Revert "Delete some superfluous helper functions in HscMain"wip/t19004

This reverts commit eb629fab96fbff43f79190767731501d8642f524.

Fixes #19004

1 files changed, 35 insertions, 16 deletions

diff --git a/compiler/GHC/Driver/Main.hs b/compiler/GHC/Driver/Main.hs
index 8685462e7d..f6214302fe 100644
--- a/compiler/GHC/Driver/Main.hs
+++ b/compiler/GHC/Driver/Main.hs
@@ -76,12 +76,12 @@ module GHC.Driver.Main
     -- * Low-level exports for hooks
     , hscCompileCoreExpr'
       -- We want to make sure that we export enough to be able to redefine
-      -- hsc_typecheck in client code
+      -- hscFileFrontEnd in client code
     , hscParse', hscSimplify', hscDesugar', tcRnModule', doCodeGen
     , getHscEnv
     , hscSimpleIface'
     , oneShotMsg
-    , dumpIfaceStats
+    , hscFileFrontEnd, genericHscFrontend, dumpIfaceStats
     , ioMsgMaybe
     , showModuleIndex
     , hscAddSptEntries
@@ -509,17 +509,23 @@ extract_renamed_stuff mod_summary tc_result = do
 -- | Rename and typecheck a module, additionally returning the renamed syntax
 hscTypecheckRename :: HscEnv -> ModSummary -> HsParsedModule
                    -> IO (TcGblEnv, RenamedStuff)
-hscTypecheckRename hsc_env mod_summary rdr_module = runHsc hsc_env $
-    hsc_typecheck True mod_summary (Just rdr_module)
+hscTypecheckRename hsc_env mod_summary rdr_module = runHsc hsc_env $ do
+    tc_result <- hsc_typecheck True mod_summary (Just rdr_module)
+    rn_info <- extract_renamed_stuff mod_summary tc_result
+    return (tc_result, rn_info)
 
+-- | Rename and typecheck a module, but don't return the renamed syntax
+hscTypecheck :: Bool -- ^ Keep renamed source?
+             -> ModSummary -> Maybe HsParsedModule
+             -> Hsc TcGblEnv
+hscTypecheck keep_rn mod_summary mb_rdr_module = do
+    tc_result <- hsc_typecheck keep_rn mod_summary mb_rdr_module
+    _ <- extract_renamed_stuff mod_summary tc_result
+    return tc_result
 
--- | A bunch of logic piled around @tcRnModule'@, concerning a) backpack
--- b) concerning dumping rename info and hie files. It would be nice to further
--- separate this stuff out, probably in conjunction better separating renaming
--- and type checking (#17781).
 hsc_typecheck :: Bool -- ^ Keep renamed source?
               -> ModSummary -> Maybe HsParsedModule
-              -> Hsc (TcGblEnv, RenamedStuff)
+              -> Hsc TcGblEnv
 hsc_typecheck keep_rn mod_summary mb_rdr_module = do
     hsc_env <- getHscEnv
     let hsc_src = ms_hsc_src mod_summary
@@ -533,7 +539,7 @@ hsc_typecheck keep_rn mod_summary mb_rdr_module = do
         real_loc = realSrcLocSpan $ mkRealSrcLoc (mkFastString src_filename) 1 1
         keep_rn' = gopt Opt_WriteHie dflags || keep_rn
     MASSERT( isHomeModule home_unit outer_mod )
-    tc_result <- if hsc_src == HsigFile && not (isHoleModule inner_mod)
+    if hsc_src == HsigFile && not (isHoleModule inner_mod)
         then ioMsgMaybe $ tcRnInstantiateSignature hsc_env outer_mod' real_loc
         else
          do hpm <- case mb_rdr_module of
@@ -545,10 +551,6 @@ hsc_typecheck keep_rn mod_summary mb_rdr_module = do
                         ioMsgMaybe $
                             tcRnMergeSignatures hsc_env hpm tc_result0 iface
                 else return tc_result0
-    -- TODO are we extracting anything when we merely instantiate a signature?
-    -- If not, try to move this into the "else" case above.
-    rn_info <- extract_renamed_stuff mod_summary tc_result
-    return (tc_result, rn_info)
 
 -- wrapper around tcRnModule to handle safe haskell extras
 tcRnModule' :: ModSummary -> Bool -> HsParsedModule
@@ -707,8 +709,8 @@ hscIncrementalFrontend
 
         compile mb_old_hash reason = do
             liftIO $ msg reason
-            (tc_result, _) <- hsc_typecheck False mod_summary Nothing
-            return $ Right (FrontendTypecheck tc_result, mb_old_hash)
+            result <- genericHscFrontend mod_summary
+            return $ Right (result, mb_old_hash)
 
         stable = case source_modified of
                      SourceUnmodifiedAndStable -> True
@@ -755,6 +757,14 @@ hscIncrementalFrontend
                     Just tc_result ->
                         return $ Right (FrontendTypecheck tc_result, mb_old_hash)
 
+genericHscFrontend :: ModSummary -> Hsc FrontendResult
+genericHscFrontend mod_summary =
+  getHooked hscFrontendHook genericHscFrontend' >>= ($ mod_summary)
+
+genericHscFrontend' :: ModSummary -> Hsc FrontendResult
+genericHscFrontend' mod_summary
+    = FrontendTypecheck `fmap` hscFileFrontEnd mod_summary
+
 --------------------------------------------------------------
 -- Compilers
 --------------------------------------------------------------
@@ -1044,6 +1054,15 @@ batchMsg hsc_env mod_index recomp mod_summary =
                 <> reason
 
 --------------------------------------------------------------
+-- FrontEnds
+--------------------------------------------------------------
+
+-- | Given a 'ModSummary', parses and typechecks it, returning the
+-- 'TcGblEnv' resulting from type-checking.
+hscFileFrontEnd :: ModSummary -> Hsc TcGblEnv
+hscFileFrontEnd mod_summary = hscTypecheck False mod_summary Nothing
+
+--------------------------------------------------------------
 -- Safe Haskell
 --------------------------------------------------------------