Always enable the external interpreter

You can always just not use or even build `iserv`. I don't think the
maintenance cost of the CPP is worth...I can't even tell what the
benefit is.

7 files changed, 15 insertions, 74 deletions

diff --git a/compiler/ghc.cabal.in b/compiler/ghc.cabal.in
index f191370071..a612733de6 100644
--- a/compiler/ghc.cabal.in
+++ b/compiler/ghc.cabal.in
@@ -25,11 +25,6 @@ Flag ghci
     Default: False
     Manual: True
 
-Flag ext-interp
-    Description: Support external interpreter
-    Default: True
-    Manual: True
-
 Flag stage1
     Description: Is this stage 1?
     Default: False
@@ -98,12 +93,6 @@ Library
         CPP-Options: -DHAVE_INTERNAL_INTERPRETER
         Include-Dirs: ../rts/dist/build @FFIIncludeDir@
 
-    if flag(ext-interp)
-        CPP-Options: -DHAVE_EXTERNAL_INTERPRETER
-
-    if flag(ghci) || flag(ext-interp)
-        CPP-Options: -DHAVE_INTERPRETER
-
     -- sanity-check to ensure not more than one integer flag is set
     if flag(integer-gmp) && flag(integer-simple)
         build-depends: invalid-cabal-flag-settings<0
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 9e9e70ad28..465dd2737b 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -4360,26 +4360,25 @@ supportedLanguages = map (flagSpecName . snd) languageFlagsDeps
 supportedLanguageOverlays :: [String]
 supportedLanguageOverlays = map (flagSpecName . snd) safeHaskellFlagsDeps
 
-supportedExtensions :: [String]
-supportedExtensions = concatMap toFlagSpecNamePair xFlags
+supportedExtensions :: PlatformMini -> [String]
+supportedExtensions targetPlatformMini = concatMap toFlagSpecNamePair xFlags
   where
     toFlagSpecNamePair flg
-#if !defined(HAVE_INTERPRETER)
       -- IMPORTANT! Make sure that `ghc --supported-extensions` omits
       -- "TemplateHaskell"/"QuasiQuotes" when it's known not to work out of the
       -- box. See also GHC #11102 and #16331 for more details about
       -- the rationale
-      | flagSpecFlag flg == LangExt.TemplateHaskell  = [noName]
-      | flagSpecFlag flg == LangExt.QuasiQuotes      = [noName]
-#endif
+      | isAIX, flagSpecFlag flg == LangExt.TemplateHaskell  = [noName]
+      | isAIX, flagSpecFlag flg == LangExt.QuasiQuotes      = [noName]
       | otherwise = [name, noName]
       where
+        isAIX = platformMini_os targetPlatformMini == OSAIX
         noName = "No" ++ name
         name = flagSpecName flg
 
-supportedLanguagesAndExtensions :: [String]
-supportedLanguagesAndExtensions =
-    supportedLanguages ++ supportedLanguageOverlays ++ supportedExtensions
+supportedLanguagesAndExtensions :: PlatformMini -> [String]
+supportedLanguagesAndExtensions targetPlatformMini =
+    supportedLanguages ++ supportedLanguageOverlays ++ supportedExtensions targetPlatformMini
 
 -- | These -X<blah> flags cannot be reversed with -XNo<blah>
 languageFlagsDeps :: [(Deprecation, FlagSpec Language)]
diff --git a/compiler/main/DynamicLoading.hs b/compiler/main/DynamicLoading.hs
index 64cc0a1216..ea09a8ceb5 100644
--- a/compiler/main/DynamicLoading.hs
+++ b/compiler/main/DynamicLoading.hs
@@ -3,7 +3,6 @@
 -- | Dynamically lookup up values from modules and loading them.
 module DynamicLoading (
         initializePlugins,
-#if defined(HAVE_INTERPRETER)
         -- * Loading plugins
         loadFrontendPlugin,
 
@@ -19,15 +18,11 @@ module DynamicLoading (
         getValueSafely,
         getHValueSafely,
         lessUnsafeCoerce
-#else
-        pluginError
-#endif
     ) where
 
 import GhcPrelude
 import DynFlags
 
-#if defined(HAVE_INTERPRETER)
 import Linker           ( linkModule, getHValue )
 import GHCi             ( wormhole )
 import SrcLoc           ( noSrcSpan )
@@ -60,28 +55,11 @@ import Control.Monad     ( when, unless )
 import Data.Maybe        ( mapMaybe )
 import GHC.Exts          ( unsafeCoerce# )
 
-#else
-
-import HscTypes         ( HscEnv )
-import Module           ( ModuleName, moduleNameString )
-import Panic
-
-import Data.List        ( intercalate )
-import Control.Monad    ( unless )
-
-#endif
-
 -- | Loads the plugins specified in the pluginModNames field of the dynamic
 -- flags. Should be called after command line arguments are parsed, but before
 -- actual compilation starts. Idempotent operation. Should be re-called if
 -- pluginModNames or pluginModNameOpts changes.
 initializePlugins :: HscEnv -> DynFlags -> IO DynFlags
-#if !defined(HAVE_INTERPRETER)
-initializePlugins _ df
-  = do let pluginMods = pluginModNames df
-       unless (null pluginMods) (pluginError pluginMods)
-       return df
-#else
 initializePlugins hsc_env df
   | map lpModuleName (cachedPlugins df)
          == pluginModNames df -- plugins not changed
@@ -93,10 +71,6 @@ initializePlugins hsc_env df
   = do loadedPlugins <- loadPlugins (hsc_env { hsc_dflags = df })
        return $ df { cachedPlugins = loadedPlugins }
   where argumentsForPlugin p = map snd . filter ((== lpModuleName p) . fst)
-#endif
-
-
-#if defined(HAVE_INTERPRETER)
 
 loadPlugins :: HscEnv -> IO [LoadedPlugin]
 loadPlugins hsc_env
@@ -302,15 +276,3 @@ throwCmdLineErrorS dflags = throwCmdLineError . showSDoc dflags
 
 throwCmdLineError :: String -> IO a
 throwCmdLineError = throwGhcExceptionIO . CmdLineError
-
-#else
-
-pluginError :: [ModuleName] -> a
-pluginError modnames = throwGhcException (CmdLineError msg)
-  where
-    msg = "not built for interactive use - can't load plugins ("
-            -- module names are not z-encoded
-          ++ intercalate ", " (map moduleNameString modnames)
-          ++ ")"
-
-#endif
diff --git a/compiler/main/HeaderInfo.hs b/compiler/main/HeaderInfo.hs
index d534fab1d5..bd984618a4 100644
--- a/compiler/main/HeaderInfo.hs
+++ b/compiler/main/HeaderInfo.hs
@@ -22,6 +22,7 @@ module HeaderInfo ( getImports
 
 import GhcPrelude
 
+import GHC.Platform
 import HscTypes
 import Parser           ( parseHeader )
 import Lexer
@@ -306,10 +307,12 @@ checkExtension :: DynFlags -> Located FastString -> Located String
 checkExtension dflags (dL->L l ext)
 -- Checks if a given extension is valid, and if so returns
 -- its corresponding flag. Otherwise it throws an exception.
- =  let ext' = unpackFS ext in
-    if ext' `elem` supportedLanguagesAndExtensions
+  = if ext' `elem` supported
     then cL l ("-X"++ext')
     else unsupportedExtnError dflags l ext'
+  where
+    ext' = unpackFS ext
+    supported = supportedLanguagesAndExtensions $ platformMini $ targetPlatform dflags
 
 languagePragParseError :: DynFlags -> SrcSpan -> a
 languagePragParseError dflags loc =
@@ -325,7 +328,8 @@ unsupportedExtnError dflags loc unsup =
         text "Unsupported extension: " <> text unsup $$
         if null suggestions then Outputable.empty else text "Perhaps you meant" <+> quotedListWithOr (map text suggestions)
   where
-     suggestions = fuzzyMatch unsup supportedLanguagesAndExtensions
+     supported = supportedLanguagesAndExtensions $ platformMini $ targetPlatform dflags
+     suggestions = fuzzyMatch unsup supported
 
 
 optionsErrorMsgs :: DynFlags -> [String] -> [Located String] -> FilePath -> Messages
diff --git a/compiler/rename/RnExpr.hs b/compiler/rename/RnExpr.hs
index f2f0685159..3ec24a7a6d 100644
--- a/compiler/rename/RnExpr.hs
+++ b/compiler/rename/RnExpr.hs
@@ -211,8 +211,6 @@ rnExpr (NegApp _ e _)
 
 ------------------------------------------
 -- Template Haskell extensions
--- Don't ifdef-HAVE_INTERPRETER them because we want to fail gracefully
--- (not with an rnExpr crash) in a stage-1 compiler.
 rnExpr e@(HsBracket _ br_body) = rnBracket e br_body
 
 rnExpr (HsSpliceE _ splice) = rnSpliceExpr splice
diff --git a/compiler/simplCore/SimplCore.hs b/compiler/simplCore/SimplCore.hs
index 572084c420..b3af87b2af 100644
--- a/compiler/simplCore/SimplCore.hs
+++ b/compiler/simplCore/SimplCore.hs
@@ -462,11 +462,7 @@ doCorePass (CoreDoRuleCheck phase pat)  = ruleCheckPass phase pat
 doCorePass CoreDoNothing                = return
 doCorePass (CoreDoPasses passes)        = runCorePasses passes
 
-#if defined(HAVE_INTERPRETER)
 doCorePass (CoreDoPluginPass _ pass) = {-# SCC "Plugin" #-} pass
-#else
-doCorePass pass@CoreDoPluginPass {}  = pprPanic "doCorePass" (ppr pass)
-#endif
 
 doCorePass pass@CoreDesugar          = pprPanic "doCorePass" (ppr pass)
 doCorePass pass@CoreDesugarOpt       = pprPanic "doCorePass" (ppr pass)
diff --git a/compiler/typecheck/TcPluginM.hs b/compiler/typecheck/TcPluginM.hs
index 3785a4aac5..f4fe3013a3 100644
--- a/compiler/typecheck/TcPluginM.hs
+++ b/compiler/typecheck/TcPluginM.hs
@@ -3,7 +3,6 @@
 -- access select functions of the 'TcM', principally those to do with
 -- reading parts of the state.
 module TcPluginM (
-#if defined(HAVE_INTERPRETER)
         -- * Basic TcPluginM functionality
         TcPluginM,
         tcPluginIO,
@@ -49,10 +48,8 @@ module TcPluginM (
         newEvVar,
         setEvBind,
         getEvBindsTcPluginM
-#endif
     ) where
 
-#if defined(HAVE_INTERPRETER)
 import GhcPrelude
 
 import qualified TcRnMonad as TcM
@@ -190,7 +187,3 @@ setEvBind :: EvBind -> TcPluginM ()
 setEvBind ev_bind = do
     tc_evbinds <- getEvBindsTcPluginM
     unsafeTcPluginTcM $ TcM.addTcEvBind tc_evbinds ev_bind
-#else
--- this dummy import is needed as a consequence of NoImplicitPrelude
-import GhcPrelude ()
-#endif