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 relevant to GHCi
868 data InteractiveContext
869 = InteractiveContext {
870 ic_toplev_scope :: [Module] -- ^ The context includes the "top-level" scope of
873 , ic_exports :: [(Module, Maybe (ImportDecl RdrName))] -- ^ The context includes just the exported parts of these
876 , ic_rn_gbl_env :: GlobalRdrEnv -- ^ The contexts' cached 'GlobalRdrEnv', built from
877 -- 'ic_toplev_scope' and 'ic_exports'
879 , ic_tmp_ids :: [Id] -- ^ Names bound during interaction with the user.
880 -- Later Ids shadow earlier ones with the same OccName
881 -- Expressions are typed with these Ids in the envt
882 -- For runtime-debugging, these Ids may have free
883 -- TcTyVars of RuntimUnkSkol flavour, but no free TyVars
884 -- (because the typechecker doesn't expect that)
887 , ic_resume :: [Resume] -- ^ The stack of breakpoint contexts
890 , ic_cwd :: Maybe FilePath -- virtual CWD of the program
894 emptyInteractiveContext :: InteractiveContext
895 emptyInteractiveContext
896 = InteractiveContext { ic_toplev_scope = [],
898 ic_rn_gbl_env = emptyGlobalRdrEnv,
906 icPrintUnqual :: DynFlags -> InteractiveContext -> PrintUnqualified
907 icPrintUnqual dflags ictxt = mkPrintUnqualified dflags (ic_rn_gbl_env ictxt)
910 extendInteractiveContext
911 :: InteractiveContext
913 -> InteractiveContext
914 extendInteractiveContext ictxt ids
915 = ictxt { ic_tmp_ids = snub ((ic_tmp_ids ictxt \\ ids) ++ ids)
916 -- NB. must be this way around, because we want
917 -- new ids to shadow existing bindings.
919 where snub = map head . group . sort
921 substInteractiveContext :: InteractiveContext -> TvSubst -> InteractiveContext
922 substInteractiveContext ictxt subst | isEmptyTvSubst subst = ictxt
923 substInteractiveContext ictxt@InteractiveContext{ic_tmp_ids=ids} subst
924 = ictxt { ic_tmp_ids = map subst_ty ids }
926 subst_ty id = id `setIdType` substTy subst (idType id)
929 %************************************************************************
931 Building a PrintUnqualified
933 %************************************************************************
935 Note [Printing original names]
936 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
937 Deciding how to print names is pretty tricky. We are given a name
938 P:M.T, where P is the package name, M is the defining module, and T is
939 the occurrence name, and we have to decide in which form to display
940 the name given a GlobalRdrEnv describing the current scope.
942 Ideally we want to display the name in the form in which it is in
943 scope. However, the name might not be in scope at all, and that's
944 where it gets tricky. Here are the cases:
946 1. T uniquely maps to P:M.T ---> "T" NameUnqual
947 2. There is an X for which X.T
948 uniquely maps to P:M.T ---> "X.T" NameQual X
949 3. There is no binding for "M.T" ---> "M.T" NameNotInScope1
950 4. Otherwise ---> "P:M.T" NameNotInScope2
952 (3) and (4) apply when the entity P:M.T is not in the GlobalRdrEnv at
953 all. In these cases we still want to refer to the name as "M.T", *but*
954 "M.T" might mean something else in the current scope (e.g. if there's
955 an "import X as M"), so to avoid confusion we avoid using "M.T" if
956 there's already a binding for it. Instead we write P:M.T.
958 There's one further subtlety: in case (3), what if there are two
959 things around, P1:M.T and P2:M.T? Then we don't want to print both of
960 them as M.T! However only one of the modules P1:M and P2:M can be
961 exposed (say P2), so we use M.T for that, and P1:M.T for the other one.
962 This is handled by the qual_mod component of PrintUnqualified, inside
963 the (ppr mod) of case (3), in Name.pprModulePrefix
966 -- | Creates some functions that work out the best ways to format
967 -- names for the user according to a set of heuristics
968 mkPrintUnqualified :: DynFlags -> GlobalRdrEnv -> PrintUnqualified
969 mkPrintUnqualified dflags env = (qual_name, qual_mod)
971 qual_name mod occ -- The (mod,occ) pair is the original name of the thing
972 | [gre] <- unqual_gres, right_name gre = NameUnqual
973 -- If there's a unique entity that's in scope unqualified with 'occ'
974 -- AND that entity is the right one, then we can use the unqualified name
976 | [gre] <- qual_gres = NameQual (get_qual_mod (gre_prov gre))
979 if null (lookupGRE_RdrName (mkRdrQual (moduleName mod) occ) env)
983 | otherwise = panic "mkPrintUnqualified"
985 right_name gre = nameModule_maybe (gre_name gre) == Just mod
987 unqual_gres = lookupGRE_RdrName (mkRdrUnqual occ) env
988 qual_gres = filter right_name (lookupGlobalRdrEnv env occ)
990 get_qual_mod LocalDef = moduleName mod
991 get_qual_mod (Imported is) = ASSERT( not (null is) ) is_as (is_decl (head is))
993 -- we can mention a module P:M without the P: qualifier iff
994 -- "import M" would resolve unambiguously to P:M. (if P is the
995 -- current package we can just assume it is unqualified).
998 | modulePackageId mod == thisPackage dflags = False
1000 | [pkgconfig] <- [pkg | (pkg,exposed_module) <- lookup,
1001 exposed pkg && exposed_module],
1002 packageConfigId pkgconfig == modulePackageId mod
1003 -- this says: we are given a module P:M, is there just one exposed package
1004 -- that exposes a module M, and is it package P?
1008 where lookup = lookupModuleInAllPackages dflags (moduleName mod)
1012 %************************************************************************
1016 %************************************************************************
1019 -- | Determine the 'TyThing's brought into scope by another 'TyThing'
1020 -- /other/ than itself. For example, Id's don't have any implicit TyThings
1021 -- as they just bring themselves into scope, but classes bring their
1022 -- dictionary datatype, type constructor and some selector functions into
1023 -- scope, just for a start!
1025 -- N.B. the set of TyThings returned here *must* match the set of
1026 -- names returned by LoadIface.ifaceDeclSubBndrs, in the sense that
1027 -- TyThing.getOccName should define a bijection between the two lists.
1028 -- This invariant is used in LoadIface.loadDecl (see note [Tricky iface loop])
1029 -- The order of the list does not matter.
1030 implicitTyThings :: TyThing -> [TyThing]
1031 implicitTyThings (AnId _) = []
1032 implicitTyThings (ACoAxiom _cc) = []
1033 implicitTyThings (ATyCon tc) = implicitTyConThings tc
1034 implicitTyThings (AClass cl) = implicitClassThings cl
1035 implicitTyThings (ADataCon dc) = map AnId (dataConImplicitIds dc)
1036 -- For data cons add the worker and (possibly) wrapper
1038 implicitClassThings :: Class -> [TyThing]
1039 implicitClassThings cl
1040 = -- Does not include default methods, because those Ids may have
1041 -- their own pragmas, unfoldings etc, not derived from the Class object
1042 -- Dictionary datatype:
1045 -- [recursive call:]
1046 -- (possibly) newtype coercion; definitely no family coercion here
1049 -- (no wrapper by invariant)
1050 extras_plus (ATyCon (classTyCon cl)) ++
1052 -- No extras_plus (recursive call) for the classATs, because they
1053 -- are only the family decls; they have no implicit things
1054 map ATyCon (classATs cl) ++
1055 -- superclass and operation selectors
1056 map AnId (classAllSelIds cl)
1058 implicitTyConThings :: TyCon -> [TyThing]
1059 implicitTyConThings tc
1060 = -- fields (names of selectors)
1061 -- (possibly) implicit coercion and family coercion
1062 -- depending on whether it's a newtype or a family instance or both
1063 implicitCoTyCon tc ++
1064 -- for each data constructor in order,
1065 -- the contructor, worker, and (possibly) wrapper
1066 concatMap (extras_plus . ADataCon) (tyConDataCons tc)
1069 -- add a thing and recursive call
1070 extras_plus :: TyThing -> [TyThing]
1071 extras_plus thing = thing : implicitTyThings thing
1073 -- For newtypes and indexed data types (and both),
1074 -- add the implicit coercion tycon
1075 implicitCoTyCon :: TyCon -> [TyThing]
1077 = map ACoAxiom . catMaybes $ [-- Just if newtype, Nothing if not
1078 newTyConCo_maybe tc,
1079 -- Just if family instance, Nothing if not
1080 tyConFamilyCoercion_maybe tc]
1082 -- sortByOcc = sortBy (\ x -> \ y -> getOccName x < getOccName y)
1085 -- | Returns @True@ if there should be no interface-file declaration
1086 -- for this thing on its own: either it is built-in, or it is part
1087 -- of some other declaration, or it is generated implicitly by some
1088 -- other declaration.
1089 isImplicitTyThing :: TyThing -> Bool
1090 isImplicitTyThing (ADataCon {}) = True
1091 isImplicitTyThing (AnId id) = isImplicitId id
1092 isImplicitTyThing (AClass {}) = False
1093 isImplicitTyThing (ATyCon tc) = isImplicitTyCon tc
1094 isImplicitTyThing (ACoAxiom {}) = True
1096 extendTypeEnvWithIds :: TypeEnv -> [Id] -> TypeEnv
1097 extendTypeEnvWithIds env ids
1098 = extendNameEnvList env [(getName id, AnId id) | id <- ids]
1101 %************************************************************************
1105 %************************************************************************
1108 -- | A map from 'Name's to 'TyThing's, constructed by typechecking
1109 -- local declarations or interface files
1110 type TypeEnv = NameEnv TyThing
1112 emptyTypeEnv :: TypeEnv
1113 typeEnvElts :: TypeEnv -> [TyThing]
1114 typeEnvClasses :: TypeEnv -> [Class]
1115 typeEnvTyCons :: TypeEnv -> [TyCon]
1116 typeEnvCoAxioms :: TypeEnv -> [CoAxiom]
1117 typeEnvIds :: TypeEnv -> [Id]
1118 typeEnvDataCons :: TypeEnv -> [DataCon]
1119 lookupTypeEnv :: TypeEnv -> Name -> Maybe TyThing
1121 emptyTypeEnv = emptyNameEnv
1122 typeEnvElts env = nameEnvElts env
1123 typeEnvClasses env = [cl | AClass cl <- typeEnvElts env]
1124 typeEnvTyCons env = [tc | ATyCon tc <- typeEnvElts env]
1125 typeEnvCoAxioms env = [ax | ACoAxiom ax <- typeEnvElts env]
1126 typeEnvIds env = [id | AnId id <- typeEnvElts env]
1127 typeEnvDataCons env = [dc | ADataCon dc <- typeEnvElts env]
1129 mkTypeEnv :: [TyThing] -> TypeEnv
1130 mkTypeEnv things = extendTypeEnvList emptyTypeEnv things
1132 lookupTypeEnv = lookupNameEnv
1134 -- Extend the type environment
1135 extendTypeEnv :: TypeEnv -> TyThing -> TypeEnv
1136 extendTypeEnv env thing = extendNameEnv env (getName thing) thing
1138 extendTypeEnvList :: TypeEnv -> [TyThing] -> TypeEnv
1139 extendTypeEnvList env things = foldl extendTypeEnv env things
1143 -- | Find the 'TyThing' for the given 'Name' by using all the resources
1144 -- at our disposal: the compiled modules in the 'HomePackageTable' and the
1145 -- compiled modules in other packages that live in 'PackageTypeEnv'. Note
1146 -- that this does NOT look up the 'TyThing' in the module being compiled: you
1147 -- have to do that yourself, if desired
1148 lookupType :: DynFlags
1154 lookupType dflags hpt pte name
1155 -- in one-shot, we don't use the HPT
1156 | not (isOneShot (ghcMode dflags)) && modulePackageId mod == this_pkg
1157 = do hm <- lookupUFM hpt (moduleName mod) -- Maybe monad
1158 lookupNameEnv (md_types (hm_details hm)) name
1160 = lookupNameEnv pte name
1161 where mod = ASSERT( isExternalName name ) nameModule name
1162 this_pkg = thisPackage dflags
1164 -- | As 'lookupType', but with a marginally easier-to-use interface
1165 -- if you have a 'HscEnv'
1166 lookupTypeHscEnv :: HscEnv -> Name -> IO (Maybe TyThing)
1167 lookupTypeHscEnv hsc_env name = do
1168 eps <- readIORef (hsc_EPS hsc_env)
1169 return $! lookupType dflags hpt (eps_PTE eps) name
1171 dflags = hsc_dflags hsc_env
1172 hpt = hsc_HPT hsc_env
1176 -- | Get the 'TyCon' from a 'TyThing' if it is a type constructor thing. Panics otherwise
1177 tyThingTyCon :: TyThing -> TyCon
1178 tyThingTyCon (ATyCon tc) = tc
1179 tyThingTyCon other = pprPanic "tyThingTyCon" (pprTyThing other)
1181 -- | Get the 'CoAxiom' from a 'TyThing' if it is a coercion axiom thing. Panics otherwise
1182 tyThingCoAxiom :: TyThing -> CoAxiom
1183 tyThingCoAxiom (ACoAxiom ax) = ax
1184 tyThingCoAxiom other = pprPanic "tyThingCoAxiom" (pprTyThing other)
1186 -- | Get the 'Class' from a 'TyThing' if it is a class thing. Panics otherwise
1187 tyThingClass :: TyThing -> Class
1188 tyThingClass (AClass cls) = cls
1189 tyThingClass other = pprPanic "tyThingClass" (pprTyThing other)
1191 -- | Get the 'DataCon' from a 'TyThing' if it is a data constructor thing. Panics otherwise
1192 tyThingDataCon :: TyThing -> DataCon
1193 tyThingDataCon (ADataCon dc) = dc
1194 tyThingDataCon other = pprPanic "tyThingDataCon" (pprTyThing other)
1196 -- | Get the 'Id' from a 'TyThing' if it is a id *or* data constructor thing. Panics otherwise
1197 tyThingId :: TyThing -> Id
1198 tyThingId (AnId id) = id
1199 tyThingId (ADataCon dc) = dataConWrapId dc
1200 tyThingId other = pprPanic "tyThingId" (pprTyThing other)
1203 %************************************************************************
1205 \subsection{MonadThings and friends}
1207 %************************************************************************
1210 -- | Class that abstracts out the common ability of the monads in GHC
1211 -- to lookup a 'TyThing' in the monadic environment by 'Name'. Provides
1212 -- a number of related convenience functions for accessing particular
1213 -- kinds of 'TyThing'
1214 class Monad m => MonadThings m where
1215 lookupThing :: Name -> m TyThing
1217 lookupId :: Name -> m Id
1218 lookupId = liftM tyThingId . lookupThing
1220 lookupDataCon :: Name -> m DataCon
1221 lookupDataCon = liftM tyThingDataCon . lookupThing
1223 lookupTyCon :: Name -> m TyCon
1224 lookupTyCon = liftM tyThingTyCon . lookupThing
1226 lookupClass :: Name -> m Class
1227 lookupClass = liftM tyThingClass . lookupThing
1231 -- | Constructs cache for the 'mi_hash_fn' field of a 'ModIface'
1232 mkIfaceHashCache :: [(Fingerprint,IfaceDecl)]
1233 -> (OccName -> Maybe (OccName, Fingerprint))
1234 mkIfaceHashCache pairs
1235 = \occ -> lookupOccEnv env occ
1237 env = foldr add_decl emptyOccEnv pairs
1238 add_decl (v,d) env0 = foldr add_imp env1 (ifaceDeclSubBndrs d)
1240 decl_name = ifName d
1241 env1 = extendOccEnv env0 decl_name (decl_name, v)
1242 add_imp bndr env = extendOccEnv env bndr (decl_name, v)
1244 emptyIfaceHashCache :: OccName -> Maybe (OccName, Fingerprint)
1245 emptyIfaceHashCache _occ = Nothing
1248 %************************************************************************
1250 \subsection{Auxiliary types}
1252 %************************************************************************
1254 These types are defined here because they are mentioned in ModDetails,
1255 but they are mostly elaborated elsewhere
1258 ------------------ Warnings -------------------------
1259 -- | Warning information for a module
1261 = NoWarnings -- ^ Nothing deprecated
1262 | WarnAll WarningTxt -- ^ Whole module deprecated
1263 | WarnSome [(OccName,WarningTxt)] -- ^ Some specific things deprecated
1265 -- Only an OccName is needed because
1266 -- (1) a deprecation always applies to a binding
1267 -- defined in the module in which the deprecation appears.
1268 -- (2) deprecations are only reported outside the defining module.
1269 -- this is important because, otherwise, if we saw something like
1271 -- {-# DEPRECATED f "" #-}
1274 -- g = let f = undefined in f
1276 -- we'd need more information than an OccName to know to say something
1277 -- about the use of f in h but not the use of the locally bound f in g
1279 -- however, because we only report about deprecations from the outside,
1280 -- and a module can only export one value called f,
1281 -- an OccName suffices.
1283 -- this is in contrast with fixity declarations, where we need to map
1284 -- a Name to its fixity declaration.
1287 -- | Constructs the cache for the 'mi_warn_fn' field of a 'ModIface'
1288 mkIfaceWarnCache :: Warnings -> Name -> Maybe WarningTxt
1289 mkIfaceWarnCache NoWarnings = \_ -> Nothing
1290 mkIfaceWarnCache (WarnAll t) = \_ -> Just t
1291 mkIfaceWarnCache (WarnSome pairs) = lookupOccEnv (mkOccEnv pairs) . nameOccName
1293 emptyIfaceWarnCache :: Name -> Maybe WarningTxt
1294 emptyIfaceWarnCache _ = Nothing
1296 plusWarns :: Warnings -> Warnings -> Warnings
1297 plusWarns d NoWarnings = d
1298 plusWarns NoWarnings d = d
1299 plusWarns _ (WarnAll t) = WarnAll t
1300 plusWarns (WarnAll t) _ = WarnAll t
1301 plusWarns (WarnSome v1) (WarnSome v2) = WarnSome (v1 ++ v2)
1304 -- | A collection of 'AvailInfo' - several things that are \"available\"
1305 type Avails = [AvailInfo]
1306 -- | 'Name'd things that are available
1307 type AvailInfo = GenAvailInfo Name
1308 -- | 'RdrName'd things that are available
1309 type RdrAvailInfo = GenAvailInfo OccName
1311 -- | Records what things are "available", i.e. in scope
1312 data GenAvailInfo name = Avail name -- ^ An ordinary identifier in scope
1314 [name] -- ^ A type or class in scope. Parameters:
1316 -- 1) The name of the type or class
1318 -- 2) The available pieces of type or class.
1319 -- NB: If the type or class is itself
1320 -- to be in scope, it must be in this list.
1321 -- Thus, typically: @AvailTC Eq [Eq, ==, \/=]@
1323 -- Equality used when deciding if the interface has changed
1325 -- | The original names declared of a certain module that are exported
1326 type IfaceExport = (Module, [GenAvailInfo OccName])
1328 availsToNameSet :: [AvailInfo] -> NameSet
1329 availsToNameSet avails = foldr add emptyNameSet avails
1330 where add avail set = addListToNameSet set (availNames avail)
1332 availsToNameEnv :: [AvailInfo] -> NameEnv AvailInfo
1333 availsToNameEnv avails = foldr add emptyNameEnv avails
1334 where add avail env = extendNameEnvList env
1335 (zip (availNames avail) (repeat avail))
1337 -- | Just the main name made available, i.e. not the available pieces
1338 -- of type or class brought into scope by the 'GenAvailInfo'
1339 availName :: GenAvailInfo name -> name
1340 availName (Avail n) = n
1341 availName (AvailTC n _) = n
1343 -- | All names made available by the availability information
1344 availNames :: GenAvailInfo name -> [name]
1345 availNames (Avail n) = [n]
1346 availNames (AvailTC _ ns) = ns
1348 instance Outputable n => Outputable (GenAvailInfo n) where
1351 pprAvail :: Outputable n => GenAvailInfo n -> SDoc
1352 pprAvail (Avail n) = ppr n
1353 pprAvail (AvailTC n ns) = ppr n <> braces (hsep (punctuate comma (map ppr ns)))
1357 -- | Creates cached lookup for the 'mi_fix_fn' field of 'ModIface'
1358 mkIfaceFixCache :: [(OccName, Fixity)] -> OccName -> Fixity
1359 mkIfaceFixCache pairs
1360 = \n -> lookupOccEnv env n `orElse` defaultFixity
1362 env = mkOccEnv pairs
1364 emptyIfaceFixCache :: OccName -> Fixity
1365 emptyIfaceFixCache _ = defaultFixity
1367 -- | Fixity environment mapping names to their fixities
1368 type FixityEnv = NameEnv FixItem
1370 -- | Fixity information for an 'Name'. We keep the OccName in the range
1371 -- so that we can generate an interface from it
1372 data FixItem = FixItem OccName Fixity
1374 instance Outputable FixItem where
1375 ppr (FixItem occ fix) = ppr fix <+> ppr occ
1377 emptyFixityEnv :: FixityEnv
1378 emptyFixityEnv = emptyNameEnv
1380 lookupFixity :: FixityEnv -> Name -> Fixity
1381 lookupFixity env n = case lookupNameEnv env n of
1382 Just (FixItem _ fix) -> fix
1383 Nothing -> defaultFixity
1387 %************************************************************************
1389 \subsection{WhatsImported}
1391 %************************************************************************
1394 -- | Records whether a module has orphans. An \"orphan\" is one of:
1396 -- * An instance declaration in a module other than the definition
1397 -- module for one of the type constructors or classes in the instance head
1399 -- * A transformation rule in a module other than the one defining
1400 -- the function in the head of the rule
1401 type WhetherHasOrphans = Bool
1403 -- | Does this module define family instances?
1404 type WhetherHasFamInst = Bool
1406 -- | Did this module originate from a *-boot file?
1407 type IsBootInterface = Bool
1409 -- | Dependency information about modules and packages below this one
1410 -- in the import hierarchy.
1412 -- Invariant: the dependencies of a module @M@ never includes @M@.
1414 -- Invariant: none of the lists contain duplicates.
1416 = Deps { dep_mods :: [(ModuleName, IsBootInterface)]
1417 -- ^ Home-package module dependencies
1418 , dep_pkgs :: [PackageId]
1419 -- ^ External package dependencies
1420 , dep_orphs :: [Module]
1421 -- ^ Orphan modules (whether home or external pkg),
1422 -- *not* including family instance orphans as they
1423 -- are anyway included in 'dep_finsts'
1424 , dep_finsts :: [Module]
1425 -- ^ Modules that contain family instances (whether the
1426 -- instances are from the home or an external package)
1429 -- Equality used only for old/new comparison in MkIface.addVersionInfo
1431 -- See 'TcRnTypes.ImportAvails' for details on dependencies.
1433 noDependencies :: Dependencies
1434 noDependencies = Deps [] [] [] []
1436 -- | Records modules that we depend on by making a direct import from
1438 = UsagePackageModule {
1440 -- ^ External package module depended on
1441 usg_mod_hash :: Fingerprint
1442 } -- ^ Module from another package
1444 usg_mod_name :: ModuleName,
1445 -- ^ Name of the module
1446 usg_mod_hash :: Fingerprint,
1447 -- ^ Cached module fingerprint
1448 usg_entities :: [(OccName,Fingerprint)],
1449 -- ^ Entities we depend on, sorted by occurrence name and fingerprinted.
1450 -- NB: usages are for parent names only, e.g. type constructors
1451 -- but not the associated data constructors.
1452 usg_exports :: Maybe Fingerprint
1453 -- ^ Fingerprint for the export list we used to depend on this module,
1454 -- if we depend on the export list
1455 } -- ^ Module from the current package
1457 -- The export list field is (Just v) if we depend on the export list:
1458 -- i.e. we imported the module directly, whether or not we
1459 -- enumerated the things we imported, or just imported
1461 -- We need to recompile if M's exports change, because
1462 -- if the import was import M, we might now have a name clash
1463 -- in the importing module.
1464 -- if the import was import M(x) M might no longer export x
1465 -- The only way we don't depend on the export list is if we have
1467 -- And of course, for modules that aren't imported directly we don't
1468 -- depend on their export lists
1472 %************************************************************************
1474 The External Package State
1476 %************************************************************************
1479 type PackageTypeEnv = TypeEnv
1480 type PackageRuleBase = RuleBase
1481 type PackageInstEnv = InstEnv
1482 type PackageFamInstEnv = FamInstEnv
1483 type PackageVectInfo = VectInfo
1484 type PackageAnnEnv = AnnEnv
1486 -- | Information about other packages that we have slurped in by reading
1487 -- their interface files
1488 data ExternalPackageState
1490 eps_is_boot :: !(ModuleNameEnv (ModuleName, IsBootInterface)),
1491 -- ^ In OneShot mode (only), home-package modules
1492 -- accumulate in the external package state, and are
1493 -- sucked in lazily. For these home-pkg modules
1494 -- (only) we need to record which are boot modules.
1495 -- We set this field after loading all the
1496 -- explicitly-imported interfaces, but before doing
1499 -- The 'ModuleName' part is not necessary, but it's useful for
1500 -- debug prints, and it's convenient because this field comes
1501 -- direct from 'TcRnTypes.imp_dep_mods'
1503 eps_PIT :: !PackageIfaceTable,
1504 -- ^ The 'ModIface's for modules in external packages
1505 -- whose interfaces we have opened.
1506 -- The declarations in these interface files are held in the
1507 -- 'eps_decls', 'eps_inst_env', 'eps_fam_inst_env' and 'eps_rules'
1508 -- fields of this record, not in the 'mi_decls' fields of the
1509 -- interface we have sucked in.
1511 -- What /is/ in the PIT is:
1515 -- * Fingerprint info
1521 -- * Deprecations and warnings
1523 eps_PTE :: !PackageTypeEnv,
1524 -- ^ Result of typechecking all the external package
1525 -- interface files we have sucked in. The domain of
1526 -- the mapping is external-package modules
1528 eps_inst_env :: !PackageInstEnv, -- ^ The total 'InstEnv' accumulated
1529 -- from all the external-package modules
1530 eps_fam_inst_env :: !PackageFamInstEnv,-- ^ The total 'FamInstEnv' accumulated
1531 -- from all the external-package modules
1532 eps_rule_base :: !PackageRuleBase, -- ^ The total 'RuleEnv' accumulated
1533 -- from all the external-package modules
1534 eps_vect_info :: !PackageVectInfo, -- ^ The total 'VectInfo' accumulated
1535 -- from all the external-package modules
1536 eps_ann_env :: !PackageAnnEnv, -- ^ The total 'AnnEnv' accumulated
1537 -- from all the external-package modules
1539 eps_mod_fam_inst_env :: !(ModuleEnv FamInstEnv), -- ^ The family instances accumulated from external
1540 -- packages, keyed off the module that declared them
1542 eps_stats :: !EpsStats -- ^ Stastics about what was loaded from external packages
1545 -- | Accumulated statistics about what we are putting into the 'ExternalPackageState'.
1546 -- \"In\" means stuff that is just /read/ from interface files,
1547 -- \"Out\" means actually sucked in and type-checked
1548 data EpsStats = EpsStats { n_ifaces_in
1549 , n_decls_in, n_decls_out
1550 , n_rules_in, n_rules_out
1551 , n_insts_in, n_insts_out :: !Int }
1553 addEpsInStats :: EpsStats -> Int -> Int -> Int -> EpsStats
1554 -- ^ Add stats for one newly-read interface
1555 addEpsInStats stats n_decls n_insts n_rules
1556 = stats { n_ifaces_in = n_ifaces_in stats + 1
1557 , n_decls_in = n_decls_in stats + n_decls
1558 , n_insts_in = n_insts_in stats + n_insts
1559 , n_rules_in = n_rules_in stats + n_rules }
1562 Names in a NameCache are always stored as a Global, and have the SrcLoc
1563 of their binding locations.
1565 Actually that's not quite right. When we first encounter the original
1566 name, we might not be at its binding site (e.g. we are reading an
1567 interface file); so we give it 'noSrcLoc' then. Later, when we find
1568 its binding site, we fix it up.
1571 -- | The NameCache makes sure that there is just one Unique assigned for
1572 -- each original name; i.e. (module-name, occ-name) pair and provides
1573 -- something of a lookup mechanism for those names.
1575 = NameCache { nsUniqs :: UniqSupply,
1576 -- ^ Supply of uniques
1577 nsNames :: OrigNameCache,
1578 -- ^ Ensures that one original name gets one unique
1579 nsIPs :: OrigIParamCache
1580 -- ^ Ensures that one implicit parameter name gets one unique
1583 -- | Per-module cache of original 'OccName's given 'Name's
1584 type OrigNameCache = ModuleEnv (OccEnv Name)
1586 -- | Module-local cache of implicit parameter 'OccName's given 'Name's
1587 type OrigIParamCache = Map (IPName OccName) (IPName Name)
1592 %************************************************************************
1594 The module graph and ModSummary type
1595 A ModSummary is a node in the compilation manager's
1596 dependency graph, and it's also passed to hscMain
1598 %************************************************************************
1601 -- | A ModuleGraph contains all the nodes from the home package (only).
1602 -- There will be a node for each source module, plus a node for each hi-boot
1605 -- The graph is not necessarily stored in topologically-sorted order. Use
1606 -- 'GHC.topSortModuleGraph' and 'Digraph.flattenSCC' to achieve this.
1607 type ModuleGraph = [ModSummary]
1609 emptyMG :: ModuleGraph
1612 -- | A single node in a 'ModuleGraph. The nodes of the module graph are one of:
1614 -- * A regular Haskell source module
1616 -- * A hi-boot source module
1618 -- * An external-core source module
1621 ms_mod :: Module, -- ^ Identity of the module
1622 ms_hsc_src :: HscSource, -- ^ The module source either plain Haskell, hs-boot or external core
1623 ms_location :: ModLocation, -- ^ Location of the various files belonging to the module
1624 ms_hs_date :: ClockTime, -- ^ Timestamp of source file
1625 ms_obj_date :: Maybe ClockTime, -- ^ Timestamp of object, if we have one
1626 ms_srcimps :: [Located (ImportDecl RdrName)], -- ^ Source imports of the module
1627 ms_imps :: [Located (ImportDecl RdrName)], -- ^ Non-source imports of the module
1628 ms_hspp_file :: FilePath, -- ^ Filename of preprocessed source file
1629 ms_hspp_opts :: DynFlags, -- ^ Cached flags from @OPTIONS@, @INCLUDE@
1630 -- and @LANGUAGE@ pragmas in the modules source code
1631 ms_hspp_buf :: Maybe StringBuffer -- ^ The actual preprocessed source, if we have it
1634 ms_mod_name :: ModSummary -> ModuleName
1635 ms_mod_name = moduleName . ms_mod
1637 -- The ModLocation contains both the original source filename and the
1638 -- filename of the cleaned-up source file after all preprocessing has been
1639 -- done. The point is that the summariser will have to cpp/unlit/whatever
1640 -- all files anyway, and there's no point in doing this twice -- just
1641 -- park the result in a temp file, put the name of it in the location,
1642 -- and let @compile@ read from that file on the way back up.
1644 -- The ModLocation is stable over successive up-sweeps in GHCi, wheres
1645 -- the ms_hs_date and imports can, of course, change
1647 msHsFilePath, msHiFilePath, msObjFilePath :: ModSummary -> FilePath
1648 msHsFilePath ms = expectJust "msHsFilePath" (ml_hs_file (ms_location ms))
1649 msHiFilePath ms = ml_hi_file (ms_location ms)
1650 msObjFilePath ms = ml_obj_file (ms_location ms)
1652 -- | Did this 'ModSummary' originate from a hs-boot file?
1653 isBootSummary :: ModSummary -> Bool
1654 isBootSummary ms = isHsBoot (ms_hsc_src ms)
1656 instance Outputable ModSummary where
1658 = sep [text "ModSummary {",
1659 nest 3 (sep [text "ms_hs_date = " <> text (show (ms_hs_date ms)),
1660 text "ms_mod =" <+> ppr (ms_mod ms)
1661 <> text (hscSourceString (ms_hsc_src ms)) <> comma,
1662 text "ms_imps =" <+> ppr (ms_imps ms),
1663 text "ms_srcimps =" <+> ppr (ms_srcimps ms)]),
1667 showModMsg :: HscTarget -> Bool -> ModSummary -> String
1668 showModMsg target recomp mod_summary
1670 hsep [text (mod_str ++ replicate (max 0 (16 - length mod_str)) ' '),
1671 char '(', text (normalise $ msHsFilePath mod_summary) <> comma,
1673 HscInterpreted | recomp
1674 -> text "interpreted"
1675 HscNothing -> text "nothing"
1676 _ -> text (normalise $ msObjFilePath mod_summary),
1679 mod = moduleName (ms_mod mod_summary)
1680 mod_str = showSDoc (ppr mod) ++ hscSourceString (ms_hsc_src mod_summary)
1684 %************************************************************************
1686 \subsection{Hpc Support}
1688 %************************************************************************
1691 -- | Information about a modules use of Haskell Program Coverage
1694 { hpcInfoTickCount :: Int
1695 , hpcInfoHash :: Int
1698 { hpcUsed :: AnyHpcUsage -- ^ Is hpc used anywhere on the module \*tree\*?
1701 -- | This is used to signal if one of my imports used HPC instrumentation
1702 -- even if there is no module-local HPC usage
1703 type AnyHpcUsage = Bool
1705 emptyHpcInfo :: AnyHpcUsage -> HpcInfo
1706 emptyHpcInfo = NoHpcInfo
1708 -- | Find out if HPC is used by this module or any of the modules
1710 isHpcUsed :: HpcInfo -> AnyHpcUsage
1711 isHpcUsed (HpcInfo {}) = True
1712 isHpcUsed (NoHpcInfo { hpcUsed = used }) = used
1715 %************************************************************************
1717 \subsection{Vectorisation Support}
1719 %************************************************************************
1721 The following information is generated and consumed by the vectorisation
1722 subsystem. It communicates the vectorisation status of declarations from one
1725 Why do we need both f and f_v in the ModGuts/ModDetails/EPS version VectInfo
1726 below? We need to know `f' when converting to IfaceVectInfo. However, during
1727 vectorisation, we need to know `f_v', whose `Var' we cannot lookup based
1728 on just the OccName easily in a Core pass.
1731 -- |Vectorisation information for 'ModGuts', 'ModDetails' and 'ExternalPackageState'; see also
1732 -- documentation at 'Vectorise.Env.GlobalEnv'.
1735 { vectInfoVar :: VarEnv (Var , Var ) -- ^ @(f, f_v)@ keyed on @f@
1736 , vectInfoTyCon :: NameEnv (TyCon , TyCon) -- ^ @(T, T_v)@ keyed on @T@
1737 , vectInfoDataCon :: NameEnv (DataCon, DataCon) -- ^ @(C, C_v)@ keyed on @C@
1738 , vectInfoPADFun :: NameEnv (TyCon , Var) -- ^ @(T_v, paT)@ keyed on @T_v@
1739 , vectInfoIso :: NameEnv (TyCon , Var) -- ^ @(T, isoT)@ keyed on @T@
1740 , vectInfoScalarVars :: VarSet -- ^ set of purely scalar variables
1741 , vectInfoScalarTyCons :: NameSet -- ^ set of scalar type constructors
1744 -- |Vectorisation information for 'ModIface'; i.e, the vectorisation information propagated
1745 -- across module boundaries.
1749 { ifaceVectInfoVar :: [Name] -- ^ All variables in here have a vectorised variant
1750 , ifaceVectInfoTyCon :: [Name] -- ^ All 'TyCon's in here have a vectorised variant;
1751 -- the name of the vectorised variant and those of its
1752 -- data constructors are determined by
1753 -- 'OccName.mkVectTyConOcc' and
1754 -- 'OccName.mkVectDataConOcc'; the names of the
1755 -- isomorphisms are determined by 'OccName.mkVectIsoOcc'
1756 , ifaceVectInfoTyConReuse :: [Name] -- ^ The vectorised form of all the 'TyCon's in here
1757 -- coincides with the unconverted form; the name of the
1758 -- isomorphisms is determined by 'OccName.mkVectIsoOcc'
1759 , ifaceVectInfoScalarVars :: [Name] -- iface version of 'vectInfoScalarVar'
1760 , ifaceVectInfoScalarTyCons :: [Name] -- iface version of 'vectInfoScalarTyCon'
1763 noVectInfo :: VectInfo
1765 = VectInfo emptyVarEnv emptyNameEnv emptyNameEnv emptyNameEnv emptyNameEnv emptyVarSet
1768 plusVectInfo :: VectInfo -> VectInfo -> VectInfo
1769 plusVectInfo vi1 vi2 =
1770 VectInfo (vectInfoVar vi1 `plusVarEnv` vectInfoVar vi2)
1771 (vectInfoTyCon vi1 `plusNameEnv` vectInfoTyCon vi2)
1772 (vectInfoDataCon vi1 `plusNameEnv` vectInfoDataCon vi2)
1773 (vectInfoPADFun vi1 `plusNameEnv` vectInfoPADFun vi2)
1774 (vectInfoIso vi1 `plusNameEnv` vectInfoIso vi2)
1775 (vectInfoScalarVars vi1 `unionVarSet` vectInfoScalarVars vi2)
1776 (vectInfoScalarTyCons vi1 `unionNameSets` vectInfoScalarTyCons vi2)
1778 concatVectInfo :: [VectInfo] -> VectInfo
1779 concatVectInfo = foldr plusVectInfo noVectInfo
1781 noIfaceVectInfo :: IfaceVectInfo
1782 noIfaceVectInfo = IfaceVectInfo [] [] [] [] []
1785 %************************************************************************
1787 \subsection{Linkable stuff}
1789 %************************************************************************
1791 This stuff is in here, rather than (say) in Linker.lhs, because the Linker.lhs
1792 stuff is the *dynamic* linker, and isn't present in a stage-1 compiler
1795 -- | Information we can use to dynamically link modules into the compiler
1796 data Linkable = LM {
1797 linkableTime :: ClockTime, -- ^ Time at which this linkable was built
1798 -- (i.e. when the bytecodes were produced,
1799 -- or the mod date on the files)
1800 linkableModule :: Module, -- ^ The linkable module itself
1801 linkableUnlinked :: [Unlinked]
1802 -- ^ Those files and chunks of code we have yet to link.
1804 -- INVARIANT: A valid linkable always has at least one 'Unlinked' item.
1805 -- If this list is empty, the Linkable represents a fake linkable, which
1806 -- is generated in HscNothing mode to avoid recompiling modules.
1808 -- XXX: Do items get removed from this list when they get linked?
1811 isObjectLinkable :: Linkable -> Bool
1812 isObjectLinkable l = not (null unlinked) && all isObject unlinked
1813 where unlinked = linkableUnlinked l
1814 -- A linkable with no Unlinked's is treated as a BCO. We can
1815 -- generate a linkable with no Unlinked's as a result of
1816 -- compiling a module in HscNothing mode, and this choice
1817 -- happens to work well with checkStability in module GHC.
1819 linkableObjs :: Linkable -> [FilePath]
1820 linkableObjs l = [ f | DotO f <- linkableUnlinked l ]
1822 instance Outputable Linkable where
1823 ppr (LM when_made mod unlinkeds)
1824 = (text "LinkableM" <+> parens (text (show when_made)) <+> ppr mod)
1825 $$ nest 3 (ppr unlinkeds)
1827 -------------------------------------------
1829 -- | Objects which have yet to be linked by the compiler
1831 = DotO FilePath -- ^ An object file (.o)
1832 | DotA FilePath -- ^ Static archive file (.a)
1833 | DotDLL FilePath -- ^ Dynamically linked library file (.so, .dll, .dylib)
1834 | BCOs CompiledByteCode ModBreaks -- ^ A byte-code object, lives only in memory
1837 data CompiledByteCode = CompiledByteCodeUndefined
1838 _unused :: CompiledByteCode
1839 _unused = CompiledByteCodeUndefined
1842 instance Outputable Unlinked where
1843 ppr (DotO path) = text "DotO" <+> text path
1844 ppr (DotA path) = text "DotA" <+> text path
1845 ppr (DotDLL path) = text "DotDLL" <+> text path
1847 ppr (BCOs bcos _) = text "BCOs" <+> ppr bcos
1849 ppr (BCOs _ _) = text "No byte code"
1852 -- | Is this an actual file on disk we can link in somehow?
1853 isObject :: Unlinked -> Bool
1854 isObject (DotO _) = True
1855 isObject (DotA _) = True
1856 isObject (DotDLL _) = True
1859 -- | Is this a bytecode linkable with no file on disk?
1860 isInterpretable :: Unlinked -> Bool
1861 isInterpretable = not . isObject
1863 -- | Retrieve the filename of the linkable if possible. Panic if it is a byte-code object
1864 nameOfObject :: Unlinked -> FilePath
1865 nameOfObject (DotO fn) = fn
1866 nameOfObject (DotA fn) = fn
1867 nameOfObject (DotDLL fn) = fn
1868 nameOfObject other = pprPanic "nameOfObject" (ppr other)
1870 -- | Retrieve the compiled byte-code if possible. Panic if it is a file-based linkable
1871 byteCodeOfObject :: Unlinked -> CompiledByteCode
1872 byteCodeOfObject (BCOs bc _) = bc
1873 byteCodeOfObject other = pprPanic "byteCodeOfObject" (ppr other)
1876 %************************************************************************
1878 \subsection{Breakpoint Support}
1880 %************************************************************************
1883 -- | Breakpoint index
1884 type BreakIndex = Int
1886 -- | All the information about the breakpoints for a given module
1889 { modBreaks_flags :: BreakArray
1890 -- ^ The array of flags, one per breakpoint,
1891 -- indicating which breakpoints are enabled.
1892 , modBreaks_locs :: !(Array BreakIndex SrcSpan)
1893 -- ^ An array giving the source span of each breakpoint.
1894 , modBreaks_vars :: !(Array BreakIndex [OccName])
1895 -- ^ An array giving the names of the free variables at each breakpoint.
1896 , modBreaks_decls :: !(Array BreakIndex [String])
1897 -- ^ An array giving the names of the declarations enclosing each breakpoint.
1900 emptyModBreaks :: ModBreaks
1901 emptyModBreaks = ModBreaks
1902 { modBreaks_flags = error "ModBreaks.modBreaks_array not initialised"
1903 -- Todo: can we avoid this?
1904 , modBreaks_locs = array (0,-1) []
1905 , modBreaks_vars = array (0,-1) []
1906 , modBreaks_decls = array (0,-1) []