X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fghci%2FInteractiveUI.hs;h=cf749d2abce35d02c40fc0807d54feb9f11ab7c9;hb=a48967de2c4240997a81c23f21cbfc22f8c7a0f6;hp=58266f5a1487e355263d958099d3a10b4d65eea4;hpb=ef46487bb4c0c3199186d6e1e6ca025a45b2e4d0;p=ghc-hetmet.git

diff --git a/ghc/compiler/ghci/InteractiveUI.hs b/ghc/compiler/ghci/InteractiveUI.hs
index 58266f5..cf749d2 100644
--- a/ghc/compiler/ghci/InteractiveUI.hs
+++ b/ghc/compiler/ghci/InteractiveUI.hs
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------------
--- $Id: InteractiveUI.hs,v 1.56 2001/03/23 12:12:18 simonmar Exp $
+-- $Id: InteractiveUI.hs,v 1.83 2001/07/24 04:41:40 ken Exp $
 --
 -- GHC Interactive User Interface
 --
@@ -8,27 +8,37 @@
 -----------------------------------------------------------------------------
 
 {-# OPTIONS -#include "Linker.h" #-}
+{-# OPTIONS -#include "SchedAPI.h" #-}
 module InteractiveUI ( interactiveUI, ghciWelcomeMsg ) where
 
+#include "../includes/config.h"
 #include "HsVersions.h"
 
+import Packages
 import CompManager
-import CmStaticInfo
+import HscTypes		( GhciMode(..) )
+import MkIface          ( ifaceTyCls )
 import ByteCodeLink
 import DriverFlags
 import DriverState
 import DriverUtil
 import Linker
+import Finder		( flushPackageCache )
 import Util
 import Name		( Name )
 import Outputable
+import CmdLineOpts	( DynFlag(..), getDynFlags, saveDynFlags, restoreDynFlags, dopt_unset )
 import Panic		( GhcException(..) )
 import Config
 
+#ifndef mingw32_TARGET_OS
+import Posix
+#endif
+
 import Exception
 import Dynamic
-#ifndef NO_READLINE
-import Readline
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+import Readline 
 #endif
 import IOExts
 
@@ -50,7 +60,7 @@ import CString		( peekCString )
 ghciWelcomeMsg = "\ 
 \   ___         ___ _\n\ 
 \  / _ \\ /\\  /\\/ __(_)\n\ 
-\ / /_\\// /_/ / /  | |      GHC Interactive, version " ++ cProjectVersion ++ ", For Haskell 98.\n\ 
+\ / /_\\// /_/ / /  | |      GHC Interactive, version " ++ cProjectVersion ++ ", for Haskell 98.\n\ 
 \/ /_\\\\/ __  / /___| |      http://www.haskell.org/ghc/\n\ 
 \\\____/\\/ /_/\\____/|_|      Type :? for help.\n"
 
@@ -63,6 +73,7 @@ builtin_commands = [
   ("def",	keepGoing defineMacro),
   ("help",	keepGoing help),
   ("?",		keepGoing help),
+  ("info",      keepGoing info),
   ("load",	keepGoing loadModule),
   ("module",	keepGoing setContext),
   ("reload",	keepGoing reloadModule),
@@ -80,19 +91,23 @@ shortHelpText = "use :? for help.\n"
 
 helpText = "\ 
 \ Commands available from the prompt:\n\ 
-\\  
-\   <stmt>		evaluate/run <stmt>\n\ 
-\   :cd <dir>		change directory to <dir>\n\ 
-\   :def <cmd> <expr>   define a macro :<cmd>\n\ 
-\   :help, :?		display this list of commands\n\ 
-\   :load <filename>    load a module (and it 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\ 
-\   :type <expr>	show the type of <expr>\n\ 
-\   :unset <option> ...	unset options\n\ 
-\   :quit		exit GHCi\n\ 
-\   :!<command>		run the shell command <command>\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\ 
+\   :info [<name> ...]     display information about the given names, or\n\ 
+\                          about currently loaded files if no names given\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\ 
+\   :undef <cmd> 	   undefine user-defined command :<cmd>\n\ 
+\   :type <expr>	   show the type of <expr>\n\ 
+\   :unset <option> ...	   unset options\n\ 
+\   :quit		   exit GHCi\n\ 
+\   :!<command>		   run the shell command <command>\n\ 
 \\ 
 \ Options for `:set' and `:unset':\n\ 
 \\ 
@@ -102,24 +117,23 @@ helpText = "\
 \    -<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
 
    -- link in the available packages
    pkgs <- getPackageInfo
    initLinker
-   linkPackages cmdline_libs (reverse pkgs)
+   linkPackages cmdline_libs pkgs
 
    (cmstate, ok, mods) <-
-   	case mod of
-	     Nothing  -> return (cmstate, True, [])
-	     Just m -> cmLoadModule cmstate m
+   	case paths of
+	     [] -> return (cmstate, True, [])
+	     _  -> cmLoadModule cmstate paths
 
-#ifndef NO_READLINE
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
    Readline.initialize
 #endif
 
@@ -137,32 +151,47 @@ interactiveUI cmstate mod cmdline_libs = do
 	Just hval -> writeIORef flush_stdout (unsafeCoerce# hval :: IO ())
 	_ -> panic "interactiveUI:stdout"
 
-   (unGHCi runGHCi) GHCiState{ target = mod,
-			       cmstate = cmstate,
-			       options = [ShowTiming] }
+   startGHCi runGHCi GHCiState{ targets = paths,
+			        cmstate = cmstate,
+			        options = [] }
+
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
+   Readline.resetTerminal Nothing
+#endif
+
    return ()
 
 
 runGHCi :: GHCi ()
 runGHCi = do
-  -- read in ./.ghci
-  dot_ghci <- io (IO.try (openFile "./.ghci" ReadMode))
-  case dot_ghci of
-	Left e -> return ()
-	Right hdl -> fileLoop hdl False
+  -- 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 ~/.ghci
-  home <- io (IO.try (getEnv "HOME"))
-  case home of
-   Left e  -> return ()
-   Right dir -> do
-  	dot_ghci <- io (IO.try (openFile (dir ++ "/.ghci") ReadMode))
-	case dot_ghci 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
 
   -- read commands from stdin
-#ifndef NO_READLINE
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
   readlineLoop
 #else
   fileLoop stdin True
@@ -172,11 +201,42 @@ runGHCi = do
   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 . 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 =
+  handle (\_ -> return False) $ do
+#ifdef mingw32_TARGET_OS
+     doesFileExist name
+#else
+     st <- getFileStatus name
+     me <- getRealUserID
+     if fileOwner st /= me then do
+   	putStrLn $ "WARNING: " ++ name ++ " is owned by someone else, IGNORING!"
+   	return False
+      else do
+   	let mode =  fileMode st
+   	if (groupWriteMode == (mode `intersectFileModes` groupWriteMode))
+   	   || (otherWriteMode == (mode `intersectFileModes` otherWriteMode)) 
+   	   then do
+   	       putStrLn $ "*** WARNING: " ++ name ++ 
+   			  " is writable by someone else, IGNORING!"
+   	       return False
+   	  else return True
+#endif
+
 fileLoop :: Handle -> Bool -> GHCi ()
 fileLoop hdl prompt = do
    st <- getGHCiState
    mod <- io (cmGetContext (cmstate st))
-   when prompt (io (hPutStr hdl (mod ++ "> ")))
+   when prompt (io (putStr (mod ++ "> ")))
    l <- io (IO.try (hGetLine hdl))
    case l of
 	Left e | isEOFError e -> return ()
@@ -196,7 +256,7 @@ stringLoop (s:ss) = do
 	l  -> do quit <- runCommand l
                  if quit then return () else stringLoop ss
 
-#ifndef NO_READLINE
+#if HAVE_READLINE_HEADERS && HAVE_READLINE_LIBS
 readlineLoop :: GHCi ()
 readlineLoop = do
    st <- getGHCiState
@@ -217,25 +277,28 @@ readlineLoop = do
 -- 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.")
-		    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 (PhaseFailed phase code) ->
+	io (putStrLn ("Phase " ++ phase ++ " failed (code "
+		       ++ show code ++ ")"))
+    Just Interrupted ->
+	io (putStrLn "Interrupted.")
+    Just (CmdLineError s) -> 
+	io (putStrLn s)	 -- omit the location for CmdLineError
+    Just other_ghc_ex ->
+	io (putStrLn (show other_ghc_ex))
+showException other_exception
+  = io (putStrLn ("*** Exception: " ++ show other_exception))
 
 doCommand (':' : command) = specialCommand command
 doCommand stmt
@@ -250,8 +313,9 @@ runStmt stmt
  = return Nothing
  | otherwise
  = do st <- getGHCiState
-      dflags <- io (getDynFlags)
-      (new_cmstate, names) <- io (cmRunStmt (cmstate st) dflags stmt)
+      dflags <- io getDynFlags
+      let dflags' = dopt_unset dflags Opt_WarnUnusedBinds
+      (new_cmstate, names) <- io (cmRunStmt (cmstate st) dflags' stmt)
       setGHCiState st{cmstate = new_cmstate}
       return (Just names)
 
@@ -296,7 +360,7 @@ specialCommand str = do
 	         	     	       foldr1 (\a b -> a ++ ',':b) (map fst cs)
 					 ++ ")") >> return False)
 
-noArgs c = io (hPutStrLn stdout ("command `:" ++ c ++ "' takes no arguments"))
+noArgs c = throwDyn (CmdLineError ("command `" ++ c ++ "' takes no arguments"))
 
 -----------------------------------------------------------------------------
 -- Commands
@@ -304,14 +368,37 @@ noArgs c = io (hPutStrLn stdout ("command `:" ++ c ++ "' takes no arguments"))
 help :: String -> GHCi ()
 help _ = io (putStr helpText)
 
+info :: String -> GHCi ()
+info "" = do io (putStr "dunno, mate")
+info s = do
+  let names = words s
+  st <- getGHCiState
+  let cmst = cmstate st
+  dflags <- io getDynFlags
+  things <- io (mapM (cmInfoThing cmst dflags) names)
+  let real_things = [ x | Just x <- things ]
+  let descs = map (`ifaceTyCls` []) real_things
+  let strings = map (showSDoc . ppr) descs
+  io (mapM_ putStr strings)
+
 addModule :: String -> GHCi ()
-addModule _ = throwDyn (OtherError ":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 ""
-  = throwDyn (OtherError "syntax: `:m <module>'")
-setContext m | not (isUpper (head m)) || not (all isAlphaNum (tail m))
-  = throwDyn (OtherError ("strange looking module name: `" ++ m ++ "'"))
+  = throwDyn (CmdLineError "syntax: `:m <module>'")
+setContext m | not (isUpper (head m)) || not (all isAlphaNumEx (tail m))
+  = throwDyn (CmdLineError ("strange looking module name: `" ++ m ++ "'"))
+    where
+       isAlphaNumEx c = isAlphaNum c || c == '_'
 setContext str
   = do st <- getGHCiState
        new_cmstate <- io (cmSetContext (cmstate st) str)
@@ -328,10 +415,10 @@ defineMacro s = do
   let (macro_name, definition) = break isSpace s
   cmds <- io (readIORef commands)
   if (null macro_name) 
-	then throwDyn (OtherError "invalid macro name") 
+	then throwDyn (CmdLineError "invalid macro name") 
 	else do
   if (macro_name `elem` map fst cmds) 
-	then throwDyn (OtherError 
+	then throwDyn (CmdLineError 
 		("command `" ++ macro_name ++ "' is already defined"))
 	else do
 
@@ -341,7 +428,7 @@ defineMacro s = do
 
   -- compile the expression
   st <- getGHCiState
-  dflags <- io (getDynFlags)
+  dflags <- io getDynFlags
   (new_cmstate, maybe_hv) <- io (cmCompileExpr (cmstate st) dflags new_expr)
   setGHCiState st{cmstate = new_cmstate}
   case maybe_hv of
@@ -358,37 +445,37 @@ undefineMacro :: String -> GHCi ()
 undefineMacro macro_name = do
   cmds <- io (readIORef commands)
   if (macro_name `elem` map fst builtin_commands) 
-	then throwDyn (OtherError
+	then throwDyn (CmdLineError
 		("command `" ++ macro_name ++ "' cannot be undefined"))
 	else do
   if (macro_name `notElem` map fst cmds) 
-	then throwDyn (OtherError 
+	then throwDyn (CmdLineError 
 		("command `" ++ macro_name ++ "' not defined"))
 	else do
   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
-  cmstate1 <- io (cmUnload (cmstate state))
+  dflags <- io getDynFlags
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, targets = [] }
   io (revertCAFs)			-- always revert CAFs on load.
-  (cmstate2, ok, mods) <- io (cmLoadModule cmstate1 path)
-  let new_state = state{ cmstate = cmstate2,
-			 target = Just path
-		       }
-  setGHCiState new_state
+  (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
 
@@ -410,7 +497,7 @@ modulesLoadedMsg ok mods = do
 typeOfExpr :: String -> GHCi ()
 typeOfExpr str 
   = do st <- getGHCiState
-       dflags <- io (getDynFlags)
+       dflags <- io getDynFlags
        (new_cmstate, maybe_tystr) <- io (cmTypeOfExpr (cmstate st) dflags str)
        setGHCiState st{cmstate = new_cmstate}
        case maybe_tystr of
@@ -445,32 +532,29 @@ setOptions ""
    	   ))
 setOptions str
   = do -- first, deal with the GHCi opts (+s, +t, etc.)
-       let opts = words str
-	   (minus_opts, rest1) = partition isMinus opts
-	   (plus_opts, rest2)  = partition isPlus rest1
-
-       if (not (null rest2)) 
-	  then io (putStrLn ("unknown option: `" ++ head rest2 ++ "'"))
-	  else do
-
-       mapM setOpt plus_opts
-
-       -- now, the GHC flags
-       io (do -- first, static flags
-	      leftovers <- processArgs static_flags minus_opts []
-
-	      -- then, dynamic flags
-	      dyn_flags <- readIORef v_InitDynFlags
-	      writeIORef v_DynFlags dyn_flags
-	      leftovers <- processArgs dynamic_flags leftovers []
-	      dyn_flags <- readIORef v_DynFlags
-	      writeIORef v_InitDynFlags dyn_flags
-
-              if (not (null leftovers))
-		 then throwDyn (OtherError ("unrecognised flags: " ++ 
+      let (plus_opts, minus_opts)  = partition isPlus (words str)
+      mapM setOpt plus_opts
+
+      -- now, the GHC flags
+      pkgs_before <- io (readIORef v_Packages)
+      leftovers   <- io (processArgs static_flags minus_opts [])
+      pkgs_after  <- io (readIORef v_Packages)
+
+      -- update things if the users wants more packages
+      when (pkgs_before /= pkgs_after) $
+	 newPackages (pkgs_after \\ pkgs_before)
+
+      -- then, dynamic flags
+      io $ do 
+	restoreDynFlags
+        leftovers <- processArgs dynamic_flags leftovers []
+	saveDynFlags
+
+        if (not (null leftovers))
+		then throwDyn (CmdLineError ("unrecognised flags: " ++ 
 						unwords leftovers))
-		 else return ()
-         )
+		else return ()
+
 
 unsetOptions :: String -> GHCi ()
 unsetOptions str
@@ -487,7 +571,7 @@ unsetOptions str
  
        -- can't do GHC flags for now
        if (not (null minus_opts))
-	  then throwDyn (OtherError "can't unset GHC command-line flags")
+	  then throwDyn (CmdLineError "can't unset GHC command-line flags")
 	  else return ()
 
 isMinus ('-':s) = True
@@ -517,12 +601,25 @@ optToStr ShowTiming = "s"
 optToStr ShowType   = "t"
 optToStr RevertCAFs = "r"
 
+newPackages new_pkgs = do
+  state <- getGHCiState
+  dflags <- io getDynFlags
+  cmstate1 <- io (cmUnload (cmstate state) dflags)
+  setGHCiState state{ cmstate = cmstate1, targets = [] }
+
+  io $ do
+    pkgs <- getPackageInfo
+    flushPackageCache pkgs
+   
+    new_pkg_info <- getPackageDetails new_pkgs
+    mapM_ (linkPackage False) (reverse new_pkg_info)
+
 -----------------------------------------------------------------------------
 -- GHCi monad
 
 data GHCiState = GHCiState
      { 
-	target         :: Maybe FilePath,
+	targets        :: [FilePath],
 	cmstate        :: CmState,
 	options        :: [GHCiOption]
      }
@@ -536,14 +633,17 @@ data GHCiOption
 GLOBAL_VAR(flush_stdout, error "no flush_stdout", IO ())
 GLOBAL_VAR(flush_stderr, error "no flush_stdout", IO ())
 
-newtype GHCi a = GHCi { unGHCi :: GHCiState -> IO (GHCiState, a) }
+newtype GHCi a = GHCi { unGHCi :: IORef GHCiState -> IO a }
+
+startGHCi :: GHCi a -> GHCiState -> IO a
+startGHCi g state = do ref <- newIORef state; unGHCi g ref
 
 instance Monad GHCi where
-  (GHCi m) >>= k  =  GHCi $ \s -> m s >>= \(s,a) -> unGHCi (k a) s
-  return a  = GHCi $ \s -> return (s,a)
+  (GHCi m) >>= k  =  GHCi $ \s -> m s >>= \a -> unGHCi (k a) s
+  return a  = GHCi $ \s -> return a
 
-getGHCiState   = GHCi $ \s -> return (s,s)
-setGHCiState s = GHCi $ \_ -> return (s,())
+getGHCiState   = GHCi $ \r -> readIORef r
+setGHCiState s = GHCi $ \r -> writeIORef r s
 
 isOptionSet :: GHCiOption -> GHCi Bool
 isOptionSet opt
@@ -560,7 +660,8 @@ unsetOption opt
  = do st <- getGHCiState
       setGHCiState (st{ options = filter (/= opt) (options st) })
 
-io m = GHCi $ \s -> m >>= \a -> return (s,a)
+io :: IO a -> GHCi a
+io m = GHCi { unGHCi = \s -> m >>= return }
 
 -----------------------------------------------------------------------------
 -- recursive exception handlers
@@ -585,7 +686,11 @@ ghciUnblock (GHCi a) = GHCi $ \s -> Exception.unblock (a s)
 --        e.g.    On unix     "qt"  denotes "libqt.so"
 --                On WinDoze  "burble"  denotes "burble.DLL"
 --        addDLL is platform-specific and adds the lib/.so/.DLL
---        prefixes plaform-dependently; we don't do that here.
+--        suffixes platform-dependently; we don't do that here.
+-- 
+-- For dynamic objects only, try to find the object file in all the 
+-- directories specified in v_Library_Paths before giving up.
+
 type LibrarySpec
    = Either FilePath String
 
@@ -594,33 +699,64 @@ showLS (Right nm) = "(dynamic) " ++ nm
 
 linkPackages :: [LibrarySpec] -> [PackageConfig] -> IO ()
 linkPackages cmdline_lib_specs pkgs
-   = do mapM_ linkPackage pkgs
-        mapM_ preloadLib cmdline_lib_specs
+   = do sequence_ [ linkPackage (name p `elem` loaded) p | p <- reverse pkgs ]
+        lib_paths <- readIORef v_Library_paths
+        mapM_ (preloadLib lib_paths) cmdline_lib_specs
      where
-        preloadLib lib_spec
+	-- 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 
+#          ifndef mingw32_TARGET_OS
+           = [ "gmp", "rts", "std", "concurrent", "posix", "text", "util" ]
+#          else
+           = [ "gmp", "rts" ]
+#          endif
+
+        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 <- doesFileExist static_ish
-                            if    not b
-                             then do putStr "not found.\n"
-                                     croak
-                             else do loadObj static_ish
-                                     putStr "done.\n"
+                      -> do b <- preload_static lib_paths static_ish
+                            putStrLn (if b then "done" else "not found")
                    Right dll_unadorned
-                      -> do maybe_errmsg <- addDLL dll_unadorned
-                            if    maybe_errmsg == nullPtr
-                             then putStr "done.\n"
-                             else do str <- peekCString maybe_errmsg
-                                     putStr ("failed (" ++ str ++ ")\n")
-                                     croak
-
-        croak = throwDyn (OtherError "user specified .o/.so/.DLL could not be loaded.")
-
-
-linkPackage :: PackageConfig -> IO ()
+                      -> -- 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)
+                            putStrLn "done"
+
+        cantFind :: [String] -> LibrarySpec -> IO ()
+        cantFind paths spec
+           = do putStr ("failed.\nCan't find " ++ showLS spec
+                        ++ " in directories:\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
+
+        preload_dynamic [] name
+           = return False
+        preload_dynamic (path:paths) rootname
+           = do maybe_errmsg <- addDLL path rootname
+                if    maybe_errmsg /= nullPtr
+                 then preload_dynamic paths rootname
+                 else return True
+
+        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 pkg 
+linkPackage loaded_in_ghci pkg
    | name pkg `elem` ["rts", "gmp"] 
    = return ()
    | otherwise
@@ -630,8 +766,13 @@ linkPackage pkg
         let dirs      =  library_dirs pkg
         let objs      =  hs_libraries pkg ++ extra_libraries pkg
         classifieds   <- mapM (locateOneObj dirs) objs
-        let sos_first = filter isRight classifieds 
-                        ++ filter (not.isRight) classifieds
+
+	-- 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
+
         mapM loadClassified sos_first
         putStr "linking ... "
         resolveObjs
@@ -644,11 +785,11 @@ loadClassified :: LibrarySpec -> IO ()
 loadClassified (Left obj_absolute_filename)
    = do loadObj obj_absolute_filename
 loadClassified (Right dll_unadorned)
-   = do maybe_errmsg <- addDLL dll_unadorned
+   = do maybe_errmsg <- addDLL "" dll_unadorned -- doesn't seem right to me
         if    maybe_errmsg == nullPtr
          then return ()
          else do str <- peekCString maybe_errmsg
-                 throwDyn (OtherError ("can't find .o or .so/.DLL for: " 
+                 throwDyn (CmdLineError ("can't load .so/.DLL for: " 
                                        ++ dll_unadorned ++ " (" ++ str ++ ")" ))
 
 locateOneObj :: [FilePath] -> String -> IO LibrarySpec