Linker.lhs 39.7 KB
Newer Older
1
%
2
% (c) The University of Glasgow 2005-2006
3
%
4 5 6 7 8 9 10 11 12

-- --------------------------------------
-- 	The dynamic linker for GHCi      
-- --------------------------------------

This module deals with the top-level issues of dynamic linking,
calling the object-code linker and the byte-code linker where
necessary.

13 14

\begin{code}
15
{-# OPTIONS -optc-DNON_POSIX_SOURCE -#include "Linker.h" #-}
16

mnislaih's avatar
mnislaih committed
17
module Linker ( HValue, getHValue, showLinkerState,
18 19 20
		linkExpr, unload, withExtendedLinkEnv,
                extendLinkEnv, deleteFromLinkEnv,
                extendLoadedPkgs, 
mnislaih's avatar
mnislaih committed
21
		linkPackages,initDynLinker,
22
                dataConInfoPtrToName
23
	) where
sof's avatar
sof committed
24

25
#include "HsVersions.h"
26

27 28 29 30
import ObjLink
import ByteCodeLink
import ByteCodeItbls
import ByteCodeAsm
31 32
import CgInfoTbls
import SMRep
33 34
import IfaceEnv
import TcRnMonad
35
import Packages
36 37
import DriverPhases
import Finder
38
import HscTypes
39
import Name
40
import NameEnv
41
import NameSet
42
import qualified OccName
43
import UniqFM
44
import Module
45 46 47
import ListSetOps
import DynFlags
import BasicTypes
48
import Outputable
49 50 51 52 53 54 55
import PackageConfig
import Panic
import Util
import StaticFlags
import ErrUtils
import DriverPhases
import SrcLoc
Simon Marlow's avatar
Simon Marlow committed
56
import UniqSet
57
import Constants
58
import FastString
59 60

-- Standard libraries
61
import Control.Monad
62

63
import Data.Char
64 65
import Data.IORef
import Data.List
66
import Foreign
67

68 69
import System.IO
import System.Directory
70

71 72
import Control.Exception
import Data.Maybe
73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89
\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}
90 91
GLOBAL_VAR(v_PersistentLinkerState, panic "Dynamic linker not initialised", PersistentLinkerState)
GLOBAL_VAR(v_InitLinkerDone, False, Bool)	-- Set True when dynamic linker is initialised
92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114

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
115
	pkgs_loaded :: [PackageId]
116 117
     }

118 119 120 121 122 123
emptyPLS :: DynFlags -> PersistentLinkerState
emptyPLS dflags = PersistentLinkerState { 
			closure_env = emptyNameEnv,
			itbl_env    = emptyNameEnv,
			pkgs_loaded = init_pkgs,
			bcos_loaded = [],
124 125
			objs_loaded = [] }
                    
126 127 128 129 130
  -- 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.
Simon Marlow's avatar
Simon Marlow committed
131
  where init_pkgs = [rtsPackageId]
132 133 134
\end{code}

\begin{code}
135 136 137 138
extendLoadedPkgs :: [PackageId] -> IO ()
extendLoadedPkgs pkgs
    = modifyIORef v_PersistentLinkerState (\s -> s{pkgs_loaded = pkgs ++ pkgs_loaded s})

139 140 141 142 143 144 145 146
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

147 148 149 150 151 152 153
deleteFromLinkEnv :: [Name] -> IO ()
deleteFromLinkEnv to_remove
  = do	pls <- readIORef v_PersistentLinkerState
	let new_closure_env = delListFromNameEnv (closure_env pls) to_remove
	    new_pls = pls { closure_env = new_closure_env }
	writeIORef v_PersistentLinkerState new_pls

154 155 156 157
-- | Given a data constructor in the heap, find its Name.
--   The info tables for data constructors have a field which records
--   the source name of the constructor as a Ptr Word8 (UTF-8 encoded
--   string). The format is:
158 159 160 161 162
--
--    Package:Module.Name
--
--   We use this string to lookup the interpreter's internal representation of the name
--   using the lookupOrig.    
163

164 165
dataConInfoPtrToName :: Ptr () -> TcM Name
dataConInfoPtrToName x = do 
166
   theString <- ioToTcRn $ do
167
      let ptr = castPtr x :: Ptr StgInfoTable
168
      conDescAddress <- getConDescAddress ptr 
169
      peekArray0 0 conDescAddress  
170
   let (pkg, mod, occ) = parse theString 
171 172 173 174 175
       pkgFS = mkFastStringByteList pkg
       modFS = mkFastStringByteList mod
       occFS = mkFastStringByteList occ
       occName = mkOccNameFS OccName.dataName occFS
       modName = mkModule (fsToPackageId pkgFS) (mkModuleNameFS modFS) 
176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
   lookupOrig modName occName

   where

   {- To find the string in the constructor's info table we need to consider 
      the layout of info tables relative to the entry code for a closure.

      An info table can be next to the entry code for the closure, or it can
      be separate. The former (faster) is used in registerised versions of ghc, 
      and the latter (portable) is for non-registerised versions. 

      The diagrams below show where the string is to be found relative to 
      the normal info table of the closure.

      1) Code next to table:

         --------------
         |            |   <- pointer to the start of the string
         --------------
         |            |   <- the (start of the) info table structure
         |            |
         |            |
         --------------
         | entry code | 
         |    ....    |

         In this case the pointer to the start of the string can be found in
         the memory location _one word before_ the first entry in the normal info 
         table.

      2) Code NOT next to table:

                                 --------------
         info table structure -> |     *------------------> --------------
                                 |            |             | entry code |
                                 |            |             |    ....    | 
                                 --------------
         ptr to start of str ->  |            |   
                                 --------------

         In this case the pointer to the start of the string can be found
         in the memory location: info_table_ptr + info_table_size
   -}

220
   getConDescAddress :: Ptr StgInfoTable -> IO (Ptr Word8)
221 222
   getConDescAddress ptr = do
#ifdef GHCI_TABLES_NEXT_TO_CODE
223 224 225 226
       offsetToString <- peek $ ptr `plusPtr` (- wORD_SIZE)
       return $ (ptr `plusPtr` stdInfoTableSizeB) `plusPtr` (fromIntegral (offsetToString :: StgWord))
#else
       peek $ intPtrToPtr $ (ptrToIntPtr ptr) + stdInfoTableSizeB
227 228 229 230 231 232 233 234 235
#endif

   -- parsing names is a little bit fiddly because we have a string in the form: 
   -- pkg:A.B.C.foo, and we want to split it into three parts: ("pkg", "A.B.C", "foo").
   -- Thus we split at the leftmost colon and the rightmost occurrence of the dot.
   -- It would be easier if the string was in the form pkg:A.B.C:foo, but alas
   -- this is not the conventional way of writing Haskell names. We stick with
   -- convention, even though it makes the parsing code more troublesome.
   -- Warning: this code assumes that the string is well formed.
236
   parse :: [Word8] -> ([Word8], [Word8], [Word8])
237 238 239
   parse input 
      = ASSERT (all (>0) (map length [pkg, mod, occ])) (pkg, mod, occ)
      where
240 241
      dot = fromIntegral (ord '.')
      (pkg, rest1) = break (== fromIntegral (ord ':')) input 
242
      (mod, occ) 
243
         = (concat $ intersperse [dot] $ reverse modWords, occWord)
244 245
         where
         (modWords, occWord) = ASSERT (length rest1 > 0) (parseModOcc [] (tail rest1))
246
      parseModOcc :: [[Word8]] -> [Word8] -> ([[Word8]], [Word8])
247
      parseModOcc acc str
248
         = case break (== dot) str of
249
              (top, []) -> (acc, top)
250
              (top, _:bot) -> parseModOcc (top : acc) bot
251
       
252

253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279
getHValue :: HscEnv -> Name -> IO HValue
getHValue hsc_env name = do
   when (isExternalName name) $ do
        ok <- linkDependencies hsc_env noSrcSpan [nameModule name]
        when (failed ok) $ throwDyn (ProgramError "")
   pls <- readIORef v_PersistentLinkerState
   lookupName (closure_env pls) name
        
linkDependencies :: HscEnv -> SrcSpan -> [Module] -> IO SuccessFlag
linkDependencies hsc_env span needed_mods = do
   let hpt = hsc_HPT hsc_env
       dflags = hsc_dflags hsc_env
	-- The interpreter and dynamic linker can only handle object code built
	-- the "normal" way, i.e. no non-std ways like profiling or ticky-ticky.
	-- So here we check the build tag: if we're building a non-standard way
	-- then we need to find & link object files built the "normal" way.
   maybe_normal_osuf <- checkNonStdWay dflags span

	-- Find what packages and linkables are required
   eps <- readIORef (hsc_EPS hsc_env)
   (lnks, pkgs) <- getLinkDeps hsc_env hpt (eps_PIT eps) 
				maybe_normal_osuf span needed_mods

	-- Link the packages and modules required
   linkPackages dflags pkgs
   linkModules dflags lnks

280

281 282 283 284 285 286 287 288 289
withExtendedLinkEnv :: [(Name,HValue)] -> IO a -> IO a
withExtendedLinkEnv new_env action
    = bracket set_new_env
              reset_old_env
              (const action)
    where set_new_env = do pls <- readIORef v_PersistentLinkerState
                           let new_closure_env = extendClosureEnv (closure_env pls) new_env
                               new_pls = pls { closure_env = new_closure_env }
                           writeIORef v_PersistentLinkerState new_pls
290 291
                           return (closure_env pls)
          reset_old_env env = modifyIORef v_PersistentLinkerState (\pls -> pls{ closure_env = env })
292

293 294 295 296 297 298
-- 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

299
filterNameMap :: [Module] -> NameEnv (Name, a) -> NameEnv (Name, a)
300 301 302 303
filterNameMap mods env 
   = filterNameEnv keep_elt env
   where
     keep_elt (n,_) = isExternalName n 
304
		      && (nameModule n `elem` mods)
305 306 307 308 309 310 311 312 313 314 315
\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),
316
			text "BCOs:" <+> ppr (bcos_loaded pls)])
317 318 319 320
\end{code}
			
	

321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342

%************************************************************************
%*									*
\subsection{Initialisation}
%*									*
%************************************************************************

We initialise the dynamic linker by

a) calling the C initialisation procedure

b) Loading any packages specified on the command line,

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}
343
initDynLinker :: DynFlags -> IO ()
344 345
-- 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
346
initDynLinker dflags
347 348 349
  = do	{ done <- readIORef v_InitLinkerDone
	; if done then return () 
		  else do { writeIORef v_InitLinkerDone True
350
			  ; reallyInitDynLinker dflags }
351 352
	}

353 354 355
reallyInitDynLinker dflags
  = do  {  -- Initialise the linker state
	; writeIORef v_PersistentLinkerState (emptyPLS dflags)
356 357 358 359 360

	 	-- (a) initialise the C dynamic linker
	; initObjLinker 

		-- (b) Load packages from the command-line
361
	; linkPackages dflags (preloadPackages (pkgState dflags))
362 363

	   	-- (c) Link libraries from the command-line
364 365
	; let optl = getOpts dflags opt_l
	; let minus_ls = [ lib | '-':'l':lib <- optl ]
366 367

	   	-- (d) Link .o files from the command-line
368
	; let lib_paths = libraryPaths dflags
369 370
	; cmdline_ld_inputs <- readIORef v_Ld_inputs

371
	; classified_ld_inputs <- mapM classifyLdInput cmdline_ld_inputs
372 373 374

	   	-- (e) Link any MacOS frameworks
#ifdef darwin_TARGET_OS	
375 376
	; let framework_paths = frameworkPaths dflags
	; let frameworks      = cmdlineFrameworks dflags
377 378 379 380 381
#else
	; let frameworks      = []
	; let framework_paths = []
#endif
		-- Finally do (c),(d),(e)	
382
        ; let cmdline_lib_specs = [ l | Just l <- classified_ld_inputs ]
383 384 385 386 387 388 389 390 391 392 393 394 395
			       ++ 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")
	}}

396 397 398 399 400 401 402
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
403

404 405 406 407 408 409 410 411 412 413 414 415 416 417
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
418 419 420 421 422 423 424

	  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

425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452
#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}


453 454 455 456 457 458 459
%************************************************************************
%*									*
		Link a byte-code expression
%*									*
%************************************************************************

\begin{code}
460
linkExpr :: HscEnv -> SrcSpan -> UnlinkedBCO -> IO HValue
461 462 463 464 465 466

-- 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.
467 468
--
-- Note: This function side-effects the linker state (Pepe)
469

470
linkExpr hsc_env span root_ul_bco
471
  = do {  
472
	-- Initialise the linker (if it's not been done already)
473 474
     let dflags = hsc_dflags hsc_env
   ; initDynLinker dflags
475

476
	-- Link the packages and modules required
477
   ; ok <- linkDependencies hsc_env span needed_mods
478
   ; if failed ok then
479
	throwDyn (ProgramError "")
480 481 482 483 484 485 486 487
     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
488
   ; (_, (root_hval:_)) <- linkSomeBCOs False ie ce [root_ul_bco]
489
   ; return root_hval
490
   }}
491
   where
492 493
     free_names = nameSetToList (bcoFreeNames root_ul_bco)

494
     needed_mods :: [Module]
495 496 497 498 499 500 501 502
     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.
503
 
504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520
dieWith span msg = throwDyn (ProgramError (showSDoc (mkLocMessage span msg)))


checkNonStdWay :: DynFlags -> SrcSpan -> IO (Maybe String)
checkNonStdWay dflags srcspan = do
  tag <- readIORef v_Build_tag
  if null tag then return Nothing else do
  let default_osuf = phaseInputExt StopLn
  if objectSuf dflags == default_osuf
	then failNonStd srcspan
	else return (Just default_osuf)

failNonStd srcspan = dieWith srcspan $
  ptext SLIT("Dynamic linking required, but this is a non-standard build (eg. prof).") $$
  ptext SLIT("You need to build the program twice: once the normal way, and then") $$
  ptext SLIT("in the desired way using -osuf to set the object file suffix.")
  
521

522
getLinkDeps :: HscEnv -> HomePackageTable -> PackageIfaceTable
523 524
	    -> Maybe String			-- the "normal" object suffix
	    -> SrcSpan				-- for error messages
525
	    -> [Module]				-- If you need these
526
	    -> IO ([Linkable], [PackageId])	-- ... then link these first
527
-- Fails with an IO exception if it can't find enough files
528

529
getLinkDeps hsc_env hpt pit maybe_normal_osuf span mods
530
-- Find all the packages and linkables that a set of modules depends on
531 532
 = do {	pls <- readIORef v_PersistentLinkerState ;
	let {
533
	-- 1.  Find the dependent home-pkg-modules/packages from each iface
Simon Marlow's avatar
Simon Marlow committed
534
	    (mods_s, pkgs_s) = follow_deps mods emptyUniqSet emptyUniqSet;
535 536 537

	-- 2.  Exclude ones already linked
	--	Main reason: avoid findModule calls in get_linkable
Simon Marlow's avatar
Simon Marlow committed
538 539
	    mods_needed = mods_s `minusList` linked_mods     ;
	    pkgs_needed = pkgs_s `minusList` pkgs_loaded pls ;
540

Simon Marlow's avatar
Simon Marlow committed
541 542
	    linked_mods = map (moduleName.linkableModule) 
                                (objs_loaded pls ++ bcos_loaded pls)
543
	} ;
544
	
Simon Marlow's avatar
Simon Marlow committed
545
--        putStrLn (showSDoc (ppr mods_s)) ;
546
	-- 3.  For each dependent module, find its linkable
547 548
	--     This will either be in the HPT or (in the case of one-shot
	--     compilation) we may need to use maybe_getFileLinkable
549
	lnks_needed <- mapM (get_linkable maybe_normal_osuf) mods_needed ;
550

551
	return (lnks_needed, pkgs_needed) }
552
  where
Simon Marlow's avatar
Simon Marlow committed
553 554 555
    dflags = hsc_dflags hsc_env
    this_pkg = thisPackage dflags

Simon Marlow's avatar
Simon Marlow committed
556 557 558 559 560 561 562 563 564 565 566 567
        -- The ModIface contains the transitive closure of the module dependencies
        -- within the current package, *except* for boot modules: if we encounter
        -- a boot module, we have to find its real interface and discover the
        -- dependencies of that.  Hence we need to traverse the dependency
        -- tree recursively.  See bug #936, testcase ghci/prog007.
    follow_deps :: [Module]             -- modules to follow
                -> UniqSet ModuleName         -- accum. module dependencies
                -> UniqSet PackageId          -- accum. package dependencies
                -> ([ModuleName], [PackageId]) -- result
    follow_deps []     acc_mods acc_pkgs
        = (uniqSetToList acc_mods, uniqSetToList acc_pkgs)
    follow_deps (mod:mods) acc_mods acc_pkgs
Simon Marlow's avatar
Simon Marlow committed
568
        | pkg /= this_pkg
Simon Marlow's avatar
Simon Marlow committed
569 570 571
        = follow_deps mods acc_mods (addOneToUniqSet acc_pkgs' pkg)
        | mi_boot iface
        = link_boot_mod_error mod
572
	| otherwise
573
        = follow_deps (map (mkModule this_pkg) boot_deps' ++ mods) acc_mods' acc_pkgs'
Simon Marlow's avatar
Simon Marlow committed
574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592
      where
        pkg   = modulePackageId mod
        iface = get_iface mod
	deps  = mi_deps iface

	pkg_deps = dep_pkgs deps
        (boot_deps, mod_deps) = partitionWith is_boot (dep_mods deps)
                where is_boot (m,True)  = Left m
                      is_boot (m,False) = Right m

        boot_deps' = filter (not . (`elementOfUniqSet` acc_mods)) boot_deps
        acc_mods'  = addListToUniqSet acc_mods (moduleName mod : mod_deps)
        acc_pkgs'  = addListToUniqSet acc_pkgs pkg_deps


    link_boot_mod_error mod = 
        throwDyn (ProgramError (showSDoc (
            text "module" <+> ppr mod <+> 
            text "cannot be linked; it is only available as a boot module")))
593

Simon Marlow's avatar
Simon Marlow committed
594
    get_iface mod = case lookupIfaceByModule dflags hpt pit mod of
595 596
			    Just iface -> iface
			    Nothing    -> pprPanic "getLinkDeps" (no_iface mod)
597 598 599
    no_iface mod = ptext SLIT("No iface for") <+> ppr mod
	-- This one is a GHC bug

600 601 602 603 604 605 606
    no_obj mod = dieWith span $
		     ptext SLIT("cannot find object file for module ") <> 
			quotes (ppr mod) $$
		     while_linking_expr
		
    while_linking_expr = ptext SLIT("while linking an interpreted expression")

607 608
	-- This one is a build-system bug

609
    get_linkable maybe_normal_osuf mod_name	-- A home-package module
Simon Marlow's avatar
Simon Marlow committed
610
	| Just mod_info <- lookupUFM hpt mod_name 
611
	= ASSERT(isJust (hm_linkable mod_info))
612
	  adjust_linkable (fromJust (hm_linkable mod_info))
613
	| otherwise	
Simon Marlow's avatar
Simon Marlow committed
614
	= do	-- It's not in the HPT because we are in one shot mode, 
615
		-- so use the Finder to get a ModLocation...
Simon Marlow's avatar
Simon Marlow committed
616 617 618
	     mb_stuff <- findHomeModule hsc_env mod_name
	     case mb_stuff of
		  Found loc mod -> found loc mod
619
		  _ -> no_obj mod_name
620 621
        where
            found loc mod = do {
622
		-- ...and then find the linkable for it
Simon Marlow's avatar
Simon Marlow committed
623
	       mb_lnk <- findObjectLinkableMaybe mod loc ;
624
	       case mb_lnk of {
Simon Marlow's avatar
Simon Marlow committed
625
		  Nothing -> no_obj mod ;
626
		  Just lnk -> adjust_linkable lnk
627
	      }}
628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643

	    adjust_linkable lnk
		| Just osuf <- maybe_normal_osuf = do
			new_uls <- mapM (adjust_ul osuf) (linkableUnlinked lnk)
        		return lnk{ linkableUnlinked=new_uls }
		| otherwise =
			return lnk

	    adjust_ul osuf (DotO file) = do
		let new_file = replaceFilenameSuffix file osuf
		ok <- doesFileExist new_file
		if (not ok)
		   then dieWith span $
			  ptext SLIT("cannot find normal object file ")
				<> quotes (text new_file) $$ while_linking_expr
		   else return (DotO new_file)
644
\end{code}
645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685


%************************************************************************
%*									*
		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]

686
findModuleLinkable_maybe :: [Linkable] -> Module -> Maybe Linkable
687 688 689 690 691 692 693 694
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 =
695
  case findModuleLinkable_maybe objs_loaded (linkableModule l) of
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773
	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

774
        (final_gce, linked_bcos) <- linkSomeBCOs True final_ie gce ul_bcos
775 776 777 778 779 780 781 782 783 784 785 786 787 788
		-- 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]
789
             -> IO (ClosureEnv, [HValue])
790 791 792 793
			-- The returned HValues are associated 1-1 with
			-- the incoming unlinked BCOs.  Each gives the
			-- value of the corresponding unlinked BCO
					
794
linkSomeBCOs toplevs_only ie ce_in ul_bcos
795
   = do let nms = map unlinkedBCOName ul_bcos
796 797 798 799 800 801 802 803 804 805 806
        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
807
        return (ce_out, hvals)
808

809 810 811 812 813 814 815 816 817 818
\end{code}


%************************************************************************
%*									*
		Unload some object modules
%*									*
%************************************************************************

\begin{code}
sof's avatar
sof committed
819
-- ---------------------------------------------------------------------------
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837
-- Unloading old objects ready for a new compilation sweep.
--
-- The compilation manager provides us with a list of linkables that it
-- considers "stable", i.e. won't be recompiled this time around.  For
-- each of the modules current linked in memory,
--
--	* if the linkable is stable (and it's the same one - the
--	  user may have recompiled the module on the side), we keep it,
--
--	* otherwise, we unload it.
--
--      * we also implicitly unload all temporary bindings at this point.

unload :: DynFlags -> [Linkable] -> IO ()
-- The 'linkables' are the ones to *keep*

unload dflags linkables
  = block $ do -- block, so we're safe from Ctrl-C in here
838 839 840
  
	-- Initialise the linker (if it's not been done already)
	initDynLinker dflags
sof's avatar
sof committed
841

842 843 844
	pls	<- readIORef v_PersistentLinkerState
	new_pls <- unload_wkr dflags linkables pls
	writeIORef v_PersistentLinkerState new_pls
845

846 847 848
	debugTraceMsg dflags 3 (text "unload: retaining objs" <+> ppr (objs_loaded new_pls))
	debugTraceMsg dflags 3 (text "unload: retaining bcos" <+> ppr (bcos_loaded new_pls))
	return ()
849

850 851 852 853 854 855
unload_wkr :: DynFlags
           -> [Linkable]		-- stable linkables
	   -> PersistentLinkerState
           -> IO PersistentLinkerState
-- Does the core unload business
-- (the wrapper blocks exceptions and deals with the PLS get and put)
856

857 858 859 860 861 862
unload_wkr dflags linkables pls
  = do	let (objs_to_keep, bcos_to_keep) = partition isObjectLinkable linkables

	objs_loaded' <- filterM (maybeUnload objs_to_keep) (objs_loaded pls)
        bcos_loaded' <- filterM (maybeUnload bcos_to_keep) (bcos_loaded pls)

863
       	let bcos_retained = map linkableModule bcos_loaded'
864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906
	    itbl_env'     = filterNameMap bcos_retained (itbl_env pls)
            closure_env'  = filterNameMap bcos_retained (closure_env pls)
  	    new_pls = pls { itbl_env = itbl_env',
			    closure_env = closure_env',
			    bcos_loaded = bcos_loaded',
			    objs_loaded = objs_loaded' }

	return new_pls
  where
    maybeUnload :: [Linkable] -> Linkable -> IO Bool
    maybeUnload keep_linkables lnk
      | linkableInSet lnk linkables = return True
      | otherwise		    
      = do mapM_ unloadObj [f | DotO f <- linkableUnlinked lnk]
		-- The components of a BCO linkable may contain
		-- dot-o files.  Which is very confusing.
		--
		-- But the BCO parts can be unlinked just by 
		-- letting go of them (plus of course depopulating
		-- the symbol table which is done in the main body)
	   return False
\end{code}


%************************************************************************
%*									*
		Loading packages
%*									*
%************************************************************************


\begin{code}
data LibrarySpec 
   = Object FilePath 	-- Full path name of a .o file, including trailing .o
			-- For dynamic objects only, try to find the object 
			-- file in all the directories specified in 
			-- v_Library_paths before giving up.

   | DLL String		-- "Unadorned" name of a .DLL/.so
			--  e.g.    On unix     "qt"  denotes "libqt.so"
			--          On WinDoze  "burble"  denotes "burble.DLL"
			--  loadDLL is platform-specific and adds the lib/.so/.DLL
			--  suffixes platform-dependently
907

908 909 910
   | DLLPath FilePath   -- Absolute or relative pathname to a dynamic library
			-- (ends with .dll or .so).

911
   | Framework String	-- Only used for darwin, but does no harm
912 913 914 915 916 917 918 919 920 921

-- If this package is already part of the GHCi binary, we'll already
-- have the right DLLs for this package loaded, so don't try to
-- load them again.
-- 
-- But on Win32 we must load them 'again'; doing so is a harmless no-op
-- as far as the loader is concerned, but it does initialise the list
-- of DLL handles that rts/Linker.c maintains, and that in turn is 
-- used by lookupSymbol.  So we must call addDLL for each library 
-- just to get the DLL handle into the list.
922 923 924
partOfGHCi
#          if defined(mingw32_TARGET_OS) || defined(darwin_TARGET_OS)
           = [ ]
925
#          else
926
           = [ "base", "haskell98", "template-haskell", "readline" ]
927 928
#          endif

929 930
showLS (Object nm)    = "(static) " ++ nm
showLS (DLL nm)       = "(dynamic) " ++ nm
931
showLS (DLLPath nm)   = "(dynamic) " ++ nm
932 933
showLS (Framework nm) = "(framework) " ++ nm

934
linkPackages :: DynFlags -> [PackageId] -> IO ()
935 936 937 938
-- Link exactly the specified packages, and their dependents
-- (unless of course they are already linked)
-- The dependents are linked automatically, and it doesn't matter
-- what order you specify the input packages.
939 940 941 942 943 944 945
--
-- NOTE: in fact, since each module tracks all the packages it depends on,
--	 we don't really need to use the package-config dependencies.
-- However we do need the package-config stuff (to find aux libs etc),
-- and following them lets us load libraries in the right order, which 
-- perhaps makes the error message a bit more localised if we get a link
-- failure.  So the dependency walking code is still here.
946 947 948

linkPackages dflags new_pkgs
   = do	{ pls 	  <- readIORef v_PersistentLinkerState
949
	; let pkg_map = pkgIdMap (pkgState dflags)
950 951 952 953 954 955

	; pkgs' <- link pkg_map (pkgs_loaded pls) new_pkgs

	; writeIORef v_PersistentLinkerState (pls { pkgs_loaded = pkgs' })
	}
   where
956
     link :: PackageConfigMap -> [PackageId] -> [PackageId] -> IO [PackageId]
957 958 959 960 961 962 963
     link pkg_map pkgs new_pkgs 
	= foldM (link_one pkg_map) pkgs new_pkgs

     link_one pkg_map pkgs new_pkg
	| new_pkg `elem` pkgs	-- Already linked
	= return pkgs

964
	| Just pkg_cfg <- lookupPackage pkg_map new_pkg
965
	= do { 	-- Link dependents first
966
	       pkgs' <- link pkg_map pkgs (map mkPackageId (depends pkg_cfg))
967 968 969 970 971
		-- Now link the package itself
	     ; linkPackage dflags pkg_cfg
	     ; return (new_pkg : pkgs') }

	| otherwise
972
	= throwDyn (CmdLineError ("unknown package: " ++ packageIdString new_pkg))
973 974 975 976 977


linkPackage :: DynFlags -> PackageConfig -> IO ()
linkPackage dflags pkg
   = do 
978
        let dirs      =  Packages.libraryDirs pkg
979 980 981 982 983 984 985 986 987 988 989 990 991

        let libs      =  Packages.hsLibraries pkg
        -- Because of slight differences between the GHC dynamic linker and
        -- the native system linker some packages have to link with a
        -- different list of libraries when using GHCi. Examples include: libs
        -- that are actually gnu ld scripts, and the possability that the .a
        -- libs do not exactly match the .so/.dll equivalents. So if the
        -- package file provides an "extra-ghci-libraries" field then we use
        -- that instead of the "extra-libraries" field.
                      ++ (if null (Packages.extraGHCiLibraries pkg)
                            then Packages.extraLibraries pkg
                            else Packages.extraGHCiLibraries pkg)
                      ++ [ lib | '-':'l':lib <- Packages.ldOptions pkg ]
992 993 994 995 996 997
        classifieds   <- mapM (locateOneObj dirs) libs

        -- Complication: all the .so's must be loaded before any of the .o's.  
	let dlls = [ dll | DLL dll    <- classifieds ]
	    objs = [ obj | Object obj <- classifieds ]

998
	maybePutStr dflags ("Loading package " ++ showPackageId (package pkg) ++ " ... ")
999 1000

	-- See comments with partOfGHCi
1001
	when (pkgName (package pkg) `notElem` partOfGHCi) $ do
1002
	    loadFrameworks pkg
1003 1004 1005 1006 1007 1008 1009
            -- When a library A needs symbols from a library B, the order in
            -- extra_libraries/extra_ld_opts is "-lA -lB", because that's the
            -- way ld expects it for static linking. Dynamic linking is a
            -- different story: When A has no dependency information for B,
            -- dlopen-ing A with RTLD_NOW (see addDLL in Linker.c) will fail
            -- when B has not been loaded before. In a nutshell: Reverse the
            -- order of DLLs for dynamic linking.
1010 1011
	    -- This fixes a problem with the HOpenGL package (see "Compiling
	    -- HOpenGL under recent versions of GHC" on the HOpenGL list).
1012
	    mapM_ (load_dyn dirs) (reverse dlls)
1013 1014
	
	-- After loading all the DLLs, we can load the static objects.
1015 1016
	-- Ordering isn't important here, because we do one final link
	-- step to resolve everything.
1017 1018 1019 1020 1021
	mapM_ loadObj objs

        maybePutStr dflags "linking ... "
        ok <- resolveObjs
	if succeeded ok then maybePutStrLn dflags "done."
1022
	      else throwDyn (InstallationError ("unable to load package `" ++ showPackageId (package pkg) ++ "'"))
1023

1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
load_dyn dirs dll = do r <- loadDynamic dirs dll
		       case r of
			 Nothing  -> return ()
			 Just err -> throwDyn (CmdLineError ("can't load .so/.DLL for: " 
                                 			      ++ dll ++ " (" ++ err ++ ")" ))
#ifndef darwin_TARGET_OS
loadFrameworks pkg = return ()
#else
loadFrameworks pkg = mapM_ load frameworks
  where
1034
    fw_dirs    = Packages.frameworkDirs pkg
ross's avatar
ross committed
1035
    frameworks = Packages.frameworks pkg
1036 1037 1038 1039 1040 1041

    load fw = do  r <- loadFramework fw_dirs fw
		  case r of
		    Nothing  -> return ()
		    Just err -> throwDyn (CmdLineError ("can't load framework: " 
                               			        ++ fw ++ " (" ++ err ++ ")" ))
1042 1043 1044 1045 1046 1047 1048 1049 1050
#endif

-- Try to find an object file for a given library in the given paths.
-- If it isn't present, we assume it's a dynamic library.
locateOneObj :: [FilePath] -> String -> IO LibrarySpec
locateOneObj dirs lib
  = do	{ mb_obj_path <- findFile mk_obj_path dirs 
	; case mb_obj_path of
	    Just obj_path -> return (Object obj_path)
1051 1052 1053 1054 1055
	    Nothing	  -> 
                do { mb_lib_path <- findFile mk_dyn_lib_path dirs
                   ; case mb_lib_path of
                       Just lib_path -> return (DLL (lib ++ "_dyn"))
                       Nothing       -> return (DLL lib) }}		-- We assume
1056
   where
1057 1058
     mk_obj_path dir = dir `joinFileName` (lib `joinFileExt` "o")
     mk_dyn_lib_path dir = dir `joinFileName` mkSOName (lib ++ "_dyn")
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072


-- ----------------------------------------------------------------------------
-- Loading a dyanmic library (dlopen()-ish on Unix, LoadLibrary-ish on Win32)

-- return Nothing == success, else Just error message from dlopen
loadDynamic paths rootname
  = do	{ mb_dll <- findFile mk_dll_path paths
	; case mb_dll of
	    Just dll -> loadDLL dll
	    Nothing  -> loadDLL (mkSOName rootname) }
			-- Tried all our known library paths, so let 
			-- dlopen() search its own builtin paths now.
  where
1073
    mk_dll_path dir = dir `joinFileName` mkSOName rootname
1074 1075

#if defined(darwin_TARGET_OS)
1076
mkSOName root = ("lib" ++ root) `joinFileExt` "dylib"
1077 1078 1079 1080 1081
#elif defined(mingw32_TARGET_OS)
-- Win32 DLLs have no .dll extension here, because addDLL tries
-- both foo.dll and foo.drv
mkSOName root = root
#else
1082
mkSOName root = ("lib" ++ root) `joinFileExt` "so"
1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
#endif

-- Darwin / MacOS X only: load a framework
-- a framework is a dynamic library packaged inside a directory of the same
-- name. They are searched for in different paths than normal libraries.
#ifdef darwin_TARGET_OS
loadFramework extraPaths rootname
   = do	{ mb_fwk <- findFile mk_fwk (extraPaths ++ defaultFrameworkPaths)
	; case mb_fwk of
	    Just fwk_path -> loadDLL fwk_path
1093
	    Nothing	  -> return (Just "not found") }
1094 1095 1096
 		-- Tried all our known library paths, but dlopen()
		-- has no built-in paths for frameworks: give up
   where
1097
     mk_fwk dir = dir `joinFileName` (rootname ++ ".framework/" ++ rootname)
1098 1099
	-- sorry for the hardcoded paths, I hope they won't change anytime soon:
     defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126
#endif
\end{code}

%************************************************************************
%*									*
		Helper functions
%*									*
%************************************************************************

\begin{code}
findFile :: (FilePath -> FilePath)	-- Maps a directory path to a file path
	 -> [FilePath]			-- Directories to look in
	 -> IO (Maybe FilePath)		-- The first file path to match
findFile mk_file_path [] 
  = return Nothing
findFile mk_file_path (dir:dirs)
  = do	{ let file_path = mk_file_path dir
	; b <- doesFileExist file_path
	; if b then 
	     return (Just file_path)
	  else
	     findFile mk_file_path dirs }
\end{code}

\begin{code}
maybePutStr dflags s | verbosity dflags > 0 = putStr s
		     | otherwise	    = return ()
1127

1128 1129
maybePutStrLn dflags s | verbosity dflags > 0 = putStrLn s
		       | otherwise	      = return ()
1130
\end{code}