Distribution/Simple/GHC.hs

    {-# LANGUAGE PatternGuards #-}

    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Distribution.Simple.GHC
    -- Copyright   :  Isaac Jones 2003-2007
    -- License     :  BSD3
    --
    -- 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.

    module Distribution.Simple.GHC (
            getGhcInfo,
            configure,
            getInstalledPackages,
            getInstalledPackagesMonitorFiles,
            getPackageDBContents,
            buildLib, buildExe,
            replLib, replExe,
            startInterpreter,
            installLib, installExe,
            libAbiHash,
            hcPkgInfo,
            registerPackage,
            componentGhcOptions,
            componentCcGhcOptions,
            getLibDir,
            isDynamic,
            getGlobalPackageDB,
            pkgRoot
     ) where

    import Control.Applicative -- 7.10 -Werror workaround
    import Prelude             -- https://ghc.haskell.org/trac/ghc/wiki/Migration/7.10#GHCsaysTheimportof...isredundant

    import qualified Distribution.Simple.GHC.IPI642 as IPI642
    import qualified Distribution.Simple.GHC.Internal as Internal
    import Distribution.Simple.GHC.ImplInfo
    import Distribution.PackageDescription as PD
    import Distribution.InstalledPackageInfo (InstalledPackageInfo)
    import qualified Distribution.InstalledPackageInfo as InstalledPackageInfo
    import Distribution.Simple.PackageIndex (InstalledPackageIndex)
    import qualified Distribution.Simple.PackageIndex as PackageIndex
    import Distribution.Simple.LocalBuildInfo
    import qualified Distribution.Simple.Hpc as Hpc
    import Distribution.Simple.BuildPaths
    import Distribution.Simple.Utils
    import Distribution.Package
    import qualified Distribution.ModuleName as ModuleName
    import Distribution.Simple.Program
    import qualified Distribution.Simple.Program.HcPkg as HcPkg
    import qualified Distribution.Simple.Program.Ar    as Ar
    import qualified Distribution.Simple.Program.Ld    as Ld
    import qualified Distribution.Simple.Program.Strip as Strip
    import Distribution.Simple.Program.GHC
    import Distribution.Simple.Setup
    import qualified Distribution.Simple.Setup as Cabal
    import Distribution.Simple.Compiler hiding (Flag)
    import Distribution.Version
    import Distribution.System
    import Distribution.Verbosity
    import Distribution.Text
    import Distribution.Utils.NubList
    import Language.Haskell.Extension

    import Control.Monad            ( unless, when )
    import Data.Char                ( isDigit, isSpace )
    import Data.List
    import qualified Data.Map as M  ( fromList, lookup )
    import Data.Maybe               ( catMaybes )
    import Data.Monoid as Mon       ( Monoid(..) )
    import Data.Version             ( showVersion )
    import System.Directory
             ( doesFileExist, getAppUserDataDirectory, createDirectoryIfMissing
             , canonicalizePath )
    import System.FilePath          ( (</>), (<.>), takeExtension,
                                      takeDirectory, replaceExtension,
                                      splitExtension, isRelative )
    import qualified System.Info

    -- -----------------------------------------------------------------------------
    -- Configuring

    configure :: Verbosity -> Maybe FilePath -> Maybe FilePath
              -> ProgramConfiguration
              -> IO (Compiler, Maybe Platform, ProgramConfiguration)
    configure verbosity hcPath hcPkgPath conf0 = do

      (ghcProg, ghcVersion, conf1) <-
        requireProgramVersion verbosity ghcProgram
          (orLaterVersion (Version [6,4] []))
          (userMaybeSpecifyPath "ghc" hcPath conf0)
      let implInfo = ghcVersionImplInfo ghcVersion

      -- This is slightly tricky, we have to configure ghc first, then we use the
      -- location of ghc to help find ghc-pkg in the case that the user did not
      -- specify the location of ghc-pkg directly:
      (ghcPkgProg, ghcPkgVersion, conf2) <-
        requireProgramVersion verbosity ghcPkgProgram {
          programFindLocation = guessGhcPkgFromGhcPath ghcProg
        }
        anyVersion (userMaybeSpecifyPath "ghc-pkg" hcPkgPath conf1)

      when (ghcVersion /= ghcPkgVersion) $ die $
           "Version mismatch between ghc and ghc-pkg: "
        ++ programPath ghcProg ++ " is version " ++ display ghcVersion ++ " "
        ++ programPath ghcPkgProg ++ " is version " ++ display ghcPkgVersion

      -- Likewise we try to find the matching hsc2hs and haddock programs.
      let hsc2hsProgram' = hsc2hsProgram {
                               programFindLocation = guessHsc2hsFromGhcPath ghcProg
                           }
          haddockProgram' = haddockProgram {
                               programFindLocation = guessHaddockFromGhcPath ghcProg
                           }
          conf3 = addKnownProgram haddockProgram' $
                  addKnownProgram hsc2hsProgram' conf2

      languages  <- Internal.getLanguages verbosity implInfo ghcProg
      extensions0 <- Internal.getExtensions verbosity implInfo ghcProg

      ghcInfo <- Internal.getGhcInfo verbosity implInfo ghcProg
      let ghcInfoMap = M.fromList ghcInfo

          -- starting with GHC 8.0, `TemplateHaskell` will be omitted from
          -- `--supported-extensions` when it's not available.
          -- for older GHCs we can use the "Have interpreter" property to
          -- filter out `TemplateHaskell`
          extensions | ghcVersion < Version [8] []
                     , Just "NO" <- M.lookup "Have interpreter" ghcInfoMap
                       = filter ((/= EnableExtension TemplateHaskell) . fst) extensions0
                     | otherwise = extensions0

      let comp = Compiler {
            compilerId         = CompilerId GHC ghcVersion,
            compilerAbiTag     = NoAbiTag,
            compilerCompat     = [],
            compilerLanguages  = languages,
            compilerExtensions = extensions,
            compilerProperties = ghcInfoMap
          }
          compPlatform = Internal.targetPlatform ghcInfo
          -- configure gcc and ld
          conf4 = Internal.configureToolchain implInfo ghcProg ghcInfoMap conf3
      return (comp, compPlatform, conf4)

    -- | Given something like /usr/local/bin/ghc-6.6.1(.exe) we try and find
    -- the corresponding tool; e.g. if the tool is ghc-pkg, we try looking
    -- for a versioned or unversioned ghc-pkg in the same dir, that is:
    --
    -- > /usr/local/bin/ghc-pkg-ghc-6.6.1(.exe)
    -- > /usr/local/bin/ghc-pkg-6.6.1(.exe)
    -- > /usr/local/bin/ghc-pkg(.exe)
    --
    guessToolFromGhcPath :: Program -> ConfiguredProgram
                         -> Verbosity -> ProgramSearchPath
                         -> IO (Maybe (FilePath, [FilePath]))
    guessToolFromGhcPath tool ghcProg verbosity searchpath
      = do let toolname          = programName tool
               given_path        = programPath ghcProg
               given_dir         = takeDirectory given_path
           real_path <- canonicalizePath given_path
           let real_dir           = takeDirectory real_path
               versionSuffix path = takeVersionSuffix (dropExeExtension path)
               guessNormal       dir = dir </> toolname <.> exeExtension
               guessGhcVersioned dir = dir </> (toolname ++ "-ghc" ++ versionSuffix dir)
                                           <.> exeExtension
               guessVersioned    dir = dir </> (toolname ++ versionSuffix dir)
                                           <.> exeExtension
               mkGuesses dir | null (versionSuffix dir) = [guessNormal dir]
                             | otherwise                = [guessGhcVersioned dir,
                                                           guessVersioned dir,
                                                           guessNormal dir]
               guesses = mkGuesses given_dir ++
                                if real_path == given_path
                                    then []
                                    else mkGuesses real_dir
           info verbosity $ "looking for tool " ++ toolname
             ++ " near compiler in " ++ given_dir
           exists <- mapM doesFileExist guesses
           case [ file | (file, True) <- zip guesses exists ] of
                       -- If we can't find it near ghc, fall back to the usual
                       -- method.
             []     -> programFindLocation tool verbosity searchpath
             (fp:_) -> do info verbosity $ "found " ++ toolname ++ " in " ++ fp
                          let lookedAt = map fst
                                       . takeWhile (\(_file, exist) -> not exist)
                                       $ zip guesses exists
                          return (Just (fp, lookedAt))

      where takeVersionSuffix :: FilePath -> String
            takeVersionSuffix = takeWhileEndLE isSuffixChar

            isSuffixChar :: Char -> Bool
            isSuffixChar c = isDigit c || c == '.' || c == '-'

            dropExeExtension :: FilePath -> FilePath
            dropExeExtension filepath =
              case splitExtension filepath of
                (filepath', extension) | extension == exeExtension -> filepath'
                                       | otherwise                 -> filepath

    -- | Given something like /usr/local/bin/ghc-6.6.1(.exe) we try and find a
    -- corresponding ghc-pkg, we try looking for both a versioned and unversioned
    -- ghc-pkg in the same dir, that is:
    --
    -- > /usr/local/bin/ghc-pkg-ghc-6.6.1(.exe)
    -- > /usr/local/bin/ghc-pkg-6.6.1(.exe)
    -- > /usr/local/bin/ghc-pkg(.exe)
    --
    guessGhcPkgFromGhcPath :: ConfiguredProgram
                           -> Verbosity -> ProgramSearchPath
                           -> IO (Maybe (FilePath, [FilePath]))
    guessGhcPkgFromGhcPath = guessToolFromGhcPath ghcPkgProgram

    -- | Given something like /usr/local/bin/ghc-6.6.1(.exe) we try and find a
    -- corresponding hsc2hs, we try looking for both a versioned and unversioned
    -- hsc2hs in the same dir, that is:
    --
    -- > /usr/local/bin/hsc2hs-ghc-6.6.1(.exe)
    -- > /usr/local/bin/hsc2hs-6.6.1(.exe)
    -- > /usr/local/bin/hsc2hs(.exe)
    --
    guessHsc2hsFromGhcPath :: ConfiguredProgram
                           -> Verbosity -> ProgramSearchPath
                           -> IO (Maybe (FilePath, [FilePath]))
    guessHsc2hsFromGhcPath = guessToolFromGhcPath hsc2hsProgram

    -- | Given something like /usr/local/bin/ghc-6.6.1(.exe) we try and find a
    -- corresponding haddock, we try looking for both a versioned and unversioned
    -- haddock in the same dir, that is:
    --
    -- > /usr/local/bin/haddock-ghc-6.6.1(.exe)
    -- > /usr/local/bin/haddock-6.6.1(.exe)
    -- > /usr/local/bin/haddock(.exe)
    --
    guessHaddockFromGhcPath :: ConfiguredProgram
                           -> Verbosity -> ProgramSearchPath
                           -> IO (Maybe (FilePath, [FilePath]))
    guessHaddockFromGhcPath = guessToolFromGhcPath haddockProgram

    getGhcInfo :: Verbosity -> ConfiguredProgram -> IO [(String, String)]
    getGhcInfo verbosity ghcProg = Internal.getGhcInfo verbosity implInfo ghcProg
      where
        Just version = programVersion ghcProg
        implInfo = ghcVersionImplInfo version

    -- | Given a single package DB, return all installed packages.
    getPackageDBContents :: Verbosity -> PackageDB -> ProgramConfiguration
                            -> IO InstalledPackageIndex
    getPackageDBContents verbosity packagedb conf = do
      pkgss <- getInstalledPackages' verbosity [packagedb] conf
      toPackageIndex verbosity pkgss conf

    -- | Given a package DB stack, return all installed packages.
    getInstalledPackages :: Verbosity -> Compiler -> PackageDBStack -> ProgramConfiguration
                         -> IO InstalledPackageIndex
    getInstalledPackages verbosity comp packagedbs conf = do
      checkPackageDbEnvVar
      checkPackageDbStack comp packagedbs
      pkgss <- getInstalledPackages' verbosity packagedbs conf
      index <- toPackageIndex verbosity pkgss conf
      return $! hackRtsPackage index

      where
        hackRtsPackage index =
          case PackageIndex.lookupPackageName index (PackageName "rts") of
            [(_,[rts])]
               -> PackageIndex.insert (removeMingwIncludeDir rts) index
            _  -> index -- No (or multiple) ghc rts package is registered!!
                        -- Feh, whatever, the ghc test suite does some crazy stuff.

    -- | Given a list of @(PackageDB, InstalledPackageInfo)@ pairs, produce a
    -- @PackageIndex@. Helper function used by 'getPackageDBContents' and
    -- 'getInstalledPackages'.
    toPackageIndex :: Verbosity
                   -> [(PackageDB, [InstalledPackageInfo])]
                   -> ProgramConfiguration
                   -> IO InstalledPackageIndex
    toPackageIndex verbosity pkgss conf = do
      -- 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.
      topDir <- getLibDir' verbosity ghcProg
      let indices = [ PackageIndex.fromList (map (Internal.substTopDir topDir) pkgs)
                    | (_, pkgs) <- pkgss ]
      return $! mconcat indices

      where
        Just ghcProg = lookupProgram ghcProgram conf

    getLibDir :: Verbosity -> LocalBuildInfo -> IO FilePath
    getLibDir verbosity lbi =
        dropWhileEndLE isSpace `fmap`
         rawSystemProgramStdoutConf verbosity ghcProgram
         (withPrograms lbi) ["--print-libdir"]

    getLibDir' :: Verbosity -> ConfiguredProgram -> IO FilePath
    getLibDir' verbosity ghcProg =
        dropWhileEndLE isSpace `fmap`
         rawSystemProgramStdout verbosity ghcProg ["--print-libdir"]

    -- | Return the 'FilePath' to the global GHC package database.
    getGlobalPackageDB :: Verbosity -> ConfiguredProgram -> IO FilePath
    getGlobalPackageDB verbosity ghcProg =
        dropWhileEndLE isSpace `fmap`
         rawSystemProgramStdout verbosity ghcProg ["--print-global-package-db"]

    -- | Return the 'FilePath' to the per-user GHC package database.
    getUserPackageDB :: Verbosity -> ConfiguredProgram -> Platform -> IO FilePath
    getUserPackageDB _verbosity ghcProg (Platform arch os) = do
        -- It's rather annoying that we have to reconstruct this, because ghc
        -- hides this information from us otherwise. But for certain use cases
        -- like change monitoring it really can't remain hidden.
        appdir <- getAppUserDataDirectory "ghc"
        return (appdir </> platformAndVersion </> packageConfFileName)
      where
        platformAndVersion = intercalate "-" [ Internal.showArchString arch
                                             , Internal.showOsString os
                                             , display ghcVersion ]
        packageConfFileName
          | ghcVersion >= Version [6,12] []  = "package.conf.d"
          | otherwise                        = "package.conf"
        Just ghcVersion = programVersion ghcProg

    checkPackageDbEnvVar :: IO ()
    checkPackageDbEnvVar =
        Internal.checkPackageDbEnvVar "GHC" "GHC_PACKAGE_PATH"

    checkPackageDbStack :: Compiler -> PackageDBStack -> IO ()
    checkPackageDbStack comp = if flagPackageConf implInfo
                                  then checkPackageDbStackPre76
                                  else checkPackageDbStackPost76
      where implInfo = ghcVersionImplInfo (compilerVersion comp)

    checkPackageDbStackPost76 :: PackageDBStack -> IO ()
    checkPackageDbStackPost76 (GlobalPackageDB:rest)
      | GlobalPackageDB `notElem` rest = return ()
    checkPackageDbStackPost76 rest
      | GlobalPackageDB `elem` rest =
      die $ "If the global package db is specified, it must be "
         ++ "specified first and cannot be specified multiple times"
    checkPackageDbStackPost76 _ = return ()

    checkPackageDbStackPre76 :: PackageDBStack -> IO ()
    checkPackageDbStackPre76 (GlobalPackageDB:rest)
      | GlobalPackageDB `notElem` rest = return ()
    checkPackageDbStackPre76 rest
      | GlobalPackageDB `notElem` rest =
      die $ "With current ghc versions the global package db is always used "
         ++ "and must be listed first. This ghc limitation is lifted in GHC 7.6,"
         ++ "see http://hackage.haskell.org/trac/ghc/ticket/5977"
    checkPackageDbStackPre76 _ =
      die $ "If the global package db is specified, it must be "
         ++ "specified first and cannot be specified multiple times"

    -- GHC < 6.10 put "$topdir/include/mingw" in rts's installDirs. This
    -- breaks when you want to use a different gcc, so we need to filter
    -- it out.
    removeMingwIncludeDir :: InstalledPackageInfo -> InstalledPackageInfo
    removeMingwIncludeDir pkg =
        let ids = InstalledPackageInfo.includeDirs pkg
            ids' = filter (not . ("mingw" `isSuffixOf`)) ids
        in pkg { InstalledPackageInfo.includeDirs = ids' }

    -- | Get the packages from specific PackageDBs, not cumulative.
    --
    getInstalledPackages' :: Verbosity -> [PackageDB] -> ProgramConfiguration
                         -> IO [(PackageDB, [InstalledPackageInfo])]
    getInstalledPackages' verbosity packagedbs conf
      | ghcVersion >= Version [6,9] [] =
      sequence
        [ do pkgs <- HcPkg.dump (hcPkgInfo conf) verbosity packagedb
             return (packagedb, pkgs)
        | packagedb <- packagedbs ]

      where
        Just ghcProg    = lookupProgram ghcProgram conf
        Just ghcVersion = programVersion ghcProg

    getInstalledPackages' verbosity packagedbs conf = do
        str <- rawSystemProgramStdoutConf verbosity ghcPkgProgram conf ["list"]
        let pkgFiles = [ init line | line <- lines str, last line == ':' ]
            dbFile packagedb = case (packagedb, pkgFiles) of
              (GlobalPackageDB, global:_)      -> return $ Just global
              (UserPackageDB,  _global:user:_) -> return $ Just user
              (UserPackageDB,  _global:_)      -> return $ Nothing
              (SpecificPackageDB specific, _)  -> return $ Just specific
              _ -> die "cannot read ghc-pkg package listing"
        pkgFiles' <- mapM dbFile packagedbs
        sequence [ withFileContents file $ \content -> do
                      pkgs <- readPackages file content
                      return (db, pkgs)
                 | (db , Just file) <- zip packagedbs pkgFiles' ]
      where
        -- Depending on the version of ghc we use a different type's Read
        -- instance to parse the package file and then convert.
        -- It's a bit yuck. But that's what we get for using Read/Show.
        readPackages
          | ghcVersion >= Version [6,4,2] []
          = \file content -> case reads content of
              [(pkgs, _)] -> return (map IPI642.toCurrent pkgs)
              _           -> failToRead file
          -- We dropped support for 6.4.2 and earlier.
          | otherwise
          = \file _ -> failToRead file
        Just ghcProg = lookupProgram ghcProgram conf
        Just ghcVersion = programVersion ghcProg
        failToRead file = die $ "cannot read ghc package database " ++ file

    getInstalledPackagesMonitorFiles :: Verbosity -> Platform
                                     -> ProgramConfiguration
                                     -> [PackageDB]
                                     -> IO [FilePath]
    getInstalledPackagesMonitorFiles verbosity platform progdb =
        mapM getPackageDBPath
      where
        getPackageDBPath :: PackageDB -> IO FilePath
        getPackageDBPath GlobalPackageDB =
          selectMonitorFile =<< getGlobalPackageDB verbosity ghcProg

        getPackageDBPath UserPackageDB =
          selectMonitorFile =<< getUserPackageDB verbosity ghcProg platform

        getPackageDBPath (SpecificPackageDB path) = selectMonitorFile path

        -- GHC has old style file dbs, and new style directory dbs.
        -- Note that for dir style dbs, we only need to monitor the cache file, not
        -- the whole directory. The ghc program itself only reads the cache file
        -- so it's safe to only monitor this one file.
        selectMonitorFile path = do
          isFileStyle <- doesFileExist path
          if isFileStyle then return path
                         else return (path </> "package.cache")

        Just ghcProg = lookupProgram ghcProgram progdb

    -- -----------------------------------------------------------------------------
    -- Building

    -- | Build a library with GHC.
    --
    buildLib, replLib :: Verbosity          -> Cabal.Flag (Maybe Int)
                      -> PackageDescription -> LocalBuildInfo
                      -> Library            -> ComponentLocalBuildInfo -> IO ()
    buildLib = buildOrReplLib False
    replLib  = buildOrReplLib True

    buildOrReplLib :: Bool -> Verbosity  -> Cabal.Flag (Maybe Int)
                   -> PackageDescription -> LocalBuildInfo
                   -> Library            -> ComponentLocalBuildInfo -> IO ()
    buildOrReplLib forRepl verbosity numJobs pkg_descr lbi lib clbi = do
      let libName = componentUnitId clbi
          libTargetDir
            | componentUnitId clbi == localUnitId lbi = buildDir lbi
            | otherwise = buildDir lbi </> display libName
          whenVanillaLib forceVanilla =
            when (forceVanilla || withVanillaLib lbi)
          whenProfLib = when (withProfLib lbi)
          whenSharedLib forceShared =
            when (forceShared || withSharedLib lbi)
          whenGHCiLib = when (withGHCiLib lbi && withVanillaLib lbi)
          ifReplLib = when forRepl
          comp = compiler lbi
          ghcVersion = compilerVersion comp
          implInfo  = getImplInfo comp
          (Platform _hostArch hostOS) = hostPlatform lbi

      (ghcProg, _) <- requireProgram verbosity ghcProgram (withPrograms lbi)
      let runGhcProg = runGHC verbosity ghcProg comp

      libBi <- hackThreadedFlag verbosity
                 comp (withProfLib lbi) (libBuildInfo lib)

      let isGhcDynamic        = isDynamic comp
          dynamicTooSupported = supportsDynamicToo comp
          doingTH = EnableExtension TemplateHaskell `elem` allExtensions libBi
          forceVanillaLib = doingTH && not isGhcDynamic
          forceSharedLib  = doingTH &&     isGhcDynamic
          -- TH always needs default libs, even when building for profiling

      -- Determine if program coverage should be enabled and if so, what
      -- '-hpcdir' should be.
      let isCoverageEnabled = fromFlag $ configCoverage $ configFlags lbi
          -- Component name. Not 'libName' because that has the "HS" prefix
          -- that GHC gives Haskell libraries.
          cname = display $ PD.package $ localPkgDescr lbi
          distPref = fromFlag $ configDistPref $ configFlags lbi
          hpcdir way
            | forRepl = Mon.mempty  -- HPC is not supported in ghci
            | isCoverageEnabled = toFlag $ Hpc.mixDir distPref way cname
            | otherwise = mempty

      createDirectoryIfMissingVerbose verbosity True libTargetDir
      -- TODO: do we need to put hs-boot files into place for mutually recursive
      -- modules?
      let cObjs       = map (`replaceExtension` objExtension) (cSources libBi)
          baseOpts    = componentGhcOptions verbosity lbi libBi clbi libTargetDir
          vanillaOpts = baseOpts `mappend` mempty {
                          ghcOptMode         = toFlag GhcModeMake,
                          ghcOptNumJobs      = numJobs,
                          ghcOptInputModules = toNubListR $ libModules lib,
                          ghcOptHPCDir       = hpcdir Hpc.Vanilla
                        }

          profOpts    = vanillaOpts `mappend` mempty {
                          ghcOptProfilingMode = toFlag True,
                          ghcOptProfilingAuto = Internal.profDetailLevelFlag True
                                                  (withProfLibDetail lbi),
                          ghcOptHiSuffix      = toFlag "p_hi",
                          ghcOptObjSuffix     = toFlag "p_o",
                          ghcOptExtra         = toNubListR $ hcProfOptions GHC libBi,
                          ghcOptHPCDir        = hpcdir Hpc.Prof
                        }

          sharedOpts  = vanillaOpts `mappend` mempty {
                          ghcOptDynLinkMode = toFlag GhcDynamicOnly,
                          ghcOptFPic        = toFlag True,
                          ghcOptHiSuffix    = toFlag "dyn_hi",
                          ghcOptObjSuffix   = toFlag "dyn_o",
                          ghcOptExtra       = toNubListR $ hcSharedOptions GHC libBi,
                          ghcOptHPCDir      = hpcdir Hpc.Dyn
                        }
          linkerOpts = mempty {
                          ghcOptLinkOptions    = toNubListR $ PD.ldOptions libBi,
                          ghcOptLinkLibs       = toNubListR $ extraLibs libBi,
                          ghcOptLinkLibPath    = toNubListR $ extraLibDirs libBi,
                          ghcOptLinkFrameworks = toNubListR $ PD.frameworks libBi,
                          ghcOptInputFiles     = toNubListR
                                                 [libTargetDir </> x | x <- cObjs]
                       }
          replOpts    = vanillaOpts {
                          ghcOptExtra        = overNubListR
                                               Internal.filterGhciFlags $
                                               ghcOptExtra vanillaOpts,
                          ghcOptNumJobs      = mempty
                        }
                        `mappend` linkerOpts
                        `mappend` mempty {
                          ghcOptMode         = toFlag GhcModeInteractive,
                          ghcOptOptimisation = toFlag GhcNoOptimisation
                        }

          vanillaSharedOpts = vanillaOpts `mappend` mempty {
                          ghcOptDynLinkMode  = toFlag GhcStaticAndDynamic,
                          ghcOptDynHiSuffix  = toFlag "dyn_hi",
                          ghcOptDynObjSuffix = toFlag "dyn_o",
                          ghcOptHPCDir       = hpcdir Hpc.Dyn
                        }

      unless (forRepl || null (libModules lib)) $
        do let vanilla = whenVanillaLib forceVanillaLib (runGhcProg vanillaOpts)
               shared  = whenSharedLib  forceSharedLib  (runGhcProg sharedOpts)
               useDynToo = dynamicTooSupported &&
                           (forceVanillaLib || withVanillaLib lbi) &&
                           (forceSharedLib  || withSharedLib  lbi) &&
                           null (hcSharedOptions GHC libBi)
           if useDynToo
              then do
                  runGhcProg vanillaSharedOpts
                  case (hpcdir Hpc.Dyn, hpcdir Hpc.Vanilla) of
                    (Cabal.Flag dynDir, Cabal.Flag vanillaDir) ->
                        -- When the vanilla and shared library builds are done
                        -- in one pass, only one set of HPC module interfaces
                        -- are generated. This set should suffice for both
                        -- static and dynamically linked executables. We copy
                        -- the modules interfaces so they are available under
                        -- both ways.
                        copyDirectoryRecursive verbosity dynDir vanillaDir
                    _ -> return ()
              else if isGhcDynamic
                then do shared;  vanilla
                else do vanilla; shared
           whenProfLib (runGhcProg profOpts)

      -- build any C sources
      unless (null (cSources libBi)) $ do
        info verbosity "Building C Sources..."
        sequence_
          [ do let baseCcOpts    = Internal.componentCcGhcOptions verbosity implInfo
                                   lbi libBi clbi libTargetDir filename
                   vanillaCcOpts = if isGhcDynamic
                                   -- Dynamic GHC requires C sources to be built
                                   -- with -fPIC for REPL to work. See #2207.
                                   then baseCcOpts { ghcOptFPic = toFlag True }
                                   else baseCcOpts
                   profCcOpts    = vanillaCcOpts `mappend` mempty {
                                     ghcOptProfilingMode = toFlag True,
                                     ghcOptObjSuffix     = toFlag "p_o"
                                   }
                   sharedCcOpts  = vanillaCcOpts `mappend` mempty {
                                     ghcOptFPic        = toFlag True,
                                     ghcOptDynLinkMode = toFlag GhcDynamicOnly,
                                     ghcOptObjSuffix   = toFlag "dyn_o"
                                   }
                   odir          = fromFlag (ghcOptObjDir vanillaCcOpts)
               createDirectoryIfMissingVerbose verbosity True odir
               needsRecomp <- checkNeedsRecompilation filename vanillaCcOpts
               when needsRecomp $ do
                   runGhcProg vanillaCcOpts
                   unless forRepl $
                     whenSharedLib forceSharedLib (runGhcProg sharedCcOpts)
                   unless forRepl $ whenProfLib (runGhcProg profCcOpts)
          | filename <- cSources libBi]

      -- TODO: problem here is we need the .c files built first, so we can load them
      -- with ghci, but .c files can depend on .h files generated by ghc by ffi
      -- exports.

      ifReplLib $ do
        when (null (libModules lib)) $ warn verbosity "No exposed modules"
        ifReplLib (runGhcProg replOpts)

      -- link:
      unless forRepl $ do
        info verbosity "Linking..."
        let cProfObjs   = map (`replaceExtension` ("p_" ++ objExtension))
                          (cSources libBi)
            cSharedObjs = map (`replaceExtension` ("dyn_" ++ objExtension))
                          (cSources libBi)
            cid = compilerId (compiler lbi)
            vanillaLibFilePath = libTargetDir </> mkLibName           libName
            profileLibFilePath = libTargetDir </> mkProfLibName       libName
            sharedLibFilePath  = libTargetDir </> mkSharedLibName cid libName
            ghciLibFilePath    = libTargetDir </> Internal.mkGHCiLibName libName
            libInstallPath = libdir $ absoluteInstallDirs pkg_descr lbi NoCopyDest
            sharedLibInstallPath = libInstallPath </> mkSharedLibName cid libName

        stubObjs <- catMaybes <$> sequence
          [ findFileWithExtension [objExtension] [libTargetDir]
              (ModuleName.toFilePath x ++"_stub")
          | ghcVersion < Version [7,2] [] -- ghc-7.2+ does not make _stub.o files
          , x <- libModules lib ]
        stubProfObjs <- catMaybes <$> sequence
          [ findFileWithExtension ["p_" ++ objExtension] [libTargetDir]
              (ModuleName.toFilePath x ++"_stub")
          | ghcVersion < Version [7,2] [] -- ghc-7.2+ does not make _stub.o files
          , x <- libModules lib ]
        stubSharedObjs <- catMaybes <$> sequence
          [ findFileWithExtension ["dyn_" ++ objExtension] [libTargetDir]
              (ModuleName.toFilePath x ++"_stub")
          | ghcVersion < Version [7,2] [] -- ghc-7.2+ does not make _stub.o files
          , x <- libModules lib ]

        hObjs     <- Internal.getHaskellObjects implInfo lib lbi
                          libTargetDir objExtension True
        hProfObjs <-
          if withProfLib lbi
                  then Internal.getHaskellObjects implInfo lib lbi
                          libTargetDir ("p_" ++ objExtension) True
                  else return []
        hSharedObjs <-
          if withSharedLib lbi
                  then Internal.getHaskellObjects implInfo lib lbi
                          libTargetDir ("dyn_" ++ objExtension) False
                  else return []

        unless (null hObjs && null cObjs && null stubObjs) $ do
          rpaths <- getRPaths lbi clbi

          let staticObjectFiles =
                     hObjs
                  ++ map (libTargetDir </>) cObjs
                  ++ stubObjs
              profObjectFiles =
                     hProfObjs
                  ++ map (libTargetDir </>) cProfObjs
                  ++ stubProfObjs
              ghciObjFiles =
                     hObjs
                  ++ map (libTargetDir </>) cObjs
                  ++ stubObjs
              dynamicObjectFiles =
                     hSharedObjs
                  ++ map (libTargetDir </>) 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 =
                  mempty {
                    ghcOptShared             = toFlag True,
                    ghcOptDynLinkMode        = toFlag GhcDynamicOnly,
                    ghcOptInputFiles         = toNubListR dynamicObjectFiles,
                    ghcOptOutputFile         = toFlag sharedLibFilePath,
                    -- For dynamic libs, Mac OS/X needs to know the install location
                    -- at build time. This only applies to GHC < 7.8 - see the
                    -- discussion in #1660.
                    ghcOptDylibName          = if hostOS == OSX
                                                  && ghcVersion < Version [7,8] []
                                                then toFlag sharedLibInstallPath
                                                else mempty,
                    ghcOptNoAutoLinkPackages = toFlag True,
                    ghcOptPackageDBs         = withPackageDB lbi,
                    ghcOptPackages           = toNubListR $
                                               Internal.mkGhcOptPackages clbi ,
                    ghcOptLinkLibs           = toNubListR $ extraLibs libBi,
                    ghcOptLinkLibPath        = toNubListR $ extraLibDirs libBi,
                    ghcOptLinkFrameworks     = toNubListR $ PD.frameworks libBi,
                    ghcOptRPaths             = rpaths
                  }

          info verbosity (show (ghcOptPackages ghcSharedLinkArgs))

          whenVanillaLib False $
            Ar.createArLibArchive verbosity lbi vanillaLibFilePath staticObjectFiles

          whenProfLib $
            Ar.createArLibArchive verbosity lbi profileLibFilePath profObjectFiles

          whenGHCiLib $ do
            (ldProg, _) <- requireProgram verbosity ldProgram (withPrograms lbi)
            Ld.combineObjectFiles verbosity ldProg
              ghciLibFilePath ghciObjFiles

          whenSharedLib False $
            runGhcProg ghcSharedLinkArgs

    -- | Start a REPL without loading any source files.
    startInterpreter :: Verbosity -> ProgramConfiguration -> Compiler
                     -> PackageDBStack -> IO ()
    startInterpreter verbosity conf comp packageDBs = do
      let replOpts = mempty {
            ghcOptMode       = toFlag GhcModeInteractive,
            ghcOptPackageDBs = packageDBs
            }
      checkPackageDbStack comp packageDBs
      (ghcProg, _) <- requireProgram verbosity ghcProgram conf
      runGHC verbosity ghcProg comp replOpts

    -- | Build an executable with GHC.
    --
    buildExe, replExe :: Verbosity          -> Cabal.Flag (Maybe Int)
                      -> PackageDescription -> LocalBuildInfo
                      -> Executable         -> ComponentLocalBuildInfo -> IO ()
    buildExe = buildOrReplExe False
    replExe  = buildOrReplExe True

    buildOrReplExe :: Bool -> Verbosity  -> Cabal.Flag (Maybe Int)
                   -> PackageDescription -> LocalBuildInfo
                   -> Executable         -> ComponentLocalBuildInfo -> IO ()
    buildOrReplExe forRepl verbosity numJobs _pkg_descr lbi
      exe@Executable { exeName = exeName', modulePath = modPath } clbi = do

      (ghcProg, _) <- requireProgram verbosity ghcProgram (withPrograms lbi)
      let comp       = compiler lbi
          implInfo   = getImplInfo comp
          runGhcProg = runGHC verbosity ghcProg comp

      exeBi <- hackThreadedFlag verbosity
                 comp (withProfExe lbi) (buildInfo exe)

      -- exeNameReal, the name that GHC really uses (with .exe on Windows)
      let exeNameReal = exeName' <.>
                        (if takeExtension exeName' /= ('.':exeExtension)
                           then exeExtension
                           else "")

      let targetDir = buildDir lbi </> 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?

      -- Determine if program coverage should be enabled and if so, what
      -- '-hpcdir' should be.
      let isCoverageEnabled = fromFlag $ configCoverage $ configFlags lbi
          distPref = fromFlag $ configDistPref $ configFlags lbi
          hpcdir way
            | forRepl = mempty  -- HPC is not supported in ghci
            | isCoverageEnabled = toFlag $ Hpc.mixDir distPref way exeName'
            | otherwise = mempty

      -- build executables

      srcMainFile         <- findFile (exeDir : hsSourceDirs exeBi) modPath
      rpaths              <- getRPaths lbi clbi

      let isGhcDynamic        = isDynamic comp
          dynamicTooSupported = supportsDynamicToo comp
          isHaskellMain = elem (takeExtension srcMainFile) [".hs", ".lhs"]
          cSrcs         = cSources exeBi ++ [srcMainFile | not isHaskellMain]
          cObjs         = map (`replaceExtension` objExtension) cSrcs
          baseOpts   = (componentGhcOptions verbosity lbi exeBi clbi exeDir)
                        `mappend` mempty {
                          ghcOptMode         = toFlag GhcModeMake,
                          ghcOptInputFiles   = toNubListR
                            [ srcMainFile | isHaskellMain],
                          ghcOptInputModules = toNubListR
                            [ m | not isHaskellMain, m <- exeModules exe]
                        }
          staticOpts = baseOpts `mappend` mempty {
                          ghcOptDynLinkMode    = toFlag GhcStaticOnly,
                          ghcOptHPCDir         = hpcdir Hpc.Vanilla
                       }
          profOpts   = baseOpts `mappend` mempty {
                          ghcOptProfilingMode  = toFlag True,
                          ghcOptProfilingAuto  = Internal.profDetailLevelFlag False
                                                   (withProfExeDetail lbi),
                          ghcOptHiSuffix       = toFlag "p_hi",
                          ghcOptObjSuffix      = toFlag "p_o",
                          ghcOptExtra          = toNubListR (hcProfOptions GHC exeBi),
                          ghcOptHPCDir         = hpcdir Hpc.Prof
                        }
          dynOpts    = baseOpts `mappend` mempty {
                          ghcOptDynLinkMode    = toFlag GhcDynamicOnly,
                          ghcOptHiSuffix       = toFlag "dyn_hi",
                          ghcOptObjSuffix      = toFlag "dyn_o",
                          ghcOptExtra          = toNubListR $
                                                 hcSharedOptions GHC exeBi,
                          ghcOptHPCDir         = hpcdir Hpc.Dyn
                        }
          dynTooOpts = staticOpts `mappend` mempty {
                          ghcOptDynLinkMode    = toFlag GhcStaticAndDynamic,
                          ghcOptDynHiSuffix    = toFlag "dyn_hi",
                          ghcOptDynObjSuffix   = toFlag "dyn_o",
                          ghcOptHPCDir         = hpcdir Hpc.Dyn
                        }
          linkerOpts = mempty {
                          ghcOptLinkOptions    = toNubListR $ PD.ldOptions exeBi,
                          ghcOptLinkLibs       = toNubListR $ extraLibs exeBi,
                          ghcOptLinkLibPath    = toNubListR $ extraLibDirs exeBi,
                          ghcOptLinkFrameworks = toNubListR $ PD.frameworks exeBi,
                          ghcOptInputFiles     = toNubListR
                                                 [exeDir </> x | x <- cObjs]
                        }
          dynLinkerOpts = mempty {
                          ghcOptRPaths         = rpaths
                       }
          replOpts   = baseOpts {
                          ghcOptExtra          = overNubListR
                                                 Internal.filterGhciFlags
                                                 (ghcOptExtra baseOpts)
                       }
                       -- For a normal compile we do separate invocations of ghc for
                       -- compiling as for linking. But for repl we have to do just
                       -- the one invocation, so that one has to include all the
                       -- linker stuff too, like -l flags and any .o files from C
                       -- files etc.
                       `mappend` linkerOpts
                       `mappend` mempty {
                          ghcOptMode           = toFlag GhcModeInteractive,
                          ghcOptOptimisation   = toFlag GhcNoOptimisation
                       }
          commonOpts  | withProfExe lbi = profOpts
                      | withDynExe  lbi = dynOpts
                      | otherwise       = staticOpts
          compileOpts | useDynToo = dynTooOpts
                      | otherwise = commonOpts
          withStaticExe = (not $ withProfExe lbi) && (not $ withDynExe lbi)

          -- For building exe's that use TH with -prof or -dynamic we actually have
          -- to build twice, once without -prof/-dynamic and then again with
          -- -prof/-dynamic. 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.
          -- With dynamic-by-default GHC the TH object files loaded at compile-time
          -- need to be .dyn_o instead of .o.
          doingTH = EnableExtension TemplateHaskell `elem` allExtensions exeBi
          -- Should we use -dynamic-too instead of compiling twice?
          useDynToo = dynamicTooSupported && isGhcDynamic
                      && doingTH && withStaticExe
                      && null (hcSharedOptions GHC exeBi)
          compileTHOpts | isGhcDynamic = dynOpts
                        | otherwise    = staticOpts
          compileForTH
            | forRepl      = False
            | useDynToo    = False
            | isGhcDynamic = doingTH && (withProfExe lbi || withStaticExe)
            | otherwise    = doingTH && (withProfExe lbi || withDynExe lbi)

          linkOpts = commonOpts `mappend`
                     linkerOpts `mappend`
                     mempty { ghcOptLinkNoHsMain   = toFlag (not isHaskellMain) } `mappend`
                     (if withDynExe lbi then dynLinkerOpts else mempty)

      -- Build static/dynamic object files for TH, if needed.
      when compileForTH $
        runGhcProg compileTHOpts { ghcOptNoLink  = toFlag True
                                 , ghcOptNumJobs = numJobs }

      unless forRepl $
        runGhcProg compileOpts { ghcOptNoLink  = toFlag True
                               , ghcOptNumJobs = numJobs }

      -- build any C sources
      unless (null cSrcs) $ do
       info verbosity "Building C Sources..."
       sequence_
         [ do let opts = (Internal.componentCcGhcOptions verbosity implInfo lbi exeBi
                             clbi exeDir filename) `mappend` mempty {
                           ghcOptDynLinkMode   = toFlag (if withDynExe lbi
                                                           then GhcDynamicOnly
                                                           else GhcStaticOnly),
                           ghcOptProfilingMode = toFlag (withProfExe lbi)
                         }
                  odir  = fromFlag (ghcOptObjDir opts)
              createDirectoryIfMissingVerbose verbosity True odir
              needsRecomp <- checkNeedsRecompilation filename opts
              when needsRecomp $
                runGhcProg opts
         | filename <- cSrcs ]

      -- TODO: problem here is we need the .c files built first, so we can load them
      -- with ghci, but .c files can depend on .h files generated by ghc by ffi
      -- exports.
      when forRepl $ runGhcProg replOpts

      -- link:
      unless forRepl $ do
        info verbosity "Linking..."
        runGhcProg linkOpts { ghcOptOutputFile = toFlag (targetDir </> exeNameReal) }

    -- | Returns True if the modification date of the given source file is newer than
    -- the object file we last compiled for it, or if no object file exists yet.
    checkNeedsRecompilation :: FilePath -> GhcOptions -> IO Bool
    checkNeedsRecompilation filename opts = filename `moreRecentFile` oname
        where oname = getObjectFileName filename opts

    -- | Finds the object file name of the given source file
    getObjectFileName :: FilePath -> GhcOptions -> FilePath
    getObjectFileName filename opts = oname
        where odir  = fromFlag (ghcOptObjDir opts)
              oext  = fromFlagOrDefault "o" (ghcOptObjSuffix opts)
              oname = odir </> replaceExtension filename oext

    -- | Calculate the RPATHs for the component we are building.
    --
    -- Calculates relative RPATHs when 'relocatable' is set.
    getRPaths :: LocalBuildInfo
              -> ComponentLocalBuildInfo -- ^ Component we are building
              -> IO (NubListR FilePath)
    getRPaths lbi clbi | supportRPaths hostOS = do
        libraryPaths <- depLibraryPaths False (relocatable lbi) lbi clbi
        let hostPref = case hostOS of
                         OSX -> "@loader_path"
                         _   -> "$ORIGIN"
            relPath p = if isRelative p then hostPref </> p else p
            rpaths    = toNubListR (map relPath libraryPaths)
        return rpaths
      where
        (Platform _ hostOS) = hostPlatform lbi

        -- The list of RPath-supported operating systems below reflects the
        -- platforms on which Cabal's RPATH handling is tested. It does _NOT_
        -- reflect whether the OS supports RPATH.

        -- E.g. when this comment was written, the *BSD operating systems were
        -- untested with regards to Cabal RPATH handling, and were hence set to
        -- 'False', while those operating systems themselves do support RPATH.
        supportRPaths Linux   = True
        supportRPaths Windows     = False
        supportRPaths OSX     = True
        supportRPaths FreeBSD = False
        supportRPaths OpenBSD = False
        supportRPaths NetBSD  = False
        supportRPaths DragonFly   = False
        supportRPaths Solaris     = False
        supportRPaths AIX         = False
        supportRPaths HPUX        = False
        supportRPaths IRIX        = False
        supportRPaths HaLVM       = False
        supportRPaths IOS         = False
        supportRPaths Android     = False
        supportRPaths Ghcjs       = False
        supportRPaths Hurd        = False
        supportRPaths (OtherOS _) = False
        -- Do _not_ add a default case so that we get a warning here when a new OS
        -- is added.

    getRPaths _ _ = return mempty

    -- | 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 ]

    -- | Extracts a String representing a hash of the ABI of a built
    -- library.  It can fail if the library has not yet been built.
    --
    libAbiHash :: Verbosity -> PackageDescription -> LocalBuildInfo
               -> Library -> ComponentLocalBuildInfo -> IO String
    libAbiHash verbosity _pkg_descr lbi lib clbi = do
      libBi <- hackThreadedFlag verbosity
                 (compiler lbi) (withProfLib lbi) (libBuildInfo lib)
      let
          comp        = compiler lbi
          vanillaArgs =
            (componentGhcOptions verbosity lbi libBi clbi (buildDir lbi))
            `mappend` mempty {
              ghcOptMode         = toFlag GhcModeAbiHash,
              ghcOptInputModules = toNubListR $ exposedModules lib
            }
          sharedArgs = vanillaArgs `mappend` mempty {
                           ghcOptDynLinkMode = toFlag GhcDynamicOnly,
                           ghcOptFPic        = toFlag True,
                           ghcOptHiSuffix    = toFlag "dyn_hi",
                           ghcOptObjSuffix   = toFlag "dyn_o",
                           ghcOptExtra       = toNubListR $ hcSharedOptions GHC libBi
                       }
          profArgs   = vanillaArgs `mappend` mempty {
                         ghcOptProfilingMode = toFlag True,
                         ghcOptProfilingAuto = Internal.profDetailLevelFlag True
                                                 (withProfLibDetail lbi),
                         ghcOptHiSuffix      = toFlag "p_hi",
                         ghcOptObjSuffix     = toFlag "p_o",
                         ghcOptExtra         = toNubListR $ hcProfOptions GHC libBi
                       }
          ghcArgs
            | withVanillaLib lbi = vanillaArgs
            | withSharedLib lbi = sharedArgs
            | withProfLib lbi = profArgs
            | otherwise = error "libAbiHash: Can't find an enabled library way"

      (ghcProg, _) <- requireProgram verbosity ghcProgram (withPrograms lbi)
      hash <- getProgramInvocationOutput verbosity
              (ghcInvocation ghcProg comp ghcArgs)
      return (takeWhile (not . isSpace) hash)

    componentGhcOptions :: Verbosity -> LocalBuildInfo
                        -> BuildInfo -> ComponentLocalBuildInfo -> FilePath
                        -> GhcOptions
    componentGhcOptions = Internal.componentGhcOptions

    componentCcGhcOptions :: Verbosity -> LocalBuildInfo
                          -> BuildInfo -> ComponentLocalBuildInfo
                          -> FilePath -> FilePath
                          -> GhcOptions
    componentCcGhcOptions verbosity lbi =
        Internal.componentCcGhcOptions verbosity implInfo lbi
      where
        comp     = compiler lbi
        implInfo = getImplInfo comp

    -- -----------------------------------------------------------------------------
    -- 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)
              when (stripExes lbi) $
                Strip.stripExe verbosity (hostPlatform lbi) (withPrograms lbi)
                               (dest <.> exeExtension)
      installBinary (binDir </> fixedExeBaseName)

    -- |Install for ghc, .hi, .a and, if --with-ghci given, .o
    installLib    :: Verbosity
                  -> LocalBuildInfo
                  -> FilePath  -- ^install location
                  -> FilePath  -- ^install location for dynamic libraries
                  -> FilePath  -- ^Build location
                  -> PackageDescription
                  -> Library
                  -> ComponentLocalBuildInfo
                  -> IO ()
    installLib verbosity lbi targetDir dynlibTargetDir builtDir _pkg lib clbi = do
      -- copy .hi files over:
      whenVanilla $ copyModuleFiles "hi"
      whenProf    $ copyModuleFiles "p_hi"
      whenShared  $ copyModuleFiles "dyn_hi"

      -- copy the built library files over:
      whenVanilla $ installOrdinary builtDir targetDir       vanillaLibName
      whenProf    $ installOrdinary builtDir targetDir       profileLibName
      whenGHCi    $ installOrdinary builtDir targetDir       ghciLibName
      whenShared  $ installShared   builtDir dynlibTargetDir sharedLibName

      where
        install isShared srcDir dstDir name = do
          let src = srcDir </> name
              dst = dstDir </> name
          createDirectoryIfMissingVerbose verbosity True dstDir

          if isShared
            then installExecutableFile verbosity src dst
            else installOrdinaryFile   verbosity src dst

          when (stripLibs lbi) $ Strip.stripLib verbosity
                                 (hostPlatform lbi) (withPrograms lbi) dst

        installOrdinary = install False
        installShared   = install True

        copyModuleFiles ext =
          findModuleFiles [builtDir] [ext] (libModules lib)
          >>= installOrdinaryFiles verbosity targetDir

        cid = compilerId (compiler lbi)
        libName = componentUnitId clbi
        vanillaLibName = mkLibName              libName
        profileLibName = mkProfLibName          libName
        ghciLibName    = Internal.mkGHCiLibName libName
        sharedLibName  = (mkSharedLibName cid)  libName

        hasLib    = not $ null (libModules lib)
                       && null (cSources (libBuildInfo lib))
        whenVanilla = when (hasLib && withVanillaLib lbi)
        whenProf    = when (hasLib && withProfLib    lbi)
        whenGHCi    = when (hasLib && withGHCiLib    lbi)
        whenShared  = when (hasLib && withSharedLib  lbi)

    -- -----------------------------------------------------------------------------
    -- Registering

    hcPkgInfo :: ProgramConfiguration -> HcPkg.HcPkgInfo
    hcPkgInfo conf = HcPkg.HcPkgInfo { HcPkg.hcPkgProgram    = ghcPkgProg
                                     , HcPkg.noPkgDbStack    = v < [6,9]
                                     , HcPkg.noVerboseFlag   = v < [6,11]
                                     , HcPkg.flagPackageConf = v < [7,5]
                                     , HcPkg.supportsDirDbs  = v >= [6,8]
                                     , HcPkg.requiresDirDbs  = v >= [7,10]
                                     , HcPkg.nativeMultiInstance  = v >= [7,10]
                                     , HcPkg.recacheMultiInstance = v >= [6,12]
                                     }
      where
        v               = versionBranch ver
        Just ghcPkgProg = lookupProgram ghcPkgProgram conf
        Just ver        = programVersion ghcPkgProg

    registerPackage
      :: Verbosity
      -> ProgramConfiguration
      -> Bool
      -> PackageDBStack
      -> InstalledPackageInfo
      -> IO ()
    registerPackage verbosity progdb multiInstance packageDbs installedPkgInfo
      | multiInstance
      = HcPkg.registerMultiInstance (hcPkgInfo progdb) verbosity
          packageDbs installedPkgInfo

      | otherwise
      = HcPkg.reregister (hcPkgInfo progdb) verbosity
          packageDbs (Right installedPkgInfo)

    pkgRoot :: Verbosity -> LocalBuildInfo -> PackageDB -> IO FilePath
    pkgRoot verbosity lbi = pkgRoot'
       where
        pkgRoot' GlobalPackageDB =
          let Just ghcProg = lookupProgram ghcProgram (withPrograms lbi)
          in  fmap takeDirectory (getGlobalPackageDB verbosity ghcProg)
        pkgRoot' UserPackageDB = do
          appDir <- getAppUserDataDirectory "ghc"
          let ver      = compilerVersion (compiler lbi)
              subdir   = System.Info.arch ++ '-':System.Info.os
                         ++ '-':showVersion ver
              rootDir  = appDir </> subdir
          -- We must create the root directory for the user package database if it
          -- does not yet exists. Otherwise '${pkgroot}' will resolve to a
          -- directory at the time of 'ghc-pkg register', and registration will
          -- fail.
          createDirectoryIfMissing True rootDir
          return rootDir
        pkgRoot' (SpecificPackageDB fp) = return (takeDirectory fp)

    -- -----------------------------------------------------------------------------
    -- Utils

    isDynamic :: Compiler -> Bool
    isDynamic = Internal.ghcLookupProperty "GHC Dynamic"

    supportsDynamicToo :: Compiler -> Bool
    supportsDynamicToo = Internal.ghcLookupProperty "Support dynamic-too"