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
60 import qualified Maybes
64 import Config ( cProjectVersion )
74 import System.FilePath
76 import System.Directory
78 import Distribution.Package hiding (depends, PackageId)
84 %************************************************************************
88 %************************************************************************
90 The persistent linker state *must* match the actual state of the
91 C dynamic linker at all times, so we keep it in a private global variable.
94 The PersistentLinkerState maps Names to actual closures (for
95 interpreted code only), for use during linking.
98 GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
99 GLOBAL_VAR(v_InitLinkerDone, False, Bool) -- Set True when dynamic linker is initialised
101 data PersistentLinkerState
102 = PersistentLinkerState {
104 -- Current global mapping from Names to their true values
105 closure_env :: ClosureEnv,
107 -- The current global mapping from RdrNames of DataCons to
108 -- info table addresses.
109 -- When a new Unlinked is linked into the running image, or an existing
110 -- module in the image is replaced, the itbl_env must be updated
114 -- The currently loaded interpreted modules (home package)
115 bcos_loaded :: [Linkable],
117 -- And the currently-loaded compiled modules (home package)
118 objs_loaded :: [Linkable],
120 -- The currently-loaded packages; always object code
121 -- Held, as usual, in dependency order; though I am not sure if
122 -- that is really important
123 pkgs_loaded :: [PackageId]
126 emptyPLS :: DynFlags -> PersistentLinkerState
127 emptyPLS _ = PersistentLinkerState {
128 closure_env = emptyNameEnv,
129 itbl_env = emptyNameEnv,
130 pkgs_loaded = init_pkgs,
134 -- Packages that don't need loading, because the compiler
135 -- shares them with the interpreted program.
137 -- The linker's symbol table is populated with RTS symbols using an
138 -- explicit list. See rts/Linker.c for details.
139 where init_pkgs = [rtsPackageId]
143 extendLoadedPkgs :: [PackageId] -> IO ()
144 extendLoadedPkgs pkgs
145 = modifyIORef v_PersistentLinkerState (\s -> s{pkgs_loaded = pkgs ++ pkgs_loaded s})
147 extendLinkEnv :: [(Name,HValue)] -> IO ()
148 -- Automatically discards shadowed bindings
149 extendLinkEnv new_bindings
150 = do pls <- readIORef v_PersistentLinkerState
151 let new_closure_env = extendClosureEnv (closure_env pls) new_bindings
152 new_pls = pls { closure_env = new_closure_env }
153 writeIORef v_PersistentLinkerState new_pls
155 deleteFromLinkEnv :: [Name] -> IO ()
156 deleteFromLinkEnv to_remove
157 = do pls <- readIORef v_PersistentLinkerState
158 let new_closure_env = delListFromNameEnv (closure_env pls) to_remove
159 new_pls = pls { closure_env = new_closure_env }
160 writeIORef v_PersistentLinkerState new_pls
162 -- | Given a data constructor in the heap, find its Name.
163 -- The info tables for data constructors have a field which records
164 -- the source name of the constructor as a Ptr Word8 (UTF-8 encoded
165 -- string). The format is:
167 -- Package:Module.Name
169 -- We use this string to lookup the interpreter's internal representation of the name
170 -- using the lookupOrig.
172 dataConInfoPtrToName :: Ptr () -> TcM (Either String Name)
173 dataConInfoPtrToName x = do
174 theString <- liftIO $ do
175 let ptr = castPtr x :: Ptr StgInfoTable
176 conDescAddress <- getConDescAddress ptr
177 peekArray0 0 conDescAddress
178 let (pkg, mod, occ) = parse theString
179 pkgFS = mkFastStringByteList pkg
180 modFS = mkFastStringByteList mod
181 occFS = mkFastStringByteList occ
182 occName = mkOccNameFS OccName.dataName occFS
183 modName = mkModule (fsToPackageId pkgFS) (mkModuleNameFS modFS)
184 return (Left$ showSDoc$ ppr modName <> dot <> ppr occName )
185 `recoverM` (Right `fmap` lookupOrig modName occName)
189 {- To find the string in the constructor's info table we need to consider
190 the layout of info tables relative to the entry code for a closure.
192 An info table can be next to the entry code for the closure, or it can
193 be separate. The former (faster) is used in registerised versions of ghc,
194 and the latter (portable) is for non-registerised versions.
196 The diagrams below show where the string is to be found relative to
197 the normal info table of the closure.
199 1) Code next to table:
202 | | <- pointer to the start of the string
204 | | <- the (start of the) info table structure
211 In this case the pointer to the start of the string can be found in
212 the memory location _one word before_ the first entry in the normal info
215 2) Code NOT next to table:
218 info table structure -> | *------------------> --------------
222 ptr to start of str -> | |
225 In this case the pointer to the start of the string can be found
226 in the memory location: info_table_ptr + info_table_size
229 getConDescAddress :: Ptr StgInfoTable -> IO (Ptr Word8)
230 getConDescAddress ptr
231 | ghciTablesNextToCode = do
232 offsetToString <- peek $ ptr `plusPtr` (- wORD_SIZE)
233 return $ (ptr `plusPtr` stdInfoTableSizeB) `plusPtr` (fromIntegral (offsetToString :: StgWord))
235 peek $ intPtrToPtr $ (ptrToIntPtr ptr) + fromIntegral stdInfoTableSizeB
237 -- parsing names is a little bit fiddly because we have a string in the form:
238 -- pkg:A.B.C.foo, and we want to split it into three parts: ("pkg", "A.B.C", "foo").
239 -- Thus we split at the leftmost colon and the rightmost occurrence of the dot.
240 -- It would be easier if the string was in the form pkg:A.B.C:foo, but alas
241 -- this is not the conventional way of writing Haskell names. We stick with
242 -- convention, even though it makes the parsing code more troublesome.
243 -- Warning: this code assumes that the string is well formed.
244 parse :: [Word8] -> ([Word8], [Word8], [Word8])
246 = ASSERT (all (>0) (map length [pkg, mod, occ])) (pkg, mod, occ)
248 dot = fromIntegral (ord '.')
249 (pkg, rest1) = break (== fromIntegral (ord ':')) input
251 = (concat $ intersperse [dot] $ reverse modWords, occWord)
253 (modWords, occWord) = ASSERT (length rest1 > 0) (parseModOcc [] (tail rest1))
254 parseModOcc :: [[Word8]] -> [Word8] -> ([[Word8]], [Word8])
256 = case break (== dot) str of
257 (top, []) -> (acc, top)
258 (top, _:bot) -> parseModOcc (top : acc) bot
261 getHValue :: HscEnv -> Name -> IO HValue
262 getHValue hsc_env name = do
263 when (isExternalName name) $ do
264 ok <- linkDependencies hsc_env noSrcSpan [nameModule name]
265 when (failed ok) $ ghcError (ProgramError "")
266 pls <- readIORef v_PersistentLinkerState
267 lookupName (closure_env pls) name
269 linkDependencies :: HscEnv -> SrcSpan -> [Module] -> IO SuccessFlag
270 linkDependencies hsc_env span needed_mods = do
271 let hpt = hsc_HPT hsc_env
272 dflags = hsc_dflags hsc_env
273 -- The interpreter and dynamic linker can only handle object code built
274 -- the "normal" way, i.e. no non-std ways like profiling or ticky-ticky.
275 -- So here we check the build tag: if we're building a non-standard way
276 -- then we need to find & link object files built the "normal" way.
277 maybe_normal_osuf <- checkNonStdWay dflags span
279 -- Find what packages and linkables are required
280 eps <- readIORef (hsc_EPS hsc_env)
281 (lnks, pkgs) <- getLinkDeps hsc_env hpt (eps_PIT eps)
282 maybe_normal_osuf span needed_mods
284 -- Link the packages and modules required
285 linkPackages dflags pkgs
286 linkModules dflags lnks
289 -- | Temporarily extend the linker state.
291 withExtendedLinkEnv :: (MonadIO m, ExceptionMonad m) =>
292 [(Name,HValue)] -> m a -> m a
293 withExtendedLinkEnv new_env action
294 = gbracket set_new_env
295 (\_ -> reset_old_env)
297 where set_new_env = do
298 pls <- liftIO $ readIORef v_PersistentLinkerState
299 let new_closure_env = extendClosureEnv (closure_env pls) new_env
300 new_pls = pls { closure_env = new_closure_env }
301 liftIO $ writeIORef v_PersistentLinkerState new_pls
304 -- Remember that the linker state might be side-effected
305 -- during the execution of the IO action, and we don't want to
306 -- lose those changes (we might have linked a new module or
307 -- package), so the reset action only removes the names we
309 reset_old_env = liftIO $ do
310 modifyIORef v_PersistentLinkerState $ \pls ->
311 let cur = closure_env pls
312 new = delListFromNameEnv cur (map fst new_env)
314 pls{ closure_env = new }
316 -- filterNameMap removes from the environment all entries except
317 -- those for a given set of modules;
318 -- Note that this removes all *local* (i.e. non-isExternal) names too
319 -- (these are the temporary bindings from the command line).
320 -- Used to filter both the ClosureEnv and ItblEnv
322 filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
323 filterNameMap mods env
324 = filterNameEnv keep_elt env
326 keep_elt (n,_) = isExternalName n
327 && (nameModule n `elem` mods)
332 showLinkerState :: IO ()
333 -- Display the persistent linker state
335 = do pls <- readIORef v_PersistentLinkerState
336 printDump (vcat [text "----- Linker state -----",
337 text "Pkgs:" <+> ppr (pkgs_loaded pls),
338 text "Objs:" <+> ppr (objs_loaded pls),
339 text "BCOs:" <+> ppr (bcos_loaded pls)])
345 %************************************************************************
347 \subsection{Initialisation}
349 %************************************************************************
351 We initialise the dynamic linker by
353 a) calling the C initialisation procedure
355 b) Loading any packages specified on the command line,
357 c) Loading any packages specified on the command line,
358 now held in the -l options in v_Opt_l
360 d) Loading any .o/.dll files specified on the command line,
361 now held in v_Ld_inputs
363 e) Loading any MacOS frameworks
366 initDynLinker :: DynFlags -> IO ()
367 -- This function is idempotent; if called more than once, it does nothing
368 -- This is useful in Template Haskell, where we call it before trying to link
370 = do { done <- readIORef v_InitLinkerDone
371 ; if done then return ()
372 else do { writeIORef v_InitLinkerDone True
373 ; reallyInitDynLinker dflags }
376 reallyInitDynLinker :: DynFlags -> IO ()
377 reallyInitDynLinker dflags
378 = do { -- Initialise the linker state
379 ; writeIORef v_PersistentLinkerState (emptyPLS dflags)
381 -- (a) initialise the C dynamic linker
384 -- (b) Load packages from the command-line
385 ; linkPackages dflags (preloadPackages (pkgState dflags))
387 -- (c) Link libraries from the command-line
388 ; let optl = getOpts dflags opt_l
389 ; let minus_ls = [ lib | '-':'l':lib <- optl ]
391 -- (d) Link .o files from the command-line
392 ; let lib_paths = libraryPaths dflags
393 ; cmdline_ld_inputs <- readIORef v_Ld_inputs
395 ; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
397 -- (e) Link any MacOS frameworks
398 ; let framework_paths
399 | isDarwinTarget = frameworkPaths dflags
402 | isDarwinTarget = cmdlineFrameworks dflags
404 -- Finally do (c),(d),(e)
405 ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
407 ++ map Framework frameworks
408 ; if null cmdline_lib_specs then return ()
411 { mapM_ (preloadLib dflags lib_paths framework_paths) cmdline_lib_specs
412 ; maybePutStr dflags "final link ... "
415 ; if succeeded ok then maybePutStrLn dflags "done"
416 else ghcError (ProgramError "linking extra libraries/objects failed")
419 classifyLdInput :: FilePath -> IO (Maybe LibrarySpec)
421 | isObjectFilename f = return (Just (Object f))
422 | isDynLibFilename f = return (Just (DLLPath f))
424 hPutStrLn stderr ("Warning: ignoring unrecognised input `" ++ f ++ "'")
427 preloadLib :: DynFlags -> [String] -> [String] -> LibrarySpec -> IO ()
428 preloadLib dflags lib_paths framework_paths lib_spec
429 = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
432 -> do b <- preload_static lib_paths static_ish
433 maybePutStrLn dflags (if b then "done"
437 -> do maybe_errstr <- loadDynamic lib_paths dll_unadorned
439 Nothing -> maybePutStrLn dflags "done"
440 Just mm -> preloadFailed mm lib_paths lib_spec
443 -> do maybe_errstr <- loadDLL dll_path
445 Nothing -> maybePutStrLn dflags "done"
446 Just mm -> preloadFailed mm lib_paths lib_spec
450 -> do maybe_errstr <- loadFramework framework_paths framework
452 Nothing -> maybePutStrLn dflags "done"
453 Just mm -> preloadFailed mm framework_paths lib_spec
454 | otherwise -> panic "preloadLib Framework"
457 preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
458 preloadFailed sys_errmsg paths spec
459 = do maybePutStr dflags "failed.\n"
462 "user specified .o/.so/.DLL could not be loaded ("
463 ++ sys_errmsg ++ ")\nWhilst trying to load: "
464 ++ showLS spec ++ "\nAdditional directories searched:"
465 ++ (if null paths then " (none)" else
466 (concat (intersperse "\n" (map (" "++) paths)))))
468 -- Not interested in the paths in the static case.
469 preload_static _paths name
470 = do b <- doesFileExist name
471 if not b then return False
472 else loadObj name >> return True
476 %************************************************************************
478 Link a byte-code expression
480 %************************************************************************
483 linkExpr :: HscEnv -> SrcSpan -> UnlinkedBCO -> IO HValue
485 -- Link a single expression, *including* first linking packages and
486 -- modules that this expression depends on.
488 -- Raises an IO exception if it can't find a compiled version of the
489 -- dependents to link.
491 -- Note: This function side-effects the linker state (Pepe)
493 linkExpr hsc_env span root_ul_bco
495 -- Initialise the linker (if it's not been done already)
496 let dflags = hsc_dflags hsc_env
497 ; initDynLinker dflags
499 -- Link the packages and modules required
500 ; ok <- linkDependencies hsc_env span needed_mods
502 ghcError (ProgramError "")
505 -- Link the expression itself
506 pls <- readIORef v_PersistentLinkerState
507 ; let ie = itbl_env pls
510 -- Link the necessary packages and linkables
511 ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
515 free_names = nameSetToList (bcoFreeNames root_ul_bco)
517 needed_mods :: [Module]
518 needed_mods = [ nameModule n | n <- free_names,
519 isExternalName n, -- Names from other modules
520 not (isWiredInName n) -- Exclude wired-in names
521 ] -- (see note below)
522 -- Exclude wired-in names because we may not have read
523 -- their interface files, so getLinkDeps will fail
524 -- All wired-in names are in the base package, which we link
525 -- by default, so we can safely ignore them here.
527 dieWith :: SrcSpan -> Message -> IO a
528 dieWith span msg = ghcError (ProgramError (showSDoc (mkLocMessage span msg)))
531 checkNonStdWay :: DynFlags -> SrcSpan -> IO (Maybe String)
532 checkNonStdWay dflags srcspan = do
533 tag <- readIORef v_Build_tag
534 if null tag then return Nothing else do
535 let default_osuf = phaseInputExt StopLn
536 if objectSuf dflags == default_osuf
537 then failNonStd srcspan
538 else return (Just default_osuf)
540 failNonStd :: SrcSpan -> IO (Maybe String)
541 failNonStd srcspan = dieWith srcspan $
542 ptext (sLit "Dynamic linking required, but this is a non-standard build (eg. prof).") $$
543 ptext (sLit "You need to build the program twice: once the normal way, and then") $$
544 ptext (sLit "in the desired way using -osuf to set the object file suffix.")
547 getLinkDeps :: HscEnv -> HomePackageTable -> PackageIfaceTable
548 -> Maybe String -- the "normal" object suffix
549 -> SrcSpan -- for error messages
550 -> [Module] -- If you need these
551 -> IO ([Linkable], [PackageId]) -- ... then link these first
552 -- Fails with an IO exception if it can't find enough files
554 getLinkDeps hsc_env hpt _ maybe_normal_osuf span mods
555 -- Find all the packages and linkables that a set of modules depends on
556 = do { pls <- readIORef v_PersistentLinkerState ;
557 -- 1. Find the dependent home-pkg-modules/packages from each iface
558 (mods_s, pkgs_s) <- follow_deps mods emptyUniqSet emptyUniqSet;
561 -- 2. Exclude ones already linked
562 -- Main reason: avoid findModule calls in get_linkable
563 mods_needed = mods_s `minusList` linked_mods ;
564 pkgs_needed = pkgs_s `minusList` pkgs_loaded pls ;
566 linked_mods = map (moduleName.linkableModule)
567 (objs_loaded pls ++ bcos_loaded pls)
570 -- putStrLn (showSDoc (ppr mods_s)) ;
571 -- 3. For each dependent module, find its linkable
572 -- This will either be in the HPT or (in the case of one-shot
573 -- compilation) we may need to use maybe_getFileLinkable
574 lnks_needed <- mapM (get_linkable maybe_normal_osuf) mods_needed ;
576 return (lnks_needed, pkgs_needed) }
578 dflags = hsc_dflags hsc_env
579 this_pkg = thisPackage dflags
581 -- The ModIface contains the transitive closure of the module dependencies
582 -- within the current package, *except* for boot modules: if we encounter
583 -- a boot module, we have to find its real interface and discover the
584 -- dependencies of that. Hence we need to traverse the dependency
585 -- tree recursively. See bug #936, testcase ghci/prog007.
586 follow_deps :: [Module] -- modules to follow
587 -> UniqSet ModuleName -- accum. module dependencies
588 -> UniqSet PackageId -- accum. package dependencies
589 -> IO ([ModuleName], [PackageId]) -- result
590 follow_deps [] acc_mods acc_pkgs
591 = return (uniqSetToList acc_mods, uniqSetToList acc_pkgs)
592 follow_deps (mod:mods) acc_mods acc_pkgs
594 mb_iface <- initIfaceCheck hsc_env $
595 loadInterface msg mod (ImportByUser False)
596 iface <- case mb_iface of
597 Maybes.Failed err -> ghcError (ProgramError (showSDoc err))
598 Maybes.Succeeded iface -> return iface
600 when (mi_boot iface) $ link_boot_mod_error mod
603 pkg = modulePackageId mod
606 pkg_deps = dep_pkgs deps
607 (boot_deps, mod_deps) = partitionWith is_boot (dep_mods deps)
608 where is_boot (m,True) = Left m
609 is_boot (m,False) = Right m
611 boot_deps' = filter (not . (`elementOfUniqSet` acc_mods)) boot_deps
612 acc_mods' = addListToUniqSet acc_mods (moduleName mod : mod_deps)
613 acc_pkgs' = addListToUniqSet acc_pkgs pkg_deps
616 then follow_deps mods acc_mods (addOneToUniqSet acc_pkgs' pkg)
617 else follow_deps (map (mkModule this_pkg) boot_deps' ++ mods)
620 msg = text "need to link module" <+> ppr mod <+>
621 text "due to use of Template Haskell"
624 link_boot_mod_error mod =
625 ghcError (ProgramError (showSDoc (
626 text "module" <+> ppr mod <+>
627 text "cannot be linked; it is only available as a boot module")))
629 no_obj mod = dieWith span $
630 ptext (sLit "cannot find object file for module ") <>
634 while_linking_expr = ptext (sLit "while linking an interpreted expression")
636 -- This one is a build-system bug
638 get_linkable maybe_normal_osuf mod_name -- A home-package module
639 | Just mod_info <- lookupUFM hpt mod_name
640 = adjust_linkable (Maybes.expectJust "getLinkDeps" (hm_linkable mod_info))
642 = do -- It's not in the HPT because we are in one shot mode,
643 -- so use the Finder to get a ModLocation...
644 mb_stuff <- findHomeModule hsc_env mod_name
646 Found loc mod -> found loc mod
650 -- ...and then find the linkable for it
651 mb_lnk <- findObjectLinkableMaybe mod loc ;
653 Nothing -> no_obj mod ;
654 Just lnk -> adjust_linkable lnk
658 | Just osuf <- maybe_normal_osuf = do
659 new_uls <- mapM (adjust_ul osuf) (linkableUnlinked lnk)
660 return lnk{ linkableUnlinked=new_uls }
664 adjust_ul osuf (DotO file) = do
665 let new_file = replaceExtension file osuf
666 ok <- doesFileExist new_file
669 ptext (sLit "cannot find normal object file ")
670 <> quotes (text new_file) $$ while_linking_expr
671 else return (DotO new_file)
672 adjust_ul _ _ = panic "adjust_ul"
676 %************************************************************************
679 The linkables may consist of a mixture of
680 byte-code modules and object modules
682 %************************************************************************
685 linkModules :: DynFlags -> [Linkable] -> IO SuccessFlag
686 linkModules dflags linkables
687 = block $ do -- don't want to be interrupted by ^C in here
689 let (objs, bcos) = partition isObjectLinkable
690 (concatMap partitionLinkable linkables)
692 -- Load objects first; they can't depend on BCOs
693 ok_flag <- dynLinkObjs dflags objs
695 if failed ok_flag then
702 -- HACK to support f-x-dynamic in the interpreter; no other purpose
703 partitionLinkable :: Linkable -> [Linkable]
705 = let li_uls = linkableUnlinked li
706 li_uls_obj = filter isObject li_uls
707 li_uls_bco = filter isInterpretable li_uls
709 case (li_uls_obj, li_uls_bco) of
710 (_:_, _:_) -> [li {linkableUnlinked=li_uls_obj},
711 li {linkableUnlinked=li_uls_bco}]
714 findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
715 findModuleLinkable_maybe lis mod
716 = case [LM time nm us | LM time nm us <- lis, nm == mod] of
719 _ -> pprPanic "findModuleLinkable" (ppr mod)
721 linkableInSet :: Linkable -> [Linkable] -> Bool
722 linkableInSet l objs_loaded =
723 case findModuleLinkable_maybe objs_loaded (linkableModule l) of
725 Just m -> linkableTime l == linkableTime m
729 %************************************************************************
731 \subsection{The object-code linker}
733 %************************************************************************
736 dynLinkObjs :: DynFlags -> [Linkable] -> IO SuccessFlag
737 -- Side-effects the PersistentLinkerState
739 dynLinkObjs dflags objs
740 = do pls <- readIORef v_PersistentLinkerState
742 -- Load the object files and link them
743 let (objs_loaded', new_objs) = rmDupLinkables (objs_loaded pls) objs
744 pls1 = pls { objs_loaded = objs_loaded' }
745 unlinkeds = concatMap linkableUnlinked new_objs
747 mapM loadObj (map nameOfObject unlinkeds)
749 -- Link the all together
752 -- If resolving failed, unload all our
753 -- object modules and carry on
754 if succeeded ok then do
755 writeIORef v_PersistentLinkerState pls1
758 pls2 <- unload_wkr dflags [] pls1
759 writeIORef v_PersistentLinkerState pls2
763 rmDupLinkables :: [Linkable] -- Already loaded
764 -> [Linkable] -- New linkables
765 -> ([Linkable], -- New loaded set (including new ones)
766 [Linkable]) -- New linkables (excluding dups)
767 rmDupLinkables already ls
770 go already extras [] = (already, extras)
771 go already extras (l:ls)
772 | linkableInSet l already = go already extras ls
773 | otherwise = go (l:already) (l:extras) ls
776 %************************************************************************
778 \subsection{The byte-code linker}
780 %************************************************************************
783 dynLinkBCOs :: [Linkable] -> IO ()
784 -- Side-effects the persistent linker state
786 = do pls <- readIORef v_PersistentLinkerState
788 let (bcos_loaded', new_bcos) = rmDupLinkables (bcos_loaded pls) bcos
789 pls1 = pls { bcos_loaded = bcos_loaded' }
790 unlinkeds :: [Unlinked]
791 unlinkeds = concatMap linkableUnlinked new_bcos
793 cbcs :: [CompiledByteCode]
794 cbcs = map byteCodeOfObject unlinkeds
797 ul_bcos = [b | ByteCode bs _ <- cbcs, b <- bs]
798 ies = [ie | ByteCode _ ie <- cbcs]
799 gce = closure_env pls
800 final_ie = foldr plusNameEnv (itbl_env pls) ies
802 (final_gce, _linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
803 -- XXX What happens to these linked_bcos?
805 let pls2 = pls1 { closure_env = final_gce,
806 itbl_env = final_ie }
808 writeIORef v_PersistentLinkerState pls2
811 -- Link a bunch of BCOs and return them + updated closure env.
812 linkSomeBCOs :: Bool -- False <=> add _all_ BCOs to returned closure env
813 -- True <=> add only toplevel BCOs to closure env
817 -> IO (ClosureEnv, [HValue])
818 -- The returned HValues are associated 1-1 with
819 -- the incoming unlinked BCOs. Each gives the
820 -- value of the corresponding unlinked BCO
822 linkSomeBCOs toplevs_only ie ce_in ul_bcos
823 = do let nms = map unlinkedBCOName ul_bcos
825 ( \ hvs -> let ce_out = extendClosureEnv ce_in (zipLazy nms hvs)
826 in mapM (linkBCO ie ce_out) ul_bcos )
827 let ce_all_additions = zip nms hvals
828 ce_top_additions = filter (isExternalName.fst) ce_all_additions
829 ce_additions = if toplevs_only then ce_top_additions
830 else ce_all_additions
831 ce_out = -- make sure we're not inserting duplicate names into the
832 -- closure environment, which leads to trouble.
833 ASSERT (all (not . (`elemNameEnv` ce_in)) (map fst ce_additions))
834 extendClosureEnv ce_in ce_additions
835 return (ce_out, hvals)
840 %************************************************************************
842 Unload some object modules
844 %************************************************************************
847 -- ---------------------------------------------------------------------------
848 -- Unloading old objects ready for a new compilation sweep.
850 -- The compilation manager provides us with a list of linkables that it
851 -- considers "stable", i.e. won't be recompiled this time around. For
852 -- each of the modules current linked in memory,
854 -- * if the linkable is stable (and it's the same one - the
855 -- user may have recompiled the module on the side), we keep it,
857 -- * otherwise, we unload it.
859 -- * we also implicitly unload all temporary bindings at this point.
861 unload :: DynFlags -> [Linkable] -> IO ()
862 -- The 'linkables' are the ones to *keep*
864 unload dflags linkables
865 = block $ do -- block, so we're safe from Ctrl-C in here
867 -- Initialise the linker (if it's not been done already)
870 pls <- readIORef v_PersistentLinkerState
871 new_pls <- unload_wkr dflags linkables pls
872 writeIORef v_PersistentLinkerState new_pls
874 debugTraceMsg dflags 3 (text "unload: retaining objs" <+> ppr (objs_loaded new_pls))
875 debugTraceMsg dflags 3 (text "unload: retaining bcos" <+> ppr (bcos_loaded new_pls))
878 unload_wkr :: DynFlags
879 -> [Linkable] -- stable linkables
880 -> PersistentLinkerState
881 -> IO PersistentLinkerState
882 -- Does the core unload business
883 -- (the wrapper blocks exceptions and deals with the PLS get and put)
885 unload_wkr _ linkables pls
886 = do let (objs_to_keep, bcos_to_keep) = partition isObjectLinkable linkables
888 objs_loaded' <- filterM (maybeUnload objs_to_keep) (objs_loaded pls)
889 bcos_loaded' <- filterM (maybeUnload bcos_to_keep) (bcos_loaded pls)
891 let bcos_retained = map linkableModule bcos_loaded'
892 itbl_env' = filterNameMap bcos_retained (itbl_env pls)
893 closure_env' = filterNameMap bcos_retained (closure_env pls)
894 new_pls = pls { itbl_env = itbl_env',
895 closure_env = closure_env',
896 bcos_loaded = bcos_loaded',
897 objs_loaded = objs_loaded' }
901 maybeUnload :: [Linkable] -> Linkable -> IO Bool
902 maybeUnload keep_linkables lnk
903 | linkableInSet lnk keep_linkables = return True
905 = do mapM_ unloadObj [f | DotO f <- linkableUnlinked lnk]
906 -- The components of a BCO linkable may contain
907 -- dot-o files. Which is very confusing.
909 -- But the BCO parts can be unlinked just by
910 -- letting go of them (plus of course depopulating
911 -- the symbol table which is done in the main body)
916 %************************************************************************
920 %************************************************************************
925 = Object FilePath -- Full path name of a .o file, including trailing .o
926 -- For dynamic objects only, try to find the object
927 -- file in all the directories specified in
928 -- v_Library_paths before giving up.
930 | DLL String -- "Unadorned" name of a .DLL/.so
931 -- e.g. On unix "qt" denotes "libqt.so"
932 -- On WinDoze "burble" denotes "burble.DLL"
933 -- loadDLL is platform-specific and adds the lib/.so/.DLL
934 -- suffixes platform-dependently
936 | DLLPath FilePath -- Absolute or relative pathname to a dynamic library
937 -- (ends with .dll or .so).
939 | Framework String -- Only used for darwin, but does no harm
941 -- If this package is already part of the GHCi binary, we'll already
942 -- have the right DLLs for this package loaded, so don't try to
945 -- But on Win32 we must load them 'again'; doing so is a harmless no-op
946 -- as far as the loader is concerned, but it does initialise the list
947 -- of DLL handles that rts/Linker.c maintains, and that in turn is
948 -- used by lookupSymbol. So we must call addDLL for each library
949 -- just to get the DLL handle into the list.
950 partOfGHCi :: [PackageName]
952 | isWindowsTarget || isDarwinTarget = []
953 | otherwise = map PackageName
954 ["base", "haskell98", "template-haskell", "editline"]
956 showLS :: LibrarySpec -> String
957 showLS (Object nm) = "(static) " ++ nm
958 showLS (DLL nm) = "(dynamic) " ++ nm
959 showLS (DLLPath nm) = "(dynamic) " ++ nm
960 showLS (Framework nm) = "(framework) " ++ nm
962 linkPackages :: DynFlags -> [PackageId] -> IO ()
963 -- Link exactly the specified packages, and their dependents
964 -- (unless of course they are already linked)
965 -- The dependents are linked automatically, and it doesn't matter
966 -- what order you specify the input packages.
968 -- NOTE: in fact, since each module tracks all the packages it depends on,
969 -- we don't really need to use the package-config dependencies.
970 -- However we do need the package-config stuff (to find aux libs etc),
971 -- and following them lets us load libraries in the right order, which
972 -- perhaps makes the error message a bit more localised if we get a link
973 -- failure. So the dependency walking code is still here.
975 linkPackages dflags new_pkgs
976 = do { pls <- readIORef v_PersistentLinkerState
977 ; let pkg_map = pkgIdMap (pkgState dflags)
979 ; pkgs' <- link pkg_map (pkgs_loaded pls) new_pkgs
981 ; writeIORef v_PersistentLinkerState (pls { pkgs_loaded = pkgs' })
984 link :: PackageConfigMap -> [PackageId] -> [PackageId] -> IO [PackageId]
985 link pkg_map pkgs new_pkgs
986 = foldM (link_one pkg_map) pkgs new_pkgs
988 link_one pkg_map pkgs new_pkg
989 | new_pkg `elem` pkgs -- Already linked
992 | Just pkg_cfg <- lookupPackage pkg_map new_pkg
993 = do { -- Link dependents first
994 pkgs' <- link pkg_map pkgs (map mkPackageId (depends pkg_cfg))
995 -- Now link the package itself
996 ; linkPackage dflags pkg_cfg
997 ; return (new_pkg : pkgs') }
1000 = ghcError (CmdLineError ("unknown package: " ++ packageIdString new_pkg))
1003 linkPackage :: DynFlags -> PackageConfig -> IO ()
1004 linkPackage dflags pkg
1006 let dirs = Packages.libraryDirs pkg
1008 let libs = Packages.hsLibraries pkg
1009 -- Because of slight differences between the GHC dynamic linker and
1010 -- the native system linker some packages have to link with a
1011 -- different list of libraries when using GHCi. Examples include: libs
1012 -- that are actually gnu ld scripts, and the possability that the .a
1013 -- libs do not exactly match the .so/.dll equivalents. So if the
1014 -- package file provides an "extra-ghci-libraries" field then we use
1015 -- that instead of the "extra-libraries" field.
1016 ++ (if null (Packages.extraGHCiLibraries pkg)
1017 then Packages.extraLibraries pkg
1018 else Packages.extraGHCiLibraries pkg)
1019 ++ [ lib | '-':'l':lib <- Packages.ldOptions pkg ]
1020 classifieds <- mapM (locateOneObj dirs) libs
1022 -- Complication: all the .so's must be loaded before any of the .o's.
1023 let dlls = [ dll | DLL dll <- classifieds ]
1024 objs = [ obj | Object obj <- classifieds ]
1026 maybePutStr dflags ("Loading package " ++ display (package pkg) ++ " ... ")
1028 -- See comments with partOfGHCi
1029 when (packageName pkg `notElem` partOfGHCi) $ do
1031 -- When a library A needs symbols from a library B, the order in
1032 -- extra_libraries/extra_ld_opts is "-lA -lB", because that's the
1033 -- way ld expects it for static linking. Dynamic linking is a
1034 -- different story: When A has no dependency information for B,
1035 -- dlopen-ing A with RTLD_NOW (see addDLL in Linker.c) will fail
1036 -- when B has not been loaded before. In a nutshell: Reverse the
1037 -- order of DLLs for dynamic linking.
1038 -- This fixes a problem with the HOpenGL package (see "Compiling
1039 -- HOpenGL under recent versions of GHC" on the HOpenGL list).
1040 mapM_ (load_dyn dirs) (reverse dlls)
1042 -- After loading all the DLLs, we can load the static objects.
1043 -- Ordering isn't important here, because we do one final link
1044 -- step to resolve everything.
1047 maybePutStr dflags "linking ... "
1049 if succeeded ok then maybePutStrLn dflags "done."
1050 else ghcError (InstallationError ("unable to load package `" ++ display (package pkg) ++ "'"))
1052 load_dyn :: [FilePath] -> FilePath -> IO ()
1053 load_dyn dirs dll = do r <- loadDynamic dirs dll
1055 Nothing -> return ()
1056 Just err -> ghcError (CmdLineError ("can't load .so/.DLL for: "
1057 ++ dll ++ " (" ++ err ++ ")" ))
1059 loadFrameworks :: InstalledPackageInfo_ ModuleName -> IO ()
1061 | isDarwinTarget = mapM_ load frameworks
1062 | otherwise = return ()
1064 fw_dirs = Packages.frameworkDirs pkg
1065 frameworks = Packages.frameworks pkg
1067 load fw = do r <- loadFramework fw_dirs fw
1069 Nothing -> return ()
1070 Just err -> ghcError (CmdLineError ("can't load framework: "
1071 ++ fw ++ " (" ++ err ++ ")" ))
1073 -- Try to find an object file for a given library in the given paths.
1074 -- If it isn't present, we assume it's a dynamic library.
1075 locateOneObj :: [FilePath] -> String -> IO LibrarySpec
1076 locateOneObj dirs lib
1078 -- When the GHC package was not compiled as dynamic library
1079 -- (=__PIC__ not set), we search for .o libraries first.
1080 = do { mb_obj_path <- findFile mk_obj_path dirs
1081 ; case mb_obj_path of
1082 Just obj_path -> return (Object obj_path)
1084 do { mb_lib_path <- findFile mk_dyn_lib_path dirs
1085 ; case mb_lib_path of
1086 Just _ -> return (DLL dyn_lib_name)
1087 Nothing -> return (DLL lib) }} -- We assume
1089 -- When the GHC package was compiled as dynamic library (=__PIC__ set),
1090 -- we search for .so libraries first.
1091 = do { mb_lib_path <- findFile mk_dyn_lib_path dirs
1092 ; case mb_lib_path of
1093 Just _ -> return (DLL (lib ++ "-ghc" ++ cProjectVersion))
1095 do { mb_obj_path <- findFile mk_obj_path dirs
1096 ; case mb_obj_path of
1097 Just obj_path -> return (Object obj_path)
1098 Nothing -> return (DLL lib) }} -- We assume
1100 mk_obj_path dir = dir </> (lib <.> "o")
1101 dyn_lib_name = lib ++ "-ghc" ++ cProjectVersion
1102 mk_dyn_lib_path dir = dir </> mkSOName dyn_lib_name
1104 -- ----------------------------------------------------------------------------
1105 -- Loading a dyanmic library (dlopen()-ish on Unix, LoadLibrary-ish on Win32)
1107 -- return Nothing == success, else Just error message from dlopen
1108 loadDynamic :: [FilePath] -> FilePath -> IO (Maybe String)
1109 loadDynamic paths rootname
1110 = do { mb_dll <- findFile mk_dll_path paths
1112 Just dll -> loadDLL dll
1113 Nothing -> loadDLL (mkSOName rootname) }
1114 -- Tried all our known library paths, so let
1115 -- dlopen() search its own builtin paths now.
1117 mk_dll_path dir = dir </> mkSOName rootname
1119 mkSOName :: FilePath -> FilePath
1121 | isDarwinTarget = ("lib" ++ root) <.> "dylib"
1122 | isWindowsTarget = -- Win32 DLLs have no .dll extension here, because
1123 -- addDLL tries both foo.dll and foo.drv
1125 | otherwise = ("lib" ++ root) <.> "so"
1127 -- Darwin / MacOS X only: load a framework
1128 -- a framework is a dynamic library packaged inside a directory of the same
1129 -- name. They are searched for in different paths than normal libraries.
1130 loadFramework :: [FilePath] -> FilePath -> IO (Maybe String)
1131 loadFramework extraPaths rootname
1132 = do { either_dir <- tryIO getHomeDirectory
1133 ; let homeFrameworkPath = case either_dir of
1135 Right dir -> [dir ++ "/Library/Frameworks"]
1136 ps = extraPaths ++ homeFrameworkPath ++ defaultFrameworkPaths
1137 ; mb_fwk <- findFile mk_fwk ps
1139 Just fwk_path -> loadDLL fwk_path
1140 Nothing -> return (Just "not found") }
1141 -- Tried all our known library paths, but dlopen()
1142 -- has no built-in paths for frameworks: give up
1144 mk_fwk dir = dir </> (rootname ++ ".framework/" ++ rootname)
1145 -- sorry for the hardcoded paths, I hope they won't change anytime soon:
1146 defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
1149 %************************************************************************
1153 %************************************************************************
1156 findFile :: (FilePath -> FilePath) -- Maps a directory path to a file path
1157 -> [FilePath] -- Directories to look in
1158 -> IO (Maybe FilePath) -- The first file path to match
1161 findFile mk_file_path (dir:dirs)
1162 = do { let file_path = mk_file_path dir
1163 ; b <- doesFileExist file_path
1165 return (Just file_path)
1167 findFile mk_file_path dirs }
1171 maybePutStr :: DynFlags -> String -> IO ()
1172 maybePutStr dflags s | verbosity dflags > 0 = putStr s
1173 | otherwise = return ()
1175 maybePutStrLn :: DynFlags -> String -> IO ()
1176 maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
1177 | otherwise = return ()