Refactor runtime interpreter code

In #14335 we want to be able to use both the internal interpreter (for
the plugins) and the external interpreter (for TH and GHCi) at the same
time.

This patch performs some preliminary refactoring: the `hsc_interp` field
of HscEnv replaces `hsc_iserv` and is now used to indicate which
interpreter (internal, external) to use to execute TH and GHCi.

Opt_ExternalInterpreter flag and iserv options in DynFlags are now
queried only when we set the session DynFlags. It should help making GHC
multi-target in the future by selecting an interpreter according to the
selected target.

1 files changed, 10 insertions, 10 deletions

diff --git a/compiler/GHC/Runtime/Loader.hs b/compiler/GHC/Runtime/Loader.hs
index 15d0b7d5dc..c595b53c4e 100644
--- a/compiler/GHC/Runtime/Loader.hs
+++ b/compiler/GHC/Runtime/Loader.hs
@@ -24,9 +24,10 @@ import GhcPrelude
 import GHC.Driver.Session
 
 import GHC.Runtime.Linker      ( linkModule, getHValue )
-import GHC.Runtime.Interpreter ( wormhole )
+import GHC.Runtime.Interpreter ( wormhole, withInterp )
+import GHC.Runtime.Interpreter.Types
 import SrcLoc           ( noSrcSpan )
-import GHC.Driver.Finder           ( findPluginModule, cannotFindModule )
+import GHC.Driver.Finder( findPluginModule, cannotFindModule )
 import TcRnMonad        ( initTcInteractive, initIfaceTcRn )
 import GHC.Iface.Load   ( loadPluginInterface )
 import RdrName          ( RdrName, ImportSpec(..), ImpDeclSpec(..)
@@ -52,7 +53,7 @@ import Outputable
 import Exception
 import GHC.Driver.Hooks
 
-import Control.Monad     ( when, unless )
+import Control.Monad     ( unless )
 import Data.Maybe        ( mapMaybe )
 import Unsafe.Coerce     ( unsafeCoerce )
 
@@ -103,12 +104,11 @@ loadFrontendPlugin hsc_env mod_name = do
 
 -- #14335
 checkExternalInterpreter :: HscEnv -> IO ()
-checkExternalInterpreter hsc_env =
-    when (gopt Opt_ExternalInterpreter dflags) $
-      throwCmdLineError $ showSDoc dflags $
-        text "Plugins require -fno-external-interpreter"
-  where
-    dflags = hsc_dflags hsc_env
+checkExternalInterpreter hsc_env
+  | Just (ExternalInterp _) <- hsc_interp hsc_env
+  = throwIO (InstallationError "Plugins require -fno-external-interpreter")
+  | otherwise
+  = pure ()
 
 loadPlugin' :: OccName -> Name -> HscEnv -> ModuleName -> IO (a, ModIface)
 loadPlugin' occ_name plugin_name hsc_env mod_name
@@ -206,7 +206,7 @@ getHValueSafely hsc_env val_name expected_type = do
                                    return ()
                     Nothing ->  return ()
                 -- Find the value that we just linked in and cast it given that we have proved it's type
-                hval <- getHValue hsc_env val_name >>= wormhole dflags
+                hval <- withInterp hsc_env $ \interp -> getHValue hsc_env val_name >>= wormhole interp
                 return (Just hval)
              else return Nothing
         Just val_thing -> throwCmdLineErrorS dflags $ wrongTyThingError val_name val_thing