content: -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Simple.GHC.ImplInfo
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This module contains the data structure describing invocation
  -- details for a GHC or GHC-derived compiler, such as supported flags
  -- and workarounds for bugs.
  
  module Distribution.Simple.GHC.ImplInfo (
          GhcImplInfo(..), getImplInfo,
          ghcVersionImplInfo, ghcjsVersionImplInfo, etaVersionImplInfo, lhcVersionImplInfo
          ) where
  
  import Prelude ()
  import Distribution.Compat.Prelude
  
  import Distribution.Simple.Compiler
  import Distribution.Version
  
  {- |
       Information about features and quirks of a GHC-based implementation.
  
       Compiler flavors based on GHC behave similarly enough that some of
       the support code for them is shared. Every implementation has its
       own peculiarities, that may or may not be a direct result of the
       underlying GHC version. This record keeps track of these differences.
  
       All shared code (i.e. everything not in the Distribution.Simple.FLAVOR
       module) should use implementation info rather than version numbers
       to test for supported features.
  -}
  
  data GhcImplInfo = GhcImplInfo
    { supportsHaskell2010  :: Bool -- ^ -XHaskell2010 and -XHaskell98 flags
    , reportsNoExt         :: Bool -- ^ --supported-languages gives Ext and NoExt
    , alwaysNondecIndent   :: Bool -- ^ NondecreasingIndentation is always on
    , flagGhciScript       :: Bool -- ^ -ghci-script flag supported
    , flagProfAuto         :: Bool -- ^ new style -fprof-auto* flags
    , flagPackageConf      :: Bool -- ^ use package-conf instead of package-db
    , flagDebugInfo        :: Bool -- ^ -g flag supported
    , supportsPkgEnvFiles  :: Bool -- ^ picks up @.eta.environment@ files
    , flagWarnMissingHomeModules :: Bool -- ^ -Wmissing-home-modules is supported
    }
  
  getImplInfo :: Compiler -> GhcImplInfo
  getImplInfo comp =
    case compilerFlavor comp of
      GHC   -> ghcVersionImplInfo (compilerVersion comp)
      LHC   -> lhcVersionImplInfo (compilerVersion comp)
      GHCJS -> case compilerCompatVersion GHC comp of
                 Just ghcVer -> ghcjsVersionImplInfo (compilerVersion comp) ghcVer
                 _  -> error ("Distribution.Simple.GHC.Props.getImplProps: " ++
                             "could not find GHC version for GHCJS compiler")
      Eta   -> case compilerCompatVersion GHC comp of
                 Just ghcVer -> etaVersionImplInfo (compilerVersion comp) ghcVer
                 _  -> error ("Distribution.Simple.GHC.Props.getImplProps: " ++
                             "could not find GHC version for Eta compiler")
      x     -> error ("Distribution.Simple.GHC.Props.getImplProps only works" ++
                      "for GHC-like compilers (GHC, GHCJS, Eta, LHC)" ++
                      ", but found " ++ show x)
  
  ghcVersionImplInfo :: Version -> GhcImplInfo
  ghcVersionImplInfo ver = GhcImplInfo
    { supportsHaskell2010  = v >= [7]
    , reportsNoExt         = v >= [7]
    , alwaysNondecIndent   = v <  [7,1]
    , flagGhciScript       = v >= [7,2]
    , flagProfAuto         = v >= [7,4]
    , flagPackageConf      = v <  [7,5]
    , flagDebugInfo        = v >= [7,10]
    , supportsPkgEnvFiles  = v >= [8,0,1,20160901] -- broken in 8.0.1, fixed in 8.0.2
    , flagWarnMissingHomeModules = v >= [8,2,1]
    }
    where
      v = versionNumbers ver
  
  ghcjsVersionImplInfo :: Version  -- ^ The GHCJS version
                       -> Version  -- ^ The GHC version
                       -> GhcImplInfo
  ghcjsVersionImplInfo _ghcjsver ghcver = GhcImplInfo
    { supportsHaskell2010  = True
    , reportsNoExt         = True
    , alwaysNondecIndent   = False
    , flagGhciScript       = True
    , flagProfAuto         = True
    , flagPackageConf      = False
    , flagDebugInfo        = False
    , supportsPkgEnvFiles  = ghcv >= [8,0,2] --TODO: check this works in ghcjs
    , flagWarnMissingHomeModules = False
    }
    where
      ghcv = versionNumbers ghcver
  
  etaVersionImplInfo :: Version
                     -> Version
                     -> GhcImplInfo
  etaVersionImplInfo _etaVer _ghcVer = GhcImplInfo
    { supportsHaskell2010        = True
    , reportsNoExt               = True
    , alwaysNondecIndent         = False
    , flagGhciScript             = False -- TODO: Update when Eta REPL is done
    , flagProfAuto               = True
    , flagPackageConf            = False
    , flagDebugInfo              = True
    , supportsPkgEnvFiles        = True
    , flagWarnMissingHomeModules = False
    }
  
  lhcVersionImplInfo :: Version -> GhcImplInfo
  lhcVersionImplInfo = ghcVersionImplInfo
  