GHC.hs 87 KB
Newer Older
1
-- -----------------------------------------------------------------------------
2
--
3
-- (c) The University of Glasgow, 2005
4
5
6
--
-- The GHC API
--
7
-- -----------------------------------------------------------------------------
8
9
10

module GHC (
	-- * Initialisation
11
	Session,
12
13
14
15
16
	defaultErrorHandler,
	defaultCleanupHandler,
	newSession,

	-- * Flags and settings
17
18
	DynFlags(..), DynFlag(..), Severity(..), HscTarget(..), dopt,
        GhcMode(..), GhcLink(..),
19
	parseDynamicFlags,
20
21
	getSessionDynFlags,
	setSessionDynFlags,
22
23

	-- * Targets
24
	Target(..), TargetId(..), Phase,
25
26
27
	setTargets,
	getTargets,
	addTarget,
28
	removeTarget,
29
30
	guessTarget,
	
31
32
33
34
35
36
        -- * Extending the program scope 
        extendGlobalRdrScope,  -- :: Session -> [GlobalRdrElt] -> IO ()
        setGlobalRdrScope,     -- :: Session -> [GlobalRdrElt] -> IO ()
        extendGlobalTypeScope, -- :: Session -> [Id] -> IO ()
        setGlobalTypeScope,    -- :: Session -> [Id] -> IO ()

37
	-- * Loading\/compiling the program
38
	depanal,
39
	load, LoadHowMuch(..), SuccessFlag(..),	-- also does depanal
40
	workingDirectoryChanged,
41
	checkModule, CheckedModule(..),
42
	TypecheckedSource, ParsedSource, RenamedSource,
43

44
45
46
	-- * Parsing Haddock comments
	parseHaddockComment,

47
	-- * Inspecting the module structure of the program
Simon Marlow's avatar
Simon Marlow committed
48
	ModuleGraph, ModSummary(..), ms_mod_name, ModLocation(..),
49
	getModuleGraph,
50
	isLoaded,
51
52
	topSortModuleGraph,

53
54
55
56
	-- * Inspecting modules
	ModuleInfo,
	getModuleInfo,
	modInfoTyThings,
57
	modInfoTopLevelScope,
58
59
	modInfoPrintUnqualified,
	modInfoExports,
60
	modInfoInstances,
61
62
	modInfoIsExportedName,
	modInfoLookupName,
63
	lookupGlobalName,
64

65
66
67
	-- * Printing
	PrintUnqualified, alwaysQualify,

68
69
	-- * Interactive evaluation
	getBindings, getPrintUnqual,
Simon Marlow's avatar
Simon Marlow committed
70
        findModule,
71
72
#ifdef GHCI
	setContext, getContext,	
73
	getNamesInScope,
Simon Marlow's avatar
Simon Marlow committed
74
	getRdrNamesInScope,
75
	moduleIsInterpreted,
76
	getInfo,
77
78
	exprType,
	typeKind,
79
	parseName,
80
	RunResult(..),  ResumeHandle,
81
	runStmt,
82
        resume,
83
	showModule,
84
        isModuleInterpreted,
ei@vuokko.info's avatar
ei@vuokko.info committed
85
	compileExpr, HValue, dynCompileExpr,
86
	lookupName,
mnislaih's avatar
mnislaih committed
87
        obtainTerm, obtainTerm1,
88
89
        ModBreaks(..), BreakIndex,
        BreakInfo(breakInfo_number, breakInfo_module),
90
        BreakArray, setBreakOn, setBreakOff, getBreak,
91
        modInfoModBreaks, 
92
93
94
#endif

	-- * Abstract syntax elements
95

Simon Marlow's avatar
Simon Marlow committed
96
97
98
        -- ** Packages
        PackageId,

99
	-- ** Modules
Simon Marlow's avatar
Simon Marlow committed
100
101
	Module, mkModule, pprModule, moduleName, modulePackageId,
        ModuleName, mkModuleName, moduleNameString,
102

103
	-- ** Names
104
	Name, 
105
	nameModule, pprParenSymName, nameSrcLoc,
106
	NamedThing(..),
Simon Marlow's avatar
Simon Marlow committed
107
	RdrName(Qual,Unqual),
108
109
	
	-- ** Identifiers
110
	Id, idType,
111
	isImplicitId, isDeadBinder,
112
	isExportedId, isLocalId, isGlobalId,
113
	isRecordSelector,
114
	isPrimOpId, isFCallId, isClassOpId_maybe,
115
116
	isDataConWorkId, idDataCon,
	isBottomingId, isDictonaryId,
117
	recordSelectorFieldLabel,
118
119
120

	-- ** Type constructors
	TyCon, 
121
	tyConTyVars, tyConDataCons, tyConArity,
122
	isClassTyCon, isSynTyCon, isNewTyCon, isPrimTyCon, isFunTyCon,
123
124
	isOpenTyCon,
	synTyConDefn, synTyConType, synTyConResKind,
125

126
127
128
129
	-- ** Type variables
	TyVar,
	alphaTyVars,

130
131
	-- ** Data constructors
	DataCon,
132
133
134
135
	dataConSig, dataConType, dataConTyCon, dataConFieldLabels,
	dataConIsInfix, isVanillaDataCon,
	dataConStrictMarks,  
	StrictnessMark(..), isMarkedStrict,
136
137
138

	-- ** Classes
	Class, 
139
140
	classMethods, classSCTheta, classTvsFds,
	pprFundeps,
141

142
	-- ** Instances
143
	Instance, 
144
	instanceDFunId, pprInstance, pprInstanceHdr,
145

146
	-- ** Types and Kinds
147
148
	Type, dropForAlls, splitForAllTys, funResultTy, 
	pprParendType, pprTypeApp,
149
	Kind,
150
151
	PredType,
	ThetaType, pprThetaArrow,
152
153

	-- ** Entities
154
155
	TyThing(..), 

156
157
158
	-- ** Syntax
	module HsSyn, -- ToDo: remove extraneous bits

159
160
161
162
163
164
165
166
	-- ** Fixities
	FixityDirection(..), 
	defaultFixity, maxPrecedence, 
	negateFixity,
	compareFixity,

	-- ** Source locations
	SrcLoc, pprDefnLoc,
Simon Marlow's avatar
Simon Marlow committed
167
168
169
170
171
172
173
174
        mkSrcLoc, isGoodSrcLoc,
	srcLocFile, srcLocLine, srcLocCol,
        SrcSpan,
        mkSrcSpan, srcLocSpan,
        srcSpanStart, srcSpanEnd,
	srcSpanFile, 
        srcSpanStartLine, srcSpanEndLine, 
        srcSpanStartCol, srcSpanEndCol,
175

176
177
178
179
	-- * Exceptions
	GhcException(..), showGhcException,

	-- * Miscellaneous
180
181
	sessionHscEnv,
	cyclicModuleErr,
182
183
  ) where

184
185
186
{-
 ToDo:

187
  * inline bits of HscMain here to simplify layering: hscTcExpr, hscStmt.
188
189
190
191
192
193
  * what StaticFlags should we expose, if any?
-}

#include "HsVersions.h"

#ifdef GHCI
mnislaih's avatar
mnislaih committed
194
import RtClosureInspect ( cvObtainTerm, Term )
195
196
import TcRnDriver	( tcRnLookupRdrName, tcRnGetInfo,
			  tcRnLookupName, getModuleExports )
197
import GHC.Exts         ( unsafeCoerce#, Ptr )
198
import Foreign.StablePtr( deRefStablePtr, StablePtr, newStablePtr, freeStablePtr )
199
import Foreign          ( poke )
mnislaih's avatar
mnislaih committed
200
import qualified Linker
201
import Linker           ( HValue )
mnislaih's avatar
mnislaih committed
202
203

import Data.Dynamic     ( Dynamic )
204

205
206
207
import ByteCodeInstr
import IdInfo
import HscMain          ( hscParseIdentifier, hscTcExpr, hscKcType, hscStmt )
208
import BreakArray
209
210
#endif

211
212
213
import Packages
import NameSet
import RdrName
214
import HsSyn 
215
import Type             hiding (typeKind)
216
import TcType           hiding (typeKind)
217
218
import Id
import Var              hiding (setIdType)
219
220
import VarEnv
import VarSet
221
import TysPrim		( alphaTyVars )
222
223
224
225
226
import TyCon
import Class
import FunDeps
import DataCon
import Name             hiding ( varName )
227
import OccName		( parenSymOcc )
228
import NameEnv
229
import InstEnv		( Instance, instanceDFunId, pprInstance, pprInstanceHdr )
230
import SrcLoc
231
232
import DriverPipeline
import DriverPhases	( Phase(..), isHaskellSrcFilename, startPhase )
233
import HeaderInfo	( getImports, getOptions )
234
import Finder
235
import HscMain          ( newHscEnv, hscFileCheck, HscChecked(..) )
236
237
import HscTypes
import DynFlags
238
239
import SysTools     ( initSysTools, cleanTempFiles, cleanTempFilesExcept,
                      cleanTempDirs )
240
import Module
Simon Marlow's avatar
Simon Marlow committed
241
import UniqFM
242
import PackageConfig
243
244
import FiniteMap
import Panic
245
import Digraph
246
import Bag		( unitBag, listToBag )
247
import ErrUtils		( Severity(..), showPass, fatalErrorMsg, debugTraceMsg,
248
249
			  mkPlainErrMsg, printBagOfErrors, printBagOfWarnings,
			  WarnMsg )
250
import qualified ErrUtils
251
import Util
252
import StringBuffer	( StringBuffer, hGetStringBuffer )
253
import Outputable
254
import BasicTypes
255
import Maybes		( expectJust, mapCatMaybes )
256
import HaddockParse
257
import HaddockLex       ( tokenise )
258
import Unique
259

260
import System.IO.Unsafe
261
import Data.Array
262
263
import Control.Concurrent
import System.Directory ( getModificationTime, doesFileExist )
264
265
import Data.Maybe
import Data.List
266
import qualified Data.List as List
267
import Control.Monad
268
269
270
271
272
import System.Exit	( exitWith, ExitCode(..) )
import System.Time	( ClockTime )
import Control.Exception as Exception hiding (handle)
import Data.IORef
import System.IO
273
import System.IO.Error	( isDoesNotExistError )
274
import Prelude hiding (init)
275

276
277
278
279
280
281
#if __GLASGOW_HASKELL__ < 600
import System.IO as System.IO.Error ( try )
#else
import System.IO.Error	( try )
#endif

282
-- -----------------------------------------------------------------------------
283
-- Exception handlers
284
285
286
287
288

-- | Install some default exception handlers and run the inner computation.
-- Unless you want to handle exceptions yourself, you should wrap this around
-- the top level of your program.  The default handlers output the error
-- message(s) to stderr and exit cleanly.
289
290
defaultErrorHandler :: DynFlags -> IO a -> IO a
defaultErrorHandler dflags inner = 
291
292
293
294
295
  -- top-level exception handler: any unrecognised exception is a compiler bug.
  handle (\exception -> do
  	   hFlush stdout
	   case exception of
		-- an IO exception probably isn't our fault, so don't panic
296
297
		IOException _ ->
		  fatalErrorMsg dflags (text (show exception))
298
		AsyncException StackOverflow ->
299
300
301
		  fatalErrorMsg dflags (text "stack overflow: use +RTS -K<size> to increase it")
		_other ->
		  fatalErrorMsg dflags (text (show (Panic (show exception))))
302
303
304
	   exitWith (ExitFailure 1)
         ) $

305
306
  -- program errors: messages with locations attached.  Sometimes it is
  -- convenient to just throw these as exceptions.
307
  handleDyn (\dyn -> do printBagOfErrors dflags (unitBag dyn)
308
309
310
			exitWith (ExitFailure 1)) $

  -- error messages propagated as exceptions
311
312
313
314
315
  handleDyn (\dyn -> do
  		hFlush stdout
  		case dyn of
		     PhaseFailed _ code -> exitWith code
		     Interrupted -> exitWith (ExitFailure 1)
316
		     _ -> do fatalErrorMsg dflags (text (show (dyn :: GhcException)))
317
318
319
320
321
322
323
324
			     exitWith (ExitFailure 1)
	    ) $
  inner

-- | Install a default cleanup handler to remove temporary files
-- deposited by a GHC run.  This is seperate from
-- 'defaultErrorHandler', because you might want to override the error
-- handling, but still get the ordinary cleanup behaviour.
325
326
defaultCleanupHandler :: DynFlags -> IO a -> IO a
defaultCleanupHandler dflags inner = 
327
    -- make sure we clean up after ourselves
328
329
    later (do cleanTempFiles dflags
              cleanTempDirs dflags
330
331
332
333
334
          )
          -- exceptions will be blocked while we clean the temporary files,
          -- so there shouldn't be any difficulty if we receive further
          -- signals.
    inner
335
336
337
338


-- | Starts a new session.  A session consists of a set of loaded
-- modules, a set of options (DynFlags), and an interactive context.
339
340
newSession :: Maybe FilePath -> IO Session
newSession mb_top_dir = do
341
342
  -- catch ^C
  main_thread <- myThreadId
343
  modifyMVar_ interruptTargetThread (return . (main_thread :))
344
345
346
347
  installSignalHandlers

  dflags0 <- initSysTools mb_top_dir defaultDynFlags
  dflags  <- initDynFlags dflags0
348
  env <- newHscEnv dflags
349
  ref <- newIORef env
350
351
352
353
354
355
356
357
358
359
360
361
  return (Session ref)

-- tmp: this breaks the abstraction, but required because DriverMkDepend
-- needs to call the Finder.  ToDo: untangle this.
sessionHscEnv :: Session -> IO HscEnv
sessionHscEnv (Session ref) = readIORef ref

withSession :: Session -> (HscEnv -> IO a) -> IO a
withSession (Session ref) f = do h <- readIORef ref; f h

modifySession :: Session -> (HscEnv -> HscEnv) -> IO ()
modifySession (Session ref) f = do h <- readIORef ref; writeIORef ref $! f h
362
363
364
365
366
367

-- -----------------------------------------------------------------------------
-- Flags & settings

-- | Grabs the DynFlags from the Session
getSessionDynFlags :: Session -> IO DynFlags
368
getSessionDynFlags s = withSession s (return . hsc_dflags)
369

370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
-- | Updates the DynFlags in a Session.  This also reads
-- the package database (unless it has already been read),
-- and prepares the compilers knowledge about packages.  It
-- can be called again to load new packages: just add new
-- package flags to (packageFlags dflags).
--
-- Returns a list of new packages that may need to be linked in using
-- the dynamic linker (see 'linkPackages') as a result of new package
-- flags.  If you are not doing linking or doing static linking, you
-- can ignore the list of packages returned.
--
setSessionDynFlags :: Session -> DynFlags -> IO [PackageId]
setSessionDynFlags (Session ref) dflags = do
  hsc_env <- readIORef ref
  (dflags', preload) <- initPackages dflags
  writeIORef ref $! hsc_env{ hsc_dflags = dflags' }
  return preload
387

388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
-- | If there is no -o option, guess the name of target executable
-- by using top-level source file name as a base.
guessOutputFile :: Session -> IO ()
guessOutputFile s = modifySession s $ \env ->
    let dflags = hsc_dflags env
        mod_graph = hsc_mod_graph env
        mainModuleSrcPath, guessedName :: Maybe String
        mainModuleSrcPath = do
            let isMain = (== mainModIs dflags) . ms_mod
            [ms] <- return (filter isMain mod_graph)
            ml_hs_file (ms_location ms)
        guessedName = fmap basenameOf mainModuleSrcPath
    in
    case outputFile dflags of
        Just _ -> env
        Nothing -> env { hsc_dflags = dflags { outputFile = guessedName } }

405
-- -----------------------------------------------------------------------------
406
-- Targets
407
408
409
410
411
412

-- ToDo: think about relative vs. absolute file paths. And what
-- happens when the current directory changes.

-- | Sets the targets for this session.  Each target may be a module name
-- or a filename.  The targets correspond to the set of root modules for
413
-- the program\/library.  Unloading the current program is achieved by
414
-- setting the current set of targets to be empty, followed by load.
415
setTargets :: Session -> [Target] -> IO ()
416
setTargets s targets = modifySession s (\h -> h{ hsc_targets = targets })
417
418

-- | returns the current set of targets
419
420
getTargets :: Session -> IO [Target]
getTargets s = withSession s (return . hsc_targets)
421

422
-- | Add another target
423
424
425
addTarget :: Session -> Target -> IO ()
addTarget s target
  = modifySession s (\h -> h{ hsc_targets = target : hsc_targets h })
426

427
428
429
430
431
432
-- | Remove a target
removeTarget :: Session -> TargetId -> IO ()
removeTarget s target_id
  = modifySession s (\h -> h{ hsc_targets = filter (hsc_targets h) })
  where
   filter targets = [ t | t@(Target id _) <- targets, id /= target_id ]
433

434
435
436
437
438
439
440
441
442
-- Attempts to guess what Target a string refers to.  This function implements
-- the --make/GHCi command-line syntax for filenames: 
--
-- 	- if the string looks like a Haskell source filename, then interpret
--	  it as such
--	- if adding a .hs or .lhs suffix yields the name of an existing file,
--	  then use that
-- 	- otherwise interpret the string as a module name
--
443
444
445
446
guessTarget :: String -> Maybe Phase -> IO Target
guessTarget file (Just phase)
   = return (Target (TargetFile file (Just phase)) Nothing)
guessTarget file Nothing
447
   | isHaskellSrcFilename file
448
   = return (Target (TargetFile file Nothing) Nothing)
449
450
   | otherwise
   = do exists <- doesFileExist hs_file
451
452
453
	if exists
	   then return (Target (TargetFile hs_file Nothing) Nothing)
	   else do
454
	exists <- doesFileExist lhs_file
455
456
457
	if exists
	   then return (Target (TargetFile lhs_file Nothing) Nothing)
	   else do
Simon Marlow's avatar
Simon Marlow committed
458
	return (Target (TargetModule (mkModuleName file)) Nothing)
459
     where 
460
461
	 hs_file  = file `joinFileExt` "hs"
	 lhs_file = file `joinFileExt` "lhs"
462

463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
-- -----------------------------------------------------------------------------
-- Extending the program scope

extendGlobalRdrScope :: Session -> [GlobalRdrElt] -> IO ()
extendGlobalRdrScope session rdrElts
    = modifySession session $ \hscEnv ->
      let global_rdr = hsc_global_rdr_env hscEnv
      in hscEnv{ hsc_global_rdr_env = foldl extendGlobalRdrEnv global_rdr rdrElts }

setGlobalRdrScope :: Session -> [GlobalRdrElt] -> IO ()
setGlobalRdrScope session rdrElts
    = modifySession session $ \hscEnv ->
      hscEnv{ hsc_global_rdr_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv rdrElts }

extendGlobalTypeScope :: Session -> [Id] -> IO ()
extendGlobalTypeScope session ids
    = modifySession session $ \hscEnv ->
      let global_type = hsc_global_type_env hscEnv
      in hscEnv{ hsc_global_type_env = extendTypeEnvWithIds global_type ids }

setGlobalTypeScope :: Session -> [Id] -> IO ()
setGlobalTypeScope session ids
    = modifySession session $ \hscEnv ->
      hscEnv{ hsc_global_type_env = extendTypeEnvWithIds emptyTypeEnv ids }

488
489
490
491
492
493
-- -----------------------------------------------------------------------------
-- Parsing Haddock comments

parseHaddockComment :: String -> Either String (HsDoc RdrName)
parseHaddockComment string = parseHaddockParagraphs (tokenise string)

494
495
-- -----------------------------------------------------------------------------
-- Loading the program
496

497
498
-- Perform a dependency analysis starting from the current targets
-- and update the session with the new module graph.
Simon Marlow's avatar
Simon Marlow committed
499
depanal :: Session -> [ModuleName] -> Bool -> IO (Maybe ModuleGraph)
500
depanal (Session ref) excluded_mods allow_dup_roots = do
501
502
503
504
505
506
507
  hsc_env <- readIORef ref
  let
	 dflags  = hsc_dflags hsc_env
	 targets = hsc_targets hsc_env
	 old_graph = hsc_mod_graph hsc_env
	
  showPass dflags "Chasing dependencies"
508
509
510
  debugTraceMsg dflags 2 (hcat [
	     text "Chasing modules from: ",
	     hcat (punctuate comma (map pprTarget targets))])
511

512
  r <- downsweep hsc_env old_graph excluded_mods allow_dup_roots
513
  case r of
514
    Just mod_graph -> writeIORef ref hsc_env{ hsc_mod_graph = mod_graph }
515
516
    _ -> return ()
  return r
517

518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
{-
-- | The result of load.
data LoadResult
  = LoadOk	Errors	-- ^ all specified targets were loaded successfully.
  | LoadFailed  Errors	-- ^ not all modules were loaded.

type Errors = [String]

data ErrMsg = ErrMsg { 
	errMsgSeverity  :: Severity,  -- warning, error, etc.
	errMsgSpans     :: [SrcSpan],
	errMsgShortDoc  :: Doc,
	errMsgExtraInfo :: Doc
	}
-}

data LoadHowMuch
   = LoadAllTargets
Simon Marlow's avatar
Simon Marlow committed
536
537
   | LoadUpTo ModuleName
   | LoadDependenciesOf ModuleName
538
539
540
541

-- | Try to load the program.  If a Module is supplied, then just
-- attempt to load up to this target.  If no Module is supplied,
-- then try to load all targets.
542
load :: Session -> LoadHowMuch -> IO SuccessFlag
543
load s@(Session ref) how_much
544
   = do 
545
546
547
548
	-- Dependency analysis first.  Note that this fixes the module graph:
	-- even if we don't get a fully successful upsweep, the full module
	-- graph is still retained in the Session.  We can tell which modules
	-- were successfully loaded by inspecting the Session's HPT.
549
	mb_graph <- depanal s [] False
550
551
552
	case mb_graph of	   
	   Just mod_graph -> load2 s how_much mod_graph 
	   Nothing        -> return Failed
553

554
load2 s@(Session ref) how_much mod_graph = do
555
        guessOutputFile s
556
557
558
559
560
561
562
563
564
	hsc_env <- readIORef ref

        let hpt1      = hsc_HPT hsc_env
        let dflags    = hsc_dflags hsc_env

	-- The "bad" boot modules are the ones for which we have
	-- B.hs-boot in the module graph, but no B.hs
	-- The downsweep should have ensured this does not happen
	-- (see msDeps)
Simon Marlow's avatar
Simon Marlow committed
565
566
        let all_home_mods = [ms_mod_name s 
			    | s <- mod_graph, not (isBootSummary s)]
567
#ifdef DEBUG
568
	    bad_boot_mods = [s 	      | s <- mod_graph, isBootSummary s,
Simon Marlow's avatar
Simon Marlow committed
569
					not (ms_mod_name s `elem` all_home_mods)]
570
#endif
571
572
573
574
575
576
577
578
	ASSERT( null bad_boot_mods ) return ()

        -- mg2_with_srcimps drops the hi-boot nodes, returning a 
	-- graph with cycles.  Among other things, it is used for
        -- backing out partially complete cycles following a failed
        -- upsweep, and for removing from hpt all the modules
        -- not in strict downwards closure, during calls to compile.
        let mg2_with_srcimps :: [SCC ModSummary]
579
	    mg2_with_srcimps = topSortModuleGraph True mod_graph Nothing
580

581
582
583
584
585
	-- If we can determine that any of the {-# SOURCE #-} imports
	-- are definitely unnecessary, then emit a warning.
	warnUnnecessarySourceImports dflags mg2_with_srcimps

 	let
586
587
	    -- check the stability property for each module.
	    stable_mods@(stable_obj,stable_bco)
588
	        = checkStability hpt1 mg2_with_srcimps all_home_mods
589
590
591
592
593
594
595
596
597

	    -- prune bits of the HPT which are definitely redundant now,
	    -- to save space.
	    pruned_hpt = pruneHomePackageTable hpt1 
				(flattenSCCs mg2_with_srcimps)
				stable_mods

	evaluate pruned_hpt

598
599
	debugTraceMsg dflags 2 (text "Stable obj:" <+> ppr stable_obj $$
				text "Stable BCO:" <+> ppr stable_bco)
600
601

	-- Unload any modules which are going to be re-linked this time around.
602
603
	let stable_linkables = [ linkable
			       | m <- stable_obj++stable_bco,
Simon Marlow's avatar
Simon Marlow committed
604
				 Just hmi <- [lookupUFM pruned_hpt m],
605
				 Just linkable <- [hm_linkable hmi] ]
606
607
608
609
610
611
612
613
614
615
616
617
	unload hsc_env stable_linkables

        -- We could at this point detect cycles which aren't broken by
        -- a source-import, and complain immediately, but it seems better
        -- to let upsweep_mods do this, so at least some useful work gets
        -- done before the upsweep is abandoned.
        --hPutStrLn stderr "after tsort:\n"
        --hPutStrLn stderr (showSDoc (vcat (map ppr mg2)))

        -- Now do the upsweep, calling compile for each module in
        -- turn.  Final result is version 3 of everything.

618
619
620
621
622
623
        -- Topologically sort the module graph, this time including hi-boot
	-- nodes, and possibly just including the portion of the graph
	-- reachable from the module specified in the 2nd argument to load.
	-- This graph should be cycle-free.
	-- If we're restricting the upsweep to a portion of the graph, we
	-- also want to retain everything that is still stable.
624
        let full_mg :: [SCC ModSummary]
625
	    full_mg    = topSortModuleGraph False mod_graph Nothing
626
627
628

	    maybe_top_mod = case how_much of
				LoadUpTo m           -> Just m
629
			  	LoadDependenciesOf m -> Just m
630
631
			  	_		     -> Nothing

632
633
634
635
636
637
638
639
640
	    partial_mg0 :: [SCC ModSummary]
	    partial_mg0 = topSortModuleGraph False mod_graph maybe_top_mod

	    -- LoadDependenciesOf m: we want the upsweep to stop just
	    -- short of the specified module (unless the specified module
	    -- is stable).
	    partial_mg
		| LoadDependenciesOf mod <- how_much
		= ASSERT( case last partial_mg0 of 
Simon Marlow's avatar
Simon Marlow committed
641
			    AcyclicSCC ms -> ms_mod_name ms == mod; _ -> False )
642
643
644
645
		  List.init partial_mg0
		| otherwise
		= partial_mg0
  
646
647
648
	    stable_mg = 
		[ AcyclicSCC ms
	        | AcyclicSCC ms <- full_mg,
Simon Marlow's avatar
Simon Marlow committed
649
650
651
		  ms_mod_name ms `elem` stable_obj++stable_bco,
		  ms_mod_name ms `notElem` [ ms_mod_name ms' | 
						AcyclicSCC ms' <- partial_mg ] ]
652
653
654

	    mg = stable_mg ++ partial_mg

655
656
	-- clean up between compilations
	let cleanup = cleanTempFilesExcept dflags
657
			  (ppFilesFromSummaries (flattenSCCs mg2_with_srcimps))
658

659
660
	debugTraceMsg dflags 2 (hang (text "Ready for upsweep") 
				   2 (ppr mg))
661
662
        (upsweep_ok, hsc_env1, modsUpswept)
           <- upsweep (hsc_env { hsc_HPT = emptyHomePackageTable })
663
			   pruned_hpt stable_mods cleanup mg
664
665
666
667
668

	-- Make modsDone be the summaries for each home module now
	-- available; this should equal the domain of hpt3.
        -- Get in in a roughly top .. bottom order (hence reverse).

669
        let modsDone = reverse modsUpswept
670
671
672
673
674
675
676
677

        -- Try and do linking in some form, depending on whether the
        -- upsweep was completely or only partially successful.

        if succeeded upsweep_ok

         then 
           -- Easy; just relink it all.
678
           do debugTraceMsg dflags 2 (text "Upsweep completely successful.")
679
680
681
682
683
684
685
686
687
688
689
690
691

	      -- Clean up after ourselves
	      cleanTempFilesExcept dflags (ppFilesFromSummaries modsDone)

	      -- Issue a warning for the confusing case where the user
	      -- said '-o foo' but we're not going to do any linking.
	      -- We attempt linking if either (a) one of the modules is
	      -- called Main, or (b) the user said -no-hs-main, indicating
	      -- that main() is going to come from somewhere else.
	      --
	      let ofile = outputFile dflags
	      let no_hs_main = dopt Opt_NoHsMain dflags
	      let 
692
693
	 	main_mod = mainModIs dflags
		a_root_is_Main = any ((==main_mod).ms_mod) mod_graph
694
695
		do_linking = a_root_is_Main || no_hs_main

696
697
698
699
700
701
702
	      when (ghcLink dflags == LinkBinary 
                    && isJust ofile && not do_linking) $
	        debugTraceMsg dflags 1 $
                    text ("Warning: output was redirected with -o, " ++
                          "but no output will be generated\n" ++
			  "because there is no " ++ 
                          moduleNameString (moduleName main_mod) ++ " module.")
703
704

	      -- link everything together
705
              linkresult <- link (ghcLink dflags) dflags do_linking (hsc_HPT hsc_env1)
706

707
	      loadFinish Succeeded linkresult ref hsc_env1
708
709
710
711
712

         else 
           -- Tricky.  We need to back out the effects of compiling any
           -- half-done cycles, both so as to clean up the top level envs
           -- and to avoid telling the interactive linker to link them.
713
           do debugTraceMsg dflags 2 (text "Upsweep partially successful.")
714
715
716
717
718
719
720
721
722
723

              let modsDone_names
                     = map ms_mod modsDone
              let mods_to_zap_names 
                     = findPartiallyCompletedCycles modsDone_names 
			  mg2_with_srcimps
              let mods_to_keep
                     = filter ((`notElem` mods_to_zap_names).ms_mod) 
			  modsDone

Simon Marlow's avatar
Simon Marlow committed
724
              let hpt4 = retainInTopLevelEnvs (map ms_mod_name mods_to_keep) 
725
					      (hsc_HPT hsc_env1)
726
727
728
729

	      -- Clean up after ourselves
	      cleanTempFilesExcept dflags (ppFilesFromSummaries mods_to_keep)

730
731
	      -- there should be no Nothings where linkables should be, now
	      ASSERT(all (isJust.hm_linkable) 
Simon Marlow's avatar
Simon Marlow committed
732
			(eltsUFM (hsc_HPT hsc_env))) do
733
	
734
	      -- Link everything together
735
              linkresult <- link (ghcLink dflags) dflags False hpt4
736

737
	      let hsc_env4 = hsc_env1{ hsc_HPT = hpt4 }
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
	      loadFinish Failed linkresult ref hsc_env4

-- Finish up after a load.

-- If the link failed, unload everything and return.
loadFinish all_ok Failed ref hsc_env
  = do unload hsc_env []
       writeIORef ref $! discardProg hsc_env
       return Failed

-- Empty the interactive context and set the module context to the topmost
-- newly loaded module, or the Prelude if none were loaded.
loadFinish all_ok Succeeded ref hsc_env
  = do writeIORef ref $! hsc_env{ hsc_IC = emptyInteractiveContext }
       return all_ok

754

755
756
757
758
759
760
761
762
763
764
-- Forget the current program, but retain the persistent info in HscEnv
discardProg :: HscEnv -> HscEnv
discardProg hsc_env
  = hsc_env { hsc_mod_graph = emptyMG, 
	      hsc_IC = emptyInteractiveContext,
	      hsc_HPT = emptyHomePackageTable }

-- used to fish out the preprocess output files for the purposes of
-- cleaning up.  The preprocessed file *might* be the same as the
-- source file, but that doesn't do any harm.
765
ppFilesFromSummaries summaries = map ms_hspp_file summaries
766

767
768
769
770
771
-- -----------------------------------------------------------------------------
-- Check module

data CheckedModule = 
  CheckedModule { parsedSource      :: ParsedSource,
772
		  renamedSource     :: Maybe RenamedSource,
773
774
775
		  typecheckedSource :: Maybe TypecheckedSource,
		  checkedModuleInfo :: Maybe ModuleInfo
	        }
776
777
778
779
780
	-- ToDo: improvements that could be made here:
	--  if the module succeeded renaming but not typechecking,
	--  we can still get back the GlobalRdrEnv and exports, so
	--  perhaps the ModuleInfo should be split up into separate
	--  fields within CheckedModule.
781

782
type ParsedSource      = Located (HsModule RdrName)
783
784
type RenamedSource     = (HsGroup Name, [LImportDecl Name], Maybe [LIE Name],
                          Maybe (HsDoc Name), HaddockModInfo Name)
785
786
type TypecheckedSource = LHsBinds Id

787
788
789
790
791
792
793
794
795
796
797
798
799
-- NOTE:
--   - things that aren't in the output of the typechecker right now:
--     - the export list
--     - the imports
--     - type signatures
--     - type/data/newtype declarations
--     - class declarations
--     - instances
--   - extra things in the typechecker's output:
--     - default methods are turned into top-level decls.
--     - dictionary bindings


800
801
802
803
-- | This is the way to get access to parsed and typechecked source code
-- for a module.  'checkModule' loads all the dependencies of the specified
-- module in the Session, and then attempts to typecheck the module.  If
-- successful, it returns the abstract syntax for the module.
Simon Marlow's avatar
Simon Marlow committed
804
checkModule :: Session -> ModuleName -> IO (Maybe CheckedModule)
805
checkModule session@(Session ref) mod = do
806
	-- load up the dependencies first
807
   r <- load session (LoadDependenciesOf mod)
808
809
810
811
812
   if (failed r) then return Nothing else do

	-- now parse & typecheck the module
   hsc_env <- readIORef ref   
   let mg  = hsc_mod_graph hsc_env
Simon Marlow's avatar
Simon Marlow committed
813
   case [ ms | ms <- mg, ms_mod_name ms == mod ] of
814
815
	[] -> return Nothing
	(ms:_) -> do 
816
	   mbChecked <- hscFileCheck hsc_env{hsc_dflags=ms_hspp_opts ms} ms
817
818
819
	   case mbChecked of
             Nothing -> return Nothing
             Just (HscChecked parsed renamed Nothing) ->
820
821
822
823
824
		   return (Just (CheckedModule {
					parsedSource = parsed,
					renamedSource = renamed,
					typecheckedSource = Nothing,
					checkedModuleInfo = Nothing }))
825
826
             Just (HscChecked parsed renamed
			   (Just (tc_binds, rdr_env, details))) -> do
827
		   let minf = ModuleInfo {
828
				minf_type_env  = md_types details,
829
830
				minf_exports   = availsToNameSet $
                                                     md_exports details,
831
832
				minf_rdr_env   = Just rdr_env,
				minf_instances = md_insts details
mnislaih's avatar
mnislaih committed
833
#ifdef GHCI
834
                               ,minf_modBreaks = emptyModBreaks 
mnislaih's avatar
mnislaih committed
835
#endif
836
837
838
			      }
		   return (Just (CheckedModule {
					parsedSource = parsed,
839
					renamedSource = renamed,
840
841
842
843
					typecheckedSource = Just tc_binds,
					checkedModuleInfo = Just minf }))

-- ---------------------------------------------------------------------------
844
845
846
847
-- Unloading

unload :: HscEnv -> [Linkable] -> IO ()
unload hsc_env stable_linkables	-- Unload everthing *except* 'stable_linkables'
848
  = case ghcLink (hsc_dflags hsc_env) of
849
#ifdef GHCI
850
	LinkInMemory -> Linker.unload (hsc_dflags hsc_env) stable_linkables
851
#else
852
	LinkInMemory -> panic "unload: no interpreter"
853
#endif
854
	other -> return ()
855

856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
-- -----------------------------------------------------------------------------
-- checkStability

{-
  Stability tells us which modules definitely do not need to be recompiled.
  There are two main reasons for having stability:
  
   - avoid doing a complete upsweep of the module graph in GHCi when
     modules near the bottom of the tree have not changed.

   - to tell GHCi when it can load object code: we can only load object code
     for a module when we also load object code fo  all of the imports of the
     module.  So we need to know that we will definitely not be recompiling
     any of these modules, and we can use the object code.

  The stability check is as follows.  Both stableObject and
  stableBCO are used during the upsweep phase later.

  -------------------
  stable m = stableObject m || stableBCO m

  stableObject m = 
	all stableObject (imports m)
	&& old linkable does not exist, or is == on-disk .o
	&& date(on-disk .o) > date(.hs)

  stableBCO m =
	all stable (imports m)
	&& date(BCO) > date(.hs)
  -------------------    

  These properties embody the following ideas:

889
    - if a module is stable, then:
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
	- if it has been compiled in a previous pass (present in HPT)
	  then it does not need to be compiled or re-linked.
        - if it has not been compiled in a previous pass,
	  then we only need to read its .hi file from disk and
	  link it to produce a ModDetails.

    - if a modules is not stable, we will definitely be at least
      re-linking, and possibly re-compiling it during the upsweep.
      All non-stable modules can (and should) therefore be unlinked
      before the upsweep.

    - Note that objects are only considered stable if they only depend
      on other objects.  We can't link object code against byte code.
-}

checkStability
	:: HomePackageTable		-- HPT from last compilation
	-> [SCC ModSummary]		-- current module graph (cyclic)
Simon Marlow's avatar
Simon Marlow committed
908
909
910
	-> [ModuleName]			-- all home modules
	-> ([ModuleName],		-- stableObject
	    [ModuleName])		-- stableBCO
911
912
913
914
915
916
917
918
919

checkStability hpt sccs all_home_mods = foldl checkSCC ([],[]) sccs
  where
   checkSCC (stable_obj, stable_bco) scc0
     | stableObjects = (scc_mods ++ stable_obj, stable_bco)
     | stableBCOs    = (stable_obj, scc_mods ++ stable_bco)
     | otherwise     = (stable_obj, stable_bco)
     where
	scc = flattenSCC scc0
Simon Marlow's avatar
Simon Marlow committed
920
	scc_mods = map ms_mod_name scc
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
	home_module m   = m `elem` all_home_mods && m `notElem` scc_mods

        scc_allimps = nub (filter home_module (concatMap ms_allimps scc))
	    -- all imports outside the current SCC, but in the home pkg
	
	stable_obj_imps = map (`elem` stable_obj) scc_allimps
	stable_bco_imps = map (`elem` stable_bco) scc_allimps

	stableObjects = 
	   and stable_obj_imps
	   && all object_ok scc

	stableBCOs = 
	   and (zipWith (||) stable_obj_imps stable_bco_imps)
	   && all bco_ok scc

	object_ok ms
	  | Just t <- ms_obj_date ms  =  t >= ms_hs_date ms 
					 && same_as_prev t
	  | otherwise = False
	  where
Simon Marlow's avatar
Simon Marlow committed
942
	     same_as_prev t = case lookupUFM hpt (ms_mod_name ms) of
943
944
				Just hmi  | Just l <- hm_linkable hmi
				 -> isObjectLinkable l && t == linkableTime l
945
				_other  -> True
946
		-- why '>=' rather than '>' above?  If the filesystem stores
947
948
949
950
951
952
		-- times to the nearset second, we may occasionally find that
		-- the object & source have the same modification time, 
		-- especially if the source was automatically generated
		-- and compiled.  Using >= is slightly unsafe, but it matches
		-- make's behaviour.

953
	bco_ok ms
Simon Marlow's avatar
Simon Marlow committed
954
	  = case lookupUFM hpt (ms_mod_name ms) of
955
956
957
		Just hmi  | Just l <- hm_linkable hmi ->
			not (isObjectLinkable l) && 
			linkableTime l >= ms_hs_date ms
958
		_other  -> False
959

Simon Marlow's avatar
Simon Marlow committed
960
ms_allimps :: ModSummary -> [ModuleName]
961
ms_allimps ms = map unLoc (ms_srcimps ms ++ ms_imps ms)
962

963
964
-- -----------------------------------------------------------------------------
-- Prune the HomePackageTable
965

966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
-- Before doing an upsweep, we can throw away:
--
--   - For non-stable modules:
--	- all ModDetails, all linked code
--   - all unlinked code that is out of date with respect to
--     the source file
--
-- This is VERY IMPORTANT otherwise we'll end up requiring 2x the
-- space at the end of the upsweep, because the topmost ModDetails of the
-- old HPT holds on to the entire type environment from the previous
-- compilation.

pruneHomePackageTable
   :: HomePackageTable
   -> [ModSummary]
Simon Marlow's avatar
Simon Marlow committed
981
   -> ([ModuleName],[ModuleName])
982
983
984
   -> HomePackageTable

pruneHomePackageTable hpt summ (stable_obj, stable_bco)
Simon Marlow's avatar
Simon Marlow committed
985
  = mapUFM prune hpt
986
987
988
989
  where prune hmi
	  | is_stable modl = hmi'
	  | otherwise      = hmi'{ hm_details = emptyModDetails }
	  where
Simon Marlow's avatar
Simon Marlow committed
990
	   modl = moduleName (mi_module (hm_iface hmi))
991
992
993
994
	   hmi' | Just l <- hm_linkable hmi, linkableTime l < ms_hs_date ms
		= hmi{ hm_linkable = Nothing }
		| otherwise
		= hmi
Simon Marlow's avatar
Simon Marlow committed
995
		where ms = expectJust "prune" (lookupUFM ms_map modl)
996

Simon Marlow's avatar
Simon Marlow committed
997
        ms_map = listToUFM [(ms_mod_name ms, ms) | ms <- summ]
998

999
1000
1001
	is_stable m = m `elem` stable_obj || m `elem` stable_bco

-- -----------------------------------------------------------------------------
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022

-- Return (names of) all those in modsDone who are part of a cycle
-- as defined by theGraph.
findPartiallyCompletedCycles :: [Module] -> [SCC ModSummary] -> [Module]
findPartiallyCompletedCycles modsDone theGraph
   = chew theGraph
     where
        chew [] = []
        chew ((AcyclicSCC v):rest) = chew rest    -- acyclic?  not interesting.
        chew ((CyclicSCC vs):rest)
           = let names_in_this_cycle = nub (map ms_mod vs)
                 mods_in_this_cycle  
                    = nub ([done | done <- modsDone, 
                                   done `elem` names_in_this_cycle])
                 chewed_rest = chew rest
             in 
             if   notNull mods_in_this_cycle
                  && length mods_in_this_cycle < length names_in_this_cycle
             then mods_in_this_cycle ++ chewed_rest
             else chewed_rest

1023
1024
1025
1026
1027
-- -----------------------------------------------------------------------------
-- The upsweep

-- This is where we compile each module in the module graph, in a pass
-- from the bottom to the top of the graph.
1028
1029

-- There better had not be any cyclic groups here -- we check for them.
1030
1031
1032
1033

upsweep
    :: HscEnv			-- Includes initially-empty HPT
    -> HomePackageTable		-- HPT from last time round (pruned)
Simon Marlow's avatar
Simon Marlow committed
1034
    -> ([ModuleName],[ModuleName]) -- stable modules (see checkStability)
1035
1036
1037
1038
1039
1040
    -> IO ()			-- How to clean up unwanted tmp files
    -> [SCC ModSummary]		-- Mods to do (the worklist)
    -> IO (SuccessFlag,
           HscEnv,		-- With an updated HPT
           [ModSummary])	-- Mods which succeeded

1041
1042
upsweep hsc_env old_hpt stable_mods cleanup mods
   = upsweep' hsc_env old_hpt stable_mods cleanup mods 1 (length mods)
1043

1044
upsweep' hsc_env old_hpt stable_mods cleanup
1045
     [] _ _
1046
1047
   = return (Succeeded, hsc_env, [])

1048
upsweep' hsc_env old_hpt stable_mods cleanup
1049
     (CyclicSCC ms:_) _ _
1050
   = do fatalErrorMsg (hsc_dflags hsc_env) (cyclicModuleErr ms)
1051
1052
        return (Failed, hsc_env, [])

1053
upsweep' hsc_env old_hpt stable_mods cleanup
1054
     (AcyclicSCC mod:mods) mod_index nmods
1055
1056
1057
1058
   = do -- putStrLn ("UPSWEEP_MOD: hpt = " ++ 
	--	     show (map (moduleUserString.moduleName.mi_module.hm_iface) 
	--		       (moduleEnvElts (hsc_HPT hsc_env)))

1059
        mb_mod_info <- upsweep_mod hsc_env old_hpt stable_mods mod 
1060
                       mod_index nmods
1061
1062
1063
1064
1065
1066

	cleanup		-- Remove unwanted tmp files between compilations

        case mb_mod_info of
	    Nothing -> return (Failed, hsc_env, [])
	    Just mod_info -> do 
Simon Marlow's avatar
Simon Marlow committed
1067
		{ let this_mod = ms_mod_name mod
1068
1069

			-- Add new info to hsc_env
Simon Marlow's avatar
Simon Marlow committed
1070
		      hpt1     = addToUFM (hsc_HPT hsc_env) this_mod mod_info
1071
		      hsc_env1 = hsc_env { hsc_HPT = hpt1 }
1072
1073
1074
1075

			-- Space-saving: delete the old HPT entry
			-- for mod BUT if mod is a hs-boot
			-- node, don't delete it.  For the
1076
1077
1078
			-- interface, the HPT entry is probaby for the
			-- main Haskell source file.  Deleting it
			-- would force .. (what?? --SDM)
1079
		      old_hpt1 | isBootSummary mod = old_hpt
Simon Marlow's avatar
Simon Marlow committed
1080
			       | otherwise = delFromUFM old_hpt this_mod
1081

1082
		; (restOK, hsc_env2, modOKs) 
1083
			<- upsweep' hsc_env1 old_hpt1 stable_mods cleanup 
1084
				mods (mod_index+1) nmods
1085
1086
		; return (restOK, hsc_env2, mod:modOKs)
		}
1087
1088
1089
1090
1091


-- Compile a single module.  Always produce a Linkable for it if 
-- successful.  If no compilation happened, return the old Linkable.
upsweep_mod :: HscEnv
1092
            -> HomePackageTable
Simon Marlow's avatar
Simon Marlow committed
1093
	    -> ([ModuleName],[ModuleName])
1094
            -> ModSummary