Cheng Shao pushed to branch wip/gbc-faster-internal-names at Glasgow Haskell Compiler / GHC Commits: 0633b3af by Cheng Shao at 2026-04-23T14:52:42+00:00 compiler: avoid unique OccNames for internal Names in bytecode objects This patch improves bytecode object serialization logic by avoiding the construction of unique `OccName`s when serializing/deserializing internal `Name`s. Closes #27213. ------------------------- Metric Decrease: LinkableUsage01 ------------------------- - - - - - 1 changed file: - compiler/GHC/ByteCode/Binary.hs Changes: ===================================== compiler/GHC/ByteCode/Binary.hs ===================================== @@ -20,7 +20,7 @@ module GHC.ByteCode.Binary ( import GHC.Prelude import GHC.ByteCode.Types -import GHC.Data.FastString +import qualified GHC.Data.Word64Map.Strict as Word64Map import GHC.Types.Name import GHC.Types.Name.Cache import GHC.Types.Name.Env @@ -269,9 +269,8 @@ addBinNameWriter bh' = do | otherwise -> do putByte bh 1 key <- getBinNameKey env_ref nm - -- Delimit the OccName from the deterministic counter to keep the - -- encoding injective, avoiding collisions like "foo1" vs "foo#1". - put_ bh (occNameFS (occName nm) `appendFS` mkFastString ('#' : show key)) + put_ bh $ occNameFS $ occName nm + put_ bh key where -- Find a deterministic key for local names. This getBinNameKey ref name = do @@ -282,7 +281,7 @@ addBinNameWriter bh' = do addBinNameReader :: NameCache -> ReadBinHandle -> IO ReadBinHandle addBinNameReader nc bh' = do - env_ref <- newIORef emptyOccEnv + env_ref <- newIORef Word64Map.empty pure $ flip addReaderToUserData bh' $ BinaryReader $ \bh -> do t <- getByte bh case t of @@ -291,15 +290,16 @@ addBinNameReader nc bh' = do pure $ BinName nm 1 -> do occ <- mkVarOccFS <$> get bh + key <- get bh -- We don't want to get a new unique from the NameCache each time we -- see a name. nm' <- unsafeInterleaveIO $ do u <- takeUniqFromNameCache nc evaluate $ mkInternalName u occ noSrcSpan fmap BinName $ atomicModifyIORef' env_ref $ \env -> - case lookupOccEnv env occ of + case Word64Map.lookup key env of Just nm -> (env, nm) - _ -> nm' `seq` (extendOccEnv env occ nm', nm') + _ -> nm' `seq` (Word64Map.insert key nm' env, nm') _ -> panic "Binary BinName: invalid byte" -- Note [Serializing Names in bytecode] View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/0633b3af561526eac32915eb7301ee4a... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/0633b3af561526eac32915eb7301ee4a... You're receiving this email because of your account on gitlab.haskell.org.