{-# LANGUAGE CPP #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Simple.LHC
-- 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.LHC (
        configure, getInstalledPackages,
        buildLib, buildExe,
        installLib, installExe,
        registerPackage,
        hcPkgInfo,
        ghcOptions,
        ghcVerbosityOptions
 ) where

import Distribution.PackageDescription as PD
         ( PackageDescription(..), BuildInfo(..), Executable(..)
         , Library(..), libModules, hcOptions, hcProfOptions, hcSharedOptions
         , 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(..),
           LibraryName(..) )
import Distribution.Simple.InstallDirs
import Distribution.Simple.BuildPaths
import Distribution.Simple.Utils
import Distribution.Package
         ( Package(..) )
import qualified Distribution.ModuleName as ModuleName
import Distribution.Simple.Program
         ( Program(..), ConfiguredProgram(..), ProgramConfiguration
         , ProgramSearchPath, ProgramLocation(..)
         , rawSystemProgram, rawSystemProgramConf
         , rawSystemProgramStdout, rawSystemProgramStdoutConf
         , requireProgramVersion
         , userMaybeSpecifyPath, programPath, lookupProgram, addKnownProgram
         , arProgram, ldProgram
         , gccProgram, stripProgram
         , lhcProgram, lhcPkgProgram )
import qualified Distribution.Simple.Program.HcPkg as HcPkg
import Distribution.Simple.Compiler
         ( CompilerFlavor(..), CompilerId(..), Compiler(..), compilerVersion
         , OptimisationLevel(..), PackageDB(..), PackageDBStack, AbiTag(..)
         , 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 qualified Data.Map as M  ( empty )
import Data.Maybe               ( catMaybes )
#if __GLASGOW_HASKELL__ < 710
import Data.Monoid              ( Monoid(..) )
#endif
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)
import Distribution.System ( Platform )

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

configure :: Verbosity -> Maybe FilePath -> Maybe FilePath
          -> ProgramConfiguration -> IO (Compiler, Maybe Platform, 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,
        compilerAbiTag         = NoAbiTag,
        compilerCompat         = [],
        compilerLanguages      = languages,
        compilerExtensions     = extensions,
        compilerProperties     = M.empty
      }
      conf''' = configureToolchain lhcProg conf'' -- configure gcc and ld
      compPlatform = Nothing
  return (comp, compPlatform, 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 -> ProgramSearchPath -> IO (Maybe FilePath)
    findProg prog location | isWindows = \verbosity searchpath -> 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 searchpath
      | otherwise = programFindLocation prog

    configureGcc :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    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 gccProg {
                                programDefaultArgs = ["-B" ++ libDir,
                                                      "-I" ++ includeDir]
                              }
          UserSpecified {} -> return gccProg
      | otherwise = \_ gccProg -> return gccProg

    -- we need to find out if ld supports the -x flag
    configureLd :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    configureLd verbosity ldProg = do
      tempDir <- getTemporaryDirectory
      ldx <- withTempFile tempDir ".c" $ \testcfile testchnd ->
             withTempFile tempDir ".o" $ \testofile testohnd -> do
               hPutStrLn testchnd "int foo() { return 0; }"
               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 ldProg { programDefaultArgs = ["-x"] }
        else return ldProg

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 InstalledPackageIndex
getInstalledPackages verbosity packagedbs conf = do
  checkPackageDbStack packagedbs
  pkgss <- getInstalledPackages' lhcPkg 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
    Just lhcPkg  = lookupProgram lhcPkgProgram 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' :: ConfiguredProgram -> Verbosity
                      -> [PackageDB] -> ProgramConfiguration
                      -> IO [(PackageDB, [InstalledPackageInfo])]
getInstalledPackages' lhcPkg 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) = "--" ++ packageDbFlag ++ "=" ++ path

    packageDbFlag
      | programVersion lhcPkg < Just (Version [7,5] [])
      = "package-conf"
      | otherwise
      = "package-db"


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
  libName <- case componentLibraries clbi of
             [libName] -> return libName
             [] -> die "No library name found when building library"
             _  -> die "Multiple library names found when building library"

  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 recursive 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"
             ]
          ++ hcProfOptions GHC libBi
      ghcArgsShared = ghcArgs
          ++ ["-dynamic",
              "-hisuf", "dyn_hi",
              "-osuf", "dyn_o", "-fPIC"
             ]
          ++ hcSharedOptions GHC 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)
      cid = compilerId (compiler lbi)
      vanillaLibFilePath = libTargetDir </> mkLibName           libName
      profileLibFilePath = libTargetDir </> mkProfLibName       libName
      sharedLibFilePath  = libTargetDir </> mkSharedLibName cid libName
      ghciLibFilePath    = libTargetDir </> mkGHCiLibName       libName

  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"
                     ] ++ hcProfOptions GHC 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 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 :: LocalBuildInfo -> [String]
ghcPackageDbOptions lbi = case dbstack of
  (GlobalPackageDB:UserPackageDB:dbs) -> concatMap specific dbs
  (GlobalPackageDB:dbs)               -> ("-no-user-" ++ packageDbFlag)
                                       : concatMap specific dbs
  _                                   -> ierror
 where
    specific (SpecificPackageDB db) = [ '-':packageDbFlag, db ]
    specific _ = ierror
    ierror     = error ("internal error: unexpected package db stack: " ++ show dbstack)

    dbstack = withPackageDB lbi
    packageDbFlag
      | compilerVersion (compiler lbi) < Version [7,5] []
      = "package-conf"
      | otherwise
      = "package-db"

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 lbi
     ++ ghcPackageFlags lbi clbi
     ++ ["-optc" ++ opt | opt <- PD.ccOptions bi]
     ++ (case withOptimization lbi of
           NoOptimisation -> []
           _              -> ["-optc-O2"])
     ++ ["-odir", odir]

mkGHCiLibName :: LibraryName -> String
mkGHCiLibName (LibraryName lib) = 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 libraries
              -> FilePath  -- ^Build location
              -> PackageDescription
              -> Library
              -> ComponentLocalBuildInfo
              -> IO ()
installLib verbosity lbi targetDir dynlibTargetDir builtDir _pkg lib clbi = 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 $ mapM_ (copy builtDir targetDir)       vanillaLibNames
  ifProf    $ mapM_ (copy builtDir targetDir)       profileLibNames
  ifGHCi    $ mapM_ (copy builtDir targetDir)       ghciLibNames
  ifShared  $ mapM_ (copy builtDir dynlibTargetDir) sharedLibNames

  where
    cid = compilerId (compiler lbi)
    libNames = componentLibraries clbi
    vanillaLibNames = map mkLibName             libNames
    profileLibNames = map mkProfLibName         libNames
    ghciLibNames    = map mkGHCiLibName         libNames
    sharedLibNames  = map (mkSharedLibName cid) libNames

    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)

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

registerPackage
  :: Verbosity
  -> InstalledPackageInfo
  -> PackageDescription
  -> LocalBuildInfo
  -> Bool
  -> PackageDBStack
  -> IO ()
registerPackage verbosity installedPkgInfo _pkg lbi _inplace packageDbs =
  HcPkg.reregister (hcPkgInfo $ withPrograms lbi) verbosity packageDbs
    (Right installedPkgInfo)

hcPkgInfo :: ProgramConfiguration -> HcPkg.HcPkgInfo
hcPkgInfo conf = HcPkg.HcPkgInfo { HcPkg.hcPkgProgram    = lhcPkgProg
                                 , HcPkg.noPkgDbStack    = False
                                 , HcPkg.noVerboseFlag   = False
                                 , HcPkg.flagPackageConf = False
                                 , HcPkg.useSingleFileDb = True
                                 }
  where
    Just lhcPkgProg = lookupProgram lhcPkgProgram conf
