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 {-# OPTIONS -fno-cse #-}
18 -- -fno-cse is needed for GLOBAL_VAR's to behave properly
20 module Linker ( HValue, getHValue, showLinkerState,
21 linkExpr, unload, withExtendedLinkEnv,
22 extendLinkEnv, deleteFromLinkEnv,
24 linkPackages,initDynLinker,
28 #include "HsVersions.h"
46 import qualified OccName
58 import qualified Maybes
62 import Config ( cProjectVersion )
72 import System.FilePath
74 import System.Directory
76 import Distribution.Package hiding (depends, PackageId)
82 %************************************************************************
86 %************************************************************************
88 The persistent linker state *must* match the actual state of the
89 C dynamic linker at all times, so we keep it in a private global variable.
92 The PersistentLinkerState maps Names to actual closures (for
93 interpreted code only), for use during linking.
96 GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
97 GLOBAL_VAR(v_InitLinkerDone, False, Bool) -- Set True when dynamic linker is initialised
99 data PersistentLinkerState
100 = PersistentLinkerState {
102 -- Current global mapping from Names to their true values
103 closure_env :: ClosureEnv,
105 -- The current global mapping from RdrNames of DataCons to
106 -- info table addresses.
107 -- When a new Unlinked is linked into the running image, or an existing
108 -- module in the image is replaced, the itbl_env must be updated
112 -- The currently loaded interpreted modules (home package)
113 bcos_loaded :: [Linkable],
115 -- And the currently-loaded compiled modules (home package)
116 objs_loaded :: [Linkable],
118 -- The currently-loaded packages; always object code
119 -- Held, as usual, in dependency order; though I am not sure if
120 -- that is really important
121 pkgs_loaded :: [PackageId]
124 emptyPLS :: DynFlags -> PersistentLinkerState
125 emptyPLS _ = PersistentLinkerState {
126 closure_env = emptyNameEnv,
127 itbl_env = emptyNameEnv,
128 pkgs_loaded = init_pkgs,
132 -- Packages that don't need loading, because the compiler
133 -- shares them with the interpreted program.
135 -- The linker's symbol table is populated with RTS symbols using an
136 -- explicit list. See rts/Linker.c for details.
137 where init_pkgs = [rtsPackageId]
141 extendLoadedPkgs :: [PackageId] -> IO ()
142 extendLoadedPkgs pkgs
143 = modifyIORef v_PersistentLinkerState (\s -> s{pkgs_loaded = pkgs ++ pkgs_loaded s})
145 extendLinkEnv :: [(Name,HValue)] -> IO ()
146 -- Automatically discards shadowed bindings
147 extendLinkEnv new_bindings
148 = do pls <- readIORef v_PersistentLinkerState
149 let new_closure_env = extendClosureEnv (closure_env pls) new_bindings
150 new_pls = pls { closure_env = new_closure_env }
151 writeIORef v_PersistentLinkerState new_pls
153 deleteFromLinkEnv :: [Name] -> IO ()
154 deleteFromLinkEnv to_remove
155 = do pls <- readIORef v_PersistentLinkerState
156 let new_closure_env = delListFromNameEnv (closure_env pls) to_remove
157 new_pls = pls { closure_env = new_closure_env }
158 writeIORef v_PersistentLinkerState new_pls
160 -- | Given a data constructor in the heap, find its Name.
161 -- The info tables for data constructors have a field which records
162 -- the source name of the constructor as a Ptr Word8 (UTF-8 encoded
163 -- string). The format is:
165 -- Package:Module.Name
167 -- We use this string to lookup the interpreter's internal representation of the name
168 -- using the lookupOrig.
170 dataConInfoPtrToName :: Ptr () -> TcM (Either String Name)
171 dataConInfoPtrToName x = do
172 theString <- liftIO $ do
173 let ptr = castPtr x :: Ptr StgInfoTable
174 conDescAddress <- getConDescAddress ptr
175 peekArray0 0 conDescAddress
176 let (pkg, mod, occ) = parse theString
177 pkgFS = mkFastStringByteList pkg
178 modFS = mkFastStringByteList mod
179 occFS = mkFastStringByteList occ
180 occName = mkOccNameFS OccName.dataName occFS
181 modName = mkModule (fsToPackageId pkgFS) (mkModuleNameFS modFS)
182 return (Left$ showSDoc$ ppr modName <> dot <> ppr occName )
183 `recoverM` (Right `fmap` lookupOrig modName occName)
187 {- To find the string in the constructor's info table we need to consider
188 the layout of info tables relative to the entry code for a closure.
190 An info table can be next to the entry code for the closure, or it can
191 be separate. The former (faster) is used in registerised versions of ghc,
192 and the latter (portable) is for non-registerised versions.
194 The diagrams below show where the string is to be found relative to
195 the normal info table of the closure.
197 1) Code next to table:
200 | | <- pointer to the start of the string
202 | | <- the (start of the) info table structure
209 In this case the pointer to the start of the string can be found in
210 the memory location _one word before_ the first entry in the normal info
213 2) Code NOT next to table:
216 info table structure -> | *------------------> --------------
220 ptr to start of str -> | |
223 In this case the pointer to the start of the string can be found
224 in the memory location: info_table_ptr + info_table_size
227 getConDescAddress :: Ptr StgInfoTable -> IO (Ptr Word8)
228 getConDescAddress ptr
229 | ghciTablesNextToCode = do
230 offsetToString <- peek $ ptr `plusPtr` (- wORD_SIZE)
231 return $ (ptr `plusPtr` stdInfoTableSizeB) `plusPtr` (fromIntegral (offsetToString :: StgWord))
233 peek $ intPtrToPtr $ (ptrToIntPtr ptr) + fromIntegral stdInfoTableSizeB
235 -- parsing names is a little bit fiddly because we have a string in the form:
236 -- pkg:A.B.C.foo, and we want to split it into three parts: ("pkg", "A.B.C", "foo").
237 -- Thus we split at the leftmost colon and the rightmost occurrence of the dot.
238 -- It would be easier if the string was in the form pkg:A.B.C:foo, but alas
239 -- this is not the conventional way of writing Haskell names. We stick with
240 -- convention, even though it makes the parsing code more troublesome.
241 -- Warning: this code assumes that the string is well formed.
242 parse :: [Word8] -> ([Word8], [Word8], [Word8])
244 = ASSERT (all (>0) (map length [pkg, mod, occ])) (pkg, mod, occ)
246 dot = fromIntegral (ord '.')
247 (pkg, rest1) = break (== fromIntegral (ord ':')) input
249 = (concat $ intersperse [dot] $ reverse modWords, occWord)
251 (modWords, occWord) = ASSERT (length rest1 > 0) (parseModOcc [] (tail rest1))
252 parseModOcc :: [[Word8]] -> [Word8] -> ([[Word8]], [Word8])
254 = case break (== dot) str of
255 (top, []) -> (acc, top)
256 (top, _:bot) -> parseModOcc (top : acc) bot
259 getHValue :: HscEnv -> Name -> IO HValue
260 getHValue hsc_env name = do
261 when (isExternalName name) $ do
262 ok <- linkDependencies hsc_env noSrcSpan [nameModule name]
263 when (failed ok) $ ghcError (ProgramError "")
264 pls <- readIORef v_PersistentLinkerState
265 lookupName (closure_env pls) name
267 linkDependencies :: HscEnv -> SrcSpan -> [Module] -> IO SuccessFlag
268 linkDependencies hsc_env span needed_mods = do
269 let hpt = hsc_HPT hsc_env
270 dflags = hsc_dflags hsc_env
271 -- The interpreter and dynamic linker can only handle object code built
272 -- the "normal" way, i.e. no non-std ways like profiling or ticky-ticky.
273 -- So here we check the build tag: if we're building a non-standard way
274 -- then we need to find & link object files built the "normal" way.
275 maybe_normal_osuf <- checkNonStdWay dflags span
277 -- Find what packages and linkables are required
278 eps <- readIORef (hsc_EPS hsc_env)
279 (lnks, pkgs) <- getLinkDeps hsc_env hpt (eps_PIT eps)
280 maybe_normal_osuf span needed_mods
282 -- Link the packages and modules required
283 linkPackages dflags pkgs
284 linkModules dflags lnks
287 -- | Temporarily extend the linker state.
289 withExtendedLinkEnv :: (MonadIO m, ExceptionMonad m) =>
290 [(Name,HValue)] -> m a -> m a
291 withExtendedLinkEnv new_env action
292 = gbracket set_new_env
293 (\_ -> reset_old_env)
295 where set_new_env = do
296 pls <- liftIO $ readIORef v_PersistentLinkerState
297 let new_closure_env = extendClosureEnv (closure_env pls) new_env
298 new_pls = pls { closure_env = new_closure_env }
299 liftIO $ writeIORef v_PersistentLinkerState new_pls
302 -- Remember that the linker state might be side-effected
303 -- during the execution of the IO action, and we don't want to
304 -- lose those changes (we might have linked a new module or
305 -- package), so the reset action only removes the names we
307 reset_old_env = liftIO $ do
308 modifyIORef v_PersistentLinkerState $ \pls ->
309 let cur = closure_env pls
310 new = delListFromNameEnv cur (map fst new_env)
312 pls{ closure_env = new }
314 -- filterNameMap removes from the environment all entries except
315 -- those for a given set of modules;
316 -- Note that this removes all *local* (i.e. non-isExternal) names too
317 -- (these are the temporary bindings from the command line).
318 -- Used to filter both the ClosureEnv and ItblEnv
320 filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
321 filterNameMap mods env
322 = filterNameEnv keep_elt env
324 keep_elt (n,_) = isExternalName n
325 && (nameModule n `elem` mods)
330 showLinkerState :: IO ()
331 -- Display the persistent linker state
333 = do pls <- readIORef v_PersistentLinkerState
334 printDump (vcat [text "----- Linker state -----",
335 text "Pkgs:" <+> ppr (pkgs_loaded pls),
336 text "Objs:" <+> ppr (objs_loaded pls),
337 text "BCOs:" <+> ppr (bcos_loaded pls)])
343 %************************************************************************
345 \subsection{Initialisation}
347 %************************************************************************
349 We initialise the dynamic linker by
351 a) calling the C initialisation procedure
353 b) Loading any packages specified on the command line,
355 c) Loading any packages specified on the command line,
356 now held in the -l options in v_Opt_l
358 d) Loading any .o/.dll files specified on the command line,
359 now held in v_Ld_inputs
361 e) Loading any MacOS frameworks
364 initDynLinker :: DynFlags -> IO ()
365 -- This function is idempotent; if called more than once, it does nothing
366 -- This is useful in Template Haskell, where we call it before trying to link
368 = do { done <- readIORef v_InitLinkerDone
369 ; if done then return ()
370 else do { writeIORef v_InitLinkerDone True
371 ; reallyInitDynLinker dflags }
374 reallyInitDynLinker :: DynFlags -> IO ()
375 reallyInitDynLinker dflags
376 = do { -- Initialise the linker state
377 ; writeIORef v_PersistentLinkerState (emptyPLS dflags)
379 -- (a) initialise the C dynamic linker
382 -- (b) Load packages from the command-line
383 ; linkPackages dflags (preloadPackages (pkgState dflags))
385 -- (c) Link libraries from the command-line
386 ; let optl = getOpts dflags opt_l
387 ; let minus_ls = [ lib | '-':'l':lib <- optl ]
389 -- (d) Link .o files from the command-line
390 ; let lib_paths = libraryPaths dflags
391 ; cmdline_ld_inputs <- readIORef v_Ld_inputs
393 ; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
395 -- (e) Link any MacOS frameworks
396 ; let framework_paths
397 | isDarwinTarget = frameworkPaths dflags
400 | isDarwinTarget = cmdlineFrameworks dflags
402 -- Finally do (c),(d),(e)
403 ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
405 ++ map Framework frameworks
406 ; if null cmdline_lib_specs then return ()
409 { mapM_ (preloadLib dflags lib_paths framework_paths) cmdline_lib_specs
410 ; maybePutStr dflags "final link ... "
413 ; if succeeded ok then maybePutStrLn dflags "done"
414 else ghcError (ProgramError "linking extra libraries/objects failed")
417 classifyLdInput :: FilePath -> IO (Maybe LibrarySpec)
419 | isObjectFilename f = return (Just (Object f))
420 | isDynLibFilename f = return (Just (DLLPath f))
422 hPutStrLn stderr ("Warning: ignoring unrecognised input `" ++ f ++ "'")
425 preloadLib :: DynFlags -> [String] -> [String] -> LibrarySpec -> IO ()
426 preloadLib dflags lib_paths framework_paths lib_spec
427 = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
430 -> do b <- preload_static lib_paths static_ish
431 maybePutStrLn dflags (if b then "done"
435 -> do maybe_errstr <- loadDynamic lib_paths dll_unadorned
437 Nothing -> maybePutStrLn dflags "done"
438 Just mm -> preloadFailed mm lib_paths lib_spec
441 -> do maybe_errstr <- loadDLL dll_path
443 Nothing -> maybePutStrLn dflags "done"
444 Just mm -> preloadFailed mm lib_paths lib_spec
448 -> do maybe_errstr <- loadFramework framework_paths framework
450 Nothing -> maybePutStrLn dflags "done"
451 Just mm -> preloadFailed mm framework_paths lib_spec
452 | otherwise -> panic "preloadLib Framework"
455 preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
456 preloadFailed sys_errmsg paths spec
457 = do maybePutStr dflags "failed.\n"
460 "user specified .o/.so/.DLL could not be loaded ("
461 ++ sys_errmsg ++ ")\nWhilst trying to load: "
462 ++ showLS spec ++ "\nAdditional directories searched:"
463 ++ (if null paths then " (none)" else
464 (concat (intersperse "\n" (map (" "++) paths)))))
466 -- Not interested in the paths in the static case.
467 preload_static _paths name
468 = do b <- doesFileExist name
469 if not b then return False
470 else loadObj name >> return True
474 %************************************************************************
476 Link a byte-code expression
478 %************************************************************************
481 linkExpr :: HscEnv -> SrcSpan -> UnlinkedBCO -> IO HValue
483 -- Link a single expression, *including* first linking packages and
484 -- modules that this expression depends on.
486 -- Raises an IO exception if it can't find a compiled version of the
487 -- dependents to link.
489 -- Note: This function side-effects the linker state (Pepe)
491 linkExpr hsc_env span root_ul_bco
493 -- Initialise the linker (if it's not been done already)
494 let dflags = hsc_dflags hsc_env
495 ; initDynLinker dflags
497 -- Link the packages and modules required
498 ; ok <- linkDependencies hsc_env span needed_mods
500 ghcError (ProgramError "")
503 -- Link the expression itself
504 pls <- readIORef v_PersistentLinkerState
505 ; let ie = itbl_env pls
508 -- Link the necessary packages and linkables
509 ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
513 free_names = nameSetToList (bcoFreeNames root_ul_bco)
515 needed_mods :: [Module]
516 needed_mods = [ nameModule n | n <- free_names,
517 isExternalName n, -- Names from other modules
518 not (isWiredInName n) -- Exclude wired-in names
519 ] -- (see note below)
520 -- Exclude wired-in names because we may not have read
521 -- their interface files, so getLinkDeps will fail
522 -- All wired-in names are in the base package, which we link
523 -- by default, so we can safely ignore them here.
525 dieWith :: SrcSpan -> Message -> IO a
526 dieWith span msg = ghcError (ProgramError (showSDoc (mkLocMessage span msg)))
529 checkNonStdWay :: DynFlags -> SrcSpan -> IO (Maybe String)
530 checkNonStdWay dflags srcspan = do
531 tag <- readIORef v_Build_tag
532 if null tag then return Nothing else do
533 let default_osuf = phaseInputExt StopLn
534 if objectSuf dflags == default_osuf
535 then failNonStd srcspan
536 else return (Just default_osuf)
538 failNonStd :: SrcSpan -> IO (Maybe String)
539 failNonStd srcspan = dieWith srcspan $
540 ptext (sLit "Dynamic linking required, but this is a non-standard build (eg. prof).") $$
541 ptext (sLit "You need to build the program twice: once the normal way, and then") $$
542 ptext (sLit "in the desired way using -osuf to set the object file suffix.")
545 getLinkDeps :: HscEnv -> HomePackageTable -> PackageIfaceTable
546 -> Maybe String -- the "normal" object suffix
547 -> SrcSpan -- for error messages
548 -> [Module] -- If you need these
549 -> IO ([Linkable], [PackageId]) -- ... then link these first
550 -- Fails with an IO exception if it can't find enough files
552 getLinkDeps hsc_env hpt _ maybe_normal_osuf span mods
553 -- Find all the packages and linkables that a set of modules depends on
554 = do { pls <- readIORef v_PersistentLinkerState ;
555 -- 1. Find the dependent home-pkg-modules/packages from each iface
556 (mods_s, pkgs_s) <- follow_deps mods emptyUniqSet emptyUniqSet;
559 -- 2. Exclude ones already linked
560 -- Main reason: avoid findModule calls in get_linkable
561 mods_needed = mods_s `minusList` linked_mods ;
562 pkgs_needed = pkgs_s `minusList` pkgs_loaded pls ;
564 linked_mods = map (moduleName.linkableModule)
565 (objs_loaded pls ++ bcos_loaded pls)
568 -- putStrLn (showSDoc (ppr mods_s)) ;
569 -- 3. For each dependent module, find its linkable
570 -- This will either be in the HPT or (in the case of one-shot
571 -- compilation) we may need to use maybe_getFileLinkable
572 lnks_needed <- mapM (get_linkable maybe_normal_osuf) mods_needed ;
574 return (lnks_needed, pkgs_needed) }
576 dflags = hsc_dflags hsc_env
577 this_pkg = thisPackage dflags
579 -- The ModIface contains the transitive closure of the module dependencies
580 -- within the current package, *except* for boot modules: if we encounter
581 -- a boot module, we have to find its real interface and discover the
582 -- dependencies of that. Hence we need to traverse the dependency
583 -- tree recursively. See bug #936, testcase ghci/prog007.
584 follow_deps :: [Module] -- modules to follow
585 -> UniqSet ModuleName -- accum. module dependencies
586 -> UniqSet PackageId -- accum. package dependencies
587 -> IO ([ModuleName], [PackageId]) -- result
588 follow_deps [] acc_mods acc_pkgs
589 = return (uniqSetToList acc_mods, uniqSetToList acc_pkgs)
590 follow_deps (mod:mods) acc_mods acc_pkgs
592 mb_iface <- initIfaceCheck hsc_env $
593 loadInterface msg mod (ImportByUser False)
594 iface <- case mb_iface of
595 Maybes.Failed err -> ghcError (ProgramError (showSDoc err))
596 Maybes.Succeeded iface -> return iface
598 when (mi_boot iface) $ link_boot_mod_error mod
601 pkg = modulePackageId mod
604 pkg_deps = dep_pkgs deps
605 (boot_deps, mod_deps) = partitionWith is_boot (dep_mods deps)
606 where is_boot (m,True) = Left m
607 is_boot (m,False) = Right m
609 boot_deps' = filter (not . (`elementOfUniqSet` acc_mods)) boot_deps
610 acc_mods' = addListToUniqSet acc_mods (moduleName mod : mod_deps)
611 acc_pkgs' = addListToUniqSet acc_pkgs pkg_deps
614 then follow_deps mods acc_mods (addOneToUniqSet acc_pkgs' pkg)
615 else follow_deps (map (mkModule this_pkg) boot_deps' ++ mods)
618 msg = text "need to link module" <+> ppr mod <+>
619 text "due to use of Template Haskell"
622 link_boot_mod_error mod =
623 ghcError (ProgramError (showSDoc (
624 text "module" <+> ppr mod <+>
625 text "cannot be linked; it is only available as a boot module")))
627 no_obj mod = dieWith span $
628 ptext (sLit "cannot find object file for module ") <>
632 while_linking_expr = ptext (sLit "while linking an interpreted expression")
634 -- This one is a build-system bug
636 get_linkable maybe_normal_osuf mod_name -- A home-package module
637 | Just mod_info <- lookupUFM hpt mod_name
638 = adjust_linkable (Maybes.expectJust "getLinkDeps" (hm_linkable mod_info))
640 = do -- It's not in the HPT because we are in one shot mode,
641 -- so use the Finder to get a ModLocation...
642 mb_stuff <- findHomeModule hsc_env mod_name
644 Found loc mod -> found loc mod
648 -- ...and then find the linkable for it
649 mb_lnk <- findObjectLinkableMaybe mod loc ;
651 Nothing -> no_obj mod ;
652 Just lnk -> adjust_linkable lnk
656 | Just osuf <- maybe_normal_osuf = do
657 new_uls <- mapM (adjust_ul osuf) (linkableUnlinked lnk)
658 return lnk{ linkableUnlinked=new_uls }
662 adjust_ul osuf (DotO file) = do
663 let new_file = replaceExtension file osuf
664 ok <- doesFileExist new_file
667 ptext (sLit "cannot find normal object file ")
668 <> quotes (text new_file) $$ while_linking_expr
669 else return (DotO new_file)
670 adjust_ul _ _ = panic "adjust_ul"
674 %************************************************************************
677 The linkables may consist of a mixture of
678 byte-code modules and object modules
680 %************************************************************************
683 linkModules :: DynFlags -> [Linkable] -> IO SuccessFlag
684 linkModules dflags linkables
685 = block $ do -- don't want to be interrupted by ^C in here
687 let (objs, bcos) = partition isObjectLinkable
688 (concatMap partitionLinkable linkables)
690 -- Load objects first; they can't depend on BCOs
691 ok_flag <- dynLinkObjs dflags objs
693 if failed ok_flag then
700 -- HACK to support f-x-dynamic in the interpreter; no other purpose
701 partitionLinkable :: Linkable -> [Linkable]
703 = let li_uls = linkableUnlinked li
704 li_uls_obj = filter isObject li_uls
705 li_uls_bco = filter isInterpretable li_uls
707 case (li_uls_obj, li_uls_bco) of
708 (_:_, _:_) -> [li {linkableUnlinked=li_uls_obj},
709 li {linkableUnlinked=li_uls_bco}]
712 findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
713 findModuleLinkable_maybe lis mod
714 = case [LM time nm us | LM time nm us <- lis, nm == mod] of
717 _ -> pprPanic "findModuleLinkable" (ppr mod)
719 linkableInSet :: Linkable -> [Linkable] -> Bool
720 linkableInSet l objs_loaded =
721 case findModuleLinkable_maybe objs_loaded (linkableModule l) of
723 Just m -> linkableTime l == linkableTime m
727 %************************************************************************
729 \subsection{The object-code linker}
731 %************************************************************************
734 dynLinkObjs :: DynFlags -> [Linkable] -> IO SuccessFlag
735 -- Side-effects the PersistentLinkerState
737 dynLinkObjs dflags objs
738 = do pls <- readIORef v_PersistentLinkerState
740 -- Load the object files and link them
741 let (objs_loaded', new_objs) = rmDupLinkables (objs_loaded pls) objs
742 pls1 = pls { objs_loaded = objs_loaded' }
743 unlinkeds = concatMap linkableUnlinked new_objs
745 mapM_ loadObj (map nameOfObject unlinkeds)
747 -- Link the all together
750 -- If resolving failed, unload all our
751 -- object modules and carry on
752 if succeeded ok then do
753 writeIORef v_PersistentLinkerState pls1
756 pls2 <- unload_wkr dflags [] pls1
757 writeIORef v_PersistentLinkerState pls2
761 rmDupLinkables :: [Linkable] -- Already loaded
762 -> [Linkable] -- New linkables
763 -> ([Linkable], -- New loaded set (including new ones)
764 [Linkable]) -- New linkables (excluding dups)
765 rmDupLinkables already ls
768 go already extras [] = (already, extras)
769 go already extras (l:ls)
770 | linkableInSet l already = go already extras ls
771 | otherwise = go (l:already) (l:extras) ls
774 %************************************************************************
776 \subsection{The byte-code linker}
778 %************************************************************************
781 dynLinkBCOs :: [Linkable] -> IO ()
782 -- Side-effects the persistent linker state
784 = do pls <- readIORef v_PersistentLinkerState
786 let (bcos_loaded', new_bcos) = rmDupLinkables (bcos_loaded pls) bcos
787 pls1 = pls { bcos_loaded = bcos_loaded' }
788 unlinkeds :: [Unlinked]
789 unlinkeds = concatMap linkableUnlinked new_bcos
791 cbcs :: [CompiledByteCode]
792 cbcs = map byteCodeOfObject unlinkeds
795 ul_bcos = [b | ByteCode bs _ <- cbcs, b <- bs]
796 ies = [ie | ByteCode _ ie <- cbcs]
797 gce = closure_env pls
798 final_ie = foldr plusNameEnv (itbl_env pls) ies
800 (final_gce, _linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
801 -- XXX What happens to these linked_bcos?
803 let pls2 = pls1 { closure_env = final_gce,
804 itbl_env = final_ie }
806 writeIORef v_PersistentLinkerState pls2
809 -- Link a bunch of BCOs and return them + updated closure env.
810 linkSomeBCOs :: Bool -- False <=> add _all_ BCOs to returned closure env
811 -- True <=> add only toplevel BCOs to closure env
815 -> IO (ClosureEnv, [HValue])
816 -- The returned HValues are associated 1-1 with
817 -- the incoming unlinked BCOs. Each gives the
818 -- value of the corresponding unlinked BCO
820 linkSomeBCOs toplevs_only ie ce_in ul_bcos
821 = do let nms = map unlinkedBCOName ul_bcos
823 ( \ hvs -> let ce_out = extendClosureEnv ce_in (zipLazy nms hvs)
824 in mapM (linkBCO ie ce_out) ul_bcos )
825 let ce_all_additions = zip nms hvals
826 ce_top_additions = filter (isExternalName.fst) ce_all_additions
827 ce_additions = if toplevs_only then ce_top_additions
828 else ce_all_additions
829 ce_out = -- make sure we're not inserting duplicate names into the
830 -- closure environment, which leads to trouble.
831 ASSERT (all (not . (`elemNameEnv` ce_in)) (map fst ce_additions))
832 extendClosureEnv ce_in ce_additions
833 return (ce_out, hvals)
838 %************************************************************************
840 Unload some object modules
842 %************************************************************************
845 -- ---------------------------------------------------------------------------
846 -- Unloading old objects ready for a new compilation sweep.
848 -- The compilation manager provides us with a list of linkables that it
849 -- considers "stable", i.e. won't be recompiled this time around. For
850 -- each of the modules current linked in memory,
852 -- * if the linkable is stable (and it's the same one - the
853 -- user may have recompiled the module on the side), we keep it,
855 -- * otherwise, we unload it.
857 -- * we also implicitly unload all temporary bindings at this point.
859 unload :: DynFlags -> [Linkable] -> IO ()
860 -- The 'linkables' are the ones to *keep*
862 unload dflags linkables
863 = block $ do -- block, so we're safe from Ctrl-C in here
865 -- Initialise the linker (if it's not been done already)
868 pls <- readIORef v_PersistentLinkerState
869 new_pls <- unload_wkr dflags linkables pls
870 writeIORef v_PersistentLinkerState new_pls
872 debugTraceMsg dflags 3 (text "unload: retaining objs" <+> ppr (objs_loaded new_pls))
873 debugTraceMsg dflags 3 (text "unload: retaining bcos" <+> ppr (bcos_loaded new_pls))
876 unload_wkr :: DynFlags
877 -> [Linkable] -- stable linkables
878 -> PersistentLinkerState
879 -> IO PersistentLinkerState
880 -- Does the core unload business
881 -- (the wrapper blocks exceptions and deals with the PLS get and put)
883 unload_wkr _ linkables pls
884 = do let (objs_to_keep, bcos_to_keep) = partition isObjectLinkable linkables
886 objs_loaded' <- filterM (maybeUnload objs_to_keep) (objs_loaded pls)
887 bcos_loaded' <- filterM (maybeUnload bcos_to_keep) (bcos_loaded pls)
889 let bcos_retained = map linkableModule bcos_loaded'
890 itbl_env' = filterNameMap bcos_retained (itbl_env pls)
891 closure_env' = filterNameMap bcos_retained (closure_env pls)
892 new_pls = pls { itbl_env = itbl_env',
893 closure_env = closure_env',
894 bcos_loaded = bcos_loaded',
895 objs_loaded = objs_loaded' }
899 maybeUnload :: [Linkable] -> Linkable -> IO Bool
900 maybeUnload keep_linkables lnk
901 | linkableInSet lnk keep_linkables = return True
903 = do mapM_ unloadObj [f | DotO f <- linkableUnlinked lnk]
904 -- The components of a BCO linkable may contain
905 -- dot-o files. Which is very confusing.
907 -- But the BCO parts can be unlinked just by
908 -- letting go of them (plus of course depopulating
909 -- the symbol table which is done in the main body)
914 %************************************************************************
918 %************************************************************************
923 = Object FilePath -- Full path name of a .o file, including trailing .o
924 -- For dynamic objects only, try to find the object
925 -- file in all the directories specified in
926 -- v_Library_paths before giving up.
928 | DLL String -- "Unadorned" name of a .DLL/.so
929 -- e.g. On unix "qt" denotes "libqt.so"
930 -- On WinDoze "burble" denotes "burble.DLL"
931 -- loadDLL is platform-specific and adds the lib/.so/.DLL
932 -- suffixes platform-dependently
934 | DLLPath FilePath -- Absolute or relative pathname to a dynamic library
935 -- (ends with .dll or .so).
937 | Framework String -- Only used for darwin, but does no harm
939 -- If this package is already part of the GHCi binary, we'll already
940 -- have the right DLLs for this package loaded, so don't try to
943 -- But on Win32 we must load them 'again'; doing so is a harmless no-op
944 -- as far as the loader is concerned, but it does initialise the list
945 -- of DLL handles that rts/Linker.c maintains, and that in turn is
946 -- used by lookupSymbol. So we must call addDLL for each library
947 -- just to get the DLL handle into the list.
948 partOfGHCi :: [PackageName]
950 | isWindowsTarget || isDarwinTarget = []
951 | otherwise = map PackageName
952 ["base", "haskell98", "template-haskell", "editline"]
954 showLS :: LibrarySpec -> String
955 showLS (Object nm) = "(static) " ++ nm
956 showLS (DLL nm) = "(dynamic) " ++ nm
957 showLS (DLLPath nm) = "(dynamic) " ++ nm
958 showLS (Framework nm) = "(framework) " ++ nm
960 linkPackages :: DynFlags -> [PackageId] -> IO ()
961 -- Link exactly the specified packages, and their dependents
962 -- (unless of course they are already linked)
963 -- The dependents are linked automatically, and it doesn't matter
964 -- what order you specify the input packages.
966 -- NOTE: in fact, since each module tracks all the packages it depends on,
967 -- we don't really need to use the package-config dependencies.
968 -- However we do need the package-config stuff (to find aux libs etc),
969 -- and following them lets us load libraries in the right order, which
970 -- perhaps makes the error message a bit more localised if we get a link
971 -- failure. So the dependency walking code is still here.
973 linkPackages dflags new_pkgs
974 = do { pls <- readIORef v_PersistentLinkerState
975 ; let pkg_map = pkgIdMap (pkgState dflags)
977 ; pkgs' <- link pkg_map (pkgs_loaded pls) new_pkgs
979 ; writeIORef v_PersistentLinkerState (pls { pkgs_loaded = pkgs' })
982 link :: PackageConfigMap -> [PackageId] -> [PackageId] -> IO [PackageId]
983 link pkg_map pkgs new_pkgs
984 = foldM (link_one pkg_map) pkgs new_pkgs
986 link_one pkg_map pkgs new_pkg
987 | new_pkg `elem` pkgs -- Already linked
990 | Just pkg_cfg <- lookupPackage pkg_map new_pkg
991 = do { -- Link dependents first
992 pkgs' <- link pkg_map pkgs (map mkPackageId (depends pkg_cfg))
993 -- Now link the package itself
994 ; linkPackage dflags pkg_cfg
995 ; return (new_pkg : pkgs') }
998 = ghcError (CmdLineError ("unknown package: " ++ packageIdString new_pkg))
1001 linkPackage :: DynFlags -> PackageConfig -> IO ()
1002 linkPackage dflags pkg
1004 let dirs = Packages.libraryDirs pkg
1006 let libs = Packages.hsLibraries pkg
1007 -- Because of slight differences between the GHC dynamic linker and
1008 -- the native system linker some packages have to link with a
1009 -- different list of libraries when using GHCi. Examples include: libs
1010 -- that are actually gnu ld scripts, and the possability that the .a
1011 -- libs do not exactly match the .so/.dll equivalents. So if the
1012 -- package file provides an "extra-ghci-libraries" field then we use
1013 -- that instead of the "extra-libraries" field.
1014 ++ (if null (Packages.extraGHCiLibraries pkg)
1015 then Packages.extraLibraries pkg
1016 else Packages.extraGHCiLibraries pkg)
1017 ++ [ lib | '-':'l':lib <- Packages.ldOptions pkg ]
1018 classifieds <- mapM (locateOneObj dirs) libs
1020 -- Complication: all the .so's must be loaded before any of the .o's.
1021 let dlls = [ dll | DLL dll <- classifieds ]
1022 objs = [ obj | Object obj <- classifieds ]
1024 maybePutStr dflags ("Loading package " ++ display (package pkg) ++ " ... ")
1026 -- See comments with partOfGHCi
1027 when (packageName pkg `notElem` partOfGHCi) $ do
1029 -- When a library A needs symbols from a library B, the order in
1030 -- extra_libraries/extra_ld_opts is "-lA -lB", because that's the
1031 -- way ld expects it for static linking. Dynamic linking is a
1032 -- different story: When A has no dependency information for B,
1033 -- dlopen-ing A with RTLD_NOW (see addDLL in Linker.c) will fail
1034 -- when B has not been loaded before. In a nutshell: Reverse the
1035 -- order of DLLs for dynamic linking.
1036 -- This fixes a problem with the HOpenGL package (see "Compiling
1037 -- HOpenGL under recent versions of GHC" on the HOpenGL list).
1038 mapM_ (load_dyn dirs) (reverse dlls)
1040 -- After loading all the DLLs, we can load the static objects.
1041 -- Ordering isn't important here, because we do one final link
1042 -- step to resolve everything.
1045 maybePutStr dflags "linking ... "
1047 if succeeded ok then maybePutStrLn dflags "done."
1048 else ghcError (InstallationError ("unable to load package `" ++ display (package pkg) ++ "'"))
1050 load_dyn :: [FilePath] -> FilePath -> IO ()
1051 load_dyn dirs dll = do r <- loadDynamic dirs dll
1053 Nothing -> return ()
1054 Just err -> ghcError (CmdLineError ("can't load .so/.DLL for: "
1055 ++ dll ++ " (" ++ err ++ ")" ))
1057 loadFrameworks :: InstalledPackageInfo_ ModuleName -> IO ()
1059 | isDarwinTarget = mapM_ load frameworks
1060 | otherwise = return ()
1062 fw_dirs = Packages.frameworkDirs pkg
1063 frameworks = Packages.frameworks pkg
1065 load fw = do r <- loadFramework fw_dirs fw
1067 Nothing -> return ()
1068 Just err -> ghcError (CmdLineError ("can't load framework: "
1069 ++ fw ++ " (" ++ err ++ ")" ))
1071 -- Try to find an object file for a given library in the given paths.
1072 -- If it isn't present, we assume it's a dynamic library.
1073 locateOneObj :: [FilePath] -> String -> IO LibrarySpec
1074 locateOneObj dirs lib
1076 -- When the GHC package was not compiled as dynamic library
1077 -- (=__PIC__ not set), we search for .o libraries first.
1078 = do { mb_obj_path <- findFile mk_obj_path dirs
1079 ; case mb_obj_path of
1080 Just obj_path -> return (Object obj_path)
1082 do { mb_lib_path <- findFile mk_dyn_lib_path dirs
1083 ; case mb_lib_path of
1084 Just _ -> return (DLL dyn_lib_name)
1085 Nothing -> return (DLL lib) }} -- We assume
1087 -- When the GHC package was compiled as dynamic library (=__PIC__ set),
1088 -- we search for .so libraries first.
1089 = do { mb_lib_path <- findFile mk_dyn_lib_path dirs
1090 ; case mb_lib_path of
1091 Just _ -> return (DLL (lib ++ "-ghc" ++ cProjectVersion))
1093 do { mb_obj_path <- findFile mk_obj_path dirs
1094 ; case mb_obj_path of
1095 Just obj_path -> return (Object obj_path)
1096 Nothing -> return (DLL lib) }} -- We assume
1098 mk_obj_path dir = dir </> (lib <.> "o")
1099 dyn_lib_name = lib ++ "-ghc" ++ cProjectVersion
1100 mk_dyn_lib_path dir = dir </> mkSOName dyn_lib_name
1102 -- ----------------------------------------------------------------------------
1103 -- Loading a dyanmic library (dlopen()-ish on Unix, LoadLibrary-ish on Win32)
1105 -- return Nothing == success, else Just error message from dlopen
1106 loadDynamic :: [FilePath] -> FilePath -> IO (Maybe String)
1107 loadDynamic paths rootname
1108 = do { mb_dll <- findFile mk_dll_path paths
1110 Just dll -> loadDLL dll
1111 Nothing -> loadDLL (mkSOName rootname) }
1112 -- Tried all our known library paths, so let
1113 -- dlopen() search its own builtin paths now.
1115 mk_dll_path dir = dir </> mkSOName rootname
1117 mkSOName :: FilePath -> FilePath
1119 | isDarwinTarget = ("lib" ++ root) <.> "dylib"
1120 | isWindowsTarget = -- Win32 DLLs have no .dll extension here, because
1121 -- addDLL tries both foo.dll and foo.drv
1123 | otherwise = ("lib" ++ root) <.> "so"
1125 -- Darwin / MacOS X only: load a framework
1126 -- a framework is a dynamic library packaged inside a directory of the same
1127 -- name. They are searched for in different paths than normal libraries.
1128 loadFramework :: [FilePath] -> FilePath -> IO (Maybe String)
1129 loadFramework extraPaths rootname
1130 = do { either_dir <- tryIO getHomeDirectory
1131 ; let homeFrameworkPath = case either_dir of
1133 Right dir -> [dir ++ "/Library/Frameworks"]
1134 ps = extraPaths ++ homeFrameworkPath ++ defaultFrameworkPaths
1135 ; mb_fwk <- findFile mk_fwk ps
1137 Just fwk_path -> loadDLL fwk_path
1138 Nothing -> return (Just "not found") }
1139 -- Tried all our known library paths, but dlopen()
1140 -- has no built-in paths for frameworks: give up
1142 mk_fwk dir = dir </> (rootname ++ ".framework/" ++ rootname)
1143 -- sorry for the hardcoded paths, I hope they won't change anytime soon:
1144 defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
1147 %************************************************************************
1151 %************************************************************************
1154 findFile :: (FilePath -> FilePath) -- Maps a directory path to a file path
1155 -> [FilePath] -- Directories to look in
1156 -> IO (Maybe FilePath) -- The first file path to match
1159 findFile mk_file_path (dir:dirs)
1160 = do { let file_path = mk_file_path dir
1161 ; b <- doesFileExist file_path
1163 return (Just file_path)
1165 findFile mk_file_path dirs }
1169 maybePutStr :: DynFlags -> String -> IO ()
1170 maybePutStr dflags s | verbosity dflags > 0 = putStr s
1171 | otherwise = return ()
1173 maybePutStrLn :: DynFlags -> String -> IO ()
1174 maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
1175 | otherwise = return ()