Linker.lhs 31.3 KB
Newer Older
1
%
2
% (c) The University of Glasgow 2005
3
%
4
5
6
7
8
9
10
11
12

-- --------------------------------------
-- 	The dynamic linker for GHCi      
-- --------------------------------------

This module deals with the top-level issues of dynamic linking,
calling the object-code linker and the byte-code linker where
necessary.

13
14

\begin{code}
15

16
{-# OPTIONS -optc-DNON_POSIX_SOURCE -#include "Linker.h" #-}
17

18
module Linker ( HValue, showLinkerState,
19
		linkExpr, unload, extendLinkEnv, 
20
		linkPackages,
21
	) where
sof's avatar
sof committed
22

23
#include "HsVersions.h"
24

25
import ObjLink		( loadDLL, loadObj, unloadObj, resolveObjs, initObjLinker )
26
27
import ByteCodeLink	( HValue, ClosureEnv, extendClosureEnv, linkBCO )
import ByteCodeItbls	( ItblEnv )
28
import ByteCodeAsm	( CompiledByteCode(..), bcoFreeNames, UnlinkedBCO(..))
29

30
import Packages
31
import DriverPhases	( isObjectFilename, isDynLibFilename )
32
import Finder		( findModule, findObjectLinkableMaybe, FindResult(..) )
33
import HscTypes
34
import Name		( Name, nameModule, isExternalName, isWiredInName )
35
36
import NameEnv
import NameSet		( nameSetToList )
37
import Module
38
import ListSetOps	( minusList )
39
import DynFlags		( DynFlags(..), getOpts )
40
41
42
import BasicTypes	( SuccessFlag(..), succeeded, failed )
import Outputable
import Panic            ( GhcException(..) )
43
import Util             ( zipLazy, global, joinFileExt, joinFileName, suffixOf )
44
import StaticFlags	( v_Ld_inputs )
45
import ErrUtils         ( debugTraceMsg )
46
47
48
49
50

-- Standard libraries
import Control.Monad	( when, filterM, foldM )

import Data.IORef	( IORef, readIORef, writeIORef )
51
import Data.List	( partition, nub )
52
53

import System.IO	( putStr, putStrLn, hPutStrLn, stderr, fixIO )
54
import System.Directory	( doesFileExist )
55
56

import Control.Exception ( block, throwDyn )
57
import Maybe		( isJust, fromJust )
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80

#if __GLASGOW_HASKELL__ >= 503
import GHC.IOBase	( IO(..) )
#else
import PrelIOBase	( IO(..) )
#endif
\end{code}


%************************************************************************
%*									*
			The Linker's state
%*									*
%************************************************************************

The persistent linker state *must* match the actual state of the 
C dynamic linker at all times, so we keep it in a private global variable.


The PersistentLinkerState maps Names to actual closures (for
interpreted code only), for use during linking.

\begin{code}
81
82
GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
GLOBAL_VAR(v_InitLinkerDone, False, Bool)	-- Set True when dynamic linker is initialised
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105

data PersistentLinkerState
   = PersistentLinkerState {

	-- Current global mapping from Names to their true values
        closure_env :: ClosureEnv,

	-- The current global mapping from RdrNames of DataCons to
	-- info table addresses.
	-- When a new Unlinked is linked into the running image, or an existing
	-- module in the image is replaced, the itbl_env must be updated
	-- appropriately.
        itbl_env    :: ItblEnv,

	-- The currently loaded interpreted modules (home package)
	bcos_loaded :: [Linkable],

	-- And the currently-loaded compiled modules (home package)
	objs_loaded :: [Linkable],

	-- The currently-loaded packages; always object code
	-- Held, as usual, in dependency order; though I am not sure if
	-- that is really important
106
	pkgs_loaded :: [PackageId]
107
108
     }

109
110
111
112
113
114
115
116
117
118
119
120
121
emptyPLS :: DynFlags -> PersistentLinkerState
emptyPLS dflags = PersistentLinkerState { 
			closure_env = emptyNameEnv,
			itbl_env    = emptyNameEnv,
			pkgs_loaded = init_pkgs,
			bcos_loaded = [],
			objs_loaded = [] }
  -- Packages that don't need loading, because the compiler 
  -- shares them with the interpreted program.
  --
  -- The linker's symbol table is populated with RTS symbols using an
  -- explicit list.  See rts/Linker.c for details.
  where init_pkgs
122
	  | ExtPackage rts_id <- rtsPackageId (pkgState dflags) = [rts_id]
123
	  | otherwise = []
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
\end{code}

\begin{code}
extendLinkEnv :: [(Name,HValue)] -> IO ()
-- Automatically discards shadowed bindings
extendLinkEnv new_bindings
  = do	pls <- readIORef v_PersistentLinkerState
	let new_closure_env = extendClosureEnv (closure_env pls) new_bindings
	    new_pls = pls { closure_env = new_closure_env }
	writeIORef v_PersistentLinkerState new_pls

-- filterNameMap removes from the environment all entries except 
-- 	those for a given set of modules;
-- Note that this removes all *local* (i.e. non-isExternal) names too 
--	(these are the temporary bindings from the command line).
-- Used to filter both the ClosureEnv and ItblEnv

141
filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
142
143
144
145
filterNameMap mods env 
   = filterNameEnv keep_elt env
   where
     keep_elt (n,_) = isExternalName n 
146
		      && (nameModule n `elem` mods)
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
\end{code}


\begin{code}
showLinkerState :: IO ()
-- Display the persistent linker state
showLinkerState
  = do pls <- readIORef v_PersistentLinkerState
       printDump (vcat [text "----- Linker state -----",
			text "Pkgs:" <+> ppr (pkgs_loaded pls),
			text "Objs:" <+> ppr (objs_loaded pls),
			text "BCOs:" <+> ppr (bcos_loaded pls)])
\end{code}
			
	

163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185

%************************************************************************
%*									*
\subsection{Initialisation}
%*									*
%************************************************************************

We initialise the dynamic linker by

a) calling the C initialisation procedure

b) Loading any packages specified on the command line,
   now held in v_ExplicitPackages

c) Loading any packages specified on the command line,
   now held in the -l options in v_Opt_l

d) Loading any .o/.dll files specified on the command line,
   now held in v_Ld_inputs

e) Loading any MacOS frameworks

\begin{code}
186
initDynLinker :: DynFlags -> IO ()
187
188
-- This function is idempotent; if called more than once, it does nothing
-- This is useful in Template Haskell, where we call it before trying to link
189
initDynLinker dflags
190
191
192
  = do	{ done <- readIORef v_InitLinkerDone
	; if done then return () 
		  else do { writeIORef v_InitLinkerDone True
193
			  ; reallyInitDynLinker dflags }
194
195
	}

196
197
198
reallyInitDynLinker dflags
  = do  {  -- Initialise the linker state
	; writeIORef v_PersistentLinkerState (emptyPLS dflags)
199
200
201
202
203

	 	-- (a) initialise the C dynamic linker
	; initObjLinker 

		-- (b) Load packages from the command-line
204
	; linkPackages dflags (explicitPackages (pkgState dflags))
205
206

	   	-- (c) Link libraries from the command-line
207
208
	; let optl = getOpts dflags opt_l
	; let minus_ls = [ lib | '-':'l':lib <- optl ]
209
210

	   	-- (d) Link .o files from the command-line
211
	; let lib_paths = libraryPaths dflags
212
213
	; cmdline_ld_inputs <- readIORef v_Ld_inputs

214
	; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
215
216
217

	   	-- (e) Link any MacOS frameworks
#ifdef darwin_TARGET_OS	
218
219
	; let framework_paths = frameworkPaths dflags
	; let frameworks      = cmdlineFrameworks dflags
220
221
222
223
224
#else
	; let frameworks      = []
	; let framework_paths = []
#endif
		-- Finally do (c),(d),(e)	
225
        ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
226
227
228
229
230
231
232
233
234
235
236
237
238
			       ++ map DLL       minus_ls 
			       ++ map Framework frameworks
	; if null cmdline_lib_specs then return ()
				    else do

 	{ mapM_ (preloadLib dflags lib_paths framework_paths) cmdline_lib_specs
	; maybePutStr dflags "final link ... "
	; ok <- resolveObjs

	; if succeeded ok then maybePutStrLn dflags "done"
	  else throwDyn (InstallationError "linking extra libraries/objects failed")
	}}

239
240
241
242
243
244
245
classifyLdInput :: FilePath -> IO (Maybe LibrarySpec)
classifyLdInput f
  | isObjectFilename f = return (Just (Object f))
  | isDynLibFilename f = return (Just (DLLPath f))
  | otherwise 	       = do
	hPutStrLn stderr ("Warning: ignoring unrecognised input `" ++ f ++ "'")
	return Nothing
246

247
248
249
250
251
252
253
254
255
256
257
258
259
260
preloadLib :: DynFlags -> [String] -> [String] -> LibrarySpec -> IO ()
preloadLib dflags lib_paths framework_paths lib_spec
  = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
       case lib_spec of
          Object static_ish
             -> do b <- preload_static lib_paths static_ish
                   maybePutStrLn dflags (if b  then "done"
	 					else "not found")
	 
          DLL dll_unadorned
             -> do maybe_errstr <- loadDynamic lib_paths dll_unadorned
                   case maybe_errstr of
                      Nothing -> maybePutStrLn dflags "done"
                      Just mm -> preloadFailed mm lib_paths lib_spec
261
262
263
264
265
266
267

	  DLLPath dll_path
	     -> do maybe_errstr <- loadDLL dll_path
                   case maybe_errstr of
                      Nothing -> maybePutStrLn dflags "done"
                      Just mm -> preloadFailed mm lib_paths lib_spec

268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
#ifdef darwin_TARGET_OS
	  Framework framework
             -> do maybe_errstr <- loadFramework framework_paths framework
                   case maybe_errstr of
                      Nothing -> maybePutStrLn dflags "done"
                      Just mm -> preloadFailed mm framework_paths lib_spec
#endif
  where
    preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
    preloadFailed sys_errmsg paths spec
       = do maybePutStr dflags
    	       ("failed.\nDynamic linker error message was:\n   " 
                    ++ sys_errmsg  ++ "\nWhilst trying to load:  " 
                    ++ showLS spec ++ "\nDirectories to search are:\n"
                    ++ unlines (map ("   "++) paths) )
            give_up
    
    -- Not interested in the paths in the static case.
    preload_static paths name
       = do b <- doesFileExist name
            if not b then return False
                     else loadObj name >> return True
    
    give_up = throwDyn $ 
	      CmdLineError "user specified .o/.so/.DLL could not be loaded."
\end{code}


296
297
298
299
300
301
302
%************************************************************************
%*									*
		Link a byte-code expression
%*									*
%************************************************************************

\begin{code}
303
linkExpr :: HscEnv -> UnlinkedBCO -> IO HValue
304
305
306
307
308
309
310

-- Link a single expression, *including* first linking packages and 
-- modules that this expression depends on.
--
-- Raises an IO exception if it can't find a compiled version of the
-- dependents to link.

311
linkExpr hsc_env root_ul_bco
312
  = do {  
313
	-- Initialise the linker (if it's not been done already)
314
315
     let dflags = hsc_dflags hsc_env
   ; initDynLinker dflags
316

317
	-- Find what packages and linkables are required
318
   ; eps <- readIORef (hsc_EPS hsc_env)
319
   ; (lnks, pkgs) <- getLinkDeps hsc_env hpt (eps_PIT eps) needed_mods
320

321
	-- Link the packages and modules required
322
323
   ; linkPackages dflags pkgs
   ; ok <- linkModules dflags lnks
324
325
326
327
328
329
330
331
332
333
   ; if failed ok then
	dieWith empty
     else do {

	-- Link the expression itself
     pls <- readIORef v_PersistentLinkerState
   ; let ie = itbl_env pls
	 ce = closure_env pls

	-- Link the necessary packages and linkables
334
   ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
335
   ; return root_hval
336
   }}
337
338
339
   where
     hpt    = hsc_HPT hsc_env
     dflags = hsc_dflags hsc_env
340
341
     free_names = nameSetToList (bcoFreeNames root_ul_bco)

342
     needed_mods :: [Module]
343
344
345
346
347
348
349
350
     needed_mods = [ nameModule n | n <- free_names, 
				    isExternalName n,	 	-- Names from other modules
				    not (isWiredInName n)	-- Exclude wired-in names
		   ]						-- (see note below)
	-- Exclude wired-in names because we may not have read
	-- their interface files, so getLinkDeps will fail
	-- All wired-in names are in the base package, which we link
	-- by default, so we can safely ignore them here.
351
 
352
dieWith msg = throwDyn (ProgramError (showSDoc msg))
353

354
getLinkDeps :: HscEnv -> HomePackageTable -> PackageIfaceTable
355
	    -> [Module]				-- If you need these
356
	    -> IO ([Linkable], [PackageId])	-- ... then link these first
357
-- Fails with an IO exception if it can't find enough files
358

359
getLinkDeps hsc_env hpt pit mods
360
-- Find all the packages and linkables that a set of modules depends on
361
362
 = do {	pls <- readIORef v_PersistentLinkerState ;
	let {
363
364
365
366
367
368
369
370
	-- 1.  Find the dependent home-pkg-modules/packages from each iface
	    (mods_s, pkgs_s) = unzip (map get_deps mods) ;

	-- 2.  Exclude ones already linked
	--	Main reason: avoid findModule calls in get_linkable
	    mods_needed = nub (concat mods_s) `minusList` linked_mods     ;
	    pkgs_needed = nub (concat pkgs_s) `minusList` pkgs_loaded pls ;

371
	    linked_mods = map linkableModule (objs_loaded pls ++ bcos_loaded pls)
372
	} ;
373
374
	
	-- 3.  For each dependent module, find its linkable
375
376
	--     This will either be in the HPT or (in the case of one-shot
	--     compilation) we may need to use maybe_getFileLinkable
377
	lnks_needed <- mapM get_linkable mods_needed ;
378

379
	return (lnks_needed, pkgs_needed) }
380
  where
381
    get_deps :: Module -> ([Module],[PackageId])
382
383
384
	-- Get the things needed for the specified module
	-- This is rather similar to the code in RnNames.importsFromImportDecl
    get_deps mod
385
	| ExtPackage p <- mi_package iface
386
	= ([], p : dep_pkgs deps)
387
	| otherwise
388
	= (mod : [m | (m,_) <- dep_mods deps], dep_pkgs deps)
389
390
391
392
	where
	  iface = get_iface mod
	  deps  = mi_deps iface

393
    get_iface mod = case lookupIface hpt pit mod of
394
395
			    Just iface -> iface
			    Nothing    -> pprPanic "getLinkDeps" (no_iface mod)
396
397
398
    no_iface mod = ptext SLIT("No iface for") <+> ppr mod
	-- This one is a GHC bug

sof's avatar
sof committed
399
    no_obj mod = dieWith (ptext SLIT("No compiled code for") <+> ppr mod)
400
401
402
	-- This one is a build-system bug

    get_linkable mod_name	-- A home-package module
403
	| Just mod_info <- lookupModuleEnv hpt mod_name 
404
405
	= ASSERT(isJust (hm_linkable mod_info))
	  return (fromJust (hm_linkable mod_info))
406
407
408
	| otherwise	
	=	-- It's not in the HPT because we are in one shot mode, 
		-- so use the Finder to get a ModLocation...
409
	  do { mb_stuff <- findModule hsc_env mod_name False ;
410
	       case mb_stuff of {
411
412
413
		  Found loc _ -> found loc mod_name ;
		  _ -> no_obj mod_name
	     }}
414

415
    found loc mod_name = do {
416
		-- ...and then find the linkable for it
417
	       mb_lnk <- findObjectLinkableMaybe mod_name loc ;
418
419
420
	       case mb_lnk of {
		  Nothing -> no_obj mod_name ;
		  Just lnk -> return lnk
421
	      }}
422
\end{code}
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463


%************************************************************************
%*									*
		Link some linkables
	The linkables may consist of a mixture of 
	byte-code modules and object modules
%*									*
%************************************************************************

\begin{code}
linkModules :: DynFlags -> [Linkable] -> IO SuccessFlag
linkModules dflags linkables
  = block $ do  -- don't want to be interrupted by ^C in here
	
	let (objs, bcos) = partition isObjectLinkable 
                              (concatMap partitionLinkable linkables)

		-- Load objects first; they can't depend on BCOs
	ok_flag <- dynLinkObjs dflags objs

	if failed ok_flag then 
		return Failed
	  else do
		dynLinkBCOs bcos
		return Succeeded
		

-- HACK to support f-x-dynamic in the interpreter; no other purpose
partitionLinkable :: Linkable -> [Linkable]
partitionLinkable li
   = let li_uls = linkableUnlinked li
         li_uls_obj = filter isObject li_uls
         li_uls_bco = filter isInterpretable li_uls
     in 
         case (li_uls_obj, li_uls_bco) of
            (objs@(_:_), bcos@(_:_)) 
               -> [li{linkableUnlinked=li_uls_obj}, li{linkableUnlinked=li_uls_bco}]
            other
               -> [li]

464
findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
465
466
467
468
469
470
471
472
findModuleLinkable_maybe lis mod
   = case [LM time nm us | LM time nm us <- lis, nm == mod] of
        []   -> Nothing
        [li] -> Just li
        many -> pprPanic "findModuleLinkable" (ppr mod)

linkableInSet :: Linkable -> [Linkable] -> Bool
linkableInSet l objs_loaded =
473
  case findModuleLinkable_maybe objs_loaded (linkableModule l) of
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
	Nothing -> False
	Just m  -> linkableTime l == linkableTime m
\end{code}


%************************************************************************
%*									*
\subsection{The object-code linker}
%*									*
%************************************************************************

\begin{code}
dynLinkObjs :: DynFlags -> [Linkable] -> IO SuccessFlag
	-- Side-effects the PersistentLinkerState

dynLinkObjs dflags objs
  = do	pls <- readIORef v_PersistentLinkerState

	-- Load the object files and link them
	let (objs_loaded', new_objs) = rmDupLinkables (objs_loaded pls) objs
	    pls1 		     = pls { objs_loaded = objs_loaded' }
	    unlinkeds 		     = concatMap linkableUnlinked new_objs

	mapM loadObj (map nameOfObject unlinkeds)

	-- Link the all together
	ok <- resolveObjs

	-- If resolving failed, unload all our 
	-- object modules and carry on
	if succeeded ok then do
		writeIORef v_PersistentLinkerState pls1
		return Succeeded
	  else do
		pls2 <- unload_wkr dflags [] pls1
		writeIORef v_PersistentLinkerState pls2
		return Failed


rmDupLinkables :: [Linkable] 	-- Already loaded
	       -> [Linkable]	-- New linkables
	       -> ([Linkable],	-- New loaded set (including new ones)
		   [Linkable])	-- New linkables (excluding dups)
rmDupLinkables already ls
  = go already [] ls
  where
    go already extras [] = (already, extras)
    go already extras (l:ls)
	| linkableInSet l already = go already     extras     ls
	| otherwise		  = go (l:already) (l:extras) ls
\end{code}

%************************************************************************
%*									*
\subsection{The byte-code linker}
%*									*
%************************************************************************

\begin{code}
dynLinkBCOs :: [Linkable] -> IO ()
	-- Side-effects the persistent linker state
dynLinkBCOs bcos
  = do	pls <- readIORef v_PersistentLinkerState

	let (bcos_loaded', new_bcos) = rmDupLinkables (bcos_loaded pls) bcos
	    pls1 		     = pls { bcos_loaded = bcos_loaded' }
	    unlinkeds :: [Unlinked]
	    unlinkeds 		     = concatMap linkableUnlinked new_bcos

	    cbcs :: [CompiledByteCode]
	    cbcs      = map byteCodeOfObject unlinkeds
		      
	    	      
	    ul_bcos    = [b | ByteCode bs _  <- cbcs, b <- bs]
	    ies	       = [ie | ByteCode _ ie <- cbcs]
	    gce	      = closure_env pls
            final_ie  = foldr plusNameEnv (itbl_env pls) ies

        (final_gce, linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
		-- What happens to these linked_bcos?

	let pls2 = pls1 { closure_env = final_gce,
			  itbl_env    = final_ie }

	writeIORef v_PersistentLinkerState pls2
	return ()

-- Link a bunch of BCOs and return them + updated closure env.
linkSomeBCOs :: Bool 	-- False <=> add _all_ BCOs to returned closure env
                        -- True  <=> add only toplevel BCOs to closure env
             -> ItblEnv 
             -> ClosureEnv 
             -> [UnlinkedBCO]
             -> IO (ClosureEnv, [HValue])
			-- The returned HValues are associated 1-1 with
			-- the incoming unlinked BCOs.  Each gives the
			-- value of the corresponding unlinked BCO
					

linkSomeBCOs toplevs_only ie ce_in ul_bcos
574
   = do let nms = map unlinkedBCOName ul_bcos
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
        hvals <- fixIO 
                    ( \ hvs -> let ce_out = extendClosureEnv ce_in (zipLazy nms hvs)
                               in  mapM (linkBCO ie ce_out) ul_bcos )

        let ce_all_additions = zip nms hvals
            ce_top_additions = filter (isExternalName.fst) ce_all_additions
            ce_additions     = if toplevs_only then ce_top_additions 
                                               else ce_all_additions
            ce_out = -- make sure we're not inserting duplicate names into the 
		     -- closure environment, which leads to trouble.
		     ASSERT (all (not . (`elemNameEnv` ce_in)) (map fst ce_additions))
		     extendClosureEnv ce_in ce_additions
        return (ce_out, hvals)

\end{code}


%************************************************************************
%*									*
		Unload some object modules
%*									*
%************************************************************************

\begin{code}
sof's avatar
sof committed
599
-- ---------------------------------------------------------------------------
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
-- Unloading old objects ready for a new compilation sweep.
--
-- The compilation manager provides us with a list of linkables that it
-- considers "stable", i.e. won't be recompiled this time around.  For
-- each of the modules current linked in memory,
--
--	* if the linkable is stable (and it's the same one - the
--	  user may have recompiled the module on the side), we keep it,
--
--	* otherwise, we unload it.
--
--      * we also implicitly unload all temporary bindings at this point.

unload :: DynFlags -> [Linkable] -> IO ()
-- The 'linkables' are the ones to *keep*

unload dflags linkables
  = block $ do -- block, so we're safe from Ctrl-C in here
618
619
620
  
	-- Initialise the linker (if it's not been done already)
	initDynLinker dflags
sof's avatar
sof committed
621

622
623
624
	pls	<- readIORef v_PersistentLinkerState
	new_pls <- unload_wkr dflags linkables pls
	writeIORef v_PersistentLinkerState new_pls
625

626
627
628
	debugTraceMsg dflags 3 (text "unload: retaining objs" <+> ppr (objs_loaded new_pls))
	debugTraceMsg dflags 3 (text "unload: retaining bcos" <+> ppr (bcos_loaded new_pls))
	return ()
629

630
631
632
633
634
635
unload_wkr :: DynFlags
           -> [Linkable]		-- stable linkables
	   -> PersistentLinkerState
           -> IO PersistentLinkerState
-- Does the core unload business
-- (the wrapper blocks exceptions and deals with the PLS get and put)
636

637
638
639
640
641
642
unload_wkr dflags linkables pls
  = do	let (objs_to_keep, bcos_to_keep) = partition isObjectLinkable linkables

	objs_loaded' <- filterM (maybeUnload objs_to_keep) (objs_loaded pls)
        bcos_loaded' <- filterM (maybeUnload bcos_to_keep) (bcos_loaded pls)

643
       	let bcos_retained = map linkableModule bcos_loaded'
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
	    itbl_env'     = filterNameMap bcos_retained (itbl_env pls)
            closure_env'  = filterNameMap bcos_retained (closure_env pls)
  	    new_pls = pls { itbl_env = itbl_env',
			    closure_env = closure_env',
			    bcos_loaded = bcos_loaded',
			    objs_loaded = objs_loaded' }

	return new_pls
  where
    maybeUnload :: [Linkable] -> Linkable -> IO Bool
    maybeUnload keep_linkables lnk
      | linkableInSet lnk linkables = return True
      | otherwise		    
      = do mapM_ unloadObj [f | DotO f <- linkableUnlinked lnk]
		-- The components of a BCO linkable may contain
		-- dot-o files.  Which is very confusing.
		--
		-- But the BCO parts can be unlinked just by 
		-- letting go of them (plus of course depopulating
		-- the symbol table which is done in the main body)
	   return False
\end{code}


%************************************************************************
%*									*
		Loading packages
%*									*
%************************************************************************


\begin{code}
data LibrarySpec 
   = Object FilePath 	-- Full path name of a .o file, including trailing .o
			-- For dynamic objects only, try to find the object 
			-- file in all the directories specified in 
			-- v_Library_paths before giving up.

   | DLL String		-- "Unadorned" name of a .DLL/.so
			--  e.g.    On unix     "qt"  denotes "libqt.so"
			--          On WinDoze  "burble"  denotes "burble.DLL"
			--  loadDLL is platform-specific and adds the lib/.so/.DLL
			--  suffixes platform-dependently
687

688
689
690
   | DLLPath FilePath   -- Absolute or relative pathname to a dynamic library
			-- (ends with .dll or .so).

691
   | Framework String	-- Only used for darwin, but does no harm
692
693
694
695
696
697
698
699
700
701

-- If this package is already part of the GHCi binary, we'll already
-- have the right DLLs for this package loaded, so don't try to
-- load them again.
-- 
-- But on Win32 we must load them 'again'; doing so is a harmless no-op
-- as far as the loader is concerned, but it does initialise the list
-- of DLL handles that rts/Linker.c maintains, and that in turn is 
-- used by lookupSymbol.  So we must call addDLL for each library 
-- just to get the DLL handle into the list.
702
703
704
partOfGHCi
#          if defined(mingw32_TARGET_OS) || defined(darwin_TARGET_OS)
           = [ ]
705
#          else
706
           = [ "base", "haskell98", "template-haskell", "readline" ]
707
708
#          endif

709
710
showLS (Object nm)    = "(static) " ++ nm
showLS (DLL nm)       = "(dynamic) " ++ nm
711
showLS (DLLPath nm)   = "(dynamic) " ++ nm
712
713
showLS (Framework nm) = "(framework) " ++ nm

714
linkPackages :: DynFlags -> [PackageId] -> IO ()
715
716
717
718
-- Link exactly the specified packages, and their dependents
-- (unless of course they are already linked)
-- The dependents are linked automatically, and it doesn't matter
-- what order you specify the input packages.
719
720
721
722
723
724
725
--
-- NOTE: in fact, since each module tracks all the packages it depends on,
--	 we don't really need to use the package-config dependencies.
-- However we do need the package-config stuff (to find aux libs etc),
-- and following them lets us load libraries in the right order, which 
-- perhaps makes the error message a bit more localised if we get a link
-- failure.  So the dependency walking code is still here.
726
727
728

linkPackages dflags new_pkgs
   = do	{ pls 	  <- readIORef v_PersistentLinkerState
729
	; let pkg_map = pkgIdMap (pkgState dflags)
730
731
732
733
734
735

	; pkgs' <- link pkg_map (pkgs_loaded pls) new_pkgs

	; writeIORef v_PersistentLinkerState (pls { pkgs_loaded = pkgs' })
	}
   where
736
     link :: PackageConfigMap -> [PackageId] -> [PackageId] -> IO [PackageId]
737
738
739
740
741
742
743
     link pkg_map pkgs new_pkgs 
	= foldM (link_one pkg_map) pkgs new_pkgs

     link_one pkg_map pkgs new_pkg
	| new_pkg `elem` pkgs	-- Already linked
	= return pkgs

744
	| Just pkg_cfg <- lookupPackage pkg_map new_pkg
745
	= do { 	-- Link dependents first
746
	       pkgs' <- link pkg_map pkgs (map mkPackageId (depends pkg_cfg))
747
748
749
750
751
		-- Now link the package itself
	     ; linkPackage dflags pkg_cfg
	     ; return (new_pkg : pkgs') }

	| otherwise
752
	= throwDyn (CmdLineError ("unknown package: " ++ packageIdString new_pkg))
753
754
755
756
757


linkPackage :: DynFlags -> PackageConfig -> IO ()
linkPackage dflags pkg
   = do 
758
        let dirs      =  Packages.libraryDirs pkg
759
760
761
762
763
764
765
766
767
768
769
770
771

        let libs      =  Packages.hsLibraries pkg
        -- Because of slight differences between the GHC dynamic linker and
        -- the native system linker some packages have to link with a
        -- different list of libraries when using GHCi. Examples include: libs
        -- that are actually gnu ld scripts, and the possability that the .a
        -- libs do not exactly match the .so/.dll equivalents. So if the
        -- package file provides an "extra-ghci-libraries" field then we use
        -- that instead of the "extra-libraries" field.
                      ++ (if null (Packages.extraGHCiLibraries pkg)
                            then Packages.extraLibraries pkg
                            else Packages.extraGHCiLibraries pkg)
                      ++ [ lib | '-':'l':lib <- Packages.ldOptions pkg ]
772
773
774
775
776
777
        classifieds   <- mapM (locateOneObj dirs) libs

        -- Complication: all the .so's must be loaded before any of the .o's.  
	let dlls = [ dll | DLL dll    <- classifieds ]
	    objs = [ obj | Object obj <- classifieds ]

778
	maybePutStr dflags ("Loading package " ++ showPackageId (package pkg) ++ " ... ")
779
780

	-- See comments with partOfGHCi
781
	when (pkgName (package pkg) `notElem` partOfGHCi) $ do
782
	    loadFrameworks pkg
783
784
785
786
787
788
789
            -- When a library A needs symbols from a library B, the order in
            -- extra_libraries/extra_ld_opts is "-lA -lB", because that's the
            -- way ld expects it for static linking. Dynamic linking is a
            -- different story: When A has no dependency information for B,
            -- dlopen-ing A with RTLD_NOW (see addDLL in Linker.c) will fail
            -- when B has not been loaded before. In a nutshell: Reverse the
            -- order of DLLs for dynamic linking.
790
791
	    -- This fixes a problem with the HOpenGL package (see "Compiling
	    -- HOpenGL under recent versions of GHC" on the HOpenGL list).
792
	    mapM_ (load_dyn dirs) (reverse dlls)
793
794
	
	-- After loading all the DLLs, we can load the static objects.
795
796
	-- Ordering isn't important here, because we do one final link
	-- step to resolve everything.
797
798
799
800
801
	mapM_ loadObj objs

        maybePutStr dflags "linking ... "
        ok <- resolveObjs
	if succeeded ok then maybePutStrLn dflags "done."
802
	      else throwDyn (InstallationError ("unable to load package `" ++ showPackageId (package pkg) ++ "'"))
803

804
805
806
807
808
809
810
811
812
813
load_dyn dirs dll = do r <- loadDynamic dirs dll
		       case r of
			 Nothing  -> return ()
			 Just err -> throwDyn (CmdLineError ("can't load .so/.DLL for: " 
                                 			      ++ dll ++ " (" ++ err ++ ")" ))
#ifndef darwin_TARGET_OS
loadFrameworks pkg = return ()
#else
loadFrameworks pkg = mapM_ load frameworks
  where
814
    fw_dirs    = Packages.frameworkDirs pkg
ross's avatar
ross committed
815
    frameworks = Packages.frameworks pkg
816
817
818
819
820
821

    load fw = do  r <- loadFramework fw_dirs fw
		  case r of
		    Nothing  -> return ()
		    Just err -> throwDyn (CmdLineError ("can't load framework: " 
                               			        ++ fw ++ " (" ++ err ++ ")" ))
822
823
824
825
826
827
828
829
830
#endif

-- Try to find an object file for a given library in the given paths.
-- If it isn't present, we assume it's a dynamic library.
locateOneObj :: [FilePath] -> String -> IO LibrarySpec
locateOneObj dirs lib
  = do	{ mb_obj_path <- findFile mk_obj_path dirs 
	; case mb_obj_path of
	    Just obj_path -> return (Object obj_path)
831
832
833
834
835
	    Nothing	  -> 
                do { mb_lib_path <- findFile mk_dyn_lib_path dirs
                   ; case mb_lib_path of
                       Just lib_path -> return (DLL (lib ++ "_dyn"))
                       Nothing       -> return (DLL lib) }}		-- We assume
836
   where
837
838
     mk_obj_path dir = dir `joinFileName` (lib `joinFileExt` "o")
     mk_dyn_lib_path dir = dir `joinFileName` mkSOName (lib ++ "_dyn")
839
840
841
842
843
844
845
846
847
848
849
850
851
852


-- ----------------------------------------------------------------------------
-- Loading a dyanmic library (dlopen()-ish on Unix, LoadLibrary-ish on Win32)

-- return Nothing == success, else Just error message from dlopen
loadDynamic paths rootname
  = do	{ mb_dll <- findFile mk_dll_path paths
	; case mb_dll of
	    Just dll -> loadDLL dll
	    Nothing  -> loadDLL (mkSOName rootname) }
			-- Tried all our known library paths, so let 
			-- dlopen() search its own builtin paths now.
  where
853
    mk_dll_path dir = dir `joinFileName` mkSOName rootname
854
855

#if defined(darwin_TARGET_OS)
856
mkSOName root = ("lib" ++ root) `joinFileExt` "dylib"
857
858
859
860
861
#elif defined(mingw32_TARGET_OS)
-- Win32 DLLs have no .dll extension here, because addDLL tries
-- both foo.dll and foo.drv
mkSOName root = root
#else
862
mkSOName root = ("lib" ++ root) `joinFileExt` "so"
863
864
865
866
867
868
869
870
871
872
#endif

-- Darwin / MacOS X only: load a framework
-- a framework is a dynamic library packaged inside a directory of the same
-- name. They are searched for in different paths than normal libraries.
#ifdef darwin_TARGET_OS
loadFramework extraPaths rootname
   = do	{ mb_fwk <- findFile mk_fwk (extraPaths ++ defaultFrameworkPaths)
	; case mb_fwk of
	    Just fwk_path -> loadDLL fwk_path
873
	    Nothing	  -> return (Just "not found") }
874
875
876
 		-- Tried all our known library paths, but dlopen()
		-- has no built-in paths for frameworks: give up
   where
877
     mk_fwk dir = dir `joinFileName` (rootname ++ ".framework/" ++ rootname)
878
879
	-- sorry for the hardcoded paths, I hope they won't change anytime soon:
     defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
#endif
\end{code}

%************************************************************************
%*									*
		Helper functions
%*									*
%************************************************************************

\begin{code}
findFile :: (FilePath -> FilePath)	-- Maps a directory path to a file path
	 -> [FilePath]			-- Directories to look in
	 -> IO (Maybe FilePath)		-- The first file path to match
findFile mk_file_path [] 
  = return Nothing
findFile mk_file_path (dir:dirs)
  = do	{ let file_path = mk_file_path dir
	; b <- doesFileExist file_path
	; if b then 
	     return (Just file_path)
	  else
	     findFile mk_file_path dirs }
\end{code}

\begin{code}
maybePutStr dflags s | verbosity dflags > 0 = putStr s
		     | otherwise	    = return ()
907

908
909
maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
		       | otherwise	      = return ()
910
\end{code}