Cheng Shao pushed to branch wip/ghci-messages-no-string at Glasgow Haskell Compiler / GHC Commits: f86f6114 by Cheng Shao at 2026-04-03T15:40:28+00:00 ghci: use ShortByteString for LookupSymbol/LookupSymbolInDLL/LookupClosure messages This patch refactors ghci to use `ShortByteString` for `LookupSymbol`/`LookupSymbolInDLL`/`LookupClosure` messages as the first part of #27147. Co-authored-by: Codex <codex@openai.com> - - - - - 9 changed files: - compiler/GHC/Driver/Plugins.hs - compiler/GHC/Runtime/Interpreter.hs - libraries/ghci/GHCi/Message.hs - libraries/ghci/GHCi/ObjLink.hs - libraries/ghci/GHCi/Run.hs - testsuite/tests/driver/linkwhole/Main.hs - testsuite/tests/ghci/should_run/T18064.script - testsuite/tests/rts/KeepCafsMain.hs - utils/jsffi/dyld.mjs Changes: ===================================== compiler/GHC/Driver/Plugins.hs ===================================== @@ -405,7 +405,7 @@ loadExternalPlugins ps = do symbol | null unit = ztmp | otherwise = zEncodeString unit ++ "_" ++ ztmp - plugin <- lookupSymbol symbol >>= \case + plugin <- lookupSymbol (utf8EncodeShortByteString symbol) >>= \case Nothing -> pprPanic "loadExternalPlugins" (vcat [ text "Symbol not found" , text " Library path: " <> text path ===================================== compiler/GHC/Runtime/Interpreter.hs ===================================== @@ -465,27 +465,27 @@ lookupSymbol :: Interp -> InterpSymbol s -> IO (Maybe (Ptr ())) lookupSymbol interp str = withSymbolCache interp str $ case interpInstance interp of #if defined(HAVE_INTERNAL_INTERPRETER) - InternalInterp -> fmap fromRemotePtr <$> run (LookupSymbol (unpackFS (interpSymbolToCLabel str))) + InternalInterp -> fmap fromRemotePtr <$> run (LookupSymbol (fastStringToShortByteString (interpSymbolToCLabel str))) #endif ExternalInterp ext -> case ext of ExtIServ i -> withIServ i $ \inst -> fmap fromRemotePtr <$> do uninterruptibleMask_ $ - sendMessage inst (LookupSymbol (unpackFS (interpSymbolToCLabel str))) + sendMessage inst (LookupSymbol (fastStringToShortByteString (interpSymbolToCLabel str))) ExtJS {} -> pprPanic "lookupSymbol not supported by the JS interpreter" (ppr str) ExtWasm i -> withWasmInterp i $ \inst -> fmap fromRemotePtr <$> do uninterruptibleMask_ $ - sendMessage inst (LookupSymbol (unpackFS (interpSymbolToCLabel str))) + sendMessage inst (LookupSymbol (fastStringToShortByteString (interpSymbolToCLabel str))) lookupSymbolInDLL :: Interp -> RemotePtr LoadedDLL -> InterpSymbol s -> IO (Maybe (Ptr ())) lookupSymbolInDLL interp dll str = withSymbolCache interp str $ case interpInstance interp of #if defined(HAVE_INTERNAL_INTERPRETER) - InternalInterp -> fmap fromRemotePtr <$> run (LookupSymbolInDLL dll (unpackFS (interpSymbolToCLabel str))) + InternalInterp -> fmap fromRemotePtr <$> run (LookupSymbolInDLL dll (fastStringToShortByteString (interpSymbolToCLabel str))) #endif ExternalInterp ext -> case ext of ExtIServ i -> withIServ i $ \inst -> fmap fromRemotePtr <$> do uninterruptibleMask_ $ - sendMessage inst (LookupSymbolInDLL dll (unpackFS (interpSymbolToCLabel str))) + sendMessage inst (LookupSymbolInDLL dll (fastStringToShortByteString (interpSymbolToCLabel str))) ExtJS {} -> pprPanic "lookupSymbol not supported by the JS interpreter" (ppr str) -- wasm dyld doesn't track which symbol comes from which .so ExtWasm {} -> lookupSymbol interp str @@ -519,7 +519,7 @@ interpSymbolToCLabel s = eliminateInterpSymbol s interpretedInterpSymbol $ \is - lookupClosure :: Interp -> InterpSymbol s -> IO (Maybe HValueRef) lookupClosure interp str = - interpCmd interp (LookupClosure (unpackFS (interpSymbolToCLabel str))) + interpCmd interp (LookupClosure (fastStringToShortByteString (interpSymbolToCLabel str))) -- | 'withSymbolCache' tries to find a symbol in the 'interpLookupSymbolCache' -- which maps symbols to the address where they are loaded. ===================================== libraries/ghci/GHCi/Message.hs ===================================== @@ -86,9 +86,9 @@ data Message a where -- These all invoke the corresponding functions in the RTS Linker API. InitLinker :: Message () - LookupSymbol :: String -> Message (Maybe (RemotePtr ())) - LookupSymbolInDLL :: RemotePtr LoadedDLL -> String -> Message (Maybe (RemotePtr ())) - LookupClosure :: String -> Message (Maybe HValueRef) + LookupSymbol :: !BS.ShortByteString -> Message (Maybe (RemotePtr ())) + LookupSymbolInDLL :: !(RemotePtr LoadedDLL) -> !BS.ShortByteString -> Message (Maybe (RemotePtr ())) + LookupClosure :: !BS.ShortByteString -> Message (Maybe HValueRef) LoadDLLs :: [String] -> Message (Either String [RemotePtr LoadedDLL]) LoadArchive :: String -> Message () -- error? LoadObj :: String -> Message () -- error? ===================================== libraries/ghci/GHCi/ObjLink.hs ===================================== @@ -31,6 +31,8 @@ import GHCi.RemoteTypes import GHCi.Message (LoadedDLL) import Control.Exception (throwIO, ErrorCall(..)) import Control.Monad ( when ) +import qualified Data.ByteString.Short as BS +import Data.Char (ord) import Data.Foldable import Foreign.C import Foreign.Marshal.Alloc ( alloca, free ) @@ -104,15 +106,15 @@ unloadObj f = throwIO $ ErrorCall $ "unloadObj: unsupported on wasm for " <> f purgeObj :: String -> IO () purgeObj f = throwIO $ ErrorCall $ "purgeObj: unsupported on wasm for " <> f -lookupSymbol :: String -> IO (Maybe (Ptr a)) -lookupSymbol sym = do - r <- js_lookupSymbol $ toJSString sym +lookupSymbol :: BS.ShortByteString -> IO (Maybe (Ptr a)) +lookupSymbol sym@(BS.SBS ba#) = do + r <- js_lookupSymbolPtr ba# (BS.length sym) evaluate $ if r == nullPtr then Nothing else Just r -foreign import javascript unsafe "__ghc_wasm_jsffi_dyld.lookupSymbol($1)" - js_lookupSymbol :: JSString -> IO (Ptr a) +foreign import javascript unsafe "__ghc_wasm_jsffi_dyld.lookupSymbolPtr($1,$2)" + js_lookupSymbolPtr :: ByteArray# -> Int -> IO (Ptr a) -lookupSymbolInDLL :: Ptr LoadedDLL -> String -> IO (Maybe (Ptr a)) +lookupSymbolInDLL :: Ptr LoadedDLL -> BS.ShortByteString -> IO (Maybe (Ptr a)) lookupSymbolInDLL _ _ = pure Nothing resolveObjs :: IO Bool @@ -149,27 +151,27 @@ initObjLinker :: ShouldRetainCAFs -> IO () initObjLinker RetainCAFs = c_initLinker_ 1 initObjLinker _ = c_initLinker_ 0 -lookupSymbol :: String -> IO (Maybe (Ptr a)) +lookupSymbol :: BS.ShortByteString -> IO (Maybe (Ptr a)) lookupSymbol str_in = do let str = prefixUnderscore str_in - withCAString str $ \c_str -> do + BS.useAsCString str $ \c_str -> do addr <- c_lookupSymbol c_str if addr == nullPtr then return Nothing else return (Just addr) -lookupSymbolInDLL :: Ptr LoadedDLL -> String -> IO (Maybe (Ptr a)) +lookupSymbolInDLL :: Ptr LoadedDLL -> BS.ShortByteString -> IO (Maybe (Ptr a)) lookupSymbolInDLL dll str_in = do let str = prefixUnderscore str_in - withCAString str $ \c_str -> do + BS.useAsCString str $ \c_str -> do addr <- c_lookupSymbolInNativeObj dll c_str if addr == nullPtr then return Nothing else return (Just addr) -prefixUnderscore :: String -> String +prefixUnderscore :: BS.ShortByteString -> BS.ShortByteString prefixUnderscore - | cLeadingUnderscore = ('_':) + | cLeadingUnderscore = BS.cons (fromIntegral (ord '_')) | otherwise = id -- | loadDLL loads a dynamic library using the OS's native linker @@ -298,7 +300,7 @@ isWindowsHost = False #endif -lookupClosure :: String -> IO (Maybe HValueRef) +lookupClosure :: BS.ShortByteString -> IO (Maybe HValueRef) lookupClosure str = do m <- lookupSymbol str case m of ===================================== libraries/ghci/GHCi/Run.hs ===================================== @@ -135,12 +135,12 @@ foreign import javascript "((ptr,off) => globalThis.h$loadJS(h$decodeUtf8z(ptr,o foreign import javascript "((ptr,off) => globalThis.h$lookupClosure(h$decodeUtf8z(ptr,off)))" lookupJSClosure# :: CString -> State# RealWorld -> (# State# RealWorld, Int# #) -lookupJSClosure' :: String -> IO Int -lookupJSClosure' str = withCString str $ \cstr -> IO (\s -> +lookupJSClosure' :: BS.ShortByteString -> IO Int +lookupJSClosure' str = BS.useAsCString str $ \cstr -> IO (\s -> case lookupJSClosure# cstr s of (# s', r #) -> (# s', I# r #)) -lookupJSClosure :: String -> IO (Maybe HValueRef) +lookupJSClosure :: BS.ShortByteString -> IO (Maybe HValueRef) lookupJSClosure str = lookupJSClosure' str >>= \case 0 -> pure Nothing r -> pure (Just (RemoteRef (RemotePtr (fromIntegral r)))) ===================================== testsuite/tests/driver/linkwhole/Main.hs ===================================== @@ -1,9 +1,11 @@ +{-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE RecordWildCards #-} module Main (main) where import Control.Exception import Control.Monad +import Data.ByteString.Short (ShortByteString) import Foreign @@ -15,7 +17,7 @@ import GHCi.ObjLink rotateSO :: (FunPtr (IO (StablePtr a)) -> (IO (StablePtr a))) - -> String + -> ShortByteString -> (Maybe FilePath, FilePath) -> IO a rotateSO dynamicCall symName (old, newDLL) = do ===================================== testsuite/tests/ghci/should_run/T18064.script ===================================== @@ -1,2 +1,3 @@ +:set -XOverloadedStrings import GHCi.ObjLink lookupClosure "blah" ===================================== testsuite/tests/rts/KeepCafsMain.hs ===================================== @@ -1,3 +1,5 @@ +{-# LANGUAGE OverloadedStrings #-} + module Main (main) where import Foreign ===================================== utils/jsffi/dyld.mjs ===================================== @@ -1334,6 +1334,13 @@ class DyLD { } return 0; } + + lookupSymbolPtr(symPtr, symLen) { + const sym = new TextDecoder("utf-8", { fatal: true }).decode( + new Uint8Array(this.#memory.buffer, symPtr, symLen) + ); + return this.lookupSymbol(sym); + } } // The main entry point of dyld that may be run on node/browser, and View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/f86f611400fb611db436409fd39dfbdd... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/f86f611400fb611db436409fd39dfbdd... 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