+module Linker ( HValue, showLinkerState,
+ linkExpr, unload, extendLinkEnv,
+ linkPackages,
+ ) where
+
+#include "HsVersions.h"
+
+import ObjLink ( loadDLL, loadObj, unloadObj, resolveObjs, initObjLinker )
+import ByteCodeLink ( HValue, ClosureEnv, extendClosureEnv, linkBCO )
+import ByteCodeItbls ( ItblEnv )
+import ByteCodeAsm ( CompiledByteCode(..), bcoFreeNames, UnlinkedBCO(..))
+
+import Packages
+import DriverState ( v_Library_paths, v_Opt_l, v_Ld_inputs, getStaticOpts )
+import DriverPhases ( isObjectFilename, isDynLibFilename )
+import DriverUtil ( getFileSuffix )
+#ifdef darwin_TARGET_OS
+import DriverState ( v_Cmdline_frameworks, v_Framework_paths )
+#endif
+import Finder ( findModule, findLinkable, FindResult(..) )
+import HscTypes
+import Name ( Name, nameModule, isExternalName, isWiredInName )
+import NameEnv
+import NameSet ( nameSetToList )
+import Module
+import ListSetOps ( minusList )
+import CmdLineOpts ( DynFlags(..) )
+import BasicTypes ( SuccessFlag(..), succeeded, failed )
+import Outputable
+import Panic ( GhcException(..) )
+import Util ( zipLazy, global )
+
+-- Standard libraries
+import Control.Monad ( when, filterM, foldM )
+
+import Data.IORef ( IORef, readIORef, writeIORef )
+import Data.List ( partition, nub )
+
+import System.IO ( putStr, putStrLn, hPutStrLn, stderr, fixIO )
+import System.Directory ( doesFileExist )
+
+import Control.Exception ( block, throwDyn )
+
+#if __GLASGOW_HASKELL__ >= 503
+import GHC.IOBase ( IO(..) )
+#else
+import PrelIOBase ( IO(..) )
+#endif
+\end{code}
+
+
+%************************************************************************
+%* *
+ The Linker's state
+%* *
+%************************************************************************
+
+The persistent linker state *must* match the actual state of the
+C dynamic linker at all times, so we keep it in a private global variable.
+
+
+The PersistentLinkerState maps Names to actual closures (for
+interpreted code only), for use during linking.
+
+\begin{code}
+GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
+GLOBAL_VAR(v_InitLinkerDone, False, Bool) -- Set True when dynamic linker is initialised
+
+data PersistentLinkerState
+ = PersistentLinkerState {
+
+ -- Current global mapping from Names to their true values
+ closure_env :: ClosureEnv,
+
+ -- The current global mapping from RdrNames of DataCons to
+ -- info table addresses.
+ -- When a new Unlinked is linked into the running image, or an existing
+ -- module in the image is replaced, the itbl_env must be updated
+ -- appropriately.
+ itbl_env :: ItblEnv,
+
+ -- The currently loaded interpreted modules (home package)
+ bcos_loaded :: [Linkable],
+
+ -- And the currently-loaded compiled modules (home package)
+ objs_loaded :: [Linkable],
+
+ -- The currently-loaded packages; always object code
+ -- Held, as usual, in dependency order; though I am not sure if
+ -- that is really important
+ pkgs_loaded :: [PackageId]
+ }
+
+emptyPLS :: DynFlags -> PersistentLinkerState
+emptyPLS dflags = PersistentLinkerState {
+ closure_env = emptyNameEnv,
+ itbl_env = emptyNameEnv,
+ pkgs_loaded = init_pkgs,
+ bcos_loaded = [],
+ objs_loaded = [] }
+ -- Packages that don't need loading, because the compiler
+ -- shares them with the interpreted program.
+ --
+ -- The linker's symbol table is populated with RTS symbols using an
+ -- explicit list. See rts/Linker.c for details.
+ where init_pkgs
+ | ExtPackage rts_id <- rtsPackageId (pkgState dflags) = [rts_id]
+ | otherwise = []
+\end{code}
+
+\begin{code}
+extendLinkEnv :: [(Name,HValue)] -> IO ()
+-- Automatically discards shadowed bindings
+extendLinkEnv new_bindings
+ = do pls <- readIORef v_PersistentLinkerState
+ let new_closure_env = extendClosureEnv (closure_env pls) new_bindings
+ new_pls = pls { closure_env = new_closure_env }
+ writeIORef v_PersistentLinkerState new_pls
+
+-- filterNameMap removes from the environment all entries except
+-- those for a given set of modules;
+-- Note that this removes all *local* (i.e. non-isExternal) names too
+-- (these are the temporary bindings from the command line).
+-- Used to filter both the ClosureEnv and ItblEnv
+
+filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
+filterNameMap mods env
+ = filterNameEnv keep_elt env
+ where
+ keep_elt (n,_) = isExternalName n
+ && (nameModule n `elem` mods)
+\end{code}
+
+
+\begin{code}
+showLinkerState :: IO ()
+-- Display the persistent linker state
+showLinkerState
+ = do pls <- readIORef v_PersistentLinkerState
+ printDump (vcat [text "----- Linker state -----",
+ text "Pkgs:" <+> ppr (pkgs_loaded pls),
+ text "Objs:" <+> ppr (objs_loaded pls),
+ text "BCOs:" <+> ppr (bcos_loaded pls)])
+\end{code}
+
+
+
+
+%************************************************************************
+%* *
+\subsection{Initialisation}
+%* *
+%************************************************************************
+
+We initialise the dynamic linker by
+
+a) calling the C initialisation procedure
+
+b) Loading any packages specified on the command line,
+ now held in v_ExplicitPackages
+
+c) Loading any packages specified on the command line,
+ now held in the -l options in v_Opt_l
+
+d) Loading any .o/.dll files specified on the command line,
+ now held in v_Ld_inputs
+
+e) Loading any MacOS frameworks
+
+\begin{code}
+initDynLinker :: DynFlags -> IO ()
+-- This function is idempotent; if called more than once, it does nothing
+-- This is useful in Template Haskell, where we call it before trying to link
+initDynLinker dflags
+ = do { done <- readIORef v_InitLinkerDone
+ ; if done then return ()
+ else do { writeIORef v_InitLinkerDone True
+ ; reallyInitDynLinker dflags }
+ }
+
+reallyInitDynLinker dflags
+ = do { -- Initialise the linker state
+ ; writeIORef v_PersistentLinkerState (emptyPLS dflags)
+
+ -- (a) initialise the C dynamic linker
+ ; initObjLinker
+
+ -- (b) Load packages from the command-line
+ ; linkPackages dflags (explicitPackages (pkgState dflags))
+
+ -- (c) Link libraries from the command-line
+ ; opt_l <- getStaticOpts v_Opt_l
+ ; let minus_ls = [ lib | '-':'l':lib <- opt_l ]
+
+ -- (d) Link .o files from the command-line
+ ; lib_paths <- readIORef v_Library_paths
+ ; cmdline_ld_inputs <- readIORef v_Ld_inputs
+
+ ; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
+
+ -- (e) Link any MacOS frameworks
+#ifdef darwin_TARGET_OS
+ ; framework_paths <- readIORef v_Framework_paths
+ ; frameworks <- readIORef v_Cmdline_frameworks
+#else
+ ; let frameworks = []
+ ; let framework_paths = []
+#endif
+ -- Finally do (c),(d),(e)
+ ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
+ ++ map DLL minus_ls
+ ++ map Framework frameworks
+ ; if null cmdline_lib_specs then return ()
+ else do
+
+ { mapM_ (preloadLib dflags lib_paths framework_paths) cmdline_lib_specs
+ ; maybePutStr dflags "final link ... "
+ ; ok <- resolveObjs
+
+ ; if succeeded ok then maybePutStrLn dflags "done"
+ else throwDyn (InstallationError "linking extra libraries/objects failed")
+ }}
+
+classifyLdInput :: FilePath -> IO (Maybe LibrarySpec)
+classifyLdInput f
+ | isObjectFilename f = return (Just (Object f))
+ | isDynLibFilename f = return (Just (DLLPath f))
+ | otherwise = do
+ hPutStrLn stderr ("Warning: ignoring unrecognised input `" ++ f ++ "'")
+ return Nothing
+
+preloadLib :: DynFlags -> [String] -> [String] -> LibrarySpec -> IO ()
+preloadLib dflags lib_paths framework_paths lib_spec
+ = do maybePutStr dflags ("Loading object " ++ showLS lib_spec ++ " ... ")
+ case lib_spec of
+ Object static_ish
+ -> do b <- preload_static lib_paths static_ish
+ maybePutStrLn dflags (if b then "done"
+ else "not found")
+
+ DLL dll_unadorned
+ -> do maybe_errstr <- loadDynamic lib_paths dll_unadorned
+ case maybe_errstr of
+ Nothing -> maybePutStrLn dflags "done"
+ Just mm -> preloadFailed mm lib_paths lib_spec
+
+ DLLPath dll_path
+ -> do maybe_errstr <- loadDLL dll_path
+ case maybe_errstr of
+ Nothing -> maybePutStrLn dflags "done"
+ Just mm -> preloadFailed mm lib_paths lib_spec
+
+#ifdef darwin_TARGET_OS
+ Framework framework
+ -> do maybe_errstr <- loadFramework framework_paths framework
+ case maybe_errstr of
+ Nothing -> maybePutStrLn dflags "done"
+ Just mm -> preloadFailed mm framework_paths lib_spec
+#endif
+ where
+ preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
+ preloadFailed sys_errmsg paths spec
+ = do maybePutStr dflags
+ ("failed.\nDynamic linker error message was:\n "
+ ++ sys_errmsg ++ "\nWhilst trying to load: "
+ ++ showLS spec ++ "\nDirectories to search are:\n"
+ ++ unlines (map (" "++) paths) )
+ give_up
+
+ -- Not interested in the paths in the static case.
+ preload_static paths name
+ = do b <- doesFileExist name
+ if not b then return False
+ else loadObj name >> return True
+
+ give_up = throwDyn $
+ CmdLineError "user specified .o/.so/.DLL could not be loaded."
+\end{code}
+
+
+%************************************************************************
+%* *
+ Link a byte-code expression
+%* *
+%************************************************************************
+
+\begin{code}
+linkExpr :: HscEnv -> UnlinkedBCO -> IO HValue
+
+-- Link a single expression, *including* first linking packages and
+-- modules that this expression depends on.
+--
+-- Raises an IO exception if it can't find a compiled version of the
+-- dependents to link.
+
+linkExpr hsc_env root_ul_bco
+ = do {
+ -- Initialise the linker (if it's not been done already)
+ let dflags = hsc_dflags hsc_env
+ ; initDynLinker dflags
+
+ -- Find what packages and linkables are required
+ ; eps <- readIORef (hsc_EPS hsc_env)
+ ; (lnks, pkgs) <- getLinkDeps dflags hpt (eps_PIT eps) needed_mods
+
+ -- Link the packages and modules required
+ ; linkPackages dflags pkgs
+ ; ok <- linkModules dflags lnks
+ ; if failed ok then
+ dieWith empty
+ else do {
+
+ -- Link the expression itself
+ pls <- readIORef v_PersistentLinkerState
+ ; let ie = itbl_env pls
+ ce = closure_env pls
+
+ -- Link the necessary packages and linkables
+ ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
+ ; return root_hval
+ }}
+ where
+ hpt = hsc_HPT hsc_env
+ dflags = hsc_dflags hsc_env
+ free_names = nameSetToList (bcoFreeNames root_ul_bco)
+
+ needed_mods :: [Module]
+ needed_mods = [ nameModule n | n <- free_names,
+ isExternalName n, -- Names from other modules
+ not (isWiredInName n) -- Exclude wired-in names
+ ] -- (see note below)
+ -- Exclude wired-in names because we may not have read
+ -- their interface files, so getLinkDeps will fail
+ -- All wired-in names are in the base package, which we link
+ -- by default, so we can safely ignore them here.
+
+dieWith msg = throwDyn (ProgramError (showSDoc msg))
+
+getLinkDeps :: DynFlags -> HomePackageTable -> PackageIfaceTable
+ -> [Module] -- If you need these
+ -> IO ([Linkable], [PackageId]) -- ... then link these first
+-- Fails with an IO exception if it can't find enough files
+
+getLinkDeps dflags hpt pit mods
+-- Find all the packages and linkables that a set of modules depends on
+ = do { pls <- readIORef v_PersistentLinkerState ;
+ let {
+ -- 1. Find the dependent home-pkg-modules/packages from each iface
+ (mods_s, pkgs_s) = unzip (map get_deps mods) ;
+
+ -- 2. Exclude ones already linked
+ -- Main reason: avoid findModule calls in get_linkable
+ mods_needed = nub (concat mods_s) `minusList` linked_mods ;
+ pkgs_needed = nub (concat pkgs_s) `minusList` pkgs_loaded pls ;
+
+ linked_mods = map linkableModule (objs_loaded pls ++ bcos_loaded pls)
+ } ;
+
+ -- 3. For each dependent module, find its linkable
+ -- This will either be in the HPT or (in the case of one-shot
+ -- compilation) we may need to use maybe_getFileLinkable
+ lnks_needed <- mapM get_linkable mods_needed ;
+
+ return (lnks_needed, pkgs_needed) }
+ where
+ get_deps :: Module -> ([Module],[PackageId])
+ -- Get the things needed for the specified module
+ -- This is rather similar to the code in RnNames.importsFromImportDecl
+ get_deps mod
+ | ExtPackage p <- mi_package iface
+ = ([], p : dep_pkgs deps)
+ | otherwise
+ = (mod : [m | (m,_) <- dep_mods deps], dep_pkgs deps)
+ where
+ iface = get_iface mod
+ deps = mi_deps iface
+
+ get_iface mod = case lookupIface hpt pit mod of
+ Just iface -> iface
+ Nothing -> pprPanic "getLinkDeps" (no_iface mod)
+ no_iface mod = ptext SLIT("No iface for") <+> ppr mod
+ -- This one is a GHC bug
+
+ no_obj mod = dieWith (ptext SLIT("No compiled code for") <+> ppr mod)
+ -- This one is a build-system bug
+
+ get_linkable mod_name -- A home-package module
+ | Just mod_info <- lookupModuleEnv hpt mod_name
+ = return (hm_linkable mod_info)
+ | otherwise
+ = -- It's not in the HPT because we are in one shot mode,
+ -- so use the Finder to get a ModLocation...
+ do { mb_stuff <- findModule dflags mod_name False ;
+ case mb_stuff of {
+ Found loc _ -> found loc mod_name ;
+ _ -> no_obj mod_name
+ }}
+
+ found loc mod_name = do {
+ -- ...and then find the linkable for it
+ mb_lnk <- findLinkable mod_name loc ;
+ case mb_lnk of {
+ Nothing -> no_obj mod_name ;
+ Just lnk -> return lnk
+ }}
+\end{code}
+
+
+%************************************************************************
+%* *
+ Link some linkables
+ The linkables may consist of a mixture of
+ byte-code modules and object modules
+%* *
+%************************************************************************
+
+\begin{code}
+linkModules :: DynFlags -> [Linkable] -> IO SuccessFlag
+linkModules dflags linkables
+ = block $ do -- don't want to be interrupted by ^C in here
+
+ let (objs, bcos) = partition isObjectLinkable
+ (concatMap partitionLinkable linkables)
+
+ -- Load objects first; they can't depend on BCOs
+ ok_flag <- dynLinkObjs dflags objs
+
+ if failed ok_flag then
+ return Failed
+ else do
+ dynLinkBCOs bcos
+ return Succeeded
+
+
+-- HACK to support f-x-dynamic in the interpreter; no other purpose
+partitionLinkable :: Linkable -> [Linkable]
+partitionLinkable li
+ = let li_uls = linkableUnlinked li
+ li_uls_obj = filter isObject li_uls
+ li_uls_bco = filter isInterpretable li_uls
+ in
+ case (li_uls_obj, li_uls_bco) of
+ (objs@(_:_), bcos@(_:_))
+ -> [li{linkableUnlinked=li_uls_obj}, li{linkableUnlinked=li_uls_bco}]
+ other
+ -> [li]
+
+findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
+findModuleLinkable_maybe lis mod
+ = case [LM time nm us | LM time nm us <- lis, nm == mod] of
+ [] -> Nothing
+ [li] -> Just li
+ many -> pprPanic "findModuleLinkable" (ppr mod)
+
+linkableInSet :: Linkable -> [Linkable] -> Bool
+linkableInSet l objs_loaded =
+ case findModuleLinkable_maybe objs_loaded (linkableModule l) of
+ Nothing -> False
+ Just m -> linkableTime l == linkableTime m
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{The object-code linker}
+%* *
+%************************************************************************
+
+\begin{code}
+dynLinkObjs :: DynFlags -> [Linkable] -> IO SuccessFlag
+ -- Side-effects the PersistentLinkerState
+
+dynLinkObjs dflags objs
+ = do pls <- readIORef v_PersistentLinkerState
+
+ -- Load the object files and link them
+ let (objs_loaded', new_objs) = rmDupLinkables (objs_loaded pls) objs
+ pls1 = pls { objs_loaded = objs_loaded' }
+ unlinkeds = concatMap linkableUnlinked new_objs
+
+ mapM loadObj (map nameOfObject unlinkeds)
+
+ -- Link the all together
+ ok <- resolveObjs
+
+ -- If resolving failed, unload all our
+ -- object modules and carry on
+ if succeeded ok then do
+ writeIORef v_PersistentLinkerState pls1
+ return Succeeded
+ else do
+ pls2 <- unload_wkr dflags [] pls1
+ writeIORef v_PersistentLinkerState pls2
+ return Failed
+
+
+rmDupLinkables :: [Linkable] -- Already loaded
+ -> [Linkable] -- New linkables
+ -> ([Linkable], -- New loaded set (including new ones)
+ [Linkable]) -- New linkables (excluding dups)
+rmDupLinkables already ls
+ = go already [] ls
+ where
+ go already extras [] = (already, extras)
+ go already extras (l:ls)
+ | linkableInSet l already = go already extras ls
+ | otherwise = go (l:already) (l:extras) ls
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{The byte-code linker}
+%* *
+%************************************************************************
+
+\begin{code}
+dynLinkBCOs :: [Linkable] -> IO ()
+ -- Side-effects the persistent linker state
+dynLinkBCOs bcos
+ = do pls <- readIORef v_PersistentLinkerState
+
+ let (bcos_loaded', new_bcos) = rmDupLinkables (bcos_loaded pls) bcos
+ pls1 = pls { bcos_loaded = bcos_loaded' }
+ unlinkeds :: [Unlinked]
+ unlinkeds = concatMap linkableUnlinked new_bcos
+
+ cbcs :: [CompiledByteCode]
+ cbcs = map byteCodeOfObject unlinkeds
+
+
+ ul_bcos = [b | ByteCode bs _ <- cbcs, b <- bs]
+ ies = [ie | ByteCode _ ie <- cbcs]
+ gce = closure_env pls
+ final_ie = foldr plusNameEnv (itbl_env pls) ies
+
+ (final_gce, linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
+ -- What happens to these linked_bcos?
+
+ let pls2 = pls1 { closure_env = final_gce,
+ itbl_env = final_ie }
+
+ writeIORef v_PersistentLinkerState pls2
+ return ()
+
+-- Link a bunch of BCOs and return them + updated closure env.
+linkSomeBCOs :: Bool -- False <=> add _all_ BCOs to returned closure env
+ -- True <=> add only toplevel BCOs to closure env
+ -> ItblEnv
+ -> ClosureEnv
+ -> [UnlinkedBCO]
+ -> IO (ClosureEnv, [HValue])
+ -- The returned HValues are associated 1-1 with
+ -- the incoming unlinked BCOs. Each gives the
+ -- value of the corresponding unlinked BCO
+
+
+linkSomeBCOs toplevs_only ie ce_in ul_bcos
+ = do let nms = map unlinkedBCOName ul_bcos
+ hvals <- fixIO
+ ( \ hvs -> let ce_out = extendClosureEnv ce_in (zipLazy nms hvs)
+ in mapM (linkBCO ie ce_out) ul_bcos )
+
+ let ce_all_additions = zip nms hvals
+ ce_top_additions = filter (isExternalName.fst) ce_all_additions
+ ce_additions = if toplevs_only then ce_top_additions
+ else ce_all_additions
+ ce_out = -- make sure we're not inserting duplicate names into the
+ -- closure environment, which leads to trouble.
+ ASSERT (all (not . (`elemNameEnv` ce_in)) (map fst ce_additions))
+ extendClosureEnv ce_in ce_additions
+ return (ce_out, hvals)
+
+\end{code}
+
+
+%************************************************************************
+%* *
+ Unload some object modules
+%* *
+%************************************************************************
+
+\begin{code}