{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE CPP #-}

#if defined(HAVE_INTERNAL_INTERPRETER) && defined(CAN_LOAD_DLL)
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE UnboxedTuples #-}
#endif


-- | Definitions for writing /plugins/ for GHC. Plugins can hook into
-- several areas of the compiler. See the 'Plugin' type. These plugins
-- include type-checker plugins, source plugins, and core-to-core plugins.

module GHC.Driver.Plugins (
      -- * Plugins
      Plugins (..)
    , emptyPlugins
    , Plugin(..)
    , defaultPlugin
    , CommandLineOption
    , PsMessages(..)
    , ParsedResult(..)

      -- * External plugins
    , loadExternalPlugins

      -- ** Recompilation checking
    , purePlugin, impurePlugin, flagRecompile
    , PluginRecompile(..)

      -- * Plugin types
      -- ** Frontend plugins
    , FrontendPlugin(..), defaultFrontendPlugin, FrontendPluginAction
      -- ** Core plugins
      -- | Core plugins allow plugins to register as a Core-to-Core pass.
    , CorePlugin
      -- ** Typechecker plugins
      -- | Typechecker plugins allow plugins to provide evidence to the
      -- typechecker.
    , TcPlugin
      -- ** Source plugins
      -- | GHC offers a number of points where plugins can access and modify its
      -- front-end (\"source\") representation. These include:
      --
      -- - access to the parser result with 'parsedResultAction'
      -- - access to the renamed AST with 'renamedResultAction'
      -- - access to the typechecked AST with 'typeCheckResultAction'
      -- - access to the Template Haskell splices with 'spliceRunAction'
      -- - access to loaded interface files with 'interfaceLoadAction'
      --
    , keepRenamedSource
      -- ** Defaulting plugins
      -- | Defaulting plugins can add candidate types to the defaulting
      -- mechanism.
    , DefaultingPlugin
      -- ** Hole fit plugins
      -- | hole fit plugins allow plugins to change the behavior of valid hole
      -- fit suggestions
    , HoleFitPluginR

      -- * Internal
    , PluginWithArgs(..), pluginsWithArgs, pluginRecompile'
    , LoadedPlugin(..), lpModuleName
    , StaticPlugin(..)
    , ExternalPlugin(..)
    , mapPlugins, withPlugins, withPlugins_
    ) where

import GHC.Prelude

import GHC.Driver.Env
import GHC.Driver.Monad
import GHC.Driver.Phases
import GHC.Driver.Plugins.External

import GHC.Unit.Module
import GHC.Unit.Module.ModIface
import GHC.Unit.Module.ModSummary

import GHC.Parser.Errors.Types (PsWarning, PsError)

import qualified GHC.Tc.Types
import GHC.Tc.Types ( TcGblEnv, IfM, TcM, tcg_rn_decls, tcg_rn_exports  )
import GHC.Tc.Errors.Hole.FitTypes ( HoleFitPluginR )

import GHC.Core.Opt.Monad ( CoreM )
import GHC.Core.Opt.Pipeline.Types ( CoreToDo )
import GHC.Hs
import GHC.Types.Error (Messages)
import GHC.Linker.Types
import GHC.Types.Unique.DFM

import GHC.Utils.Fingerprint
import GHC.Utils.Outputable
import GHC.Utils.Panic

import Data.List (sort)

--Qualified import so we can define a Semigroup instance
-- but it doesn't clash with Outputable.<>
import qualified Data.Semigroup

import Control.Monad

#if defined(HAVE_INTERNAL_INTERPRETER) && defined(CAN_LOAD_DLL)
import GHCi.ObjLink
import GHC.Exts (addrToAny#, Ptr(..))
import GHC.Utils.Encoding
#endif


-- | Command line options gathered from the -PModule.Name:stuff syntax
-- are given to you as this type
type CommandLineOption = String

-- | Errors and warnings produced by the parser
data PsMessages = PsMessages { PsMessages -> Messages PsWarning
psWarnings :: Messages PsWarning
                             , PsMessages -> Messages PsWarning
psErrors   :: Messages PsError
                             }

-- | Result of running the parser and the parser plugin
data ParsedResult = ParsedResult
  { -- | Parsed module, potentially modified by a plugin
    ParsedResult -> HsParsedModule
parsedResultModule :: HsParsedModule
  , -- | Warnings and errors from parser, potentially modified by a plugin
    ParsedResult -> PsMessages
parsedResultMessages :: PsMessages
  }

-- | 'Plugin' is the compiler plugin data type. Try to avoid
-- constructing one of these directly, and just modify some fields of
-- 'defaultPlugin' instead: this is to try and preserve source-code
-- compatibility when we add fields to this.
--
-- Nonetheless, this API is preliminary and highly likely to change in
-- the future.
data Plugin = Plugin {
    Plugin -> CorePlugin
installCoreToDos :: CorePlugin
    -- ^ Modify the Core pipeline that will be used for compilation.
    -- This is called as the Core pipeline is built for every module
    -- being compiled, and plugins get the opportunity to modify the
    -- pipeline in a nondeterministic order.
  , Plugin -> TcPlugin
tcPlugin :: TcPlugin
    -- ^ An optional typechecker plugin, which may modify the
    -- behaviour of the constraint solver.
  , Plugin -> DefaultingPlugin
defaultingPlugin :: DefaultingPlugin
    -- ^ An optional defaulting plugin, which may specify the
    -- additional type-defaulting rules.
  , Plugin -> HoleFitPlugin
holeFitPlugin :: HoleFitPlugin
    -- ^ An optional plugin to handle hole fits, which may re-order
    --   or change the list of valid hole fits and refinement hole fits.

  , Plugin -> [CommandLineOption] -> HscEnv -> IO HscEnv
driverPlugin :: [CommandLineOption] -> HscEnv -> IO HscEnv
    -- ^ An optional plugin to update 'HscEnv', right after plugin loading. This
    -- can be used to register hooks or tweak any field of 'DynFlags' before
    -- doing actual work on a module.
    --
    --   @since 8.10.1

  , Plugin -> [CommandLineOption] -> IO PluginRecompile
pluginRecompile :: [CommandLineOption] -> IO PluginRecompile
    -- ^ Specify how the plugin should affect recompilation.
  , Plugin
-> [CommandLineOption]
-> ModSummary
-> ParsedResult
-> Hsc ParsedResult
parsedResultAction :: [CommandLineOption] -> ModSummary
                       -> ParsedResult -> Hsc ParsedResult
    -- ^ Modify the module when it is parsed. This is called by
    -- "GHC.Driver.Main" when the parser has produced no or only non-fatal
    -- errors.
    -- Compilation will fail if the messages produced by this function contain
    -- any errors.
  , Plugin
-> [CommandLineOption]
-> TcGblEnv
-> HsGroup GhcRn
-> TcM (TcGblEnv, HsGroup GhcRn)
renamedResultAction :: [CommandLineOption] -> TcGblEnv
                                -> HsGroup GhcRn -> TcM (TcGblEnv, HsGroup GhcRn)
    -- ^ Modify each group after it is renamed. This is called after each
    -- `HsGroup` has been renamed.
  , Plugin
-> [CommandLineOption] -> ModSummary -> TcGblEnv -> TcM TcGblEnv
typeCheckResultAction :: [CommandLineOption] -> ModSummary -> TcGblEnv
                               -> TcM TcGblEnv
    -- ^ Modify the module when it is type checked. This is called at the
    -- very end of typechecking.
  , Plugin
-> [CommandLineOption] -> LHsExpr GhcTc -> TcM (LHsExpr GhcTc)
spliceRunAction :: [CommandLineOption] -> LHsExpr GhcTc
                         -> TcM (LHsExpr GhcTc)
    -- ^ Modify the TH splice or quasiqoute before it is run.
  , Plugin
-> forall lcl. [CommandLineOption] -> ModIface -> IfM lcl ModIface
interfaceLoadAction :: forall lcl . [CommandLineOption] -> ModIface
                                          -> IfM lcl ModIface
    -- ^ Modify an interface that have been loaded. This is called by
    -- "GHC.Iface.Load" when an interface is successfully loaded. Not applied to
    -- the loading of the plugin interface. Tools that rely on information from
    -- modules other than the currently compiled one should implement this
    -- function.
  }

-- Note [Source plugins]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- The `Plugin` datatype have been extended by fields that allow access to the
-- different inner representations that are generated during the compilation
-- process. These fields are `parsedResultAction`, `renamedResultAction`,
-- `typeCheckResultAction`, `spliceRunAction` and `interfaceLoadAction`.
--
-- The main purpose of these plugins is to help tool developers. They allow
-- development tools to extract the information about the source code of a big
-- Haskell project during the normal build procedure. In this case the plugin
-- acts as the tools access point to the compiler that can be controlled by
-- compiler flags. This is important because the manipulation of compiler flags
-- is supported by most build environment.
--
-- For the full discussion, check the full proposal at:
-- https://gitlab.haskell.org/ghc/ghc/wikis/extended-plugins-proposal

data PluginWithArgs = PluginWithArgs
  { PluginWithArgs -> Plugin
paPlugin :: Plugin
    -- ^ the actual callable plugin
  , PluginWithArgs -> [CommandLineOption]
paArguments :: [CommandLineOption]
    -- ^ command line arguments for the plugin
  }

-- | A plugin with its arguments. The result of loading the plugin.
data LoadedPlugin = LoadedPlugin
  { LoadedPlugin -> PluginWithArgs
lpPlugin :: PluginWithArgs
  -- ^ the actual plugin together with its commandline arguments
  , LoadedPlugin -> ModIface
lpModule :: ModIface
  -- ^ the module containing the plugin
  }

-- | External plugin loaded directly from a library without loading module
-- interfaces
data ExternalPlugin = ExternalPlugin
  { ExternalPlugin -> PluginWithArgs
epPlugin :: PluginWithArgs -- ^ Plugin with its arguments
  , ExternalPlugin -> CommandLineOption
epUnit   :: String         -- ^ UnitId
  , ExternalPlugin -> CommandLineOption
epModule :: String         -- ^ Module name
  }

-- | A static plugin with its arguments. For registering compiled-in plugins
-- through the GHC API.
data StaticPlugin = StaticPlugin
  { StaticPlugin -> PluginWithArgs
spPlugin :: PluginWithArgs
  -- ^ the actual plugin together with its commandline arguments
  }

lpModuleName :: LoadedPlugin -> ModuleName
lpModuleName :: LoadedPlugin -> ModuleName
lpModuleName = forall unit. GenModule unit -> ModuleName
moduleName forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (phase :: ModIfacePhase). ModIface_ phase -> GenModule Unit
mi_module forall b c a. (b -> c) -> (a -> b) -> a -> c
. LoadedPlugin -> ModIface
lpModule

pluginRecompile' :: PluginWithArgs -> IO PluginRecompile
pluginRecompile' :: PluginWithArgs -> IO PluginRecompile
pluginRecompile' (PluginWithArgs Plugin
plugin [CommandLineOption]
args) = Plugin -> [CommandLineOption] -> IO PluginRecompile
pluginRecompile Plugin
plugin [CommandLineOption]
args

data PluginRecompile = ForceRecompile | NoForceRecompile | MaybeRecompile Fingerprint

instance Outputable PluginRecompile where
  ppr :: PluginRecompile -> SDoc
ppr PluginRecompile
ForceRecompile = forall doc. IsLine doc => CommandLineOption -> doc
text CommandLineOption
"ForceRecompile"
  ppr PluginRecompile
NoForceRecompile = forall doc. IsLine doc => CommandLineOption -> doc
text CommandLineOption
"NoForceRecompile"
  ppr (MaybeRecompile Fingerprint
fp) = forall doc. IsLine doc => CommandLineOption -> doc
text CommandLineOption
"MaybeRecompile" forall doc. IsLine doc => doc -> doc -> doc
<+> forall a. Outputable a => a -> SDoc
ppr Fingerprint
fp

instance Semigroup PluginRecompile where
  PluginRecompile
ForceRecompile <> :: PluginRecompile -> PluginRecompile -> PluginRecompile
<> PluginRecompile
_ = PluginRecompile
ForceRecompile
  PluginRecompile
NoForceRecompile <> PluginRecompile
r = PluginRecompile
r
  MaybeRecompile Fingerprint
fp <> PluginRecompile
NoForceRecompile   = Fingerprint -> PluginRecompile
MaybeRecompile Fingerprint
fp
  MaybeRecompile Fingerprint
fp <> MaybeRecompile Fingerprint
fp' = Fingerprint -> PluginRecompile
MaybeRecompile ([Fingerprint] -> Fingerprint
fingerprintFingerprints [Fingerprint
fp, Fingerprint
fp'])
  MaybeRecompile Fingerprint
_fp <> PluginRecompile
ForceRecompile     = PluginRecompile
ForceRecompile

instance Monoid PluginRecompile where
  mempty :: PluginRecompile
mempty = PluginRecompile
NoForceRecompile

type CorePlugin = [CommandLineOption] -> [CoreToDo] -> CoreM [CoreToDo]
type TcPlugin = [CommandLineOption] -> Maybe GHC.Tc.Types.TcPlugin
type DefaultingPlugin = [CommandLineOption] -> Maybe GHC.Tc.Types.DefaultingPlugin
type HoleFitPlugin = [CommandLineOption] -> Maybe HoleFitPluginR

purePlugin, impurePlugin, flagRecompile :: [CommandLineOption] -> IO PluginRecompile
purePlugin :: [CommandLineOption] -> IO PluginRecompile
purePlugin [CommandLineOption]
_args = forall (m :: * -> *) a. Monad m => a -> m a
return PluginRecompile
NoForceRecompile

impurePlugin :: [CommandLineOption] -> IO PluginRecompile
impurePlugin [CommandLineOption]
_args = forall (m :: * -> *) a. Monad m => a -> m a
return PluginRecompile
ForceRecompile

flagRecompile :: [CommandLineOption] -> IO PluginRecompile
flagRecompile =
  forall (m :: * -> *) a. Monad m => a -> m a
return forall b c a. (b -> c) -> (a -> b) -> a -> c
. Fingerprint -> PluginRecompile
MaybeRecompile forall b c a. (b -> c) -> (a -> b) -> a -> c
. [Fingerprint] -> Fingerprint
fingerprintFingerprints forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b. (a -> b) -> [a] -> [b]
map CommandLineOption -> Fingerprint
fingerprintString forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. Ord a => [a] -> [a]
sort

-- | Default plugin: does nothing at all, except for marking that safe
-- inference has failed unless @-fplugin-trustworthy@ is passed. For
-- compatibility reason you should base all your plugin definitions on this
-- default value.
defaultPlugin :: Plugin
defaultPlugin :: Plugin
defaultPlugin = Plugin {
        installCoreToDos :: CorePlugin
installCoreToDos      = forall a b. a -> b -> a
const forall (m :: * -> *) a. Monad m => a -> m a
return
      , tcPlugin :: TcPlugin
tcPlugin              = forall a b. a -> b -> a
const forall a. Maybe a
Nothing
      , defaultingPlugin :: DefaultingPlugin
defaultingPlugin      = forall a b. a -> b -> a
const forall a. Maybe a
Nothing
      , holeFitPlugin :: HoleFitPlugin
holeFitPlugin         = forall a b. a -> b -> a
const forall a. Maybe a
Nothing
      , driverPlugin :: [CommandLineOption] -> HscEnv -> IO HscEnv
driverPlugin          = forall a b. a -> b -> a
const forall (m :: * -> *) a. Monad m => a -> m a
return
      , pluginRecompile :: [CommandLineOption] -> IO PluginRecompile
pluginRecompile       = [CommandLineOption] -> IO PluginRecompile
impurePlugin
      , renamedResultAction :: [CommandLineOption]
-> TcGblEnv -> HsGroup GhcRn -> TcM (TcGblEnv, HsGroup GhcRn)
renamedResultAction   = \[CommandLineOption]
_ TcGblEnv
env HsGroup GhcRn
grp -> forall (m :: * -> *) a. Monad m => a -> m a
return (TcGblEnv
env, HsGroup GhcRn
grp)
      , parsedResultAction :: [CommandLineOption]
-> ModSummary -> ParsedResult -> Hsc ParsedResult
parsedResultAction    = \[CommandLineOption]
_ ModSummary
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return
      , typeCheckResultAction :: [CommandLineOption] -> ModSummary -> TcGblEnv -> TcM TcGblEnv
typeCheckResultAction = \[CommandLineOption]
_ ModSummary
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return
      , spliceRunAction :: [CommandLineOption] -> LHsExpr GhcTc -> TcM (LHsExpr GhcTc)
spliceRunAction       = \[CommandLineOption]
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return
      , interfaceLoadAction :: forall lcl. [CommandLineOption] -> ModIface -> IfM lcl ModIface
interfaceLoadAction   = \[CommandLineOption]
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return
    }


-- | A renamer plugin which mades the renamed source available in
-- a typechecker plugin.
keepRenamedSource :: [CommandLineOption] -> TcGblEnv
                  -> HsGroup GhcRn -> TcM (TcGblEnv, HsGroup GhcRn)
keepRenamedSource :: [CommandLineOption]
-> TcGblEnv -> HsGroup GhcRn -> TcM (TcGblEnv, HsGroup GhcRn)
keepRenamedSource [CommandLineOption]
_ TcGblEnv
gbl_env HsGroup GhcRn
group =
  forall (m :: * -> *) a. Monad m => a -> m a
return (TcGblEnv
gbl_env { tcg_rn_decls :: Maybe (HsGroup GhcRn)
tcg_rn_decls = forall {p :: Pass}.
Maybe (HsGroup (GhcPass p)) -> Maybe (HsGroup (GhcPass p))
update (TcGblEnv -> Maybe (HsGroup GhcRn)
tcg_rn_decls TcGblEnv
gbl_env)
                  , tcg_rn_exports :: Maybe [(LIE GhcRn, Avails)]
tcg_rn_exports = forall {a}. Maybe [a] -> Maybe [a]
update_exports (TcGblEnv -> Maybe [(LIE GhcRn, Avails)]
tcg_rn_exports TcGblEnv
gbl_env) }, HsGroup GhcRn
group)
  where
    update_exports :: Maybe [a] -> Maybe [a]
update_exports Maybe [a]
Nothing = forall a. a -> Maybe a
Just []
    update_exports Maybe [a]
m = Maybe [a]
m

    update :: Maybe (HsGroup (GhcPass p)) -> Maybe (HsGroup (GhcPass p))
update Maybe (HsGroup (GhcPass p))
Nothing = forall a. a -> Maybe a
Just forall (p :: Pass). HsGroup (GhcPass p)
emptyRnGroup
    update Maybe (HsGroup (GhcPass p))
m       = Maybe (HsGroup (GhcPass p))
m


type PluginOperation m a = Plugin -> [CommandLineOption] -> a -> m a
type ConstPluginOperation m a = Plugin -> [CommandLineOption] -> a -> m ()

data Plugins = Plugins
  { Plugins -> [StaticPlugin]
staticPlugins :: ![StaticPlugin]
      -- ^ Static plugins which do not need dynamic loading. These plugins are
      -- intended to be added by GHC API users directly to this list.
      --
      -- To add dynamically loaded plugins through the GHC API see
      -- 'addPluginModuleName' instead.

  , Plugins -> [ExternalPlugin]
externalPlugins :: ![ExternalPlugin]
      -- ^ External plugins loaded directly from libraries without loading
      -- module interfaces.

  , Plugins -> [LoadedPlugin]
loadedPlugins :: ![LoadedPlugin]
      -- ^ Plugins dynamically loaded after processing arguments. What
      -- will be loaded here is directed by DynFlags.pluginModNames.
      -- Arguments are loaded from DynFlags.pluginModNameOpts.
      --
      -- The purpose of this field is to cache the plugins so they
      -- don't have to be loaded each time they are needed.  See
      -- 'GHC.Runtime.Loader.initializePlugins'.
  , Plugins -> ([Linkable], PkgsLoaded)
loadedPluginDeps :: !([Linkable], PkgsLoaded)
  -- ^ The object files required by the loaded plugins
  -- See Note [Plugin dependencies]
  }

emptyPlugins :: Plugins
emptyPlugins :: Plugins
emptyPlugins = Plugins
  { staticPlugins :: [StaticPlugin]
staticPlugins    = []
  , externalPlugins :: [ExternalPlugin]
externalPlugins  = []
  , loadedPlugins :: [LoadedPlugin]
loadedPlugins    = []
  , loadedPluginDeps :: ([Linkable], PkgsLoaded)
loadedPluginDeps = ([], forall key elt. UniqDFM key elt
emptyUDFM)
  }

pluginsWithArgs :: Plugins -> [PluginWithArgs]
pluginsWithArgs :: Plugins -> [PluginWithArgs]
pluginsWithArgs Plugins
plugins =
  forall a b. (a -> b) -> [a] -> [b]
map LoadedPlugin -> PluginWithArgs
lpPlugin (Plugins -> [LoadedPlugin]
loadedPlugins Plugins
plugins) forall a. [a] -> [a] -> [a]
++
  forall a b. (a -> b) -> [a] -> [b]
map ExternalPlugin -> PluginWithArgs
epPlugin (Plugins -> [ExternalPlugin]
externalPlugins Plugins
plugins) forall a. [a] -> [a] -> [a]
++
  forall a b. (a -> b) -> [a] -> [b]
map StaticPlugin -> PluginWithArgs
spPlugin (Plugins -> [StaticPlugin]
staticPlugins Plugins
plugins)

-- | Perform an operation by using all of the plugins in turn.
withPlugins :: Monad m => Plugins -> PluginOperation m a -> a -> m a
withPlugins :: forall (m :: * -> *) a.
Monad m =>
Plugins -> PluginOperation m a -> a -> m a
withPlugins Plugins
plugins PluginOperation m a
transformation a
input = forall (t :: * -> *) (m :: * -> *) b a.
(Foldable t, Monad m) =>
(b -> a -> m b) -> b -> t a -> m b
foldM a -> PluginWithArgs -> m a
go a
input (Plugins -> [PluginWithArgs]
pluginsWithArgs Plugins
plugins)
  where
    go :: a -> PluginWithArgs -> m a
go a
arg (PluginWithArgs Plugin
p [CommandLineOption]
opts) = PluginOperation m a
transformation Plugin
p [CommandLineOption]
opts a
arg

mapPlugins :: Plugins -> (Plugin -> [CommandLineOption] -> a) -> [a]
mapPlugins :: forall a. Plugins -> (Plugin -> [CommandLineOption] -> a) -> [a]
mapPlugins Plugins
plugins Plugin -> [CommandLineOption] -> a
f = forall a b. (a -> b) -> [a] -> [b]
map (\(PluginWithArgs Plugin
p [CommandLineOption]
opts) -> Plugin -> [CommandLineOption] -> a
f Plugin
p [CommandLineOption]
opts) (Plugins -> [PluginWithArgs]
pluginsWithArgs Plugins
plugins)

-- | Perform a constant operation by using all of the plugins in turn.
withPlugins_ :: Monad m => Plugins -> ConstPluginOperation m a -> a -> m ()
withPlugins_ :: forall (m :: * -> *) a.
Monad m =>
Plugins -> ConstPluginOperation m a -> a -> m ()
withPlugins_ Plugins
plugins ConstPluginOperation m a
transformation a
input
  = forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (\(PluginWithArgs Plugin
p [CommandLineOption]
opts) -> ConstPluginOperation m a
transformation Plugin
p [CommandLineOption]
opts a
input)
          (Plugins -> [PluginWithArgs]
pluginsWithArgs Plugins
plugins)

type FrontendPluginAction = [String] -> [(String, Maybe Phase)] -> Ghc ()
data FrontendPlugin = FrontendPlugin {
      FrontendPlugin -> FrontendPluginAction
frontend :: FrontendPluginAction
    }
defaultFrontendPlugin :: FrontendPlugin
defaultFrontendPlugin :: FrontendPlugin
defaultFrontendPlugin = FrontendPlugin { frontend :: FrontendPluginAction
frontend = \[CommandLineOption]
_ [(CommandLineOption, Maybe Phase)]
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return () }


-- | Load external plugins
loadExternalPlugins :: [ExternalPluginSpec] -> IO [ExternalPlugin]
loadExternalPlugins :: [ExternalPluginSpec] -> IO [ExternalPlugin]
loadExternalPlugins [] = forall (m :: * -> *) a. Monad m => a -> m a
return []
#if !defined(HAVE_INTERNAL_INTERPRETER)
loadExternalPlugins [ExternalPluginSpec]
_ = do
  forall a. HasCallStack => CommandLineOption -> a
panic CommandLineOption
"loadExternalPlugins: can't load external plugins with GHC built without internal interpreter"
#elif !defined(CAN_LOAD_DLL)
loadExternalPlugins _ = do
  panic "loadExternalPlugins: loading shared libraries isn't supported by this compiler"
#else
loadExternalPlugins ps = do
  -- initialize the linker
  initObjLinker RetainCAFs
  -- load plugins
  forM ps $ \(ExternalPluginSpec path unit mod_name opts) -> do
    loadExternalPluginLib path
    -- lookup symbol
    let ztmp = zEncodeString mod_name ++ "_plugin_closure"
        symbol
          | null unit = ztmp
          | otherwise = zEncodeString unit ++ "_" ++ ztmp
    plugin <- lookupSymbol symbol >>= \case
      Nothing -> pprPanic "loadExternalPlugins"
                  (vcat [ text "Symbol not found"
                        , text "  Library path: " <> text path
                        , text "  Symbol      : " <> text symbol
                        ])
      Just (Ptr addr) -> case addrToAny# addr of
        (# a #) -> pure a

    pure $ ExternalPlugin (PluginWithArgs plugin opts) unit mod_name

loadExternalPluginLib :: FilePath -> IO ()
loadExternalPluginLib path = do
  -- load library
  loadDLL path >>= \case
    Just errmsg -> pprPanic "loadExternalPluginLib"
                    (vcat [ text "Can't load plugin library"
                          , text "  Library path: " <> text path
                          , text "  Error       : " <> text errmsg
                          ])
    Nothing -> do
      -- resolve objects
      resolveObjs >>= \case
        True -> return ()
        False -> pprPanic "loadExternalPluginLib" (text "Unable to resolve objects for library: " <> text path)

#endif