content: -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Simple.LHC
  -- Copyright   :  Isaac Jones 2003-2007
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This is a fairly large module. It contains most of the GHC-specific code for
  -- configuring, building and installing packages. It also exports a function
  -- for finding out what packages are already installed. Configuring involves
  -- finding the @ghc@ and @ghc-pkg@ programs, finding what language extensions
  -- this version of ghc supports and returning a 'Compiler' value.
  --
  -- 'getInstalledPackages' involves calling the @ghc-pkg@ program to find out
  -- what packages are installed.
  --
  -- Building is somewhat complex as there is quite a bit of information to take
  -- into account. We have to build libs and programs, possibly for profiling and
  -- shared libs. We have to support building libraries that will be usable by
  -- GHCi and also ghc's @-split-objs@ feature. We have to compile any C files
  -- using ghc. Linking, especially for @split-objs@ is remarkably complex,
  -- partly because there tend to be 1,000's of @.o@ files and this can often be
  -- more than we can pass to the @ld@ or @ar@ programs in one go.
  --
  -- Installing for libs and exes involves finding the right files and copying
  -- them to the right places. One of the more tricky things about this module is
  -- remembering the layout of files in the build directory (which is not
  -- explicitly documented) and thus what search dirs are used for various kinds
  -- of files.
  
  {- Copyright (c) 2003-2005, Isaac Jones
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modiication, are permitted provided that the following conditions are
  met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
  
      * Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials provided
        with the distribution.
  
      * Neither the name of Isaac Jones nor the names of other
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}
  
  module Distribution.Simple.LHC (
          configure, getInstalledPackages,
          buildLib, buildExe,
          installLib, installExe,
          registerPackage,
          ghcOptions,
          ghcVerbosityOptions
   ) where
  
  import Distribution.PackageDescription as PD
           ( PackageDescription(..), BuildInfo(..), Executable(..)
           , Library(..), libModules, hcOptions, usedExtensions, allExtensions )
  import Distribution.InstalledPackageInfo
                                  ( InstalledPackageInfo
                                  , parseInstalledPackageInfo )
  import qualified Distribution.InstalledPackageInfo as InstalledPackageInfo
                                  ( InstalledPackageInfo_(..) )
  import Distribution.Simple.PackageIndex
  import qualified Distribution.Simple.PackageIndex as PackageIndex
  import Distribution.ParseUtils  ( ParseResult(..) )
  import Distribution.Simple.LocalBuildInfo
           ( LocalBuildInfo(..), ComponentLocalBuildInfo(..) )
  import Distribution.Simple.InstallDirs
  import Distribution.Simple.BuildPaths
  import Distribution.Simple.Utils
  import Distribution.Package
           ( PackageIdentifier, Package(..) )
  import qualified Distribution.ModuleName as ModuleName
  import Distribution.Simple.Program
           ( Program(..), ConfiguredProgram(..), ProgramConfiguration, ProgArg
           , ProgramLocation(..), rawSystemProgram, rawSystemProgramConf
           , rawSystemProgramStdout, rawSystemProgramStdoutConf
           , requireProgramVersion
           , userMaybeSpecifyPath, programPath, lookupProgram, addKnownProgram
           , arProgram, ranlibProgram, ldProgram
           , gccProgram, stripProgram
           , lhcProgram, lhcPkgProgram )
  import qualified Distribution.Simple.Program.HcPkg as HcPkg
  import Distribution.Simple.Compiler
           ( CompilerFlavor(..), CompilerId(..), Compiler(..), compilerVersion
           , OptimisationLevel(..), PackageDB(..), PackageDBStack
           , Flag, languageToFlags, extensionsToFlags )
  import Distribution.Version
           ( Version(..), orLaterVersion )
  import Distribution.System
           ( OS(..), buildOS )
  import Distribution.Verbosity
  import Distribution.Text
           ( display, simpleParse )
  import Language.Haskell.Extension
           ( Language(Haskell98), Extension(..), KnownExtension(..) )
  
  import Control.Monad            ( unless, when )
  import Data.List
  import Data.Maybe               ( catMaybes )
  import Data.Monoid              ( Monoid(..) )
  import System.Directory         ( removeFile, renameFile,
                                    getDirectoryContents, doesFileExist,
                                    getTemporaryDirectory )
  import System.FilePath          ( (</>), (<.>), takeExtension,
                                    takeDirectory, replaceExtension )
  import System.IO (hClose, hPutStrLn)
  import Distribution.Compat.Exception (catchExit, catchIO)
  
  -- -----------------------------------------------------------------------------
  -- Configuring
  
  configure :: Verbosity -> Maybe FilePath -> Maybe FilePath
            -> ProgramConfiguration -> IO (Compiler, ProgramConfiguration)
  configure verbosity hcPath hcPkgPath conf = do
  
    (lhcProg, lhcVersion, conf') <-
      requireProgramVersion verbosity lhcProgram
        (orLaterVersion (Version [0,7] []))
        (userMaybeSpecifyPath "lhc" hcPath conf)
  
    (lhcPkgProg, lhcPkgVersion, conf'') <-
      requireProgramVersion verbosity lhcPkgProgram
        (orLaterVersion (Version [0,7] []))
        (userMaybeSpecifyPath "lhc-pkg" hcPkgPath conf')
  
    when (lhcVersion /= lhcPkgVersion) $ die $
         "Version mismatch between lhc and lhc-pkg: "
      ++ programPath lhcProg ++ " is version " ++ display lhcVersion ++ " "
      ++ programPath lhcPkgProg ++ " is version " ++ display lhcPkgVersion
  
    languages  <- getLanguages  verbosity lhcProg
    extensions <- getExtensions verbosity lhcProg
  
    let comp = Compiler {
          compilerId             = CompilerId LHC lhcVersion,
          compilerLanguages      = languages,
          compilerExtensions     = extensions
        }
        conf''' = configureToolchain lhcProg conf'' -- configure gcc and ld
    return (comp, conf''')
  
  -- | Adjust the way we find and configure gcc and ld
  --
  configureToolchain :: ConfiguredProgram -> ProgramConfiguration
                                          -> ProgramConfiguration
  configureToolchain lhcProg =
      addKnownProgram gccProgram {
        programFindLocation = findProg gccProgram (baseDir </> "gcc.exe"),
        programPostConf     = configureGcc
      }
    . addKnownProgram ldProgram {
        programFindLocation = findProg ldProgram (libDir </> "ld.exe"),
        programPostConf     = configureLd
      }
    where
      compilerDir = takeDirectory (programPath lhcProg)
      baseDir     = takeDirectory compilerDir
      libDir      = baseDir </> "gcc-lib"
      includeDir  = baseDir </> "include" </> "mingw"
      isWindows   = case buildOS of Windows -> True; _ -> False
  
      -- on Windows finding and configuring ghc's gcc and ld is a bit special
      findProg :: Program -> FilePath -> Verbosity -> IO (Maybe FilePath)
      findProg prog location | isWindows = \verbosity -> do
          exists <- doesFileExist location
          if exists then return (Just location)
                    else do warn verbosity ("Couldn't find " ++ programName prog ++ " where I expected it. Trying the search path.")
                            programFindLocation prog verbosity
        | otherwise = programFindLocation prog
  
      configureGcc :: Verbosity -> ConfiguredProgram -> IO [ProgArg]
      configureGcc
        | isWindows = \_ gccProg -> case programLocation gccProg of
            -- if it's found on system then it means we're using the result
            -- of programFindLocation above rather than a user-supplied path
            -- that means we should add this extra flag to tell ghc's gcc
            -- where it lives and thus where gcc can find its various files:
            FoundOnSystem {} -> return ["-B" ++ libDir, "-I" ++ includeDir]
            UserSpecified {} -> return []
        | otherwise = \_ _   -> return []
  
      -- we need to find out if ld supports the -x flag
      configureLd :: Verbosity -> ConfiguredProgram -> IO [ProgArg]
      configureLd verbosity ldProg = do
        tempDir <- getTemporaryDirectory
        ldx <- withTempFile tempDir ".c" $ \testcfile testchnd ->
               withTempFile tempDir ".o" $ \testofile testohnd -> do
                 hPutStrLn testchnd "int foo() {}"
                 hClose testchnd; hClose testohnd
                 rawSystemProgram verbosity lhcProg ["-c", testcfile,
                                                     "-o", testofile]
                 withTempFile tempDir ".o" $ \testofile' testohnd' ->
                   do
                     hClose testohnd'
                     _ <- rawSystemProgramStdout verbosity ldProg
                       ["-x", "-r", testofile, "-o", testofile']
                     return True
                   `catchIO`   (\_ -> return False)
                   `catchExit` (\_ -> return False)
        if ldx
          then return ["-x"]
          else return []
  
  getLanguages :: Verbosity -> ConfiguredProgram -> IO [(Language, Flag)]
  getLanguages _ _ = return [(Haskell98, "")]
  --FIXME: does lhc support -XHaskell98 flag? from what version?
  
  getExtensions :: Verbosity -> ConfiguredProgram -> IO [(Extension, Flag)]
  getExtensions verbosity lhcProg = do
      exts <- rawSystemStdout verbosity (programPath lhcProg)
                ["--supported-languages"]
      -- GHC has the annoying habit of inverting some of the extensions
      -- so we have to try parsing ("No" ++ ghcExtensionName) first
      let readExtension str = do
            ext <- simpleParse ("No" ++ str)
            case ext of
              UnknownExtension _ -> simpleParse str
              _                  -> return ext
      return $ [ (ext, "-X" ++ display ext)
               | Just ext <- map readExtension (lines exts) ]
  
  getInstalledPackages :: Verbosity -> PackageDBStack -> ProgramConfiguration
                       -> IO PackageIndex
  getInstalledPackages verbosity packagedbs conf = do
    checkPackageDbStack packagedbs
    pkgss <- getInstalledPackages' verbosity packagedbs conf
    let indexes = [ PackageIndex.fromList (map (substTopDir topDir) pkgs)
                  | (_, pkgs) <- pkgss ]
    return $! (mconcat indexes)
  
    where
      -- On Windows, various fields have $topdir/foo rather than full
      -- paths. We need to substitute the right value in so that when
      -- we, for example, call gcc, we have proper paths to give it
      Just ghcProg = lookupProgram lhcProgram conf
      compilerDir  = takeDirectory (programPath ghcProg)
      topDir       = takeDirectory compilerDir
  
  checkPackageDbStack :: PackageDBStack -> IO ()
  checkPackageDbStack (GlobalPackageDB:rest)
    | GlobalPackageDB `notElem` rest = return ()
  checkPackageDbStack _ =
    die $ "GHC.getInstalledPackages: the global package db must be "
       ++ "specified first and cannot be specified multiple times"
  
  -- | Get the packages from specific PackageDBs, not cumulative.
  --
  getInstalledPackages' :: Verbosity -> [PackageDB] -> ProgramConfiguration
                       -> IO [(PackageDB, [InstalledPackageInfo])]
  getInstalledPackages' verbosity packagedbs conf
    =
    sequence
      [ do str <- rawSystemProgramStdoutConf verbosity lhcPkgProgram conf
                    ["dump", packageDbGhcPkgFlag packagedb]
             `catchExit` \_ -> die $ "ghc-pkg dump failed"
           case parsePackages str of
             Left ok -> return (packagedb, ok)
             _       -> die "failed to parse output of 'ghc-pkg dump'"
      | packagedb <- packagedbs ]
  
    where
      parsePackages str =
        let parsed = map parseInstalledPackageInfo (splitPkgs str)
         in case [ msg | ParseFailed msg <- parsed ] of
              []   -> Left [ pkg | ParseOk _ pkg <- parsed ]
              msgs -> Right msgs
  
      splitPkgs :: String -> [String]
      splitPkgs = map unlines . splitWith ("---" ==) . lines
        where
          splitWith :: (a -> Bool) -> [a] -> [[a]]
          splitWith p xs = ys : case zs of
                             []   -> []
                             _:ws -> splitWith p ws
            where (ys,zs) = break p xs
  
      packageDbGhcPkgFlag GlobalPackageDB          = "--global"
      packageDbGhcPkgFlag UserPackageDB            = "--user"
      packageDbGhcPkgFlag (SpecificPackageDB path) = "--package-conf=" ++ path
  
  
  substTopDir :: FilePath -> InstalledPackageInfo -> InstalledPackageInfo
  substTopDir topDir ipo
   = ipo {
         InstalledPackageInfo.importDirs
             = map f (InstalledPackageInfo.importDirs ipo),
         InstalledPackageInfo.libraryDirs
             = map f (InstalledPackageInfo.libraryDirs ipo),
         InstalledPackageInfo.includeDirs
             = map f (InstalledPackageInfo.includeDirs ipo),
         InstalledPackageInfo.frameworkDirs
             = map f (InstalledPackageInfo.frameworkDirs ipo),
         InstalledPackageInfo.haddockInterfaces
             = map f (InstalledPackageInfo.haddockInterfaces ipo),
         InstalledPackageInfo.haddockHTMLs
             = map f (InstalledPackageInfo.haddockHTMLs ipo)
     }
      where f ('$':'t':'o':'p':'d':'i':'r':rest) = topDir ++ rest
            f x = x
  
  -- -----------------------------------------------------------------------------
  -- Building
  
  -- | Build a library with LHC.
  --
  buildLib :: Verbosity -> PackageDescription -> LocalBuildInfo
                        -> Library            -> ComponentLocalBuildInfo -> IO ()
  buildLib verbosity pkg_descr lbi lib clbi = do
    let pref = buildDir lbi
        pkgid = packageId pkg_descr
        runGhcProg = rawSystemProgramConf verbosity lhcProgram (withPrograms lbi)
        ifVanillaLib forceVanilla = when (forceVanilla || withVanillaLib lbi)
        ifProfLib = when (withProfLib lbi)
        ifSharedLib = when (withSharedLib lbi)
        ifGHCiLib = when (withGHCiLib lbi && withVanillaLib lbi)
  
    libBi <- hackThreadedFlag verbosity
               (compiler lbi) (withProfLib lbi) (libBuildInfo lib)
  
    let libTargetDir = pref
        forceVanillaLib = EnableExtension TemplateHaskell `elem` allExtensions libBi
        -- TH always needs vanilla libs, even when building for profiling
  
    createDirectoryIfMissingVerbose verbosity True libTargetDir
    -- TODO: do we need to put hs-boot files into place for mutually recurive modules?
    let ghcArgs =
               ["-package-name", display pkgid ]
            ++ constructGHCCmdLine lbi libBi clbi libTargetDir verbosity
            ++ map display (libModules lib)
        lhcWrap x = ["--build-library", "--ghc-opts=" ++ unwords x]
        ghcArgsProf = ghcArgs
            ++ ["-prof",
                "-hisuf", "p_hi",
                "-osuf", "p_o"
               ]
            ++ ghcProfOptions libBi
        ghcArgsShared = ghcArgs
            ++ ["-dynamic",
                "-hisuf", "dyn_hi",
                "-osuf", "dyn_o", "-fPIC"
               ]
            ++ ghcSharedOptions libBi
    unless (null (libModules lib)) $
      do ifVanillaLib forceVanillaLib (runGhcProg $ lhcWrap ghcArgs)
         ifProfLib (runGhcProg $ lhcWrap ghcArgsProf)
         ifSharedLib (runGhcProg $ lhcWrap ghcArgsShared)
  
    -- build any C sources
    unless (null (cSources libBi)) $ do
       info verbosity "Building C Sources..."
       sequence_ [do let (odir,args) = constructCcCmdLine lbi libBi clbi pref
                                                          filename verbosity
                     createDirectoryIfMissingVerbose verbosity True odir
                     runGhcProg args
                     ifSharedLib (runGhcProg (args ++ ["-fPIC", "-osuf dyn_o"]))
                 | filename <- cSources libBi]
  
    -- link:
    info verbosity "Linking..."
    let cObjs = map (`replaceExtension` objExtension) (cSources libBi)
        cSharedObjs = map (`replaceExtension` ("dyn_" ++ objExtension)) (cSources libBi)
        vanillaLibFilePath = libTargetDir </> mkLibName pkgid
        profileLibFilePath = libTargetDir </> mkProfLibName pkgid
        sharedLibFilePath  = libTargetDir </> mkSharedLibName pkgid
                                                (compilerId (compiler lbi))
        ghciLibFilePath    = libTargetDir </> mkGHCiLibName pkgid
  
    stubObjs <- fmap catMaybes $ sequence
      [ findFileWithExtension [objExtension] [libTargetDir]
          (ModuleName.toFilePath x ++"_stub")
      | x <- libModules lib ]
    stubProfObjs <- fmap catMaybes $ sequence
      [ findFileWithExtension ["p_" ++ objExtension] [libTargetDir]
          (ModuleName.toFilePath x ++"_stub")
      | x <- libModules lib ]
    stubSharedObjs <- fmap catMaybes $ sequence
      [ findFileWithExtension ["dyn_" ++ objExtension] [libTargetDir]
          (ModuleName.toFilePath x ++"_stub")
      | x <- libModules lib ]
  
    hObjs     <- getHaskellObjects lib lbi
                      pref objExtension True
    hProfObjs <-
      if (withProfLib lbi)
              then getHaskellObjects lib lbi
                      pref ("p_" ++ objExtension) True
              else return []
    hSharedObjs <-
      if (withSharedLib lbi)
              then getHaskellObjects lib lbi
                      pref ("dyn_" ++ objExtension) False
              else return []
  
    unless (null hObjs && null cObjs && null stubObjs) $ do
      -- first remove library files if they exists
      sequence_
        [ removeFile libFilePath `catchIO` \_ -> return ()
        | libFilePath <- [vanillaLibFilePath, profileLibFilePath
                         ,sharedLibFilePath,  ghciLibFilePath] ]
  
      let arVerbosity | verbosity >= deafening = "v"
                      | verbosity >= normal = ""
                      | otherwise = "c"
          arArgs = ["q"++ arVerbosity]
              ++ [vanillaLibFilePath]
          arObjArgs =
                 hObjs
              ++ map (pref </>) cObjs
              ++ stubObjs
          arProfArgs = ["q"++ arVerbosity]
              ++ [profileLibFilePath]
          arProfObjArgs =
                 hProfObjs
              ++ map (pref </>) cObjs
              ++ stubProfObjs
          ldArgs = ["-r"]
              ++ ["-o", ghciLibFilePath <.> "tmp"]
          ldObjArgs =
                 hObjs
              ++ map (pref </>) cObjs
              ++ stubObjs
          ghcSharedObjArgs =
                 hSharedObjs
              ++ map (pref </>) cSharedObjs
              ++ stubSharedObjs
          -- After the relocation lib is created we invoke ghc -shared
          -- with the dependencies spelled out as -package arguments
          -- and ghc invokes the linker with the proper library paths
          ghcSharedLinkArgs =
              [ "-no-auto-link-packages",
                "-shared",
                "-dynamic",
                "-o", sharedLibFilePath ]
              ++ ghcSharedObjArgs
              ++ ["-package-name", display pkgid ]
              ++ ghcPackageFlags lbi clbi
              ++ ["-l"++extraLib | extraLib <- extraLibs libBi]
              ++ ["-L"++extraLibDir | extraLibDir <- extraLibDirs libBi]
  
          runLd ldLibName args = do
            exists <- doesFileExist ldLibName
              -- This method is called iteratively by xargs. The
              -- output goes to <ldLibName>.tmp, and any existing file
              -- named <ldLibName> is included when linking. The
              -- output is renamed to <libName>.
            rawSystemProgramConf verbosity ldProgram (withPrograms lbi)
              (args ++ if exists then [ldLibName] else [])
            renameFile (ldLibName <.> "tmp") ldLibName
  
          runAr = rawSystemProgramConf verbosity arProgram (withPrograms lbi)
  
           --TODO: discover this at configure time or runtime on unix
           -- The value is 32k on Windows and posix specifies a minimum of 4k
           -- but all sensible unixes use more than 4k.
           -- we could use getSysVar ArgumentLimit but that's in the unix lib
          maxCommandLineSize = 30 * 1024
  
      ifVanillaLib False $ xargs maxCommandLineSize
        runAr arArgs arObjArgs
  
      ifProfLib $ xargs maxCommandLineSize
        runAr arProfArgs arProfObjArgs
  
      ifGHCiLib $ xargs maxCommandLineSize
        (runLd ghciLibFilePath) ldArgs ldObjArgs
  
      ifSharedLib $ runGhcProg ghcSharedLinkArgs
  
  
  -- | Build an executable with LHC.
  --
  buildExe :: Verbosity -> PackageDescription -> LocalBuildInfo
                        -> Executable         -> ComponentLocalBuildInfo -> IO ()
  buildExe verbosity _pkg_descr lbi
    exe@Executable { exeName = exeName', modulePath = modPath } clbi = do
    let pref = buildDir lbi
        runGhcProg = rawSystemProgramConf verbosity lhcProgram (withPrograms lbi)
  
    exeBi <- hackThreadedFlag verbosity
               (compiler lbi) (withProfExe lbi) (buildInfo exe)
  
    -- exeNameReal, the name that GHC really uses (with .exe on Windows)
    let exeNameReal = exeName' <.>
                      (if null $ takeExtension exeName' then exeExtension else "")
  
    let targetDir = pref </> exeName'
    let exeDir    = targetDir </> (exeName' ++ "-tmp")
    createDirectoryIfMissingVerbose verbosity True targetDir
    createDirectoryIfMissingVerbose verbosity True exeDir
    -- TODO: do we need to put hs-boot files into place for mutually recursive modules?
    -- FIX: what about exeName.hi-boot?
  
    -- build executables
    unless (null (cSources exeBi)) $ do
     info verbosity "Building C Sources."
     sequence_ [do let (odir,args) = constructCcCmdLine lbi exeBi clbi
                                            exeDir filename verbosity
                   createDirectoryIfMissingVerbose verbosity True odir
                   runGhcProg args
               | filename <- cSources exeBi]
  
    srcMainFile <- findFile (exeDir : hsSourceDirs exeBi) modPath
  
    let cObjs = map (`replaceExtension` objExtension) (cSources exeBi)
    let lhcWrap x = ("--ghc-opts\"":x) ++ ["\""]
    let binArgs linkExe profExe =
               (if linkExe
                   then ["-o", targetDir </> exeNameReal]
                   else ["-c"])
            ++ constructGHCCmdLine lbi exeBi clbi exeDir verbosity
            ++ [exeDir </> x | x <- cObjs]
            ++ [srcMainFile]
            ++ ["-optl" ++ opt | opt <- PD.ldOptions exeBi]
            ++ ["-l"++lib | lib <- extraLibs exeBi]
            ++ ["-L"++libDir | libDir <- extraLibDirs exeBi]
            ++ concat [["-framework", f] | f <- PD.frameworks exeBi]
            ++ if profExe
                  then ["-prof",
                        "-hisuf", "p_hi",
                        "-osuf", "p_o"
                       ] ++ ghcProfOptions exeBi
                  else []
  
    -- For building exe's for profiling that use TH we actually
    -- have to build twice, once without profiling and the again
    -- with profiling. This is because the code that TH needs to
    -- run at compile time needs to be the vanilla ABI so it can
    -- be loaded up and run by the compiler.
    when (withProfExe lbi && EnableExtension TemplateHaskell `elem` allExtensions exeBi)
       (runGhcProg $ lhcWrap (binArgs False False))
  
    runGhcProg (binArgs True (withProfExe lbi))
  
  -- | Filter the "-threaded" flag when profiling as it does not
  --   work with ghc-6.8 and older.
  hackThreadedFlag :: Verbosity -> Compiler -> Bool -> BuildInfo -> IO BuildInfo
  hackThreadedFlag verbosity comp prof bi
    | not mustFilterThreaded = return bi
    | otherwise              = do
      warn verbosity $ "The ghc flag '-threaded' is not compatible with "
                    ++ "profiling in ghc-6.8 and older. It will be disabled."
      return bi { options = filterHcOptions (/= "-threaded") (options bi) }
    where
      mustFilterThreaded = prof && compilerVersion comp < Version [6, 10] []
                        && "-threaded" `elem` hcOptions GHC bi
      filterHcOptions p hcoptss =
        [ (hc, if hc == GHC then filter p opts else opts)
        | (hc, opts) <- hcoptss ]
  
  -- when using -split-objs, we need to search for object files in the
  -- Module_split directory for each module.
  getHaskellObjects :: Library -> LocalBuildInfo
                    -> FilePath -> String -> Bool -> IO [FilePath]
  getHaskellObjects lib lbi pref wanted_obj_ext allow_split_objs
    | splitObjs lbi && allow_split_objs = do
          let dirs = [ pref </> (ModuleName.toFilePath x ++ "_split")
                     | x <- libModules lib ]
          objss <- mapM getDirectoryContents dirs
          let objs = [ dir </> obj
                     | (objs',dir) <- zip objss dirs, obj <- objs',
                       let obj_ext = takeExtension obj,
                       '.':wanted_obj_ext == obj_ext ]
          return objs
    | otherwise  =
          return [ pref </> ModuleName.toFilePath x <.> wanted_obj_ext
                 | x <- libModules lib ]
  
  
  constructGHCCmdLine
          :: LocalBuildInfo
          -> BuildInfo
          -> ComponentLocalBuildInfo
          -> FilePath
          -> Verbosity
          -> [String]
  constructGHCCmdLine lbi bi clbi odir verbosity =
          ["--make"]
       ++ ghcVerbosityOptions verbosity
          -- Unsupported extensions have already been checked by configure
       ++ ghcOptions lbi bi clbi odir
  
  ghcVerbosityOptions :: Verbosity -> [String]
  ghcVerbosityOptions verbosity
       | verbosity >= deafening = ["-v"]
       | verbosity >= normal    = []
       | otherwise              = ["-w", "-v0"]
  
  ghcOptions :: LocalBuildInfo -> BuildInfo -> ComponentLocalBuildInfo
             -> FilePath -> [String]
  ghcOptions lbi bi clbi odir
       =  ["-hide-all-packages"]
       ++ ghcPackageDbOptions (withPackageDB lbi)
       ++ (if splitObjs lbi then ["-split-objs"] else [])
       ++ ["-i"]
       ++ ["-i" ++ odir]
       ++ ["-i" ++ l | l <- nub (hsSourceDirs bi)]
       ++ ["-i" ++ autogenModulesDir lbi]
       ++ ["-I" ++ autogenModulesDir lbi]
       ++ ["-I" ++ odir]
       ++ ["-I" ++ dir | dir <- PD.includeDirs bi]
       ++ ["-optP" ++ opt | opt <- cppOptions bi]
       ++ [ "-optP-include", "-optP"++ (autogenModulesDir lbi </> cppHeaderName) ]
       ++ [ "-#include \"" ++ inc ++ "\"" | inc <- PD.includes bi ]
       ++ [ "-odir",  odir, "-hidir", odir ]
       ++ (if compilerVersion c >= Version [6,8] []
             then ["-stubdir", odir] else [])
       ++ ghcPackageFlags lbi clbi
       ++ (case withOptimization lbi of
             NoOptimisation      -> []
             NormalOptimisation  -> ["-O"]
             MaximumOptimisation -> ["-O2"])
       ++ hcOptions GHC bi
       ++ languageToFlags c (defaultLanguage bi)
       ++ extensionsToFlags c (usedExtensions bi)
      where c = compiler lbi
  
  ghcPackageFlags :: LocalBuildInfo -> ComponentLocalBuildInfo -> [String]
  ghcPackageFlags lbi clbi
    | ghcVer >= Version [6,11] []
                = concat [ ["-package-id", display ipkgid]
                         | (ipkgid, _) <- componentPackageDeps clbi ]
  
    | otherwise = concat [ ["-package", display pkgid]
                         | (_, pkgid)  <- componentPackageDeps clbi ]
      where
        ghcVer = compilerVersion (compiler lbi)
  
  ghcPackageDbOptions :: PackageDBStack -> [String]
  ghcPackageDbOptions dbstack = case dbstack of
    (GlobalPackageDB:UserPackageDB:dbs) -> concatMap specific dbs
    (GlobalPackageDB:dbs)               -> "-no-user-package-conf"
                                         : concatMap specific dbs
    _                                   -> ierror
   where
      specific (SpecificPackageDB db) = [ "-package-conf", db ]
      specific _ = ierror
      ierror     = error ("internal error: unexpected package db stack: " ++ show dbstack)
  
  constructCcCmdLine :: LocalBuildInfo -> BuildInfo -> ComponentLocalBuildInfo
                     -> FilePath -> FilePath -> Verbosity -> (FilePath,[String])
  constructCcCmdLine lbi bi clbi pref filename verbosity
    =  let odir | compilerVersion (compiler lbi) >= Version [6,4,1] []  = pref
                | otherwise = pref </> takeDirectory filename
                          -- ghc 6.4.1 fixed a bug in -odir handling
                          -- for C compilations.
       in
          (odir,
           ghcCcOptions lbi bi clbi odir
           ++ (if verbosity >= deafening then ["-v"] else [])
           ++ ["-c",filename])
  
  
  ghcCcOptions :: LocalBuildInfo -> BuildInfo -> ComponentLocalBuildInfo
               -> FilePath -> [String]
  ghcCcOptions lbi bi clbi odir
       =  ["-I" ++ dir | dir <- PD.includeDirs bi]
       ++ ghcPackageDbOptions (withPackageDB lbi)
       ++ ghcPackageFlags lbi clbi
       ++ ["-optc" ++ opt | opt <- PD.ccOptions bi]
       ++ (case withOptimization lbi of
             NoOptimisation -> []
             _              -> ["-optc-O2"])
       ++ ["-odir", odir]
  
  mkGHCiLibName :: PackageIdentifier -> String
  mkGHCiLibName lib = "HS" ++ display lib <.> "o"
  
  -- -----------------------------------------------------------------------------
  -- Installing
  
  -- |Install executables for GHC.
  installExe :: Verbosity
             -> LocalBuildInfo
             -> InstallDirs FilePath -- ^Where to copy the files to
             -> FilePath  -- ^Build location
             -> (FilePath, FilePath)  -- ^Executable (prefix,suffix)
             -> PackageDescription
             -> Executable
             -> IO ()
  installExe verbosity lbi installDirs buildPref (progprefix, progsuffix) _pkg exe = do
    let binDir = bindir installDirs
    createDirectoryIfMissingVerbose verbosity True binDir
    let exeFileName = exeName exe <.> exeExtension
        fixedExeBaseName = progprefix ++ exeName exe ++ progsuffix
        installBinary dest = do
            installExecutableFile verbosity
              (buildPref </> exeName exe </> exeFileName)
              (dest <.> exeExtension)
            stripExe verbosity lbi exeFileName (dest <.> exeExtension)
    installBinary (binDir </> fixedExeBaseName)
  
  stripExe :: Verbosity -> LocalBuildInfo -> FilePath -> FilePath -> IO ()
  stripExe verbosity lbi name path = when (stripExes lbi) $
    case lookupProgram stripProgram (withPrograms lbi) of
      Just strip -> rawSystemProgram verbosity strip args
      Nothing    -> unless (buildOS == Windows) $
                    -- Don't bother warning on windows, we don't expect them to
                    -- have the strip program anyway.
                    warn verbosity $ "Unable to strip executable '" ++ name
                                  ++ "' (missing the 'strip' program)"
    where
      args = path : case buildOS of
         OSX -> ["-x"] -- By default, stripping the ghc binary on at least
                       -- some OS X installations causes:
                       --     HSbase-3.0.o: unknown symbol `_environ'"
                       -- The -x flag fixes that.
         _   -> []
  
  -- |Install for ghc, .hi, .a and, if --with-ghci given, .o
  installLib    :: Verbosity
                -> LocalBuildInfo
                -> FilePath  -- ^install location
                -> FilePath  -- ^install location for dynamic librarys
                -> FilePath  -- ^Build location
                -> PackageDescription
                -> Library
                -> IO ()
  installLib verbosity lbi targetDir dynlibTargetDir builtDir pkg lib = do
    -- copy .hi files over:
    let copy src dst n = do
          createDirectoryIfMissingVerbose verbosity True dst
          installOrdinaryFile verbosity (src </> n) (dst </> n)
        copyModuleFiles ext =
          findModuleFiles [builtDir] [ext] (libModules lib)
            >>= installOrdinaryFiles verbosity targetDir
    ifVanilla $ copyModuleFiles "hi"
    ifProf    $ copyModuleFiles "p_hi"
    hcrFiles <- findModuleFiles (builtDir : hsSourceDirs (libBuildInfo lib)) ["hcr"] (libModules lib)
    flip mapM_ hcrFiles $ \(srcBase, srcFile) -> runLhc ["--install-library", srcBase </> srcFile]
  
    -- copy the built library files over:
    ifVanilla $ copy builtDir targetDir vanillaLibName
    ifProf    $ copy builtDir targetDir profileLibName
    ifGHCi    $ copy builtDir targetDir ghciLibName
    ifShared  $ copy builtDir dynlibTargetDir sharedLibName
  
    -- run ranlib if necessary:
    ifVanilla $ updateLibArchive verbosity lbi
                                 (targetDir </> vanillaLibName)
    ifProf    $ updateLibArchive verbosity lbi
                                 (targetDir </> profileLibName)
  
    where
      vanillaLibName = mkLibName pkgid
      profileLibName = mkProfLibName pkgid
      ghciLibName    = mkGHCiLibName pkgid
      sharedLibName  = mkSharedLibName pkgid (compilerId (compiler lbi))
  
      pkgid          = packageId pkg
  
      hasLib    = not $ null (libModules lib)
                     && null (cSources (libBuildInfo lib))
      ifVanilla = when (hasLib && withVanillaLib lbi)
      ifProf    = when (hasLib && withProfLib    lbi)
      ifGHCi    = when (hasLib && withGHCiLib    lbi)
      ifShared  = when (hasLib && withSharedLib  lbi)
  
      runLhc    = rawSystemProgramConf verbosity lhcProgram (withPrograms lbi)
  
  -- | use @ranlib@ or @ar -s@ to build an index. This is necessary on systems
  -- like MacOS X. If we can't find those, don't worry too much about it.
  --
  updateLibArchive :: Verbosity -> LocalBuildInfo -> FilePath -> IO ()
  updateLibArchive verbosity lbi path =
    case lookupProgram ranlibProgram (withPrograms lbi) of
      Just ranlib -> rawSystemProgram verbosity ranlib [path]
      Nothing     -> case lookupProgram arProgram (withPrograms lbi) of
        Just ar   -> rawSystemProgram verbosity ar ["-s", path]
        Nothing   -> warn verbosity $
                          "Unable to generate a symbol index for the static "
                       ++ "library '" ++ path
                       ++ "' (missing the 'ranlib' and 'ar' programs)"
  
  -- -----------------------------------------------------------------------------
  -- Registering
  
  registerPackage
    :: Verbosity
    -> InstalledPackageInfo
    -> PackageDescription
    -> LocalBuildInfo
    -> Bool
    -> PackageDBStack
    -> IO ()
  registerPackage verbosity installedPkgInfo _pkg lbi _inplace packageDbs = do
    let Just lhcPkg = lookupProgram lhcPkgProgram (withPrograms lbi)
    HcPkg.reregister verbosity lhcPkg packageDbs (Right installedPkgInfo)
  