ghc-mod/Language/Haskell/GhcMod/DynFlags.hs

{-# LANGUAGE CPP #-}

module Language.Haskell.GhcMod.DynFlags where

import Control.Applicative
import Control.Monad (void)
import GHC (DynFlags(..), GhcMode(..), GhcLink(..), HscTarget(..))
import qualified GHC as G
import GHC.Paths (libdir)
import GhcMonad
import qualified Language.Haskell.GhcMod.Gap as Gap
import Language.Haskell.GhcMod.Types
import System.IO.Unsafe (unsafePerformIO)
import Prelude

setEmptyLogger :: DynFlags -> DynFlags
setEmptyLogger df = Gap.setLogAction df $ \_ _ _ _ _ -> return ()

-- * Fast
-- * Friendly to foreign export
-- * Not friendly to -XTemplateHaskell and -XPatternSynonyms
-- * Uses little memory
setModeSimple :: DynFlags -> DynFlags
setModeSimple df = df {
    ghcMode   = CompManager
  , ghcLink   = NoLink
  , hscTarget = HscNothing
  , optLevel  = 0
  }

-- * Slow
-- * Not friendly to foreign export
-- * Friendly to -XTemplateHaskell and -XPatternSynonyms
-- * Uses lots of memory
setModeIntelligent :: DynFlags -> DynFlags
setModeIntelligent df = df {
    ghcMode   = CompManager
  , ghcLink   = LinkInMemory
  , hscTarget = HscInterpreted
  , optLevel  = 0
  }

-- | Parse command line ghc options and add them to the 'DynFlags' passed
addCmdOpts :: GhcMonad m => [GHCOption] -> DynFlags -> m DynFlags
addCmdOpts cmdOpts df =
    fst3 <$> G.parseDynamicFlags df (map G.noLoc cmdOpts)
  where
    fst3 (a,_,_) = a

----------------------------------------------------------------

withDynFlags :: GhcMonad m
             => (DynFlags -> DynFlags)
             -> m a
             -> m a
withDynFlags setFlags body = G.gbracket setup teardown (\_ -> body)
  where
    setup = do
        dflags <- G.getSessionDynFlags
        void $ G.setSessionDynFlags (setFlags dflags)
        return dflags
    teardown = void . G.setSessionDynFlags

withCmdFlags :: GhcMonad m => [GHCOption] -> m a -> m a
withCmdFlags flags body = G.gbracket setup teardown (\_ -> body)
  where
    setup = do
        dflags <- G.getSessionDynFlags
        void $ G.setSessionDynFlags =<< addCmdOpts flags dflags
        return dflags
    teardown = void . G.setSessionDynFlags

----------------------------------------------------------------

-- | Set 'DynFlags' equivalent to "-w:".
setNoWarningFlags :: DynFlags -> DynFlags
setNoWarningFlags df = df { warningFlags = Gap.emptyWarnFlags}

-- | Set 'DynFlags' equivalent to "-Wall".
setAllWarningFlags :: DynFlags -> DynFlags
setAllWarningFlags df = df { warningFlags = allWarningFlags }

allWarningFlags :: Gap.WarnFlags
allWarningFlags = unsafePerformIO $
    G.runGhc (Just libdir) $ do
        df <- G.getSessionDynFlags
        df' <- addCmdOpts ["-Wall"] df
        return $ G.warningFlags df'

----------------------------------------------------------------

-- | Set 'DynFlags' equivalent to "-fno-max-relevant-bindings".
setNoMaxRelevantBindings :: DynFlags -> DynFlags
#if __GLASGOW_HASKELL__ >= 708
setNoMaxRelevantBindings df = df { maxRelevantBinds = Nothing }
#else
setNoMaxRelevantBindings = id
#endif

deferErrors :: DynFlags -> Ghc DynFlags
deferErrors df = return $
  Gap.setWarnTypedHoles $ Gap.setDeferTypeErrors $ setNoWarningFlags df

deferErrorsAndHoles :: DynFlags -> Ghc DynFlags
deferErrorsAndHoles df = return $
  Gap.setDeferTypeErrors $ Gap.setDeferTypedHoles $ setNoWarningFlags df