+{-# OPTIONS -#include "Linker.h" -#include "SchedAPI.h" #-}
-----------------------------------------------------------------------------
--- $Id: InteractiveUI.hs,v 1.75 2001/06/15 08:29:57 simonpj Exp $
+-- $Id: InteractiveUI.hs,v 1.104 2002/01/03 17:05:50 sewardj Exp $
--
-- GHC Interactive User Interface
--
-- (c) The GHC Team 2000
--
-----------------------------------------------------------------------------
-
-{-# OPTIONS -#include "Linker.h" #-}
module InteractiveUI ( interactiveUI, ghciWelcomeMsg ) where
#include "../includes/config.h"
#include "HsVersions.h"
+import Packages
import CompManager
-import HscTypes ( GhciMode(..) )
+import HscTypes ( TyThing(..) )
+import MkIface
import ByteCodeLink
import DriverFlags
import DriverState
import Linker
import Finder ( flushPackageCache )
import Util
-import Name ( Name )
+import Id ( isRecordSelector, recordSelectorFieldLabel,
+ isDataConWrapId, idName )
+import Class ( className )
+import TyCon ( tyConName, tyConClass_maybe, isPrimTyCon )
+import FieldLabel ( fieldLabelTyCon )
+import SrcLoc ( isGoodSrcLoc )
+import Name ( Name, isHomePackageName, nameSrcLoc, nameOccName,
+ NamedThing(..) )
+import OccName ( isSymOcc )
+import BasicTypes ( defaultFixity )
import Outputable
import CmdLineOpts ( DynFlag(..), getDynFlags, saveDynFlags, restoreDynFlags, dopt_unset )
-import Panic ( GhcException(..) )
+import Panic ( GhcException(..), showGhcException )
import Config
#ifndef mingw32_TARGET_OS
#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
import Readline
#endif
+import Concurrent
import IOExts
+import SystemExts
import Numeric
import List
import Directory
import IO
import Char
-import Monad ( when )
+import Monad ( when, join )
import PrelGHC ( unsafeCoerce# )
import Foreign ( nullPtr )
("def", keepGoing defineMacro),
("help", keepGoing help),
("?", keepGoing help),
+ ("info", keepGoing info),
("load", keepGoing loadModule),
("module", keepGoing setContext),
("reload", keepGoing reloadModule),
- ("set", keepGoing setOptions),
+ ("set", keepGoing setCmd),
("type", keepGoing typeOfExpr),
("unset", keepGoing unsetOptions),
("undef", keepGoing undefineMacro),
helpText = "\
\ Commands available from the prompt:\n\
-\\
+\\
\ <stmt> evaluate/run <stmt>\n\
+\ :add <filename> ... add module(s) to the current target set\n\
\ :cd <dir> change directory to <dir>\n\
\ :def <cmd> <expr> define a command :<cmd>\n\
\ :help, :? display this list of commands\n\
-\ :load <filename> load a module (and its dependents)\n\
+\ :info [<name> ...] display information about the given names\n\
+\ :load <filename> ... load module(s) and their dependents\n\
\ :module <mod> set the context for expression evaluation to <mod>\n\
\ :reload reload the current module set\n\
\ :set <option> ... set options\n\
+\ :set args <arg> ... set the arguments returned by System.getArgs\n\
+\ :set prog <progname> set the value returned by System.getProgName\n\
\ :undef <cmd> undefine user-defined command :<cmd>\n\
\ :type <expr> show the type of <expr>\n\
\ :unset <option> ... unset options\n\
\ -<flags> most GHC command line flags can also be set here\n\
\ (eg. -v2, -fglasgow-exts, etc.)\n\
\"
- --ToDo :add <filename> add a module to the current set\n\
-interactiveUI :: CmState -> Maybe FilePath -> [LibrarySpec] -> IO ()
-interactiveUI cmstate mod cmdline_libs = do
+interactiveUI :: CmState -> [FilePath] -> [LibrarySpec] -> IO ()
+interactiveUI cmstate paths cmdline_libs = do
hFlush stdout
hSetBuffering stdout NoBuffering
initLinker
linkPackages cmdline_libs pkgs
- (cmstate, ok, mods) <-
- case mod of
- Nothing -> return (cmstate, True, [])
- Just m -> cmLoadModule cmstate m
-
-#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
- Readline.initialize
-#endif
-
dflags <- getDynFlags
(cmstate, maybe_hval)
+ <- cmCompileExpr cmstate dflags "IO.hSetBuffering IO.stdout IO.NoBuffering Prelude.>> IO.hSetBuffering IO.stderr IO.NoBuffering"
+ case maybe_hval of
+ Just hval -> unsafeCoerce# hval :: IO ()
+ _ -> panic "interactiveUI:buffering"
+
+ (cmstate, maybe_hval)
<- cmCompileExpr cmstate dflags "IO.hFlush PrelHandle.stderr"
case maybe_hval of
Just hval -> writeIORef flush_stderr (unsafeCoerce# hval :: IO ())
Just hval -> writeIORef flush_stdout (unsafeCoerce# hval :: IO ())
_ -> panic "interactiveUI:stdout"
- startGHCi runGHCi GHCiState{ target = mod,
- cmstate = cmstate,
- options = [] }
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+ Readline.initialize
+#endif
+
+ startGHCi (runGHCi paths)
+ GHCiState{ progname = "<interactive>",
+ args = [],
+ targets = paths,
+ cmstate = cmstate,
+ options = [] }
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+ Readline.resetTerminal Nothing
+#endif
+
return ()
-runGHCi :: GHCi ()
-runGHCi = do
- -- Read in ./.ghci.
- let file = "./.ghci"
- exists <- io (doesFileExist file)
- when exists $ do
- dir_ok <- io (checkPerms ".")
- file_ok <- io (checkPerms file)
- when (dir_ok && file_ok) $ do
- either_hdl <- io (IO.try (openFile "./.ghci" ReadMode))
- case either_hdl of
- Left e -> return ()
- Right hdl -> fileLoop hdl False
-
- -- Read in $HOME/.ghci
- either_dir <- io (IO.try (getEnv "HOME"))
- case either_dir of
- Left e -> return ()
- Right dir -> do
- cwd <- io (getCurrentDirectory)
- when (dir /= cwd) $ do
- let file = dir ++ "/.ghci"
- ok <- io (checkPerms file)
- either_hdl <- io (IO.try (openFile file ReadMode))
- case either_hdl of
- Left e -> return ()
- Right hdl -> fileLoop hdl False
+runGHCi :: [FilePath] -> GHCi ()
+runGHCi paths = do
+ read_dot_files <- io (readIORef v_Read_DotGHCi)
+
+ when (read_dot_files) $ do
+ -- Read in ./.ghci.
+ let file = "./.ghci"
+ exists <- io (doesFileExist file)
+ when exists $ do
+ dir_ok <- io (checkPerms ".")
+ file_ok <- io (checkPerms file)
+ when (dir_ok && file_ok) $ do
+ either_hdl <- io (IO.try (openFile "./.ghci" ReadMode))
+ case either_hdl of
+ Left e -> return ()
+ Right hdl -> fileLoop hdl False
+
+ when (read_dot_files) $ do
+ -- Read in $HOME/.ghci
+ either_dir <- io (IO.try (getEnv "HOME"))
+ case either_dir of
+ Left e -> return ()
+ Right dir -> do
+ cwd <- io (getCurrentDirectory)
+ when (dir /= cwd) $ do
+ let file = dir ++ "/.ghci"
+ ok <- io (checkPerms file)
+ when ok $ do
+ either_hdl <- io (IO.try (openFile file ReadMode))
+ case either_hdl of
+ Left e -> return ()
+ Right hdl -> fileLoop hdl False
+
+ -- perform a :load for files given on the GHCi command line
+ when (not (null paths)) $
+ ghciHandle showException $
+ loadModule (unwords paths)
+
+ -- enter the interactive loop
+ interactiveLoop
+
+ -- and finally, exit
+ io $ do putStrLn "Leaving GHCi."
+
+
+interactiveLoop = do
+ -- ignore ^C exceptions caught here
+ ghciHandleDyn (\e -> case e of Interrupted -> ghciUnblock interactiveLoop
+ _other -> return ()) $ do
-- read commands from stdin
#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
fileLoop stdin True
#endif
- -- and finally, exit
- io $ do putStrLn "Leaving GHCi."
-
-- NOTE: We only read .ghci files if they are owned by the current user,
-- and aren't world writable. Otherwise, we could be accidentally
-- running code planted by a malicious third party.
--- Furthermore, We only read ./.ghci if both . and ./.ghci are
--- owned by the current user and aren't writable by anyone else. I
--- think this is sufficient: we don't need to check .. and
--- ../.. etc. because "." always refers to the same directory while a
--- process is running.
+-- Furthermore, We only read ./.ghci if . is owned by the current user
+-- and isn't writable by anyone else. I think this is sufficient: we
+-- don't need to check .. and ../.. etc. because "." always refers to
+-- the same directory while a process is running.
checkPerms :: String -> IO Bool
checkPerms name =
readlineLoop = do
st <- getGHCiState
mod <- io (cmGetContext (cmstate st))
+ io yield
l <- io (readline (mod ++ "> "))
case l of
Nothing -> return ()
-- and carries on.
runCommand :: String -> GHCi Bool
runCommand c =
- ghciHandle ( \exception ->
- (case exception of
- DynException dyn ->
- case fromDynamic dyn of
- Nothing -> io (putStrLn ("*** Exception: (unknown)"))
- Just ghc_ex ->
- case ghc_ex of
- PhaseFailed phase code ->
- io ( putStrLn ("Phase " ++ phase ++ " failed (code "
- ++ show code ++ ")"))
- Interrupted -> io (putStrLn "Interrupted.")
- -- omit the location for CmdLineError
- CmdLineError s -> io (putStrLn s)
- other -> io (putStrLn (show (ghc_ex :: GhcException)))
-
- other -> io (putStrLn ("*** Exception: " ++ show exception))
-
- ) >> return False
- ) $
-
- doCommand c
+ ghciHandle ( \exception -> do
+ flushEverything
+ showException exception
+ return False
+ ) $
+ doCommand c
+
+showException (DynException dyn) =
+ case fromDynamic dyn of
+ Nothing -> io (putStrLn ("*** Exception: (unknown)"))
+ Just Interrupted -> io (putStrLn "Interrupted.")
+ Just (CmdLineError s) -> io (putStrLn s) -- omit the location for CmdLineError
+ Just ph@PhaseFailed{} -> io (putStrLn (showGhcException ph "")) -- ditto
+ Just other_ghc_ex -> io (print other_ghc_ex)
+
+showException other_exception
+ = io (putStrLn ("*** Exception: " ++ show other_exception))
doCommand (':' : command) = specialCommand command
doCommand stmt
- = do timeIt (do stuff <- runStmt stmt; finishEvalExpr stuff)
+ = do timeIt (do nms <- runStmt stmt; finishEvalExpr nms)
return False
--- Returns True if the expr was successfully parsed, renamed and
--- typechecked.
-runStmt :: String -> GHCi (Maybe [Name])
+runStmt :: String -> GHCi [Name]
runStmt stmt
- | null (filter (not.isSpace) stmt)
- = return Nothing
+ | null (filter (not.isSpace) stmt) = return []
| otherwise
= do st <- getGHCiState
dflags <- io getDynFlags
let dflags' = dopt_unset dflags Opt_WarnUnusedBinds
- (new_cmstate, names) <- io (cmRunStmt (cmstate st) dflags' stmt)
+ (new_cmstate, result) <-
+ io $ withProgName (progname st) $ withArgs (args st) $
+ cmRunStmt (cmstate st) dflags' stmt
setGHCiState st{cmstate = new_cmstate}
- return (Just names)
+ case result of
+ CmRunFailed -> return []
+ CmRunException e -> showException e >> return []
+ CmRunDeadlocked -> io (putStrLn "Deadlocked.") >> return []
+ CmRunOk names -> return names
-- possibly print the type and revert CAFs after evaluating an expression
-finishEvalExpr Nothing = return False
-finishEvalExpr (Just names)
+finishEvalExpr names
= do b <- isOptionSet ShowType
st <- getGHCiState
when b (mapM_ (showTypeOfName (cmstate st)) names)
flushEverything :: GHCi ()
flushEverything
- = io $ do flush_so <- readIORef flush_stdout
- flush_so
- flush_se <- readIORef flush_stdout
- flush_se
+ = io $ do Monad.join (readIORef flush_stdout)
+ Monad.join (readIORef flush_stderr)
return ()
specialCommand :: String -> GHCi Bool
help :: String -> GHCi ()
help _ = io (putStr helpText)
+info :: String -> GHCi ()
+info "" = throwDyn (CmdLineError "syntax: `:i <thing-you-want-info-about>'")
+info s = do
+ let names = words s
+ state <- getGHCiState
+ dflags <- io getDynFlags
+ let
+ infoThings cms [] = return cms
+ infoThings cms (name:names) = do
+ (cms, unqual, stuff) <- io (cmInfoThing cms dflags name)
+ io (putStrLn (showSDocForUser unqual (
+ vcat (intersperse (text "") (map showThing stuff))))
+ )
+ infoThings cms names
+
+ showThing (ty_thing, fixity)
+ = vcat [ text "-- " <> showTyThing ty_thing,
+ showFixity fixity (getName ty_thing),
+ ppr (ifaceTyThing ty_thing) ]
+
+ showFixity fix name
+ | fix == defaultFixity = empty
+ | otherwise = ppr fix <+>
+ (if isSymOcc (nameOccName name)
+ then ppr name
+ else char '`' <> ppr name <> char '`')
+
+ showTyThing (AClass cl)
+ = hcat [ppr cl, text " is a class", showSrcLoc (className cl)]
+ showTyThing (ATyCon ty)
+ | isPrimTyCon ty
+ = hcat [ppr ty, text " is a primitive type constructor"]
+ | otherwise
+ = hcat [ppr ty, text " is a type constructor", showSrcLoc (tyConName ty)]
+ showTyThing (AnId id)
+ = hcat [ppr id, text " is a ", idDescr id, showSrcLoc (idName id)]
+
+ idDescr id
+ | isRecordSelector id =
+ case tyConClass_maybe (fieldLabelTyCon (
+ recordSelectorFieldLabel id)) of
+ Nothing -> text "record selector"
+ Just c -> text "method in class " <> ppr c
+ | isDataConWrapId id = text "data constructor"
+ | otherwise = text "variable"
+
+ -- also print out the source location for home things
+ showSrcLoc name
+ | isHomePackageName name && isGoodSrcLoc loc
+ = hsep [ text ", defined at", ppr loc ]
+ | otherwise
+ = empty
+ where loc = nameSrcLoc name
+
+ cms <- infoThings (cmstate state) names
+ setGHCiState state{ cmstate = cms }
+ return ()
+
+
addModule :: String -> GHCi ()
-addModule _ = throwDyn (InstallationError ":add not implemented")
+addModule str = do
+ let files = words str
+ state <- getGHCiState
+ dflags <- io (getDynFlags)
+ io (revertCAFs) -- always revert CAFs on load/add.
+ let new_targets = files ++ targets state
+ (cmstate1, ok, mods) <- io (cmLoadModule (cmstate state) new_targets)
+ setGHCiState state{ cmstate = cmstate1, targets = new_targets }
+ modulesLoadedMsg ok mods
setContext :: String -> GHCi ()
setContext ""
io (writeIORef commands (filter ((/= macro_name) . fst) cmds))
loadModule :: String -> GHCi ()
-loadModule path = timeIt (loadModule' path)
+loadModule str = timeIt (loadModule' str)
-loadModule' path = do
+loadModule' str = do
+ let files = words str
state <- getGHCiState
dflags <- io getDynFlags
cmstate1 <- io (cmUnload (cmstate state) dflags)
- setGHCiState state{ cmstate = cmstate1, target = Nothing }
+ setGHCiState state{ cmstate = cmstate1, targets = [] }
io (revertCAFs) -- always revert CAFs on load.
- (cmstate2, ok, mods) <- io (cmLoadModule cmstate1 path)
- setGHCiState state{ cmstate = cmstate2, target = Just path }
+ (cmstate2, ok, mods) <- io (cmLoadModule cmstate1 files)
+ setGHCiState state{ cmstate = cmstate2, targets = files }
modulesLoadedMsg ok mods
reloadModule :: String -> GHCi ()
reloadModule "" = do
state <- getGHCiState
- case target state of
- Nothing -> io (putStr "no current target\n")
- Just path
+ case targets state of
+ [] -> io (putStr "no current target\n")
+ paths
-> do io (revertCAFs) -- always revert CAFs on reload.
- (new_cmstate, ok, mods) <- io (cmLoadModule (cmstate state) path)
+ (new_cmstate, ok, mods) <- io (cmLoadModule (cmstate state) paths)
setGHCiState state{ cmstate=new_cmstate }
modulesLoadedMsg ok mods
-- This is pretty fragile: most options won't work as expected. ToDo:
-- figure out which ones & disallow them.
-setOptions :: String -> GHCi ()
-setOptions ""
+setCmd :: String -> GHCi ()
+setCmd ""
= do st <- getGHCiState
let opts = options st
io $ putStrLn (showSDoc (
then text "none."
else hsep (map (\o -> char '+' <> text (optToStr o)) opts)
))
-setOptions str
- = do -- first, deal with the GHCi opts (+s, +t, etc.)
- let (plus_opts, minus_opts) = partition isPlus (words str)
+setCmd str
+ = case words str of
+ ("args":args) -> setArgs args
+ ("prog":prog) -> setProg prog
+ wds -> setOptions wds
+
+setArgs args = do
+ st <- getGHCiState
+ setGHCiState st{ args = args }
+
+setProg [prog] = do
+ st <- getGHCiState
+ setGHCiState st{ progname = prog }
+setProg _ = do
+ io (hPutStrLn stderr "syntax: :set prog <progname>")
+
+setOptions wds =
+ do -- first, deal with the GHCi opts (+s, +t, etc.)
+ let (plus_opts, minus_opts) = partition isPlus wds
mapM setOpt plus_opts
-- now, the GHC flags
state <- getGHCiState
dflags <- io getDynFlags
cmstate1 <- io (cmUnload (cmstate state) dflags)
- setGHCiState state{ cmstate = cmstate1, target = Nothing }
+ setGHCiState state{ cmstate = cmstate1, targets = [] }
io $ do
pkgs <- getPackageInfo
flushPackageCache pkgs
new_pkg_info <- getPackageDetails new_pkgs
- mapM_ (linkPackage False) (reverse new_pkg_info)
+ mapM_ linkPackage (reverse new_pkg_info)
-----------------------------------------------------------------------------
-- GHCi monad
data GHCiState = GHCiState
{
- target :: Maybe FilePath,
+ progname :: String,
+ args :: [String],
+ targets :: [FilePath],
cmstate :: CmState,
options :: [GHCiOption]
}
(GHCi m) >>= k = GHCi $ \s -> m s >>= \a -> unGHCi (k a) s
return a = GHCi $ \s -> return a
+ghciHandleDyn :: Typeable t => (t -> GHCi a) -> GHCi a -> GHCi a
+ghciHandleDyn h (GHCi m) = GHCi $ \s ->
+ Exception.catchDyn (m s) (\e -> unGHCi (h e) s)
+
getGHCiState = GHCi $ \r -> readIORef r
setGHCiState s = GHCi $ \r -> writeIORef r s
= do st <- getGHCiState
setGHCiState (st{ options = filter (/= opt) (options st) })
-io m = GHCi $ \s -> m >>= \a -> return a
+io :: IO a -> GHCi a
+io m = GHCi { unGHCi = \s -> m >>= return }
-----------------------------------------------------------------------------
-- recursive exception handlers
linkPackages :: [LibrarySpec] -> [PackageConfig] -> IO ()
linkPackages cmdline_lib_specs pkgs
- = do sequence_ [ linkPackage (name p `elem` loaded) p | p <- reverse pkgs ]
+ = do mapM_ linkPackage (reverse pkgs)
lib_paths <- readIORef v_Library_paths
mapM_ (preloadLib lib_paths) cmdline_lib_specs
+ if (null cmdline_lib_specs)
+ then return ()
+ else do putStr "final link ... "
+ ok <- resolveObjs
+ if ok then putStrLn "done."
+ else throwDyn (InstallationError
+ "linking extra libraries/objects failed")
where
- -- packages that are already linked into GHCi
- loaded = [ "concurrent", "posix", "text", "util" ]
-
preloadLib :: [String] -> LibrarySpec -> IO ()
preloadLib lib_paths lib_spec
= do putStr ("Loading object " ++ showLS lib_spec ++ " ... ")
case lib_spec of
Left static_ish
-> do b <- preload_static lib_paths static_ish
- putStrLn (if b then "done" else "not found")
+ putStrLn (if b then "done." else "not found")
Right dll_unadorned
-> -- We add "" to the set of paths to try, so that
-- if none of the real paths match, we force addDLL
-- to look in the default dynamic-link search paths.
- do b <- preload_dynamic (lib_paths++[""]) dll_unadorned
- when (not b) (cantFind lib_paths lib_spec)
+ do maybe_errstr <- preload_dynamic (lib_paths++[""])
+ dll_unadorned
+ case maybe_errstr of
+ Nothing -> return ()
+ Just mm -> preloadFailed mm lib_paths lib_spec
putStrLn "done"
- cantFind :: [String] -> LibrarySpec -> IO ()
- cantFind paths spec
- = do putStr ("failed.\nCan't find " ++ showLS spec
- ++ " in directories:\n"
+ preloadFailed :: String -> [String] -> LibrarySpec -> IO ()
+ preloadFailed sys_errmsg paths spec
+ = do putStr ("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
if not b then return False
else loadObj name >> return True
+ -- return Nothing == success, else Just error message from addDLL
preload_dynamic [] name
- = return False
+ = return Nothing
preload_dynamic (path:paths) rootname
- = do maybe_errmsg <- addDLL path rootname
- if maybe_errmsg /= nullPtr
+ = do -- addDLL returns NULL on success
+ maybe_errmsg <- addDLL path rootname
+ if maybe_errmsg == nullPtr
then preload_dynamic paths rootname
- else return True
+ else do str <- peekCString maybe_errmsg
+ return (Just str)
give_up
= (throwDyn . CmdLineError)
"user specified .o/.so/.DLL could not be loaded."
-
-linkPackage :: Bool -> PackageConfig -> IO ()
--- ignore rts and gmp for now (ToDo; better?)
-linkPackage loaded_in_ghci pkg
- | name pkg `elem` ["rts", "gmp"]
- = return ()
+-- Packages that don't need loading, because the compiler shares them with
+-- the interpreted program.
+dont_load_these = [ "gmp", "rts" ]
+
+-- Packages that are already linked into GHCi. For mingw32, we only
+-- skip gmp and rts, since std and after need to load the msvcrt.dll
+-- library which std depends on.
+loaded_in_ghci
+# ifndef mingw32_TARGET_OS
+ = [ "std", "concurrent", "posix", "text", "util" ]
+# else
+ = [ ]
+# endif
+
+linkPackage :: PackageConfig -> IO ()
+linkPackage pkg
+ | name pkg `elem` dont_load_these = return ()
| otherwise
- = do putStr ("Loading package " ++ name pkg ++ " ... ")
+ = do
-- For each obj, try obj.o and if that fails, obj.so.
-- Complication: all the .so's must be loaded before any of the .o's.
let dirs = library_dirs pkg
-- Don't load the .so libs if this is a package GHCi is already
-- linked against, because we'll already have the .so linked in.
let (so_libs, obj_libs) = partition isRight classifieds
- let sos_first | loaded_in_ghci = obj_libs
- | otherwise = so_libs ++ obj_libs
+ let sos_first | name pkg `elem` loaded_in_ghci = obj_libs
+ | otherwise = so_libs ++ obj_libs
+ putStr ("Loading package " ++ name pkg ++ " ... ")
mapM loadClassified sos_first
putStr "linking ... "
- resolveObjs
- putStrLn "done."
+ ok <- resolveObjs
+ if ok then putStrLn "done."
+ else panic ("can't load package `" ++ name pkg ++ "'")
where
isRight (Right _) = True
isRight (Left _) = False
if maybe_errmsg == nullPtr
then return ()
else do str <- peekCString maybe_errmsg
- throwDyn (CmdLineError ("can't find .o or .so/.DLL for: "
+ throwDyn (CmdLineError ("can't load .so/.DLL for: "
++ dll_unadorned ++ " (" ++ str ++ ")" ))
locateOneObj :: [FilePath] -> String -> IO LibrarySpec