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, 40 insertions, 2 deletions

diff --git a/compiler/GHC.hs b/compiler/GHC.hs
index af0fb5885a..fb1ac703a2 100644
--- a/compiler/GHC.hs
+++ b/compiler/GHC.hs
@@ -299,11 +299,13 @@ import GHC.ByteCode.Types
 import GHC.Runtime.Eval
 import GHC.Runtime.Eval.Types
 import GHC.Runtime.Interpreter
+import GHC.Runtime.Interpreter.Types
 import GHCi.RemoteTypes
 
 import GHC.Core.Ppr.TyThing  ( pprFamInst )
 import GHC.Driver.Main
 import GHC.Driver.Make
+import GHC.Driver.Hooks
 import GHC.Driver.Pipeline   ( compileOne' )
 import GHC.Driver.Monad
 import TcRnMonad        ( finalSafeMode, fixSafeInstances, initIfaceTcRn )
@@ -373,6 +375,8 @@ import System.Exit      ( exitWith, ExitCode(..) )
 import Exception
 import Data.IORef
 import System.FilePath
+import Control.Concurrent
+import Control.Applicative ((<|>))
 
 import Maybes
 import System.IO.Error  ( isDoesNotExistError )
@@ -486,7 +490,7 @@ withCleanupSession ghc = ghc `gfinally` cleanup
       liftIO $ do
           cleanTempFiles dflags
           cleanTempDirs dflags
-          stopIServ hsc_env -- shut down the IServ
+          stopInterp hsc_env -- shut down the IServ
           --  exceptions will be blocked while we clean the temporary files,
           -- so there shouldn't be any difficulty if we receive further
           -- signals.
@@ -594,8 +598,42 @@ setSessionDynFlags dflags = do
   dflags' <- checkNewDynFlags dflags
   dflags'' <- liftIO $ interpretPackageEnv dflags'
   (dflags''', preload) <- liftIO $ initPackages dflags''
+
+  -- Interpreter
+  interp  <- if gopt Opt_ExternalInterpreter dflags
+    then do
+         let
+           prog = pgm_i dflags ++ flavour
+           flavour
+             | WayProf `elem` ways dflags = "-prof"
+             | WayDyn `elem` ways dflags  = "-dyn"
+             | otherwise                  = ""
+           msg = text "Starting " <> text prog
+         tr <- if verbosity dflags >= 3
+                then return (logInfo dflags (defaultDumpStyle dflags) msg)
+                else return (pure ())
+         let
+          conf = IServConfig
+            { iservConfProgram = prog
+            , iservConfOpts    = getOpts dflags opt_i
+            , iservConfHook    = createIservProcessHook (hooks dflags)
+            , iservConfTrace   = tr
+            }
+         s <- liftIO $ newMVar (IServPending conf)
+         return (Just (ExternalInterp (IServ s)))
+    else
+#if defined(HAVE_INTERNAL_INTERPRETER)
+      return (Just InternalInterp)
+#else
+      return Nothing
+#endif
+
   modifySession $ \h -> h{ hsc_dflags = dflags'''
-                         , hsc_IC = (hsc_IC h){ ic_dflags = dflags''' } }
+                         , hsc_IC = (hsc_IC h){ ic_dflags = dflags''' }
+                         , hsc_interp = hsc_interp h <|> interp
+                           -- we only update the interpreter if there wasn't
+                           -- already one set up
+                         }
   invalidateModSummaryCache
   return preload