2 % (c) The University of Glasgow 2005-2006
5 -- --------------------------------------
6 -- The dynamic linker for GHCi
7 -- --------------------------------------
9 This module deals with the top-level issues of dynamic linking,
10 calling the object-code linker and the byte-code linker where
15 {-# OPTIONS -optc-DNON_POSIX_SOURCE -#include "Linker.h" #-}
17 module Linker ( HValue, showLinkerState,
18 linkExpr, unload, extendLinkEnv, withExtendedLinkEnv,
20 linkPackages,initDynLinker
23 #include "HsVersions.h"
58 import System.Directory
60 import Control.Exception
63 #if __GLASGOW_HASKELL__ >= 503
64 import GHC.IOBase ( IO(..) )
66 import PrelIOBase ( IO(..) )
71 %************************************************************************
75 %************************************************************************
77 The persistent linker state *must* match the actual state of the
78 C dynamic linker at all times, so we keep it in a private global variable.
81 The PersistentLinkerState maps Names to actual closures (for
82 interpreted code only), for use during linking.
85 GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
86 GLOBAL_VAR(v_InitLinkerDone, False, Bool) -- Set True when dynamic linker is initialised
88 data PersistentLinkerState
89 = PersistentLinkerState {
91 -- Current global mapping from Names to their true values
92 closure_env :: ClosureEnv,
94 -- The current global mapping from RdrNames of DataCons to
95 -- info table addresses.
96 -- When a new Unlinked is linked into the running image, or an existing
97 -- module in the image is replaced, the itbl_env must be updated
101 -- The currently loaded interpreted modules (home package)
102 bcos_loaded :: [Linkable],
104 -- And the currently-loaded compiled modules (home package)
105 objs_loaded :: [Linkable],
107 -- The currently-loaded packages; always object code
108 -- Held, as usual, in dependency order; though I am not sure if
109 -- that is really important
110 pkgs_loaded :: [PackageId]
113 emptyPLS :: DynFlags -> PersistentLinkerState
114 emptyPLS dflags = PersistentLinkerState {
115 closure_env = emptyNameEnv,
116 itbl_env = emptyNameEnv,
117 pkgs_loaded = init_pkgs,
120 -- Packages that don't need loading, because the compiler
121 -- shares them with the interpreted program.
123 -- The linker's symbol table is populated with RTS symbols using an
124 -- explicit list. See rts/Linker.c for details.
125 where init_pkgs = [rtsPackageId]
129 extendLoadedPkgs :: [PackageId] -> IO ()
130 extendLoadedPkgs pkgs
131 = modifyIORef v_PersistentLinkerState (\s -> s{pkgs_loaded = pkgs ++ pkgs_loaded s})
133 extendLinkEnv :: [(Name,HValue)] -> IO ()
134 -- Automatically discards shadowed bindings
135 extendLinkEnv new_bindings
136 = do pls <- readIORef v_PersistentLinkerState
137 let new_closure_env = extendClosureEnv (closure_env pls) new_bindings
138 new_pls = pls { closure_env = new_closure_env }
139 writeIORef v_PersistentLinkerState new_pls
141 withExtendedLinkEnv :: [(Name,HValue)] -> IO a -> IO a
142 withExtendedLinkEnv new_env action
143 = bracket set_new_env
146 where set_new_env = do pls <- readIORef v_PersistentLinkerState
147 let new_closure_env = extendClosureEnv (closure_env pls) new_env
148 new_pls = pls { closure_env = new_closure_env }
149 writeIORef v_PersistentLinkerState new_pls
150 return (closure_env pls)
151 reset_old_env env = modifyIORef v_PersistentLinkerState (\pls -> pls{ closure_env = env })
153 -- filterNameMap removes from the environment all entries except
154 -- those for a given set of modules;
155 -- Note that this removes all *local* (i.e. non-isExternal) names too
156 -- (these are the temporary bindings from the command line).
157 -- Used to filter both the ClosureEnv and ItblEnv
159 filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
160 filterNameMap mods env
161 = filterNameEnv keep_elt env
163 keep_elt (n,_) = isExternalName n
164 && (nameModule n `elem` mods)
169 showLinkerState :: IO ()
170 -- Display the persistent linker state
172 = do pls <- readIORef v_PersistentLinkerState
173 printDump (vcat [text "----- Linker state -----",
174 text "Pkgs:" <+> ppr (pkgs_loaded pls),
175 text "Objs:" <+> ppr (objs_loaded pls),
176 text "BCOs:" <+> ppr (bcos_loaded pls)])
182 %************************************************************************
184 \subsection{Initialisation}
186 %************************************************************************
188 We initialise the dynamic linker by
190 a) calling the C initialisation procedure
192 b) Loading any packages specified on the command line,
194 c) Loading any packages specified on the command line,
195 now held in the -l options in v_Opt_l
197 d) Loading any .o/.dll files specified on the command line,
198 now held in v_Ld_inputs
200 e) Loading any MacOS frameworks
203 initDynLinker :: DynFlags -> IO ()
204 -- This function is idempotent; if called more than once, it does nothing
205 -- This is useful in Template Haskell, where we call it before trying to link
207 = do { done <- readIORef v_InitLinkerDone
208 ; if done then return ()
209 else do { writeIORef v_InitLinkerDone True
210 ; reallyInitDynLinker dflags }
213 reallyInitDynLinker dflags
214 = do { -- Initialise the linker state
215 ; writeIORef v_PersistentLinkerState (emptyPLS dflags)
217 -- (a) initialise the C dynamic linker
220 -- (b) Load packages from the command-line
221 ; linkPackages dflags (preloadPackages (pkgState dflags))
223 -- (c) Link libraries from the command-line
224 ; let optl = getOpts dflags opt_l
225 ; let minus_ls = [ lib | '-':'l':lib <- optl ]
227 -- (d) Link .o files from the command-line
228 ; let lib_paths = libraryPaths dflags
229 ; cmdline_ld_inputs <- readIORef v_Ld_inputs
231 ; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
233 -- (e) Link any MacOS frameworks
234 #ifdef darwin_TARGET_OS
235 ; let framework_paths = frameworkPaths dflags
236 ; let frameworks = cmdlineFrameworks dflags
238 ; let frameworks = []
239 ; let framework_paths = []
241 -- Finally do (c),(d),(e)
242 ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
244 ++ map Framework frameworks
245 ; if null cmdline_lib_specs then return ()
248 { mapM_ (preloadLib dflags lib_paths framework_paths) cmdline_lib_specs
249 ; maybePutStr dflags "final link ... "
252 ; if succeeded ok then maybePutStrLn dflags "done"
253 else throwDyn (InstallationError "linking extra libraries/objects failed")
256 classifyLdInput :: FilePath -> IO (Maybe LibrarySpec)
258 | isObjectFilename f = return (Just (Object f))
259 | isDynLibFilename f = return (Just (DLLPath f))
261 hPutStrLn stderr ("Warning: ignoring unrecognised input `" ++ f ++ "'")
264 preloadLib :: DynFlags -> [String] -> [String] -> LibrarySpec -> IO ()
265 preloadLib dflags lib_paths framework_paths lib_spec
266 = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
269 -> do b <- preload_static lib_paths static_ish
270 maybePutStrLn dflags (if b then "done"
274 -> do maybe_errstr <- loadDynamic lib_paths dll_unadorned
276 Nothing -> maybePutStrLn dflags "done"
277 Just mm -> preloadFailed mm lib_paths lib_spec
280 -> do maybe_errstr <- loadDLL dll_path
282 Nothing -> maybePutStrLn dflags "done"
283 Just mm -> preloadFailed mm lib_paths lib_spec
285 #ifdef darwin_TARGET_OS
287 -> do maybe_errstr <- loadFramework framework_paths framework
289 Nothing -> maybePutStrLn dflags "done"
290 Just mm -> preloadFailed mm framework_paths lib_spec
293 preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
294 preloadFailed sys_errmsg paths spec
295 = do maybePutStr dflags
296 ("failed.\nDynamic linker error message was:\n "
297 ++ sys_errmsg ++ "\nWhilst trying to load: "
298 ++ showLS spec ++ "\nDirectories to search are:\n"
299 ++ unlines (map (" "++) paths) )
302 -- Not interested in the paths in the static case.
303 preload_static paths name
304 = do b <- doesFileExist name
305 if not b then return False
306 else loadObj name >> return True
309 CmdLineError "user specified .o/.so/.DLL could not be loaded."
313 %************************************************************************
315 Link a byte-code expression
317 %************************************************************************
320 linkExpr :: HscEnv -> SrcSpan -> UnlinkedBCO -> IO HValue
322 -- Link a single expression, *including* first linking packages and
323 -- modules that this expression depends on.
325 -- Raises an IO exception if it can't find a compiled version of the
326 -- dependents to link.
328 linkExpr hsc_env span root_ul_bco
330 -- Initialise the linker (if it's not been done already)
331 let dflags = hsc_dflags hsc_env
332 ; initDynLinker dflags
334 -- The interpreter and dynamic linker can only handle object code built
335 -- the "normal" way, i.e. no non-std ways like profiling or ticky-ticky.
336 -- So here we check the build tag: if we're building a non-standard way
337 -- then we need to find & link object files built the "normal" way.
338 ; maybe_normal_osuf <- checkNonStdWay dflags span
340 -- Find what packages and linkables are required
341 ; eps <- readIORef (hsc_EPS hsc_env)
342 ; (lnks, pkgs) <- getLinkDeps hsc_env hpt (eps_PIT eps)
343 maybe_normal_osuf span needed_mods
345 -- Link the packages and modules required
346 ; linkPackages dflags pkgs
347 ; ok <- linkModules dflags lnks
349 throwDyn (ProgramError "")
352 -- Link the expression itself
353 pls <- readIORef v_PersistentLinkerState
354 ; let ie = itbl_env pls
357 -- Link the necessary packages and linkables
358 ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
362 hpt = hsc_HPT hsc_env
363 free_names = nameSetToList (bcoFreeNames root_ul_bco)
365 needed_mods :: [Module]
366 needed_mods = [ nameModule n | n <- free_names,
367 isExternalName n, -- Names from other modules
368 not (isWiredInName n) -- Exclude wired-in names
369 ] -- (see note below)
370 -- Exclude wired-in names because we may not have read
371 -- their interface files, so getLinkDeps will fail
372 -- All wired-in names are in the base package, which we link
373 -- by default, so we can safely ignore them here.
375 dieWith span msg = throwDyn (ProgramError (showSDoc (mkLocMessage span msg)))
378 checkNonStdWay :: DynFlags -> SrcSpan -> IO (Maybe String)
379 checkNonStdWay dflags srcspan = do
380 tag <- readIORef v_Build_tag
381 if null tag then return Nothing else do
382 let default_osuf = phaseInputExt StopLn
383 if objectSuf dflags == default_osuf
384 then failNonStd srcspan
385 else return (Just default_osuf)
387 failNonStd srcspan = dieWith srcspan $
388 ptext SLIT("Dynamic linking required, but this is a non-standard build (eg. prof).") $$
389 ptext SLIT("You need to build the program twice: once the normal way, and then") $$
390 ptext SLIT("in the desired way using -osuf to set the object file suffix.")
393 getLinkDeps :: HscEnv -> HomePackageTable -> PackageIfaceTable
394 -> Maybe String -- the "normal" object suffix
395 -> SrcSpan -- for error messages
396 -> [Module] -- If you need these
397 -> IO ([Linkable], [PackageId]) -- ... then link these first
398 -- Fails with an IO exception if it can't find enough files
400 getLinkDeps hsc_env hpt pit maybe_normal_osuf span mods
401 -- Find all the packages and linkables that a set of modules depends on
402 = do { pls <- readIORef v_PersistentLinkerState ;
404 -- 1. Find the dependent home-pkg-modules/packages from each iface
405 (mods_s, pkgs_s) = unzip (map get_deps mods) ;
407 -- 2. Exclude ones already linked
408 -- Main reason: avoid findModule calls in get_linkable
409 mods_needed = nub (concat mods_s) `minusList` linked_mods ;
410 pkgs_needed = nub (concat pkgs_s) `minusList` pkgs_loaded pls ;
412 linked_mods = map (moduleName.linkableModule)
413 (objs_loaded pls ++ bcos_loaded pls)
416 -- 3. For each dependent module, find its linkable
417 -- This will either be in the HPT or (in the case of one-shot
418 -- compilation) we may need to use maybe_getFileLinkable
419 lnks_needed <- mapM (get_linkable maybe_normal_osuf) mods_needed ;
421 return (lnks_needed, pkgs_needed) }
423 dflags = hsc_dflags hsc_env
424 this_pkg = thisPackage dflags
426 get_deps :: Module -> ([ModuleName],[PackageId])
427 -- Get the things needed for the specified module
428 -- This is rather similar to the code in RnNames.importsFromImportDecl
431 = ([], pkg : dep_pkgs deps)
433 = (moduleName mod : [m | (m,_) <- dep_mods deps], dep_pkgs deps)
435 pkg = modulePackageId mod
436 deps = mi_deps (get_iface mod)
438 get_iface mod = case lookupIfaceByModule dflags hpt pit mod of
440 Nothing -> pprPanic "getLinkDeps" (no_iface mod)
441 no_iface mod = ptext SLIT("No iface for") <+> ppr mod
442 -- This one is a GHC bug
444 no_obj mod = dieWith span $
445 ptext SLIT("cannot find object file for module ") <>
449 while_linking_expr = ptext SLIT("while linking an interpreted expression")
451 -- This one is a build-system bug
453 get_linkable maybe_normal_osuf mod_name -- A home-package module
454 | Just mod_info <- lookupUFM hpt mod_name
455 = ASSERT(isJust (hm_linkable mod_info))
456 adjust_linkable (fromJust (hm_linkable mod_info))
458 = do -- It's not in the HPT because we are in one shot mode,
459 -- so use the Finder to get a ModLocation...
460 mb_stuff <- findHomeModule hsc_env mod_name
462 Found loc mod -> found loc mod
466 -- ...and then find the linkable for it
467 mb_lnk <- findObjectLinkableMaybe mod loc ;
469 Nothing -> no_obj mod ;
470 Just lnk -> adjust_linkable lnk
474 | Just osuf <- maybe_normal_osuf = do
475 new_uls <- mapM (adjust_ul osuf) (linkableUnlinked lnk)
476 return lnk{ linkableUnlinked=new_uls }
480 adjust_ul osuf (DotO file) = do
481 let new_file = replaceFilenameSuffix file osuf
482 ok <- doesFileExist new_file
485 ptext SLIT("cannot find normal object file ")
486 <> quotes (text new_file) $$ while_linking_expr
487 else return (DotO new_file)
491 %************************************************************************
494 The linkables may consist of a mixture of
495 byte-code modules and object modules
497 %************************************************************************
500 linkModules :: DynFlags -> [Linkable] -> IO SuccessFlag
501 linkModules dflags linkables
502 = block $ do -- don't want to be interrupted by ^C in here
504 let (objs, bcos) = partition isObjectLinkable
505 (concatMap partitionLinkable linkables)
507 -- Load objects first; they can't depend on BCOs
508 ok_flag <- dynLinkObjs dflags objs
510 if failed ok_flag then
517 -- HACK to support f-x-dynamic in the interpreter; no other purpose
518 partitionLinkable :: Linkable -> [Linkable]
520 = let li_uls = linkableUnlinked li
521 li_uls_obj = filter isObject li_uls
522 li_uls_bco = filter isInterpretable li_uls
524 case (li_uls_obj, li_uls_bco) of
525 (objs@(_:_), bcos@(_:_))
526 -> [li{linkableUnlinked=li_uls_obj}, li{linkableUnlinked=li_uls_bco}]
530 findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
531 findModuleLinkable_maybe lis mod
532 = case [LM time nm us | LM time nm us <- lis, nm == mod] of
535 many -> pprPanic "findModuleLinkable" (ppr mod)
537 linkableInSet :: Linkable -> [Linkable] -> Bool
538 linkableInSet l objs_loaded =
539 case findModuleLinkable_maybe objs_loaded (linkableModule l) of
541 Just m -> linkableTime l == linkableTime m
545 %************************************************************************
547 \subsection{The object-code linker}
549 %************************************************************************
552 dynLinkObjs :: DynFlags -> [Linkable] -> IO SuccessFlag
553 -- Side-effects the PersistentLinkerState
555 dynLinkObjs dflags objs
556 = do pls <- readIORef v_PersistentLinkerState
558 -- Load the object files and link them
559 let (objs_loaded', new_objs) = rmDupLinkables (objs_loaded pls) objs
560 pls1 = pls { objs_loaded = objs_loaded' }
561 unlinkeds = concatMap linkableUnlinked new_objs
563 mapM loadObj (map nameOfObject unlinkeds)
565 -- Link the all together
568 -- If resolving failed, unload all our
569 -- object modules and carry on
570 if succeeded ok then do
571 writeIORef v_PersistentLinkerState pls1
574 pls2 <- unload_wkr dflags [] pls1
575 writeIORef v_PersistentLinkerState pls2
579 rmDupLinkables :: [Linkable] -- Already loaded
580 -> [Linkable] -- New linkables
581 -> ([Linkable], -- New loaded set (including new ones)
582 [Linkable]) -- New linkables (excluding dups)
583 rmDupLinkables already ls
586 go already extras [] = (already, extras)
587 go already extras (l:ls)
588 | linkableInSet l already = go already extras ls
589 | otherwise = go (l:already) (l:extras) ls
592 %************************************************************************
594 \subsection{The byte-code linker}
596 %************************************************************************
599 dynLinkBCOs :: [Linkable] -> IO ()
600 -- Side-effects the persistent linker state
602 = do pls <- readIORef v_PersistentLinkerState
604 let (bcos_loaded', new_bcos) = rmDupLinkables (bcos_loaded pls) bcos
605 pls1 = pls { bcos_loaded = bcos_loaded' }
606 unlinkeds :: [Unlinked]
607 unlinkeds = concatMap linkableUnlinked new_bcos
609 cbcs :: [CompiledByteCode]
610 cbcs = map byteCodeOfObject unlinkeds
613 ul_bcos = [b | ByteCode bs _ <- cbcs, b <- bs]
614 ies = [ie | ByteCode _ ie <- cbcs]
615 gce = closure_env pls
616 final_ie = foldr plusNameEnv (itbl_env pls) ies
618 (final_gce, linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
619 -- What happens to these linked_bcos?
621 let pls2 = pls1 { closure_env = final_gce,
622 itbl_env = final_ie }
624 writeIORef v_PersistentLinkerState pls2
627 -- Link a bunch of BCOs and return them + updated closure env.
628 linkSomeBCOs :: Bool -- False <=> add _all_ BCOs to returned closure env
629 -- True <=> add only toplevel BCOs to closure env
633 -> IO (ClosureEnv, [HValue])
634 -- The returned HValues are associated 1-1 with
635 -- the incoming unlinked BCOs. Each gives the
636 -- value of the corresponding unlinked BCO
639 linkSomeBCOs toplevs_only ie ce_in ul_bcos
640 = do let nms = map unlinkedBCOName ul_bcos
642 ( \ hvs -> let ce_out = extendClosureEnv ce_in (zipLazy nms hvs)
643 in mapM (linkBCO ie ce_out) ul_bcos )
645 let ce_all_additions = zip nms hvals
646 ce_top_additions = filter (isExternalName.fst) ce_all_additions
647 ce_additions = if toplevs_only then ce_top_additions
648 else ce_all_additions
649 ce_out = -- make sure we're not inserting duplicate names into the
650 -- closure environment, which leads to trouble.
651 ASSERT (all (not . (`elemNameEnv` ce_in)) (map fst ce_additions))
652 extendClosureEnv ce_in ce_additions
653 return (ce_out, hvals)
658 %************************************************************************
660 Unload some object modules
662 %************************************************************************
665 -- ---------------------------------------------------------------------------
666 -- Unloading old objects ready for a new compilation sweep.
668 -- The compilation manager provides us with a list of linkables that it
669 -- considers "stable", i.e. won't be recompiled this time around. For
670 -- each of the modules current linked in memory,
672 -- * if the linkable is stable (and it's the same one - the
673 -- user may have recompiled the module on the side), we keep it,
675 -- * otherwise, we unload it.
677 -- * we also implicitly unload all temporary bindings at this point.
679 unload :: DynFlags -> [Linkable] -> IO ()
680 -- The 'linkables' are the ones to *keep*
682 unload dflags linkables
683 = block $ do -- block, so we're safe from Ctrl-C in here
685 -- Initialise the linker (if it's not been done already)
688 pls <- readIORef v_PersistentLinkerState
689 new_pls <- unload_wkr dflags linkables pls
690 writeIORef v_PersistentLinkerState new_pls
692 debugTraceMsg dflags 3 (text "unload: retaining objs" <+> ppr (objs_loaded new_pls))
693 debugTraceMsg dflags 3 (text "unload: retaining bcos" <+> ppr (bcos_loaded new_pls))
696 unload_wkr :: DynFlags
697 -> [Linkable] -- stable linkables
698 -> PersistentLinkerState
699 -> IO PersistentLinkerState
700 -- Does the core unload business
701 -- (the wrapper blocks exceptions and deals with the PLS get and put)
703 unload_wkr dflags linkables pls
704 = do let (objs_to_keep, bcos_to_keep) = partition isObjectLinkable linkables
706 objs_loaded' <- filterM (maybeUnload objs_to_keep) (objs_loaded pls)
707 bcos_loaded' <- filterM (maybeUnload bcos_to_keep) (bcos_loaded pls)
709 let bcos_retained = map linkableModule bcos_loaded'
710 itbl_env' = filterNameMap bcos_retained (itbl_env pls)
711 closure_env' = filterNameMap bcos_retained (closure_env pls)
712 new_pls = pls { itbl_env = itbl_env',
713 closure_env = closure_env',
714 bcos_loaded = bcos_loaded',
715 objs_loaded = objs_loaded' }
719 maybeUnload :: [Linkable] -> Linkable -> IO Bool
720 maybeUnload keep_linkables lnk
721 | linkableInSet lnk linkables = return True
723 = do mapM_ unloadObj [f | DotO f <- linkableUnlinked lnk]
724 -- The components of a BCO linkable may contain
725 -- dot-o files. Which is very confusing.
727 -- But the BCO parts can be unlinked just by
728 -- letting go of them (plus of course depopulating
729 -- the symbol table which is done in the main body)
734 %************************************************************************
738 %************************************************************************
743 = Object FilePath -- Full path name of a .o file, including trailing .o
744 -- For dynamic objects only, try to find the object
745 -- file in all the directories specified in
746 -- v_Library_paths before giving up.
748 | DLL String -- "Unadorned" name of a .DLL/.so
749 -- e.g. On unix "qt" denotes "libqt.so"
750 -- On WinDoze "burble" denotes "burble.DLL"
751 -- loadDLL is platform-specific and adds the lib/.so/.DLL
752 -- suffixes platform-dependently
754 | DLLPath FilePath -- Absolute or relative pathname to a dynamic library
755 -- (ends with .dll or .so).
757 | Framework String -- Only used for darwin, but does no harm
759 -- If this package is already part of the GHCi binary, we'll already
760 -- have the right DLLs for this package loaded, so don't try to
763 -- But on Win32 we must load them 'again'; doing so is a harmless no-op
764 -- as far as the loader is concerned, but it does initialise the list
765 -- of DLL handles that rts/Linker.c maintains, and that in turn is
766 -- used by lookupSymbol. So we must call addDLL for each library
767 -- just to get the DLL handle into the list.
769 # if defined(mingw32_TARGET_OS) || defined(darwin_TARGET_OS)
772 = [ "base", "haskell98", "template-haskell", "readline" ]
775 showLS (Object nm) = "(static) " ++ nm
776 showLS (DLL nm) = "(dynamic) " ++ nm
777 showLS (DLLPath nm) = "(dynamic) " ++ nm
778 showLS (Framework nm) = "(framework) " ++ nm
780 linkPackages :: DynFlags -> [PackageId] -> IO ()
781 -- Link exactly the specified packages, and their dependents
782 -- (unless of course they are already linked)
783 -- The dependents are linked automatically, and it doesn't matter
784 -- what order you specify the input packages.
786 -- NOTE: in fact, since each module tracks all the packages it depends on,
787 -- we don't really need to use the package-config dependencies.
788 -- However we do need the package-config stuff (to find aux libs etc),
789 -- and following them lets us load libraries in the right order, which
790 -- perhaps makes the error message a bit more localised if we get a link
791 -- failure. So the dependency walking code is still here.
793 linkPackages dflags new_pkgs
794 = do { pls <- readIORef v_PersistentLinkerState
795 ; let pkg_map = pkgIdMap (pkgState dflags)
797 ; pkgs' <- link pkg_map (pkgs_loaded pls) new_pkgs
799 ; writeIORef v_PersistentLinkerState (pls { pkgs_loaded = pkgs' })
802 link :: PackageConfigMap -> [PackageId] -> [PackageId] -> IO [PackageId]
803 link pkg_map pkgs new_pkgs
804 = foldM (link_one pkg_map) pkgs new_pkgs
806 link_one pkg_map pkgs new_pkg
807 | new_pkg `elem` pkgs -- Already linked
810 | Just pkg_cfg <- lookupPackage pkg_map new_pkg
811 = do { -- Link dependents first
812 pkgs' <- link pkg_map pkgs (map mkPackageId (depends pkg_cfg))
813 -- Now link the package itself
814 ; linkPackage dflags pkg_cfg
815 ; return (new_pkg : pkgs') }
818 = throwDyn (CmdLineError ("unknown package: " ++ packageIdString new_pkg))
821 linkPackage :: DynFlags -> PackageConfig -> IO ()
822 linkPackage dflags pkg
824 let dirs = Packages.libraryDirs pkg
826 let libs = Packages.hsLibraries pkg
827 -- Because of slight differences between the GHC dynamic linker and
828 -- the native system linker some packages have to link with a
829 -- different list of libraries when using GHCi. Examples include: libs
830 -- that are actually gnu ld scripts, and the possability that the .a
831 -- libs do not exactly match the .so/.dll equivalents. So if the
832 -- package file provides an "extra-ghci-libraries" field then we use
833 -- that instead of the "extra-libraries" field.
834 ++ (if null (Packages.extraGHCiLibraries pkg)
835 then Packages.extraLibraries pkg
836 else Packages.extraGHCiLibraries pkg)
837 ++ [ lib | '-':'l':lib <- Packages.ldOptions pkg ]
838 classifieds <- mapM (locateOneObj dirs) libs
840 -- Complication: all the .so's must be loaded before any of the .o's.
841 let dlls = [ dll | DLL dll <- classifieds ]
842 objs = [ obj | Object obj <- classifieds ]
844 maybePutStr dflags ("Loading package " ++ showPackageId (package pkg) ++ " ... ")
846 -- See comments with partOfGHCi
847 when (pkgName (package pkg) `notElem` partOfGHCi) $ do
849 -- When a library A needs symbols from a library B, the order in
850 -- extra_libraries/extra_ld_opts is "-lA -lB", because that's the
851 -- way ld expects it for static linking. Dynamic linking is a
852 -- different story: When A has no dependency information for B,
853 -- dlopen-ing A with RTLD_NOW (see addDLL in Linker.c) will fail
854 -- when B has not been loaded before. In a nutshell: Reverse the
855 -- order of DLLs for dynamic linking.
856 -- This fixes a problem with the HOpenGL package (see "Compiling
857 -- HOpenGL under recent versions of GHC" on the HOpenGL list).
858 mapM_ (load_dyn dirs) (reverse dlls)
860 -- After loading all the DLLs, we can load the static objects.
861 -- Ordering isn't important here, because we do one final link
862 -- step to resolve everything.
865 maybePutStr dflags "linking ... "
867 if succeeded ok then maybePutStrLn dflags "done."
868 else throwDyn (InstallationError ("unable to load package `" ++ showPackageId (package pkg) ++ "'"))
870 load_dyn dirs dll = do r <- loadDynamic dirs dll
873 Just err -> throwDyn (CmdLineError ("can't load .so/.DLL for: "
874 ++ dll ++ " (" ++ err ++ ")" ))
875 #ifndef darwin_TARGET_OS
876 loadFrameworks pkg = return ()
878 loadFrameworks pkg = mapM_ load frameworks
880 fw_dirs = Packages.frameworkDirs pkg
881 frameworks = Packages.frameworks pkg
883 load fw = do r <- loadFramework fw_dirs fw
886 Just err -> throwDyn (CmdLineError ("can't load framework: "
887 ++ fw ++ " (" ++ err ++ ")" ))
890 -- Try to find an object file for a given library in the given paths.
891 -- If it isn't present, we assume it's a dynamic library.
892 locateOneObj :: [FilePath] -> String -> IO LibrarySpec
893 locateOneObj dirs lib
894 = do { mb_obj_path <- findFile mk_obj_path dirs
895 ; case mb_obj_path of
896 Just obj_path -> return (Object obj_path)
898 do { mb_lib_path <- findFile mk_dyn_lib_path dirs
899 ; case mb_lib_path of
900 Just lib_path -> return (DLL (lib ++ "_dyn"))
901 Nothing -> return (DLL lib) }} -- We assume
903 mk_obj_path dir = dir `joinFileName` (lib `joinFileExt` "o")
904 mk_dyn_lib_path dir = dir `joinFileName` mkSOName (lib ++ "_dyn")
907 -- ----------------------------------------------------------------------------
908 -- Loading a dyanmic library (dlopen()-ish on Unix, LoadLibrary-ish on Win32)
910 -- return Nothing == success, else Just error message from dlopen
911 loadDynamic paths rootname
912 = do { mb_dll <- findFile mk_dll_path paths
914 Just dll -> loadDLL dll
915 Nothing -> loadDLL (mkSOName rootname) }
916 -- Tried all our known library paths, so let
917 -- dlopen() search its own builtin paths now.
919 mk_dll_path dir = dir `joinFileName` mkSOName rootname
921 #if defined(darwin_TARGET_OS)
922 mkSOName root = ("lib" ++ root) `joinFileExt` "dylib"
923 #elif defined(mingw32_TARGET_OS)
924 -- Win32 DLLs have no .dll extension here, because addDLL tries
925 -- both foo.dll and foo.drv
928 mkSOName root = ("lib" ++ root) `joinFileExt` "so"
931 -- Darwin / MacOS X only: load a framework
932 -- a framework is a dynamic library packaged inside a directory of the same
933 -- name. They are searched for in different paths than normal libraries.
934 #ifdef darwin_TARGET_OS
935 loadFramework extraPaths rootname
936 = do { mb_fwk <- findFile mk_fwk (extraPaths ++ defaultFrameworkPaths)
938 Just fwk_path -> loadDLL fwk_path
939 Nothing -> return (Just "not found") }
940 -- Tried all our known library paths, but dlopen()
941 -- has no built-in paths for frameworks: give up
943 mk_fwk dir = dir `joinFileName` (rootname ++ ".framework/" ++ rootname)
944 -- sorry for the hardcoded paths, I hope they won't change anytime soon:
945 defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
949 %************************************************************************
953 %************************************************************************
956 findFile :: (FilePath -> FilePath) -- Maps a directory path to a file path
957 -> [FilePath] -- Directories to look in
958 -> IO (Maybe FilePath) -- The first file path to match
959 findFile mk_file_path []
961 findFile mk_file_path (dir:dirs)
962 = do { let file_path = mk_file_path dir
963 ; b <- doesFileExist file_path
965 return (Just file_path)
967 findFile mk_file_path dirs }
971 maybePutStr dflags s | verbosity dflags > 0 = putStr s
972 | otherwise = return ()
974 maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
975 | otherwise = return ()