Cheng Shao pushed to branch wip/fix-clang64-split-sections at Glasgow Haskell Compiler / GHC Commits: 6213bb57 by maralorn at 2026-01-02T16:30:32+01:00 GHC.Internal.Exception.Context: Fix comment on addExceptionAnnotation - - - - - b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00 GHC.Internal.Control.Monad.replicateM: Fix comment - - - - - f9bda57b by Cheng Shao at 2026-01-05T09:25:50+01:00 compiler: change sectionProtection to take SectionType argument This commit changes `sectionProtection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. - - - - - 9f426e30 by Cheng Shao at 2026-01-05T10:33:30+01:00 compiler: change isInitOrFiniSection to take SectionType argument This commit changes `isInitOrFiniSection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. Also marks it as exported. - - - - - 043299ef by Cheng Shao at 2026-01-05T10:42:34+01:00 compiler: fix split sections on windows This patch fixes split sections on windows by emitting the right COMDAT section header in NCG, see added comment for more explanation. Fix #26696 #26494. Co-authored-by: Codex - - - - - 8 changed files: - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/InitFini.hs - compiler/GHC/CmmToAsm/Ppr.hs - compiler/GHC/CmmToAsm/Wasm/FromCmm.hs - compiler/GHC/CmmToC.hs - compiler/GHC/CmmToLlvm/Data.hs - libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs - libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs Changes: ===================================== compiler/GHC/Cmm.hs ===================================== @@ -278,8 +278,8 @@ data SectionProtection deriving (Eq) -- | Should a data in this section be considered constant at runtime -sectionProtection :: Section -> SectionProtection -sectionProtection (Section t _) = case t of +sectionProtection :: SectionType -> SectionProtection +sectionProtection t = case t of Text -> ReadOnlySection ReadOnlyData -> ReadOnlySection RelocatableReadOnlyData -> WriteProtectedSection ===================================== compiler/GHC/Cmm/InitFini.hs ===================================== @@ -2,6 +2,7 @@ module GHC.Cmm.InitFini ( InitOrFini(..) , isInitOrFiniArray + , isInitOrFiniSection ) where import GHC.Prelude @@ -63,8 +64,8 @@ finalizer CmmDecl will be emitted per module. data InitOrFini = IsInitArray | IsFiniArray isInitOrFiniArray :: RawCmmDecl -> Maybe (InitOrFini, [CLabel]) -isInitOrFiniArray (CmmData sect (CmmStaticsRaw _ lits)) - | Just initOrFini <- isInitOrFiniSection sect +isInitOrFiniArray (CmmData (Section t _) (CmmStaticsRaw _ lits)) + | Just initOrFini <- isInitOrFiniSection t = Just (initOrFini, map get_label lits) where get_label :: CmmStatic -> CLabel @@ -72,7 +73,7 @@ isInitOrFiniArray (CmmData sect (CmmStaticsRaw _ lits)) get_label static = pprPanic "isInitOrFiniArray: invalid entry" (ppr static) isInitOrFiniArray _ = Nothing -isInitOrFiniSection :: Section -> Maybe InitOrFini -isInitOrFiniSection (Section InitArray _) = Just IsInitArray -isInitOrFiniSection (Section FiniArray _) = Just IsFiniArray +isInitOrFiniSection :: SectionType -> Maybe InitOrFini +isInitOrFiniSection InitArray = Just IsInitArray +isInitOrFiniSection FiniArray = Just IsFiniArray isInitOrFiniSection _ = Nothing ===================================== compiler/GHC/CmmToAsm/Ppr.hs ===================================== @@ -1,4 +1,5 @@ {-# LANGUAGE MagicHash #-} +{-# LANGUAGE MultiWayIf #-} ----------------------------------------------------------------------------- -- @@ -23,6 +24,7 @@ import GHC.Prelude import GHC.Utils.Asm import GHC.Cmm.CLabel +import GHC.Cmm.InitFini import GHC.Cmm import GHC.CmmToAsm.Config import GHC.Utils.Outputable as SDoc @@ -240,21 +242,45 @@ pprGNUSectionHeader config t suffix = | OSMinGW32 <- platformOS platform -> text ".rdata" | otherwise -> text ".ipe" - flags = case t of - Text - | OSMinGW32 <- platformOS platform, splitSections - -> text ",\"xr\"" - | splitSections - -> text ",\"ax\"," <> sectionType platform "progbits" - CString - | OSMinGW32 <- platformOS platform - -> empty - | otherwise -> text ",\"aMS\"," <> sectionType platform "progbits" <> text ",1" - IPE - | OSMinGW32 <- platformOS platform - -> empty - | otherwise -> text ",\"a\"," <> sectionType platform "progbits" - _ -> empty + flags + -- See + -- https://github.com/llvm/llvm-project/blob/llvmorg-21.1.8/lld/COFF/Chunks.cpp... + -- and https://llvm.org/docs/Extensions.html#section-directive. + -- LLD COFF backend gc-sections only work on COMDAT sections so + -- we need to mark it as a COMDAT section. You can use clang64 + -- toolchain to compile small examples with + -- `-ffunction-sections -fdata-sections -S` to see these section + -- headers in the wild. + | OSMinGW32 <- platformOS platform, + splitSections = + if + | Just _ <- isInitOrFiniSection t -> text ",\"dw\"" + | otherwise -> + let coff_section_flags + | Text <- t = "xr" + | UninitialisedData <- t = "bw" + | ReadWriteSection <- sectionProtection t = "dw" + | otherwise = "dr" + in hcat + [ text ",\"", + text coff_section_flags, + text "\",one_only,", + pprAsmLabel platform suffix + ] + | otherwise = + case t of + Text + | splitSections + -> text ",\"ax\"," <> sectionType platform "progbits" + CString + | OSMinGW32 <- platformOS platform + -> empty + | otherwise -> text ",\"aMS\"," <> sectionType platform "progbits" <> text ",1" + IPE + | OSMinGW32 <- platformOS platform + -> empty + | otherwise -> text ",\"a\"," <> sectionType platform "progbits" + _ -> empty {-# SPECIALIZE pprGNUSectionHeader :: NCGConfig -> SectionType -> CLabel -> SDoc #-} {-# SPECIALIZE pprGNUSectionHeader :: NCGConfig -> SectionType -> CLabel -> HLine #-} -- see Note [SPECIALIZE to HDoc] in GHC.Utils.Outputable ===================================== compiler/GHC/CmmToAsm/Wasm/FromCmm.hs ===================================== @@ -107,7 +107,7 @@ symKindFromCLabel lbl -- | Calculate a data section's kind, see haddock docs of -- 'DataSectionKind' for more explanation. dataSectionKindFromCmmSection :: Section -> DataSectionKind -dataSectionKindFromCmmSection s = case sectionProtection s of +dataSectionKindFromCmmSection (Section t _) = case sectionProtection t of ReadWriteSection -> SectionData _ -> SectionROData ===================================== compiler/GHC/CmmToC.hs ===================================== @@ -121,7 +121,7 @@ pprTop platform = \case pprDataExterns platform lits $$ pprWordArray platform (isSecConstant section) lbl lits where - isSecConstant section = case sectionProtection section of + isSecConstant (Section t _) = case sectionProtection t of ReadOnlySection -> True WriteProtectedSection -> True _ -> False ===================================== compiler/GHC/CmmToLlvm/Data.hs ===================================== @@ -75,7 +75,7 @@ genLlvmData (sect, statics) IsFiniArray -> fsLit "llvm.global_dtors" in genGlobalLabelArray var clbls -genLlvmData (sec, CmmStaticsRaw lbl xs) = do +genLlvmData (sec@(Section t _), CmmStaticsRaw lbl xs) = do label <- strCLabel_llvm lbl static <- mapM genData xs lmsec <- llvmSection sec @@ -92,7 +92,7 @@ genLlvmData (sec, CmmStaticsRaw lbl xs) = do then Just 2 else Just 1 Section Data _ -> Just $ platformWordSizeInBytes platform _ -> Nothing - const = if sectionProtection sec == ReadOnlySection + const = if sectionProtection t == ReadOnlySection then Constant else Global varDef = LMGlobalVar label tyAlias link lmsec align const globDef = LMGlobal varDef struct ===================================== libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs ===================================== @@ -314,7 +314,7 @@ Core: https://gitlab.haskell.org/ghc/ghc/issues/11795#note_118976 -- | @'replicateM' n act@ performs the action @act@ @n@ times, -- and then returns the list of results. -- --- @replicateM n (pure x) == 'replicate' n x@ +-- @replicateM n (pure x) == pure ('replicate' n x)@ -- -- ==== __Examples__ -- ===================================== libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs ===================================== @@ -64,7 +64,7 @@ instance Monoid ExceptionContext where emptyExceptionContext :: ExceptionContext emptyExceptionContext = ExceptionContext [] --- | Construct a singleton 'ExceptionContext' from an 'ExceptionAnnotation'. +-- | Add an 'ExceptionAnnotation' to a given 'ExceptionContext'. -- -- @since base-4.20.0.0 addExceptionAnnotation :: ExceptionAnnotation a => a -> ExceptionContext -> ExceptionContext View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dc022bcb1aba9a5d67adaca8f0af24f... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dc022bcb1aba9a5d67adaca8f0af24f... 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