -- ^ All variables in here have a vectorised variant
1760 , ifaceVectInfoTyCon :: [Name] -- ^ All 'TyCon's in here have a vectorised variant;
1761 -- the name of the vectorised variant and those of its
1762 -- data constructors are determined by
1763 -- 'OccName.mkVectTyConOcc' and
1764 -- 'OccName.mkVectDataConOcc'; the names of the
1765 -- isomorphisms are determined by 'OccName.mkVectIsoOcc'
1766 , ifaceVectInfoTyConReuse :: [Name] -- ^ The vectorised form of all the 'TyCon's in here
1767 -- coincides with the unconverted form; the name of the
1768 -- isomorphisms is determined by 'OccName.mkVectIsoOcc'
1769 , ifaceVectInfoScalarVars :: [Name] -- iface version of 'vectInfoScalarVar'
1770 , ifaceVectInfoScalarTyCons :: [Name] -- iface version of 'vectInfoScalarTyCon'
1773 noVectInfo :: VectInfo
1775 = VectInfo emptyVarEnv emptyNameEnv emptyNameEnv emptyNameEnv emptyNameEnv emptyVarSet
1778 plusVectInfo :: VectInfo -> VectInfo -> VectInfo
1779 plusVectInfo vi1 vi2 =
1780 VectInfo (vectInfoVar vi1 `plusVarEnv` vectInfoVar vi2)
1781 (vectInfoTyCon vi1 `plusNameEnv` vectInfoTyCon vi2)
1782 (vectInfoDataCon vi1 `plusNameEnv` vectInfoDataCon vi2)
1783 (vectInfoPADFun vi1 `plusNameEnv` vectInfoPADFun vi2)
1784 (vectInfoIso vi1 `plusNameEnv` vectInfoIso vi2)
1785 (vectInfoScalarVars vi1 `unionVarSet` vectInfoScalarVars vi2)
1786 (vectInfoScalarTyCons vi1 `unionNameSets` vectInfoScalarTyCons vi2)
1788 concatVectInfo :: [VectInfo] -> VectInfo
1789 concatVectInfo = foldr plusVectInfo noVectInfo
1791 noIfaceVectInfo :: IfaceVectInfo
1792 noIfaceVectInfo = IfaceVectInfo [] [] [] [] []
1795 %************************************************************************
1797 \subsection{Linkable stuff}
1799 %************************************************************************
1801 This stuff is in here, rather than (say) in Linker.lhs, because the Linker.lhs
1802 stuff is the *dynamic* linker, and isn't present in a stage-1 compiler
1805 -- | Information we can use to dynamically link modules into the compiler
1806 data Linkable = LM {
1807 linkableTime :: ClockTime, -- ^ Time at which this linkable was built
1808 -- (i.e. when the bytecodes were produced,
1809 -- or the mod date on the files)
1810 linkableModule :: Module, -- ^ The linkable module itself
1811 linkableUnlinked :: [Unlinked]
1812 -- ^ Those files and chunks of code we have yet to link.
1814 -- INVARIANT: A valid linkable always has at least one 'Unlinked' item.
1815 -- If this list is empty, the Linkable represents a fake linkable, which
1816 -- is generated in HscNothing mode to avoid recompiling modules.
1818 -- XXX: Do items get removed from this list when they get linked?
1821 isObjectLinkable :: Linkable -> Bool
1822 isObjectLinkable l = not (null unlinked) && all isObject unlinked
1823 where unlinked = linkableUnlinked l
1824 -- A linkable with no Unlinked's is treated as a BCO. We can
1825 -- generate a linkable with no Unlinked's as a result of
1826 -- compiling a module in HscNothing mode, and this choice
1827 -- happens to work well with checkStability in module GHC.
1829 linkableObjs :: Linkable -> [FilePath]
1830 linkableObjs l = [ f | DotO f <- linkableUnlinked l ]
1832 instance Outputable Linkable where
1833 ppr (LM when_made mod unlinkeds)
1834 = (text "LinkableM" <+> parens (text (show when_made)) <+> ppr mod)
1835 $$ nest 3 (ppr unlinkeds)
1837 -------------------------------------------
1839 -- | Objects which have yet to be linked by the compiler
1841 = DotO FilePath -- ^ An object file (.o)
1842 | DotA FilePath -- ^ Static archive file (.a)
1843 | DotDLL FilePath -- ^ Dynamically linked library file (.so, .dll, .dylib)
1844 | BCOs CompiledByteCode ModBreaks -- ^ A byte-code object, lives only in memory
1847 data CompiledByteCode = CompiledByteCodeUndefined
1848 _unused :: CompiledByteCode
1849 _unused = CompiledByteCodeUndefined
1852 instance Outputable Unlinked where
1853 ppr (DotO path) = text "DotO" <+> text path
1854 ppr (DotA path) = text "DotA" <+> text path
1855 ppr (DotDLL path) = text "DotDLL" <+> text path
1857 ppr (BCOs bcos _) = text "BCOs" <+> ppr bcos
1859 ppr (BCOs _ _) = text "No byte code"
1862 -- | Is this an actual file on disk we can link in somehow?
1863 isObject :: Unlinked -> Bool
1864 isObject (DotO _) = True
1865 isObject (DotA _) = True
1866 isObject (DotDLL _) = True
1869 -- | Is this a bytecode linkable with no file on disk?
1870 isInterpretable :: Unlinked -> Bool
1871 isInterpretable = not . isObject
1873 -- | Retrieve the filename of the linkable if possible. Panic if it is a byte-code object
1874 nameOfObject :: Unlinked -> FilePath
1875 nameOfObject (DotO fn) = fn
1876 nameOfObject (DotA fn) = fn
1877 nameOfObject (DotDLL fn) = fn
1878 nameOfObject other = pprPanic "nameOfObject" (ppr other)
1880 -- | Retrieve the compiled byte-code if possible. Panic if it is a file-based linkable
1881 byteCodeOfObject :: Unlinked -> CompiledByteCode
1882 byteCodeOfObject (BCOs bc _) = bc
1883 byteCodeOfObject other = pprPanic "byteCodeOfObject" (ppr other)
1886 %************************************************************************
1888 \subsection{Breakpoint Support}
1890 %************************************************************************
1893 -- | Breakpoint index
1894 type BreakIndex = Int
1896 -- | All the information about the breakpoints for a given module
1899 { modBreaks_flags :: BreakArray
1900 -- ^ The array of flags, one per breakpoint,
1901 -- indicating which breakpoints are enabled.
1902 , modBreaks_locs :: !(Array BreakIndex SrcSpan)
1903 -- ^ An array giving the source span of each breakpoint.
1904 , modBreaks_vars :: !(Array BreakIndex [OccName])
1905 -- ^ An array giving the names of the free variables at each breakpoint.
1906 , modBreaks_decls :: !(Array BreakIndex [String])
1907 -- ^ An array giving the names of the declarations enclosing each breakpoint.
1910 emptyModBreaks :: ModBreaks
1911 emptyModBreaks = ModBreaks
1912 { modBreaks_flags = error "ModBreaks.modBreaks_array not initialised"
1913 -- Todo: can we avoid this?
1914 , modBreaks_locs = array (0,-1) []
1915 , modBreaks_vars = array (0,-1) []
1916 , modBreaks_decls = array (0,-1) []