{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}

-----------------------------------------------------------------------------
-- |
-- 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 Prelude ()
import Distribution.Compat.Prelude

import Distribution.Types.UnqualComponentName
import Distribution.PackageDescription as PD hiding (Flag)
import Distribution.InstalledPackageInfo
import qualified Distribution.InstalledPackageInfo as InstalledPackageInfo
import Distribution.Simple.PackageIndex
import qualified Distribution.Simple.PackageIndex as PackageIndex
import Distribution.Simple.LocalBuildInfo
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 Distribution.Simple.Compiler
import Distribution.Version
import Distribution.Verbosity
import Distribution.Text
import Distribution.Compat.Exception
import Distribution.System
import Language.Haskell.Extension

import qualified Data.Map as Map ( empty )
import System.Directory         ( removeFile, renameFile,
                                  getDirectoryContents, doesFileExist,
                                  getTemporaryDirectory )
import System.FilePath          ( (</>), (<.>), takeExtension,
                                  takeDirectory, replaceExtension )
import System.IO (hClose, hPutStrLn)

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

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

  (lhcProg, lhcVersion, progdb') <-
    requireProgramVersion verbosity lhcProgram
      (orLaterVersion (mkVersion [0,7]))
      (userMaybeSpecifyPath "lhc" hcPath progdb)

  (lhcPkgProg, lhcPkgVersion, progdb'') <-
    requireProgramVersion verbosity lhcPkgProgram
      (orLaterVersion (mkVersion [0,7]))
      (userMaybeSpecifyPath "lhc-pkg" hcPkgPath progdb')

  when (lhcVersion /= lhcPkgVersion) $ die' verbosity $
       "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     = Map.empty
      }
      progdb''' = configureToolchain lhcProg progdb'' -- configure gcc and ld
      compPlatform = Nothing
  return (comp, compPlatform, progdb''')

-- | Adjust the way we find and configure gcc and ld
--
configureToolchain :: ConfiguredProgram -> ProgramDb
                                        -> ProgramDb
configureToolchain lhcProg =
    addKnownProgram gccProgram {
      programFindLocation = findProg gccProgram (baseDir </> "gcc.exe"),
      programPostConf     = configureGcc
    }
  . addKnownProgram ldProgram {
      programFindLocation = findProg ldProgram (gccLibDir </> "ld.exe"),
      programPostConf     = configureLd
    }
  where
    compilerDir = takeDirectory (programPath lhcProg)
    baseDir     = takeDirectory compilerDir
    gccLibDir      = 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, [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 -> NoCallStackIO 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" ++ gccLibDir,
                                                      "-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
               runProgram verbosity lhcProg ["-c", testcfile,
                                                   "-o", testofile]
               withTempFile tempDir ".o" $ \testofile' testohnd' ->
                 do
                   hClose testohnd'
                   _ <- getProgramOutput 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 -> NoCallStackIO [(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 -> ProgramDb
                     -> IO InstalledPackageIndex
getInstalledPackages verbosity packagedbs progdb = do
  checkPackageDbStack verbosity packagedbs
  pkgss <- getInstalledPackages' lhcPkg verbosity packagedbs progdb
  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 progdb
    Just lhcPkg  = lookupProgram lhcPkgProgram progdb
    compilerDir  = takeDirectory (programPath ghcProg)
    topDir       = takeDirectory compilerDir

checkPackageDbStack :: Verbosity -> PackageDBStack -> IO ()
checkPackageDbStack _ (GlobalPackageDB:rest)
  | GlobalPackageDB `notElem` rest = return ()
checkPackageDbStack verbosity _ =
  die' verbosity $
        "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] -> ProgramDb
                      -> IO [(PackageDB, [InstalledPackageInfo])]
getInstalledPackages' lhcPkg verbosity packagedbs progdb
  =
  sequenceA
    [ do str <- getDbProgramOutput verbosity lhcPkgProgram progdb
                  ["dump", packageDbGhcPkgFlag packagedb]
           `catchExit` \_ -> die' verbosity $ "ghc-pkg dump failed"
         case parsePackages str of
           Left ok -> return (packagedb, ok)
           _       -> die' verbosity "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 (mkVersion [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
  let lib_name = componentUnitId clbi
      pref = componentBuildDir lbi clbi
      pkgid = packageId pkg_descr
      runGhcProg = runDbProgram 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 (allLibModules lib clbi)
      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 (allLibModules lib clbi)) $
    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           lib_name
      profileLibFilePath = libTargetDir </> mkProfLibName       lib_name
      sharedLibFilePath  = libTargetDir </> mkSharedLibName cid lib_name
      ghciLibFilePath    = libTargetDir </> mkGHCiLibName       lib_name

  stubObjs <- fmap catMaybes $ sequenceA
    [ findFileWithExtension [objExtension] [libTargetDir]
        (ModuleName.toFilePath x ++"_stub")
    | x <- allLibModules lib clbi ]
  stubProfObjs <- fmap catMaybes $ sequenceA
    [ findFileWithExtension ["p_" ++ objExtension] [libTargetDir]
        (ModuleName.toFilePath x ++"_stub")
    | x <- allLibModules lib clbi ]
  stubSharedObjs <- fmap catMaybes $ sequenceA
    [ findFileWithExtension ["dyn_" ++ objExtension] [libTargetDir]
        (ModuleName.toFilePath x ++"_stub")
    | x <- allLibModules lib clbi ]

  hObjs     <- getHaskellObjects lib lbi clbi
                    pref objExtension True
  hProfObjs <-
    if (withProfLib lbi)
            then getHaskellObjects lib lbi clbi
                    pref ("p_" ++ objExtension) True
            else return []
  hSharedObjs <-
    if (withSharedLib lbi)
            then getHaskellObjects lib lbi clbi
                    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 <lib_name>.
          runDbProgram verbosity ldProgram (withPrograms lbi)
            (args ++ if exists then [ldLibName] else [])
          renameFile (ldLibName <.> "tmp") ldLibName

        runAr = runDbProgram 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 exeName'' = unUnqualComponentName exeName'
  let pref = buildDir lbi
      runGhcProg = runDbProgram 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"++extraLibDir | extraLibDir <- 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 < mkVersion [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 -> ComponentLocalBuildInfo
                  -> FilePath -> String -> Bool -> NoCallStackIO [FilePath]
getHaskellObjects lib lbi clbi pref wanted_obj_ext allow_split_objs
  | splitObjs lbi && allow_split_objs = do
        let dirs = [ pref </> (ModuleName.toFilePath x ++ "_split")
                   | x <- allLibModules lib clbi ]
        objss <- traverse 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 <- allLibModules lib clbi ]


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" ++ autogenComponentModulesDir lbi clbi]
     ++ ["-i" ++ autogenPackageModulesDir lbi]
     ++ ["-I" ++ autogenComponentModulesDir lbi clbi]
     ++ ["-I" ++ autogenPackageModulesDir lbi]
     ++ ["-I" ++ odir]
     ++ ["-I" ++ dir | dir <- PD.includeDirs bi]
     ++ ["-optP" ++ opt | opt <- cppOptions bi]
     ++ [ "-optP-include", "-optP"++ (autogenComponentModulesDir lbi clbi </> cppHeaderName) ]
     ++ [ "-#include \"" ++ inc ++ "\"" | inc <- PD.includes bi ]
     ++ [ "-odir",  odir, "-hidir", odir ]
     ++ (if compilerVersion c >= mkVersion [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 >= mkVersion [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) < mkVersion [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) >= mkVersion [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 :: UnitId -> String
mkGHCiLibName lib = getHSLibraryName lib <.> "o"

-- -----------------------------------------------------------------------------
-- Installing

-- |Install executables for GHC.
installExe :: Verbosity
           -> LocalBuildInfo
           -> FilePath -- ^Where to copy the files to
           -> FilePath  -- ^Build location
           -> (FilePath, FilePath)  -- ^Executable (prefix,suffix)
           -> PackageDescription
           -> Executable
           -> IO ()
installExe verbosity lbi binDir buildPref (progprefix, progsuffix) _pkg exe = do
  createDirectoryIfMissingVerbose verbosity True binDir
  let exeFileName = unUnqualComponentName (exeName exe) <.> exeExtension
      fixedExeBaseName = progprefix ++ unUnqualComponentName (exeName exe) ++ progsuffix
      installBinary dest = do
          installExecutableFile verbosity
            (buildPref </> unUnqualComponentName (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 -> runProgram 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] (allLibModules lib clbi)
          >>= installOrdinaryFiles verbosity targetDir
  ifVanilla $ copyModuleFiles "hi"
  ifProf    $ copyModuleFiles "p_hi"
  hcrFiles <- findModuleFiles (builtDir : hsSourceDirs (libBuildInfo lib)) ["hcr"] (allLibModules lib clbi)
  flip traverse_ hcrFiles $ \(srcBase, srcFile) -> runLhc ["--install-library", srcBase </> srcFile]

  -- copy the built library files over:
  ifVanilla $ copy builtDir targetDir       vanillaLibName
  ifProf    $ copy builtDir targetDir       profileLibName
  ifGHCi    $ copy builtDir targetDir       ghciLibName
  ifShared  $ copy builtDir dynlibTargetDir sharedLibName

  where
    cid = compilerId (compiler lbi)
    lib_name = componentUnitId clbi
    vanillaLibName = mkLibName           lib_name
    profileLibName = mkProfLibName       lib_name
    ghciLibName    = mkGHCiLibName       lib_name
    sharedLibName  = mkSharedLibName cid lib_name

    hasLib    = not $ null (allLibModules lib clbi)
                   && 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    = runDbProgram verbosity lhcProgram (withPrograms lbi)

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

registerPackage
  :: Verbosity
  -> ProgramDb
  -> PackageDBStack
  -> InstalledPackageInfo
  -> HcPkg.RegisterOptions
  -> IO ()
registerPackage verbosity progdb packageDbs installedPkgInfo registerOptions =
    HcPkg.register (hcPkgInfo progdb) verbosity packageDbs
                   installedPkgInfo registerOptions

hcPkgInfo :: ProgramDb -> HcPkg.HcPkgInfo
hcPkgInfo progdb = HcPkg.HcPkgInfo { HcPkg.hcPkgProgram    = lhcPkgProg
                                   , HcPkg.noPkgDbStack    = False
                                   , HcPkg.noVerboseFlag   = False
                                   , HcPkg.flagPackageConf = False
                                   , HcPkg.supportsDirDbs  = True
                                   , HcPkg.requiresDirDbs  = True
                                   , HcPkg.nativeMultiInstance  = False -- ?
                                   , HcPkg.recacheMultiInstance = False -- ?
                                   , HcPkg.suppressFilesCheck   = True
                                   }
  where
    Just lhcPkgProg = lookupProgram lhcPkgProgram progdb