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[Git][ghc/ghc][wip/27323] Don't report -XStrict-generated bangs under -Wredundant-bang-patterns
by Sasha Bogicevic (＠Bogicevic) 22 Jul '26

22 Jul '26

Sasha Bogicevic pushed to branch wip/27323 at Glasgow Haskell Compiler / GHC Commits: 708c671a by Sasha Bogicevic at 2026-07-22T19:35:14+02:00 Don't report -XStrict-generated bangs under -Wredundant-bang-patterns XBangPat GhcTc is now Origin: user bangs are FromSource, bangs added by decideBangHood are Generated. The pattern-match checker attaches no SrcInfo to generated bangs, so they are divergence-checked but never reported as redundant. Fixes #27323 - - - - - 9 changed files: - + changelog.d/T27323 - compiler/GHC/Hs/Pat.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/HsToCore/Pmc/Check.hs - compiler/GHC/HsToCore/Pmc/Desugar.hs - compiler/GHC/HsToCore/Utils.hs - compiler/GHC/Tc/Gen/Pat.hs - + testsuite/tests/pmcheck/should_compile/T27323.hs - testsuite/tests/pmcheck/should_compile/all.T Changes: ===================================== changelog.d/T27323 ===================================== @@ -0,0 +1,15 @@ +section: compiler +synopsis: Don't report compiler-generated bang patterns under -Wredundant-bang-patterns +description: + With ``-XStrict``, GHC inserts bang patterns on binders. When such a bang + cannot force anything - for instance on a binder of unlifted type such as + ``Int#`` - it was reported by ``-Wredundant-bang-patterns``, even though + there is no bang in the source to remove. The warning now only reports + bangs the user actually wrote. + + As part of this change, the ``XBangPat GhcTc`` extension field of + ``BangPat`` changed from ``NoExtField`` to ``Origin``, recording whether a + bang was user-written or compiler-generated. GHC API users constructing or + matching typechecked bang patterns may need a one-line adjustment. +mrs: !16395 +issues: #27323 ===================================== compiler/GHC/Hs/Pat.hs ===================================== @@ -102,7 +102,11 @@ type instance XParPat GhcTc = NoExtField type instance XBangPat GhcPs = EpToken "!" type instance XBangPat GhcRn = NoExtField -type instance XBangPat GhcTc = NoExtField +-- | Was this bang written by the user, or inserted by 'decideBangHood' +-- because of -XStrict? Consulted by the pattern-match checker, which +-- only reports user-written bangs under -Wredundant-bang-patterns. +-- See Note [Dead bang patterns] in GHC.HsToCore.Pmc.Check. +type instance XBangPat GhcTc = Origin type instance XListPat GhcPs = AnnList () -- After parsing, ListPat can refer to a built-in Haskell list pattern ===================================== compiler/GHC/HsToCore/Match.hs ===================================== @@ -414,7 +414,7 @@ tidy1 :: Id -- The Id being scrutinised tidy1 v g (ParPat _ pat) = tidy1 v g (unLoc pat) tidy1 v g (SigPat _ pat _) = tidy1 v g (unLoc pat) tidy1 _ _ (WildPat ty) = return (idDsWrapper, WildPat ty) -tidy1 v g (BangPat _ (L l p)) = tidy_bang_pat v g l p +tidy1 v g (BangPat o (L l p)) = tidy_bang_pat v g o l p tidy1 v g (ModifiedPat _ _ pat) = tidy1 v g (unLoc pat) -- case v of { x -> mr[] } @@ -530,30 +530,30 @@ tidy1 _ _ non_interesting_pat = return (idDsWrapper, non_interesting_pat) -------------------- -tidy_bang_pat :: Id -> Bool -> SrcSpanAnnA -> Pat GhcTc +tidy_bang_pat :: Id -> Bool -> Origin -> SrcSpanAnnA -> Pat GhcTc -> DsM (DsWrapper, Pat GhcTc) -- Discard par/sig under a bang -tidy_bang_pat v g _ (ParPat _ (L l p)) = tidy_bang_pat v g l p -tidy_bang_pat v g _ (SigPat _ (L l p) _) = tidy_bang_pat v g l p +tidy_bang_pat v g o _ (ParPat _ (L l p)) = tidy_bang_pat v g o l p +tidy_bang_pat v g o _ (SigPat _ (L l p) _) = tidy_bang_pat v g o l p -- Push the bang-pattern inwards, in the hope that -- it may disappear next time -tidy_bang_pat v g l (AsPat x v' p) - = tidy1 v g (AsPat x v' (L l (BangPat noExtField p))) -tidy_bang_pat v g l (XPat (CoPat w p t)) - = tidy1 v g (XPat $ CoPat w (BangPat noExtField (L l p)) t) -tidy_bang_pat v g l (OrPat x (p:|ps)) -- push bang into first pat alt - = tidy1 v g (OrPat x (L l (BangPat noExtField p) :| ps)) +tidy_bang_pat v g o l (AsPat x v' p) + = tidy1 v g (AsPat x v' (L l (BangPat o p))) +tidy_bang_pat v g o l (XPat (CoPat w p t)) + = tidy1 v g (XPat $ CoPat w (BangPat o (L l p)) t) +tidy_bang_pat v g o l (OrPat x (p:|ps)) -- push bang into first pat alt + = tidy1 v g (OrPat x (L l (BangPat o p) :| ps)) -- Discard bang around strict pattern -tidy_bang_pat v g _ p@(LitPat {}) = tidy1 v g p -tidy_bang_pat v g _ p@(ListPat {}) = tidy1 v g p -tidy_bang_pat v g _ p@(TuplePat {}) = tidy1 v g p -tidy_bang_pat v g _ p@(SumPat {}) = tidy1 v g p +tidy_bang_pat v g _ _ p@(LitPat {}) = tidy1 v g p +tidy_bang_pat v g _ _ p@(ListPat {}) = tidy1 v g p +tidy_bang_pat v g _ _ p@(TuplePat {}) = tidy1 v g p +tidy_bang_pat v g _ _ p@(SumPat {}) = tidy1 v g p -- Data/newtype constructors -tidy_bang_pat v g l p@(ConPat { pat_con = L _ (RealDataCon dc) +tidy_bang_pat v g o l p@(ConPat { pat_con = L _ (RealDataCon dc) , pat_args = args , pat_con_ext = ConPatTc { cpt_arg_tys = arg_tys @@ -562,7 +562,7 @@ tidy_bang_pat v g l p@(ConPat { pat_con = L _ (RealDataCon dc) -- Newtypes: push bang inwards (#9844) = if isNewTyCon (dataConTyCon dc) - then tidy1 v g (p { pat_args = push_bang_into_newtype_arg l (scaledThing ty) args }) + then tidy1 v g (p { pat_args = push_bang_into_newtype_arg l o (scaledThing ty) args }) else tidy1 v g p -- Data types: discard the bang where (ty:_) = dataConInstArgTys dc arg_tys @@ -582,28 +582,29 @@ tidy_bang_pat v g l p@(ConPat { pat_con = L _ (RealDataCon dc) -- -- NB: SigPatIn, ConPatIn should not happen -tidy_bang_pat _ _ l p = return (idDsWrapper, BangPat noExtField (L l p)) +tidy_bang_pat _ _ o l p = return (idDsWrapper, BangPat o (L l p)) ------------------- push_bang_into_newtype_arg :: SrcSpanAnnA + -> Origin -> Type -- The type of the argument we are pushing -- onto -> HsConPatDetails GhcTc -> HsConPatDetails GhcTc -- See Note [Bang patterns and newtypes] -- We are transforming !(N p) into (N !p) -push_bang_into_newtype_arg l _ty (PrefixCon x (arg:args)) +push_bang_into_newtype_arg l o _ty (PrefixCon x (arg:args)) = assert (null args) $ - PrefixCon x [L l (BangPat noExtField arg)] -push_bang_into_newtype_arg l _ty (RecCon x rf) + PrefixCon x [L l (BangPat o arg)] +push_bang_into_newtype_arg l o _ty (RecCon x rf) | HsRecFields { rec_flds = L lf fld : flds } <- rf , HsFieldBind { hfbRHS = arg } <- fld = assert (null flds) $ RecCon x (rf { rec_flds = [L lf (fld { hfbRHS - = L l (BangPat noExtField arg) })] }) -push_bang_into_newtype_arg l ty (RecCon _ rf) -- If a user writes !(T {}) + = L l (BangPat o arg) })] }) +push_bang_into_newtype_arg l o ty (RecCon _ rf) -- If a user writes !(T {}) | HsRecFields { rec_flds = [] } <- rf - = PrefixCon noExtField [L l (BangPat noExtField (noLocA (WildPat ty)))] -push_bang_into_newtype_arg _ _ cd + = PrefixCon noExtField [L l (BangPat o (noLocA (WildPat ty)))] +push_bang_into_newtype_arg _ _ _ cd = pprPanic "push_bang_into_newtype_arg" (pprConArgs cd) {- ===================================== compiler/GHC/HsToCore/Pmc/Check.hs ===================================== @@ -128,7 +128,9 @@ checkGrd grd = CA $ \inc -> case grd of div <- addPhiCtNablas inc (PhiBotCt x) matched <- addPhiCtNablas inc (PhiNotBotCt x) -- See Note [Dead bang patterns] - -- mb_info = Just info <==> PmBang originates from bang pattern in source + -- mb_info = Just info <==> the PmBang originates from a user-written + -- bang pattern. Bangs inserted by -XStrict carry no info and are thus + -- never reported as redundant (#27323). let bangs | Just info <- mb_info = unitOL (div, info) | otherwise = NilOL tracePm "check:Bang" (ppr x <+> ppr div) @@ -267,6 +269,22 @@ dead. So for a source bang, we add the refined Nabla and the source info to the 'RedSet's 'rs_bangs'. When collecting stuff to warn, we test that Nabla for inhabitants. If it's empty, we'll warn that it's redundant. +Crucially, we only ever warn about bangs the user wrote. With -XStrict, the +compiler inserts bangs itself ('decideBangHood' in GHC.HsToCore.Utils), and +such a bang is often dead. Consider (#27323) + + {-# LANGUAGE MagicHash, Strict #-} + idInt# :: Int# -> Int# + idInt# x = x + +The binder `x` has unlifted type, so the bang that -XStrict inserts on it can +never force anything. But warning would be deeply confusing: there is no bang +in the source to delete! Whether a bang was user-written is recorded in the +'XBangPat GhcTc' extension field ('Origin'); generated bangs desugar to a +'PmBang' with no 'SrcInfo', so they still take part in divergence checking +(that matters for the inaccessible-RHS warnings of #21761) but never end up +in 'rs_bangs'. + Note that we don't want to warn for a dead bang that appears on a redundant clause. That is because in that case, we recommend to delete the clause wholly, including its leading pattern match. ===================================== compiler/GHC/HsToCore/Pmc/Desugar.hs ===================================== @@ -18,6 +18,7 @@ import GHC.Data.FastString (unpackFS, lengthFS, mkFastStringShortText) import GHC.Driver.DynFlags import GHC.Hs import GHC.Tc.Utils.TcMType (shortCutLit) +import GHC.Types.Basic (isGenerated) import GHC.Types.Id import GHC.Core.ConLike import GHC.Types.Name @@ -154,11 +155,11 @@ desugarPat x pat = case pat of VarPat _ y -> pure (mkPmLetVar (unLoc y) x) ParPat _ p -> desugarLPat x p LazyPat _ _ -> pure GdEnd -- like a wildcard - BangPat _ p@(L l p') -> + BangPat orig p@(L l p') -> -- Add the bang in front of the list, because it will happen before any -- nested stuff. consGrdDag (PmBang x pm_loc) <$> desugarLPat x p - where pm_loc = Just (SrcInfo (L (locA l) (ppr p'))) + where pm_loc = if isGenerated orig then Nothing else Just (SrcInfo (L (locA l) (ppr p'))) -- (x@pat) ==> Desugar pat with x as match var and handle impedance -- mismatch with incoming match var @@ -649,4 +650,12 @@ user *had* written a bang: + In an equation for ‘idV’: idV !v = ... So we live with the duplication. + +There is one wrinkle (#27323): the bang inserted by 'decideBangHood' is +compiler-generated, marked 'Generated' in its 'XBangPat GhcTc' field. When +'desugarPat' sees such a bang, it emits a 'PmBang' without 'SrcInfo', so +that the checker performs the usual divergence check (giving the +inaccessible-RHS warning above) but never reports the bang under +-Wredundant-bang-patterns. See Note [Dead bang patterns] in +GHC.HsToCore.Pmc.Check. -} ===================================== compiler/GHC/HsToCore/Utils.hs ===================================== @@ -53,6 +53,7 @@ import GHC.HsToCore.Monad import GHC.Core.Utils import GHC.Core.Make +import GHC.Types.Basic (Origin(Generated), GenReason(OtherExpansion), DoPmc(..)) import GHC.Types.Id.Make import GHC.Types.Id import GHC.Types.Literal @@ -956,6 +957,12 @@ Specifically: !pat => !pat -- always pat => !pat -- when -XStrict pat => pat -- otherwise + +The bangs we add here are compiler-generated: we record 'Generated' in the +'XBangPat GhcTc' extension field, whereas a user-written bang is typechecked +to 'FromSource' (GHC.Tc.Gen.Pat). The pattern-match checker consults this +field so that -Wredundant-bang-patterns only reports bangs that the user +actually wrote (#27323). See Note [Dead bang patterns] in GHC.HsToCore.Pmc.Check. -} @@ -975,7 +982,7 @@ decideBangHood dflags lpat ParPat x p -> L l (ParPat x (go p)) LazyPat _ lp' -> lp' BangPat _ _ -> lp - _ -> L l (BangPat noExtField lp) + _ -> L l (BangPat (Generated OtherExpansion DoPmc) lp) isTrueLHsExpr :: LHsExpr GhcTc -> Maybe (CoreExpr -> DsM CoreExpr) ===================================== compiler/GHC/Tc/Gen/Pat.hs ===================================== @@ -31,6 +31,7 @@ import GHC.Tc.Gen.Sig( TcPragEnv, lookupPragEnv, addInlinePrags ) import GHC.Tc.Utils.Monad import GHC.Tc.Utils.Instantiate import GHC.Types.FieldLabel +import GHC.Types.Basic (Origin (FromSource)) import GHC.Types.Id import GHC.Types.Var import GHC.Types.Name @@ -627,9 +628,9 @@ tc_pat scaled_exp_pat_ty@(Scaled w_pat exp_pat_ty) penv ps_pat thing_inside = { (pat', res) <- tc_lpat scaled_exp_pat_ty penv pat thing_inside ; return (ParPat x pat', res) } - BangPat x pat -> do + BangPat _ pat -> do { (pat', res) <- tc_lpat scaled_exp_pat_ty penv pat thing_inside - ; return (BangPat x pat', res) } + ; return (BangPat FromSource pat', res) } OrPat _ pats -> do -- See Note [Implementation of OrPatterns], Typechecker (1) { let pats_list = NE.toList pats ===================================== testsuite/tests/pmcheck/should_compile/T27323.hs ===================================== @@ -0,0 +1,9 @@ +{-# LANGUAGE MagicHash, Strict #-} +{-# OPTIONS_GHC -Wredundant-bang-patterns #-} + +import GHC.Prim (Int#) + +idInt# :: Int# -> Int# +idInt# x = x + +main = pure () ===================================== testsuite/tests/pmcheck/should_compile/all.T ===================================== @@ -190,4 +190,5 @@ test('T24845', [], compile, [overlapping_incomplete]) test('T22652', [], compile, [overlapping_incomplete]) test('T22652a', [], compile, [overlapping_incomplete]) test('T24867', [], compile_fail, [overlapping_incomplete]) +test('T27323', normal, compile, ['-Wredundant-bang-patterns']) test('T27360', normal, compile, [overlapping_incomplete + '-g3']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/708c671a5d57bc746d8c11c5ff01a60… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/708c671a5d57bc746d8c11c5ff01a60… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc] Pushed new branch wip/27323
by Sasha Bogicevic (＠Bogicevic) 22 Jul '26

22 Jul '26

Sasha Bogicevic pushed new branch wip/27323 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/27323 You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/io-manager-deadlock-detection] Try fixing test T7275
by Duncan Coutts (＠dcoutts) 22 Jul '26

22 Jul '26

Duncan Coutts pushed to branch wip/io-manager-deadlock-detection at Glasgow Haskell Compiler / GHC Commits: d645cc9e by Duncan Coutts at 2026-07-22T16:51:48+01:00 Try fixing test T7275 The hypothesis is that this test's output is sensitive to the number of major GCs run, since these are the profiling samples. This MR makes idle GC work in the non-threaded RTS, and for this test that increases the number of major GCs, since the test program is frequently idle for more than 300ms. TODO: squash into a previous commit if this works. - - - - - 1 changed file: - testsuite/tests/profiling/should_run/Makefile Changes: ===================================== testsuite/tests/profiling/should_run/Makefile ===================================== @@ -7,10 +7,13 @@ DECIMAL_REGEXP = [0-9]\+.[0-9]\+ .PHONY: T7275 T7275: "$(TEST_HC)" -prof -v0 -rtsopts T7275.hs - ./T7275 +RTS -hc -i0 + ./T7275 +RTS -hc -i0 -I0 # Suzanne should appear here, despite having produced only pinned # allocations. Strip off the actual amounts and cost-center numbers since # they will be non-determinstic. + # Note also that this test is sensitive to the number of major GC's + # performed. The use of -i0 and -I0 above are intended to make this + # deterministic, but it is still sensitive to implementation changes. grep suzanne T7275.hp | cut -f1 -d' ' | sed -re 's/$[0-9]+$//' .PHONY: T11489 View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/d645cc9e79315d67bc46671e71767b3… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/d645cc9e79315d67bc46671e71767b3… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][master] parser: don't suggest ImportQualifiedPost when it is already enabled
by Marge Bot (＠marge-bot) 22 Jul '26

22 Jul '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 0bf1d8c9 by Sasha Bogicevic at 2026-07-22T11:31:21-04:00 parser: don't suggest ImportQualifiedPost when it is already enabled -Wprepositive-qualified-module unconditionally attached a hint to enable ImportQualifiedPost, even when the extension was already on (as it is by default under GHC2021). Record the extension's state in the PsWarnImportPreQualified diagnostic and drop the hint when it is already enabled. Fixes #27380 - - - - - 8 changed files: - + changelog.d/27380 - compiler/GHC/Parser/Errors/Ppr.hs - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/PostProcess.hs - + testsuite/tests/module/T27380.hs - + testsuite/tests/module/T27380.stderr - testsuite/tests/module/all.T - testsuite/tests/module/mod184.stderr Changes: ===================================== changelog.d/27380 ===================================== @@ -0,0 +1,7 @@ +section: compiler +synopsis: Don't suggest enabling ``ImportQualifiedPost`` when it is already enabled. + The :ghc-flag:`-Wprepositive-qualified-module` warning no longer suggests + enabling the extension if it is already in effect (as it is by default + under GHC2021). +issues: #27380 +mrs: !16376 ===================================== compiler/GHC/Parser/Errors/Ppr.hs ===================================== @@ -113,7 +113,7 @@ instance Diagnostic PsMessage where <> if null prag then empty else text ":" <+> text prag PsWarnMisplacedPragma prag -> mkSimpleDecorated $ text "Misplaced" <+> pprFileHeaderPragmaType prag <+> text "pragma" - PsWarnImportPreQualified + PsWarnImportPreQualified _iqp_on -> mkSimpleDecorated $ text "Found" <+> quotes (text "qualified") <+> text "in prepositive position" @@ -603,7 +603,7 @@ instance Diagnostic PsMessage where PsWarnStarIsType -> WarningWithFlag Opt_WarnStarIsType PsWarnUnrecognisedPragma{} -> WarningWithFlag Opt_WarnUnrecognisedPragmas PsWarnMisplacedPragma{} -> WarningWithFlag Opt_WarnMisplacedPragmas - PsWarnImportPreQualified -> WarningWithFlag Opt_WarnPrepositiveQualifiedModule + PsWarnImportPreQualified{} -> WarningWithFlag Opt_WarnPrepositiveQualifiedModule PsWarnViewPatternSignatures{} -> WarningWithFlag Opt_WarnViewPatternSignatures PsErrLexer{} -> ErrorWithoutFlag PsErrCmmLexer -> ErrorWithoutFlag @@ -735,8 +735,10 @@ instance Diagnostic PsMessage where then noHints else [SuggestCorrectPragmaName suggestions] PsWarnMisplacedPragma{} -> [SuggestPlacePragmaInHeader] - PsWarnImportPreQualified -> [ SuggestQualifiedAfterModuleName - , suggestExtension LangExt.ImportQualifiedPost] + PsWarnImportPreQualified iqp_on | iqp_on -> [ SuggestQualifiedAfterModuleName ] + | otherwise -> [ SuggestQualifiedAfterModuleName + , suggestExtension LangExt.ImportQualifiedPost + ] PsWarnViewPatternSignatures{} -> [SuggestParenthesizePatternRHS] PsErrLexer{} -> noHints PsErrCmmLexer -> noHints ===================================== compiler/GHC/Parser/Errors/Types.hs ===================================== @@ -133,7 +133,7 @@ data PsMessage | PsWarnStarIsType -- | Pre qualified import with 'WarnPrepositiveQualifiedModule' enabled - | PsWarnImportPreQualified + | PsWarnImportPreQualified !Bool -- is 'ImportQualifiedPost' enabled? | PsWarnOperatorWhitespaceExtConflict !OperatorWhitespaceSymbol ===================================== compiler/GHC/Parser/PostProcess.hs ===================================== @@ -1326,7 +1326,7 @@ checkImportDecl mPre mPost preLevel postLevel = do -- Warn if 'qualified' found in prepositive position and -- 'Opt_WarnPrepositiveQualifiedModule' is enabled. whenJust mPre $ \pre -> - warnPrepositiveQualifiedModule (tokenSpan pre) + warnPrepositiveQualifiedModule (tokenSpan pre) importQualifiedPostEnabled return (qualSpec, levelSpec) @@ -3498,9 +3498,9 @@ isImpExpQcWildcard _ = False ----------------------------------------------------------------------------- -- Warnings and failures -warnPrepositiveQualifiedModule :: SrcSpan -> P () -warnPrepositiveQualifiedModule span = - addPsMessage span PsWarnImportPreQualified +warnPrepositiveQualifiedModule :: SrcSpan -> Bool -> P () +warnPrepositiveQualifiedModule span qualifiedPostEnabled = + addPsMessage span $ PsWarnImportPreQualified qualifiedPostEnabled failNotEnabledImportQualifiedPost :: SrcSpan -> P () failNotEnabledImportQualifiedPost loc = ===================================== testsuite/tests/module/T27380.hs ===================================== @@ -0,0 +1,7 @@ +{-# LANGUAGE NoImportQualifiedPost #-} +{-# OPTIONS_GHC -Wprepositive-qualified-module #-} +-- Negative control for #27380: with the extension explicitly disabled, +-- the ImportQualifiedPost suggestion must still appear. +import qualified System.IO +main :: IO () +main = System.IO.print "hi" ===================================== testsuite/tests/module/T27380.stderr ===================================== @@ -0,0 +1,6 @@ +T27380.hs:5:8: warning: [GHC-07924] [-Wprepositive-qualified-module] + Found ‘qualified’ in prepositive position + Suggested fixes: + • Place ‘qualified’ after the module name. + • Perhaps you intended to use the ‘ImportQualifiedPost’ extension + ===================================== testsuite/tests/module/all.T ===================================== @@ -295,3 +295,4 @@ test('T21826', normal, compile_fail, ['']) test('T20007', normal, compile_fail, ['']) test('T25901_imp_plain_wc', normal, compile_fail, ['']) test('T25901_exp_plain_wc', normal, compile_fail, ['']) +test('T27380', normal, compile, ['']) ===================================== testsuite/tests/module/mod184.stderr ===================================== @@ -1,6 +1,4 @@ - mod184.hs:6:8: warning: [GHC-07924] [-Wprepositive-qualified-module] Found ‘qualified’ in prepositive position - Suggested fixes: - • Place ‘qualified’ after the module name. - • Perhaps you intended to use the ‘ImportQualifiedPost’ extension + Suggested fix: Place ‘qualified’ after the module name. + View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/0bf1d8c98baea8bc6a5fd3a39c8668d… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/0bf1d8c98baea8bc6a5fd3a39c8668d… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc][master] hadrian: clean up stale cabal package flags in the tree
by Marge Bot (＠marge-bot) 22 Jul '26

22 Jul '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 94d8f83b by Cheng Shao at 2026-07-22T11:30:40-04:00 hadrian: clean up stale cabal package flags in the tree This patch cleans up stale cabal package flags in the tree and related hadrian/autoconf logic. Closes #27474. Co-authored-by: Codex <codex(a)openai.com> - - - - - 9 changed files: - configure.ac - distrib/configure.ac.in - hadrian/cfg/system.config.host.in - hadrian/cfg/system.config.target.in - hadrian/src/Oracles/Flag.hs - hadrian/src/Rules/Generate.hs - hadrian/src/Settings/Packages.hs - m4/fp_check_pthreads.m4 - rts/rts.cabal Changes: ===================================== configure.ac ===================================== @@ -894,10 +894,7 @@ dnl Keep that check as early as possible. dnl as we need to know whether we need libm dnl for math functions or not dnl (see https://gitlab.haskell.org/ghc/ghc/issues/3730) -AC_CHECK_LIB(m, atan, UseLibm=YES, UseLibm=NO) -AC_SUBST([UseLibm]) -TargetHasLibm=$UseLibm -AC_SUBST(TargetHasLibm) +AC_CHECK_LIB(m, atan, TargetHasLibm=YES, TargetHasLibm=NO) FP_BFD_FLAG AC_SUBST([UseLibbfd]) @@ -911,10 +908,6 @@ AC_SUBST(UseSystemLibFFI) AC_SUBST(FFILibDir) AC_SUBST(FFIIncludeDir) -dnl ** check whether we need -ldl to get dlopen() -AC_CHECK_LIB([dl], [dlopen], UseLibdl=YES, UseLibdl=NO) -AC_SUBST([UseLibdl]) - dnl ** check for leading underscores in symbol names FP_LEADING_UNDERSCORE AC_SUBST([LeadingUnderscore], [`echo $fptools_cv_leading_underscore | sed 'y/yesno/YESNO/'`]) @@ -923,9 +916,6 @@ dnl ** check for librt AC_CHECK_LIB([rt], [clock_gettime], UseLibrt=YES, UseLibrt=NO) AC_SUBST([UseLibrt]) -FP_CHECK_PTHREAD_LIB -AC_SUBST([UseLibpthread]) - GHC_ADJUSTORS_METHOD([Target]) AC_SUBST([UseLibffiForAdjustors]) ===================================== distrib/configure.ac.in ===================================== @@ -32,7 +32,6 @@ bootstrap_target=@TargetPlatform@ bootstrap_llvm_target=@LlvmTarget@ TargetHasLibm=@TargetHasLibm@ -AC_SUBST(TargetHasLibm) UseLibffiForAdjustors=@UseLibffiForAdjustors@ AC_SUBST(UseLibffiForAdjustors) ===================================== hadrian/cfg/system.config.host.in ===================================== @@ -58,10 +58,7 @@ libzstd-lib-dir = use-lib-zstd = NO static-lib-zstd = NO use-lib-numa = NO -use-lib-m = YES use-lib-rt = YES -use-lib-dl = YES use-lib-bfd = NO -use-lib-pthread = NO need-libatomic = NO ===================================== hadrian/cfg/system.config.target.in ===================================== @@ -64,10 +64,7 @@ libzstd-lib-dir = @LibZstdLibDir@ use-lib-zstd = @UseLibZstd@ static-lib-zstd = @UseStaticLibZstd@ use-lib-numa = @UseLibNuma@ -use-lib-m = @UseLibm@ use-lib-rt = @UseLibrt@ -use-lib-dl = @UseLibdl@ use-lib-bfd = @UseLibbfd@ -use-lib-pthread = @UseLibpthread@ need-libatomic = @NeedLibatomic@ ===================================== hadrian/src/Oracles/Flag.hs ===================================== @@ -33,13 +33,9 @@ data BuildFlag = CcLlvmBackend | UseLibnuma | UseLibzstd | StaticLibzstd - | UseLibm | UseLibrt - | UseLibdl | UseLibbfd - | UseLibpthread | NeedLibatomic - | TargetHasLibm parseFlagResult :: String -> String -> Bool parseFlagResult key value = @@ -70,13 +66,9 @@ buildFlag f st = UseLibnuma -> "use-lib-numa" UseLibzstd -> "use-lib-zstd" StaticLibzstd -> "static-lib-zstd" - UseLibm -> "use-lib-m" UseLibrt -> "use-lib-rt" - UseLibdl -> "use-lib-dl" UseLibbfd -> "use-lib-bfd" - UseLibpthread -> "use-lib-pthread" NeedLibatomic -> "need-libatomic" - TargetHasLibm -> "use-lib-m" in parseFlagResult key <$> (lookupStageBuildConfig key st) -- | Get a configuration setting. ===================================== hadrian/src/Rules/Generate.hs ===================================== @@ -440,7 +440,7 @@ bindistRules = do , interpolateSetting "ProjectVersion" ProjectVersion , interpolateVar "EnableDistroToolchain" $ interp (staged (lookupStageBuildConfig "settings-use-distro-mingw")) , interpolateVar "TablesNextToCode" $ yesNo <$> getTarget tgtTablesNextToCode - , interpolateVar "TargetHasLibm" $ yesNo <$> interp (staged (buildFlag TargetHasLibm)) + , interpolateVar "TargetHasLibm" $ yesNo <$> getTarget tgtHasLibm , interpolateVar "TargetPlatform" $ getTarget targetPlatformTriple , interpolateVar "BuildPlatform" $ interp $ queryBuild targetPlatformTriple , interpolateVar "HostPlatform" $ interp $ queryHost targetPlatformTriple ===================================== hadrian/src/Settings/Packages.hs ===================================== @@ -92,7 +92,6 @@ packageArgs = do -- target code, otherwise enable for stage2 since that runs on -- the target and can use target's own ghci object linker [ andM [expr (ghcWithInterpreter stage), orM [expr (notM cross), stage2]] `cabalFlag` "internal-interpreter" - , orM [ notM cross, haveCurses ] `cabalFlag` "terminfo" , arg "-build-tool-depends" , staged (buildFlag UseLibzstd) `cabalFlag` "with-libzstd" -- ROMES: While the boot compiler is not updated wrt -this-unit-id @@ -126,10 +125,6 @@ packageArgs = do ] ] - -------------------------------- ghcPkg -------------------------------- - , package ghcPkg ? - builder (Cabal Flags) ? orM [ notM cross, haveCurses ] `cabalFlag` "terminfo" - -------------------------------- ghcBoot ------------------------------ , package ghcBoot ? builder (Cabal Flags) ? (stage0 `cabalFlag` "bootstrap") @@ -408,12 +403,9 @@ rtsPackageArgs = package rts ? do , any (wayUnit Debug) rtsWays `cabalFlag` "debug" , any (wayUnit Dynamic) rtsWays `cabalFlag` "dynamic" , any (wayUnit Threaded) rtsWays `cabalFlag` "threaded" - , buildFlag UseLibm stage `cabalFlag` "libm" , buildFlag UseLibrt stage `cabalFlag` "librt" - , buildFlag UseLibdl stage `cabalFlag` "libdl" , useSystemFfi `cabalFlag` "use-system-libffi" , targetUseLibffiForAdjustors stage `cabalFlag` "libffi-adjustors" - , buildFlag UseLibpthread stage `cabalFlag` "need-pthread" , buildFlag UseLibbfd stage `cabalFlag` "libbfd" , buildFlag NeedLibatomic stage `cabalFlag` "need-atomic" , useLibdw stage `cabalFlag` "libdw" @@ -423,7 +415,6 @@ rtsPackageArgs = package rts ? do , queryTargetTarget stage tgtSymbolsHaveLeadingUnderscore `cabalFlag` "leading-underscore" , ghcUnreg `cabalFlag` "unregisterised" , ghcEnableTNC `cabalFlag` "tables-next-to-code" - , Debug `wayUnit` way `cabalFlag` "find-ptr" ] , builder (Cabal Setup) ? mconcat [ useLibdw stage ? cabalExtraDirs (fromMaybe "" libdwIncludeDir) (fromMaybe "" libdwLibraryDir) ===================================== m4/fp_check_pthreads.m4 ===================================== @@ -1,9 +1,6 @@ # FP_CHECK_PTHREAD_LIB # ---------------------------------- # Check whether -lpthread is needed for pthread. -# -# Sets variables: -# - UseLibpthread: [YES|NO] AC_DEFUN([FP_CHECK_PTHREAD_LIB], [ dnl Some platforms (e.g. Android's Bionic) have pthreads support available ===================================== rts/rts.cabal ===================================== @@ -64,9 +64,6 @@ flag tables-next-to-code flag smp default: True manual: True -flag find-ptr - default: False - manual: True -- Some cabal flags used to control the flavours we want to produce -- for libHSrts in hadrian. By default, we just produce vanilla and -- threaded. The flags "compose": if you enable debug and profiling, View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/94d8f83bb930dc5004d43e91b4e37fd… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/94d8f83bb930dc5004d43e91b4e37fd… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/sjakobi/T27534] testsuite: Fix T17088 flakiness and restore bug coverage
by Simon Jakobi (＠sjakobi2) 22 Jul '26

22 Jul '26

Simon Jakobi pushed to branch wip/sjakobi/T27534 at Glasgow Haskell Compiler / GHC Commits: 2e31845d by Simon Jakobi at 2026-07-22T17:25:04+02:00 testsuite: Fix T17088 flakiness and restore bug coverage T17088 reads and prints a byte from an uninitialized array. Debug RTS ways fill allocated memory with 0xaa, so the test can fail due to an output mismatch unrelated to the pointer-tagging bug it covers. Initialize the byte to zero to make the output deterministic. The original bug requires the compacting collector and particular compiler and RTS settings. Run the test only in the compacting_gc way with -O1 and -A128k. Also disable STG lambda lifting because it removes the closure shape needed to reproduce the pointer-tagging failure. This makes the test reliable while ensuring it remains an effective reproducer for #17088. Closes #27534. Assisted-by: gpt-5.6-sol via Codex CLI - - - - - 2 changed files: - testsuite/tests/rts/T17088.hs - testsuite/tests/rts/all.T Changes: ===================================== testsuite/tests/rts/T17088.hs ===================================== @@ -2,6 +2,9 @@ {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} +-- Lambda lifting removes the closure shape needed to reproduce #17088. +{-# OPTIONS_GHC -fno-stg-lift-lams #-} + module Main (main) where import Data.Word @@ -27,7 +30,9 @@ instance Show Bytes where bytesAllocRet :: Int -> IO Bytes bytesAllocRet (I# sz) = IO $ \s -> case newAlignedPinnedByteArray# sz 8# s of - (# s', mba #) -> (# s', Bytes mba #) + (# s', mba #) -> + case writeWord8Array# mba 0# (wordToWord8# 0##) s' of + s'' -> (# s'', Bytes mba #) ------------------------------------------------------------------------ ===================================== testsuite/tests/rts/all.T ===================================== @@ -540,8 +540,11 @@ test('RestartEventLogging', compile_and_run, ['RestartEventLogging_c.c']) test('T17088', - [extra_ways(['compacting_gc']), extra_run_opts('+RTS -A256k -RTS')], - compile_and_run, ['-rtsopts -O2']) + [ only_ways(['compacting_gc']) + , extra_ways(['compacting_gc']) + , extra_run_opts('+RTS -A128k -RTS') + ], + compile_and_run, ['-rtsopts -O1']) test('T15427', js_broken(22374), compile_and_run, ['']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2e31845de0c7db63506b70ad8604593… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2e31845de0c7db63506b70ad8604593… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/jeltsch/textual-bytecode-output] Arrange import declarations according to the styleguide
by Wolfgang Jeltsch (＠jeltsch) 22 Jul '26

22 Jul '26

Wolfgang Jeltsch pushed to branch wip/jeltsch/textual-bytecode-output at Glasgow Haskell Compiler / GHC Commits: db8af5ce by Wolfgang Jeltsch at 2026-07-22T18:04:49+03:00 Arrange import declarations according to the styleguide - - - - - 1 changed file: - compiler/GHC/ByteCode/Show.hs Changes: ===================================== compiler/GHC/ByteCode/Show.hs ===================================== @@ -5,6 +5,7 @@ -- of bytecode files. It is the backbone of the @--show-byte-code@ option. module GHC.ByteCode.Show (showByteCode) where +-- Prelude import GHC.Prelude ( (+), (-), Integral, div, -- Prelude @@ -23,14 +24,28 @@ import GHC.Prelude show, -- Text.Show IO, FilePath -- System.IO ) -import Control.Arrow ((>>>)) -import Data.List (zipWith4) -import Data.ByteString (ByteString) -import Data.ByteString.Short (ShortByteString) -import Data.IntMap (IntMap) -import Data.IntMap qualified as IntMap (toList) -import Data.Array (bounds, indices, elems) -import Numeric (showHex) + +-- Bytecode +import GHC.ByteCode.Types + ( + FFIInfo (..), + BCONPtr (..), + BCOPtr (..), + UnlinkedBCO (..), + ByteCodeHpcInfo (..), + CompiledByteCode (..) + ) +import GHC.ByteCode.Breakpoints + ( + InternalBreakpointId (..), + InternalBreakLoc (..), + CgBreakInfo (..), + InternalModBreaks (..) + ) +import GHC.ByteCode.Binary (OnDiskModuleByteCode (..)) +import GHC.ByteCode.Serialize (readOnDiskModuleByteCode) + +-- GHC apart from bytecode import GHC.Data.Strict qualified as Strict (Maybe, maybe) import GHC.Data.FastString (unpackFS) import GHC.Data.FlatBag (FlatBag, elemsFlatBag) @@ -62,28 +77,20 @@ import GHC.Utils.Outputable import GHC.Unit.Types (Module) import GHC.Iface.Type (IfaceType, IfaceTvBndr, IfaceIdBndr) import GHC.HsToCore.Breakpoints (ModBreaks (..)) -import GHC.ByteCode.Types - ( - FFIInfo (..), - BCONPtr (..), - BCOPtr (..), - UnlinkedBCO (..), - ByteCodeHpcInfo (..), - CompiledByteCode (..) - ) -import GHC.ByteCode.Breakpoints - ( - InternalBreakpointId (..), - InternalBreakLoc (..), - CgBreakInfo (..), - InternalModBreaks (..) - ) -import GHC.ByteCode.Binary (OnDiskModuleByteCode (..)) -import GHC.ByteCode.Serialize (readOnDiskModuleByteCode) import GHC.Driver.Env.Types (HscEnv) import GHCi.FFI (FFIType) import GHCi.Message (ConInfoTable (..)) +-- Basic things +import Control.Arrow ((>>>)) +import Data.List (zipWith4) +import Data.ByteString (ByteString) +import Data.ByteString.Short (ShortByteString) +import Data.IntMap (IntMap) +import Data.IntMap qualified as IntMap (toList) +import Data.Array (bounds, indices, elems) +import Numeric (showHex) + -- | Outputs textual information about the contents of a bytecode file. showByteCode :: Logger -> HscEnv -> FilePath -> IO () showByteCode logger env path = do View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/db8af5cee171485fdf8cabaf54f4572… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/db8af5cee171485fdf8cabaf54f4572… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/jeltsch/textual-bytecode-output] Switch to using `GHC.Prelude`
by Wolfgang Jeltsch (＠jeltsch) 22 Jul '26

22 Jul '26

Wolfgang Jeltsch pushed to branch wip/jeltsch/textual-bytecode-output at Glasgow Haskell Compiler / GHC Commits: 7598d0f5 by Wolfgang Jeltsch at 2026-07-22T17:55:20+03:00 Switch to using `GHC.Prelude` - - - - - 1 changed file: - compiler/GHC/ByteCode/Show.hs Changes: ===================================== compiler/GHC/ByteCode/Show.hs ===================================== @@ -5,28 +5,32 @@ -- of bytecode files. It is the backbone of the @--show-byte-code@ option. module GHC.ByteCode.Show (showByteCode) where -import Prelude ((+), (-), Integral, div) +import GHC.Prelude + ( + (+), (-), Integral, div, -- Prelude + (==), -- Data.Eq + (>=), -- Data.Ord + FiniteBits, finiteBitSize, -- Data.Bits + ($), id, (.), -- Data.Function + fst, uncurry, -- Data.Tuple + Bool, otherwise, not, -- Data.Bool + Int, -- Data.Int + Word, -- Data.Word + Maybe, maybe, -- Data.Maybe + Either, either, -- Data.Either + length, (++), map, take, drop, replicate, -- Data.List + String, -- Data.String + show, -- Text.Show + IO, FilePath -- System.IO + ) import Control.Arrow ((>>>)) -import Data.Eq ((==)) -import Data.Ord ((>=)) -import Data.Bits (FiniteBits, finiteBitSize) -import Data.Function (($), id, (.)) -import Data.Tuple (fst, uncurry) -import Data.Bool (Bool, otherwise, not) -import Data.Int (Int) -import Data.Word (Word) -import Data.Maybe (Maybe, maybe) -import Data.Either (Either, either) -import Data.List (length, (++), map, zipWith4, take, drop, replicate) -import Data.String (String) +import Data.List (zipWith4) import Data.ByteString (ByteString) import Data.ByteString.Short (ShortByteString) import Data.IntMap (IntMap) import Data.IntMap qualified as IntMap (toList) import Data.Array (bounds, indices, elems) import Numeric (showHex) -import Text.Show (show) -import System.IO (IO, FilePath) import GHC.Data.Strict qualified as Strict (Maybe, maybe) import GHC.Data.FastString (unpackFS) import GHC.Data.FlatBag (FlatBag, elemsFlatBag) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/7598d0f5523bf258ca9071e595be8c0… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/7598d0f5523bf258ca9071e595be8c0… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/sjakobi/T27521] ci: Reduce lint job setup costs
by Simon Jakobi (＠sjakobi2) 22 Jul '26

22 Jul '26

Simon Jakobi pushed to branch wip/sjakobi/T27521 at Glasgow Haskell Compiler / GHC Commits: cd9d0b54 by Simon Jakobi at 2026-07-22T16:19:27+02:00 ci: Reduce lint job setup costs Avoid fetching unnecessary history and submodules for lightweight lint jobs. Run changelog validation without Hadrian. Because the lint-author job is now based on the .lint template directly, we enhance it to allow Git to read from the runner-owned checkouts, In the previously used .lint-params template, this permissions issue was addressed via `chown`. Closes #27521. Assisted-by: gpt-5.6-sol via Codex CLI - - - - - 3 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - hadrian/src/Rules/Test.hs Changes: ===================================== .gitlab-ci.yml ===================================== @@ -134,6 +134,10 @@ workflow: stage: tool-lint tags: - lint + before_script: + # Allow Git to read from the runner-owned checkout. This is needed + # for example by the lint-author job. + - git config --global --add safe.directory "$CI_PROJECT_DIR" rules: - *drafts-can-fail-lint - when: always @@ -251,29 +255,16 @@ ghc-linters: lint-changelog: stage: tool-lint image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb13:$DOCKER_REV" - extends: .lint-params + extends: .lint variables: - BUILD_FLAVOUR: default CHANGELOG_EXPECT_MR: "$CI_MERGE_REQUEST_IID" + GIT_DEPTH: 1 + GIT_SUBMODULE_STRATEGY: none + before_script: + - export PATH="/opt/toolchain/bin:$PATH" + - git config --global --add safe.directory "$CI_PROJECT_DIR" script: - # Cancel the job if there is a no-changelog label - - | - [[ ",${CI_MERGE_REQUEST_LABELS}," == *",no-changelog,"* ]] && exit 0 - # Check that the MR adds at least one changelog entry - - git fetch "$CI_MERGE_REQUEST_PROJECT_URL" "$CI_MERGE_REQUEST_TARGET_BRANCH_NAME" - - base="$(git merge-base FETCH_HEAD $CI_COMMIT_SHA)" - - added=$(git diff --name-only --diff-filter=A "$base..$CI_COMMIT_SHA" -- 'changelog.d/' | grep -v '^changelog.d/config$' || true) - - | - if [ -z "$added" ]; then - echo "ERROR: No changelog entry found in changelog.d/" - echo "Please add a changelog entry file describing your user-facing changes." - echo "If this MR does not need a changelog entry, apply the 'no-changelog' label." - exit 1 - fi - - echo "Found changelog entries:" $added - # Build changelog-d and validate all entries (checks required fields, section names, MR number) - - .gitlab/ci.sh configure - - .gitlab/ci.sh run_hadrian test --test-root-dirs="testsuite/tests/linters" --only=changelog-d + - .gitlab/ci.sh lint_changelog dependencies: [] rules: - if: '$CI_MERGE_REQUEST_LABELS =~ /.*marge_bot_batch_merge_job.*/' @@ -285,6 +276,9 @@ lint-changelog: lint-linters: image: "registry.gitlab.haskell.org/ghc/ci-images/linters:$DOCKER_REV" extends: .lint + variables: + GIT_DEPTH: 1 + GIT_SUBMODULE_STRATEGY: none script: - mypy testsuite/tests/linters/regex-linters/*.py dependencies: [] @@ -293,6 +287,9 @@ lint-linters: lint-testsuite: image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb13:$DOCKER_REV" extends: .lint + variables: + GIT_DEPTH: 1 + GIT_SUBMODULE_STRATEGY: none script: - make -Ctestsuite list_broken TEST_HC=$GHC dependencies: [] @@ -301,6 +298,9 @@ lint-testsuite: typecheck-testsuite: image: "registry.gitlab.haskell.org/ghc/ci-images/linters:$DOCKER_REV" extends: .lint + variables: + GIT_DEPTH: 1 + GIT_SUBMODULE_STRATEGY: none script: - mypy testsuite/driver/runtests.py dependencies: [] @@ -323,14 +323,13 @@ typecheck-testsuite: - _build/stageBoot/bin/lint-submodule-refs . $(git rev-list $base..$CI_COMMIT_SHA) dependencies: [] -# We allow the submodule checker to fail when run on merge requests (to -# accommodate, e.g., haddock changes not yet upstream) but not on `master` or -# Marge jobs. +# Check that commits in an MR were not authored with the identity that CI uses +# when it needs to create commits itself. This only needs Git history. lint-author: image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb13:$DOCKER_REV" - extends: .lint-params + extends: .lint variables: - BUILD_FLAVOUR: default + GIT_SUBMODULE_STRATEGY: none script: - git fetch "$CI_MERGE_REQUEST_PROJECT_URL" $CI_MERGE_REQUEST_TARGET_BRANCH_NAME - base="$(git merge-base FETCH_HEAD $CI_COMMIT_SHA)" ===================================== .gitlab/ci.sh ===================================== @@ -57,6 +57,7 @@ Common Modes: save_cache Preserve the cabal cache build_hadrian Build GHC via the Hadrian build system test_hadrian Test GHC via the Hadrian build system + lint_changelog Check that an MR adds a valid changelog entry Environment variables affecting the build: @@ -971,6 +972,49 @@ function lint_author(){ done } +function lint_changelog() { + # Cancel the job if there is a no-changelog label. + if [[ ",${CI_MERGE_REQUEST_LABELS:-}," == *",no-changelog,"* ]]; then + exit 0 + fi + + # Check that the MR adds at least one changelog entry. + git fetch --depth=1 \ + "$CI_MERGE_REQUEST_PROJECT_URL" \ + "$CI_MERGE_REQUEST_DIFF_BASE_SHA" + + local added + added=$(git diff --name-only --diff-filter=A \ + "$CI_MERGE_REQUEST_DIFF_BASE_SHA..$CI_COMMIT_SHA" -- \ + 'changelog.d/' | grep -v '^changelog.d/config$' || true) + + if [ -z "$added" ]; then + error "No changelog entry found in changelog.d/" + echo "Please add a changelog entry file describing your user-facing changes." + echo "If this MR does not need a changelog entry, apply the 'no-changelog' label." + exit 1 + fi + echo "Found changelog entries: $added" + + # Build changelog-d with the bootstrap compiler and validate all entries + # (checks required fields, section names, and the MR number). + local changelog_build_dir + changelog_build_dir="$(mktemp -d)" + "$GHC" -Werror \ + -package base \ + -package bytestring \ + -package Cabal-syntax \ + -package containers \ + -package directory \ + -package filepath \ + -package pretty \ + -outputdir "$changelog_build_dir" \ + -o "$changelog_build_dir/changelog-d" \ + utils/changelog-d/ChangelogD.hs + "$changelog_build_dir/changelog-d" \ + changelog.d/ --validate --expect-mr "$CHANGELOG_EXPECT_MR" +} + function abi_of(){ DIR=$(realpath $1) mkdir -p "$OUT" @@ -1085,6 +1129,7 @@ case ${1:-help} in perf_test) run_perf_test ;; abi_test) abi_test ;; cabal_test) cabal_test ;; + lint_changelog) lint_changelog ;; lint_author) shift; lint_author "$@" ;; compare_interfaces_of) shift; compare_interfaces_of "$@" ;; clean) clean ;; ===================================== hadrian/src/Rules/Test.hs ===================================== @@ -89,6 +89,8 @@ checkPrograms = , CheckProgram "lint:notes" noteLinterProgPath noteLinterSourcePath noteLinterExtra lintNotes (const stage0Boot) id , CheckProgram "lint:codes" codeLinterProgPath codeLinterSourcePath codeLinterExtra lintCodes id id , CheckProgram "lint:whitespace" whitespaceLinterProgPath whitespaceLinterSourcePath whitespaceLinterExtra lintWhitespace (const stage0Boot) (filter (/= lintersCommon)) + -- N.B. The lint:changelog build is replicated by lint_changelog in + -- .gitlab/ci.sh. Keep its package dependencies in sync with this target. , CheckProgram "lint:changelog" changelogDProgPath changelogDSourcePath changelogDExtra changelogD (const stage0Boot) id ] View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/cd9d0b54583e37e518c7a121cae7aa1… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/cd9d0b54583e37e518c7a121cae7aa1… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/fendor/external-unit-db-cache] 49 commits: driver: enable -finter-module-far-jumps by default
by Hannes Siebenhandl (＠fendor) 22 Jul '26

22 Jul '26

Hannes Siebenhandl pushed to branch wip/fendor/external-unit-db-cache at Glasgow Haskell Compiler / GHC Commits: 57c0f32c by mangoiv at 2026-07-10T11:08:38-04:00 driver: enable -finter-module-far-jumps by default this fixes a compatibility bug with certain binutils/gcc versions where we were seeing jump offset overflow errors. This commit can probably reverted if we stop supporting the problematic binutils/gcc verions (2.44 and 14.2, respectively) Reolves #26994 - - - - - 4396a6f2 by Andrea Vezzosi at 2026-07-10T11:09:25-04:00 [Fix #27287] preserve ModBreaks in ModIface - - - - - ed261a7e by Cheng Shao at 2026-07-14T17:59:38-04:00 hadrian: fix HLS support This patch fixes hadrian's HLS support so one can rely on HLS when working on the hadrian codebase. Fixes #27480. Not building/linking shared libraries for hadrian is a severely premature optimization; this top-level setting in `cabal.project` only affects home packages while the dependencies in the cabal store are built with vanilla/dynamic anyway, and even adding dynamic builds to home packages would not be costly due to cabal's usage of `-dynamic-too`. - - - - - eee8ec5b by Cheng Shao at 2026-07-14T18:00:20-04:00 compiler: fix miscompiled %load_relaxed, add missing %store_relaxed This patch fixes the %load_relaxed cmm primop compilation logic to correctly use relaxed memory ordering, and adds the missing %store_relaxed primop. Parsing logic of %load/%store with explicit ordering is covered in the AtomicFetch test case. Fixes #27483. Co-authored-by: Codex <codex(a)openai.com> - - - - - 1718230f by Alan Zimmerman at 2026-07-14T18:01:06-04:00 EPA: Keep binds and sigs together in HsValBindsLR We combine them into a single list for GhcPs, wrapped in the ValBind data type, which is the bind equivalent of ValD, having constructors for binds and sigs. This simplifies exact print processing, especially when using it to update the contents of local binds, as we no longer need AnnSortKey BindTag - - - - - 6bd1ad2a by Andreas Klebinger at 2026-07-14T18:01:49-04:00 Bump nofib submodule to account for MonoLocalBinds. New versions of GHC enable MonoLocalBinds by default. This breaks some of the benchmarks. I've fixed this and this bump pulls in that fix. - - - - - 7eb0f1c9 by Cheng Shao at 2026-07-14T18:02:31-04:00 testsuite: fix bytecodeIPE test under +ipe flavours This patch fixes the bytecodeIPE test under +ipe flavours. It used to fail under +ipe because the RTS is built with IPE info, then stg_AP_info in RTS carries IPE info, so whereFrom wouldn't return Nothing. Now the test checks IPE info of a datacon in the ghci-loaded module which is not affected by whether the RTS is built with IPE info or not. Fixes #27498. Co-authored-by: Codex <codex(a)openai.com> - - - - - ef038aae by cydparser at 2026-07-15T04:35:41-04:00 Reduce bytes allocated for `capabilities` in RTS (fixes #27487) In rts/Capability.c, `capabilities` is an array of pointers, but it was allocated as if it were an array of Capability's. - - - - - d377e83e by Cheng Shao at 2026-07-15T04:36:27-04:00 rts: fix missing UNTAG in stg_readTVarIOzh This patch fixes missing UNTAG on the current value closure read from StgTVar. UNTAG is a no-op when it's stg_TREC_HEADER_info which is word aligned; it may be a tagged closure, and reading info table from the tagged address is an unaligned load which may cause issues on platforms with strict alignment requirements. Co-authored-by: Codex <codex(a)openai.com> - - - - - 8ed03842 by Cheng Shao at 2026-07-15T04:36:27-04:00 rts: fix missing UNTAG in stg_control0zh_ll This patch fixes missing UNTAG on the cont closure returned by captureContinuationAndAbort. In case it's not NULL, captureContinuationAndAbort returns a tagged StgContinuation closure, in which case it must be untagged before accessing the apply_mask_frame field. In the past it worked out of luck: when apply_mask_frame was NULL then mask_frame_offset is also 0 so the control flow didn't diverge to a wrong path. Still, this is horribly wrong and will crash once StgContinuation struct is refactored and fields are shuffled around. Co-authored-by: Codex <codex(a)openai.com> - - - - - 5aa7000a by Cheng Shao at 2026-07-15T04:37:08-04:00 compiler: fix redundant AP thunk codegen when not using -ticky-ap-thunk This patch fixes a double negation confusion in !7525 that results in some redundant AP thunk code generation when not using -ticky-ap-thunk. Now, we use `stgToCmmUseStdApThunk` to indicate whether precomputed AP thunks in the RTS should be used, which defaults to `True`, unless `-ticky-ap-thunk` is passed. `-finfo-table-map` now also implies `-ticky-ap-thunk`, since when doing IPE profiling we want the generated AP thunks to be unique. Fixes #27502. ------------------------- Metric Decrease: T3064 ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - d43a7b7a by Brian McKenna at 2026-07-15T20:10:04+02:00 Strip ticks when desugaring bool guards The special `considerAccessible` pattern was broken when compiling with debug info. Compiling with debug info wraps expressions with `SourceNote` ticks, which broke the internals of the `desugarBoolGuard` function. Ticks are now ignored within this function. Fixes #27360 - - - - - ede4b17b by Ben Gamari at 2026-07-15T22:59:53-04:00 base: Display ExceptionContext in WhileHandling's textual description As originally-implemented the implementation for `WhileHandling(displayExceptionAnnotation)` would display the `ExceptionContext` of the exception which it carries (as this was the behavior of `displayException`, in terms of which `displayExceptionAnnotation` was implemented). However, in 284ffab3 the definition of `SomeException(displayException)` was changed to exclude the `ExceptionContext`. This means that `WhileHandling(displayExceptionAnnotation)` fails to describe the provenance of the exception which it captures, greatly limiting its utility. Return the implementation to its originally-specified behavior by implementing `WhileHandling(displayExceptionAnnotation)` in terms of `displayExceptionWithInfo`. Fixes #27456. - - - - - 0f64f348 by Cheng Shao at 2026-07-16T15:41:08+00:00 ci: add missing docker permission workaround in abi-test job - - - - - 660cb239 by Cheng Shao at 2026-07-16T19:37:48+00:00 bindist: Fix make install -j race condition on macos/freebsd This patch fixes make install -j race condition on macos/freebsd. BSD install fails with EEXIST when multiple install processes concurrently create the same prefix directory. So we add an `install_dirs` prerequisite job that sequentially creates the directories for subsequent jobs to work with. Fixes #27499. Co-authored-by: Codex <codex(a)openai.com> - - - - - 08130257 by Cheng Shao at 2026-07-16T19:37:48+00:00 ci: run bindist make install with -j This patch makes the ci scripts run `make install` with `-j` to reduce wall clock time when installing the bindist, see related issue for benchmark numbers. This only affects ghc ci logic, the user-facing default is up to distributors and is still `-j1`. Closes #27029. - - - - - d5ae6906 by Adam Gundry at 2026-07-17T04:57:43-04:00 Mark various language extension flags as deprecated (see #27329) The following language extensions are now deprecated: - AlternativeLayoutRule - AlternativeLayoutRuleTransitional - ParallelArrays - PolymorphicComponents - Rank2Types In addition, the warning `-Walternative-layout-rule-transitional` has been marked as deprecated, as it is emitted only under the deprecated extension `XAlternativeLayoutRuleTransitional`. - - - - - fe3b059c by Andrew Lelechenko at 2026-07-17T04:58:26-04:00 base: re-export GHC.Environment.getFullArgs from System.Environment CLC proposal https://github.com/haskell/core-libraries-committee/issues/431 - - - - - 722236dd by sheaf at 2026-07-18T08:48:31-04:00 Coercion optimisation: avoid double-Sym for InstCo Ticket #27374 pointed out an issue with GHC.Core.Coercion.Opt.optCoercion's handling of InstCo: it contravened (LC2) in Note [The LiftingContext in optCoercion] because it applied the ambient 'sym' to a coercion that was then added to the lifting context substitution. Fixes #27374 Co-authored-by: Simon Jakobi <simon.jakobi(a)gmail.com> - - - - - ff70fc75 by sheaf at 2026-07-18T08:48:31-04:00 Coercion optimisation: avoid exponential behaviour The change to coercion optimisation of 'InstCo' in the previous commit introduces exponential behaviour to the coercion optimiser. To avoid this, this commit provides a way to push in 'Sym' of an already-optimised coercion: GHC.Core.Coercion.Opt.mkDeepSymCo. See Note [Pushing Sym without re-optimising] in GHC.Core.Coercion.Opt. - - - - - dfef27f0 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Move THREADED_RTS-conditional struct members to end of Capability Accessing members of the Capability struct from CMM code rely on accessor macros. (The macros are generated by deriveConstants). These macros have a single definition. This means that the offsets of all struct members must *not* vary based on THREADED_RTS vs !THREADED_RTS. This requires that any struct members that are conditional on THREADED_RTS must occur after the unconditional struct members. Hence we move all the ones that are conditional on THREADED_RTS to the end. Add a deriveConstants entry for the iomgr member of the Capability struct, which was the motivation for this change. Add warning messages to help our future selves. Debugging this took me a couple hours in gdb! - - - - - c254e022 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Make the IOManager API use CapIOManager rather than Capability This makes the API somewhat more self-contained and more consistent. Now the IOManager API and each of the backends takes just the I/O manager structure. Previously we had a bit of a mixture, depending on whether the function needed access to the Capability or just the CapIOManager. We still need access to the cap, so we introduce a back reference to reach the capability, via iomgr->cap. Convert all uses in select and poll backends, but not win32 ones. Convert callers in the scheduler and elsewhere. Also convert the three CMM primops that call IOManager APIs. They just need to use Capability_iomgr(MyCapability()). - - - - - 4f3d8f31 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Split posix/MIO.c out of posix/Signals.c The MIO I/O manager was secretly living inside the Signals file. Now it gets its own file, like any other self-respecting I/O manager. - - - - - 52ce04a9 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Rationalise some scheduler run queue utilities Move them all to the same place in the file. Make some static that were used only internally. Also remove a redundant assignment after calling truncateRunQueue that is already done within truncateRunQueue. - - - - - 75bbdebc by Duncan Coutts at 2026-07-18T08:49:12-04:00 Rename initIOManager{AfterFork} to {re}startIOManager These are more accurate names, since these actions happen after initialisation and are really about starting (or restarting) background threads. - - - - - 724c0517 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Free per-cap I/O managers during shutdown and forkProcess Historically this was not strictly necessary. The select and win32 legacy I/O managers did not maintain any dynamically allocated resources. The new poll one does (an auxillary table), and so this should be freed. After forkProcess, all threads get deleted. This includes threads waiting on I/O or timers. So as of this patch, resetting the I/O manager is just about tidying things up. For example, for the poll I/O manager this will reset the size of the AIOP table (which otherwise grows but never shrinks). In future however the re-initialising will become neeecessary for functionality, since some I/O managers will need to re-initialise wakeup fds that are set CLOEXEC. - - - - - c007d122 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Add a TODO to the MIO I/O manager The direction of travel is to make I/O managers per-capability and have all their state live in the struct CapIOManager. The MIO I/O manager however still has a number of global variables. It's not obvious how handle these globals however. - - - - - b65ab7b3 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Add a FIXME note in the Poll I/O manager - - - - - daf2bd6f by Duncan Coutts at 2026-07-18T08:49:12-04:00 Add missing updateRemembSetPushClosure in poll I/O manager For the non-moving GC. - - - - - e33ca830 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Minor doc improvement to struct StgAsyncIOOp member outcome Mention the enumeration names, as well as their numeric values. The rest of the code uses the enum names. - - - - - 4edd2579 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Minor doc improvements for StgTSOBlockInfo Clarify that certain union members are used only by certain legacy I/O managers. Hopefully we will be able to remove these at some point. - - - - - 536bedbb by Duncan Coutts at 2026-07-18T08:49:12-04:00 Avoid exporting various win32-specific rts symbols The BeginPrivate.h / EndPrivate.h scheme works perfectly well on Windows, but all of the rts/win32/*.h files were not using it. - - - - - 8139b5ac by Duncan Coutts at 2026-07-18T08:49:12-04:00 Remove wakeupIOManager, ioManagerWakeup and setIOManagerWakeupFd We no longer need wakeupIOManager for the threaded RTS case, so we can remove it and the bits only needed to support it. This includes the pipe/eventfd fd shared between the RTS and the in-library I/O manager used for waking up the I/O manager thread. The pipe/eventfd still exists, but it no longer has to be communicated to the RTS, since the RTS no longer needs to use it. So we remove the RTS API export setIOManagerWakeupFd, and remove uses of it within the I/O managers in ghc-internal. - - - - - 74fe7c66 by Duncan Coutts at 2026-07-18T08:49:12-04:00 Add a new interruptIOManager API for the I/O managers It will be used to interrupt awaitCompletedTimeoutsOrIO. Also update the return type and docs for awaitCompletedTimeoutsOrIO to have it return false when it gets interrupted, and have no useful post condition in that case. - - - - - 38792843 by Duncan Coutts at 2026-07-18T08:49:13-04:00 Add interruptIOManager support for select I/O manager Uses the FdWakup mechanism. - - - - - 2f3b00aa by Duncan Coutts at 2026-07-18T08:49:13-04:00 Add interruptIOManager support for poll I/O manager Uses the FdWakup mechanism. A quirk we have to cope with is that we now need to poll one more fd -- the wakeup_fd_r -- but this fd has no corresponding entry in the aiop_table. This is awkward since we have set up our aiop_poll_table to be an auxilliary table with matching indicies. The solution this patch uses (and described in the comments) is to have two tables: struct pollfd *aiop_poll_table, *full_poll_table; and to have the aiop_poll_table alias the tail of the full_poll_table. The head entry in the full_poll_table is the extra fd. So we poll the full_poll_table, while the aiop_poll_table still has matching indicies with the aiop_table. Hurrah for C aliasing rules. - - - - - cee50131 by Duncan Coutts at 2026-07-18T08:49:13-04:00 Add interruptIOManager support for win32 legacy I/O manager And remove unused related helper resetAbandonRequestWait. It is not called because the event is created in auto-reset mode, so never needs to be reset manually. - - - - - cf453143 by Duncan Coutts at 2026-07-18T08:49:13-04:00 Note lack of interruptIOManager support for WinIO I/O manager Though there's a plausible design, we can't sanely test it at the moment due to related WinIO bugs. Filed as issue #27403. - - - - - 1b74a0ad by Duncan Coutts at 2026-07-18T08:49:13-04:00 Be more explicit about enum IOReadOrWrite values, and type within cmm Belt and braces. - - - - - b388d093 by Brian McKenna at 2026-07-18T17:51:50-04:00 Ignore ticks in the pattern-match term oracle The term-oracle in the pattern-match checker is keyed by a canonical form of the scrutinee, computed by `makeDictsCoherent`. That canonical form was tick-sensitive: two occurrences of an otherwise identical expression that happened to carry different ticks were treated as distinct values, breaking long-distance information. This shows up in practice under `-finfo-table-map`, because the desugarer wraps every record-selector use site in a `SourceNote` carrying that site's span. For example: data Box = Box { unBox :: Maybe Int } f b = case unBox b of Nothing -> 0 Just _ -> let Just x = unBox b in x The two `unBox b` expressionss carry different SourceNote spans, the pattern-match checker sees them as different, the long-distance information from the outer `Just _` branch never reaches the let-pattern, and `Just x = unBox b` is wrongly reported as non-exhaustive. We now strip all ticks in `makeDictsCoherent`. This is documented as Wrinkle (UD1) of Note [Unique dictionaries in the TmOracle CoreMap]. Fixes #27314 - - - - - c23e1acb by Mrjtjmn at 2026-07-18T17:52:45-04:00 Add explanations for unsolved Typeable constraints This commit adds explanations for unsolved 'Typeable' constraints. GHC will now provide additional explanations for an unsolved constraint of the form 'Typeable ty', explain why GHC did not solve Typeable constraint. e.g.: - 'ty' is a polymorphic type (e.g. forall a. a -> a) - 'ty' is a qualified type (e.g. Eq Int => Int) - 'ty' is an unboxed sum type - 'ty' is an unreduced type family application - 'ty' whose kind is not typeable Fixes #26532 - - - - - cbef021e by Artem Pelenitsyn at 2026-07-19T07:49:55-04:00 ghc-internal: Lock.hs: fix typo and indentation - - - - - 42918646 by Duncan Coutts at 2026-07-19T07:50:36-04:00 Fix failing test GcStaticPointers for non-moving GC Minor mistake in asserting something before checking for that same thing. Specifically, Bdescr asserts HEAP_ALLOCED_GC, but Bdescr was being used prior to a guard that checks HEAP_ALLOCED_GC. The solution is just to move the use of Bdescr after the guard. Thanks to Simon Jakobi for identifying the problem. - - - - - c2f6dcd4 by Sasha Bogicevic at 2026-07-20T10:31:56+02:00 Improve error messages for invalid record wildcards Record wildcard hints are now shown in more contexts and include constructor arity; matching with `..` on a fieldless constructor now produces a dedicated error message. Fixes #21101 - - - - - 4c02e76b by Duncan Coutts at 2026-07-21T10:37:21-04:00 Mark test T27105 as fragile, citing issue #27522 Scheduler fairness is fine, except when it isn't. And it isn't on CI machines surprisingly often! See the issue for details. - - - - - 43dd2b15 by Recursion Ninja at 2026-07-21T17:09:53-04:00 Resolving many TTG related orphan type-class instances This is part a technical debt removal effort made possible now that separating out the AST via TTG has come to a close. As the AST in 'L.H.S' has been incrementally separated from the GHC internals, there are many accumulated orphan instance of 'Binary', 'NFData', 'Outputable', and 'Uniquable'. The orphan instance of data-types from within 'L.H.S' have had their orphan instances moved to either: 1. The module which defines the data-type 2. The module which defines the type-class; i.e. moving an orphan 'Binary' instance to 'GHC.Utils.Binary' Orphan instances resolved (37): | Data-type | Resolved instance(s) | Former orphan module(s) | | -------------------- | -------------------------- | ------------------------- | | Role | Binary, NFData, Outputable | GHC.Core.Coercion.Axiom | | SrcStrictness | Binary, NFData, Outputable | GHC.Core.DataCon | | SrcUnpackedness | Binary, NFData, Outputable | GHC.Core.DataCon | | Fixity | Binary, Outputable | GHC.Hs.Basic | | FixityDirection | Binary, Outputable | GHC.Hs.Basic | | LexicalFixity | Outputable | GHC.Hs.Basic | | CCallTarget | NFData | GHC.Hs.Decls.Foreign | | CType | NFData | GHC.Hs.Decls.Foreign | | Header | NFData | GHC.Hs.Decls.Foreign | | OverlapMode | Binary, NFData | GHC.Hs.Decls.Overlap | | WithHsDocIdentifiers | NFData, Outputable | GHC.Hs.Doc | | HsDocString | NFData | GHC.Hs.DocString | | HsDocStringChunk | Binary, Outputable | GHC.Hs.DocString | | HsDocStringDecorator | Binary, Outputable | GHC.Hs.DocString | | NamespaceSpecifier | Outputable | GHC.Hs.ImpExp | | ForAllTyFlag | Binary, NFData, Outputable | GHC.Hs.Specificity | | Specificity | Binary, NFData | GHC.Hs.Specificity | | PromotionFlag | Binary, Outputable | GHC.Types.Basic | | FieldLabelString | Outputable, Uniquable | GHC.Types.FieldLabel | | InlinePragma | Binary | GHC.Types.InlinePragma | ------------------------- Metric Decrease: hard_hole_fits ------------------------- Closes #21262, #27469 - - - - - ab9ab895 by Cheng Shao at 2026-07-21T17:10:53-04:00 rts: always use StgInt to represent cost center id Currently cost center id is modeled as `Int` and it should be `StgInt` uniformly in the RTS, hence this patch. Fixes #27524. - - - - - a1326b0b by fendor at 2026-07-22T16:27:28+02:00 Introduce global unit database cache As a first step for better sharing of `UnitInfo` across `UnitEnv`, we introduce a new datatype called `ExternalUnitDatabases`. It primarily serves as an in-memory representation of *all* `UnitDatabase`s across `UnitEnv`. This means, if multiple `HomeUnitEnv`s depend on the same database, one way or another, we make sure that we don't parse from disk every time. Instead, we store the in-memory representation in `ExternalUnitDatabases`. `ExternalUnitDatabaseCache` is the equivalent of `ExternalUnitState` in the `UnitEnv`. It is a mutable variable wrapping `ExternalUnitDatabases`. The mutable `ExternalUnitDatabaseCache` is used in `initUnits` to make sure we don't parse the same unit database multiple times. Almost by accident, we change the semantics of `initUnits` to honour modifications to `packageDBFlags`. The inability to change `packageDBFlags` while also reusing the already parsed `UnitDatabase`s was reported in #26423 as a bug. Hence, we think this behaviour change is warranted and acceptable, especially since it comes with a breaking change to the `initUnits` API. Add regression test for #26423 Closes #26423 - - - - - 88b39e7c by fendor at 2026-07-22T16:27:28+02:00 Introduce UnitIndex for global external unit caching `UnitInfo`s have been observed to cause a lot of memory usage in #27500. Especially with multiple home units, as the same (external) units are processed from scratch, even though most of the time we end up with exactly the same `UnitInfo`. We introduce a `UnitEnv` global cache that allows us to store external unit information that is used across all `HomeUnitEnv`s. The most important change in this commit is the introduction of the `UnitIndex`. It stores a global mapping of `UnitId` -> `UnitInfo`, and `initUnits` always uses the cached `UnitInfo` entry to populate each `HomeUnitEnv`'s `UnitState`. This allows us to ensure the following property: > Each `UnitInfo` should be alive exactly once in GHC. In addition, the `ExternalUnitDatabaseCache` may also hold a reference to each on-disk representation of `UnitInfo`. This means, we impose an hard upper bound on the number of `UnitInfo`s alive in the GHC session: > The number of alive `UnitInfo`s closure objects must be the > sum of all loaded unit database times two. We add performance regression tests that make sure the number of live `UnitInfo` cannot exceed this threshold. Closes #27500 ------------------------- Metric Decrease: MultiComponentModules MultiComponentModulesRecomp MultiComponentModulesRecomp100 mhu-perf ------------------------- These metrics increases are especially notable, as we are not even sharing anything big but merely the global package database with 50 entries. It shows how careful sharing of `UnitInfo` can improve memory usage. We expect this to be much more notable when the whole cabal package database is shared across multiple home units. --- Technical details To share the `UnitInfo`s correctly, it is important that we extract the `WireMap` into the `UnitIndex`. At the moment of writing, `WireMap` must be globally the same for all `HomeUnitEnv`s. This is important, as we could otherwise not cache the "fully-resolved" `UnitInfo`. We consider a `UnitInfo` fully-resolved, if wired-in units have been updated, the `UnitInfo` has been validated and variables in the unit config, such as `${pkgroot}` have been resolved. Updating the wired-in units requires the `WireMap` to be globally the same. - - - - - 273 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - + changelog.d/21101 - + changelog.d/T26423 - + changelog.d/T26532 - + changelog.d/T27314.md - + changelog.d/T27329 - + changelog.d/T27360 - + changelog.d/T27374 - + changelog.d/T27456 - + changelog.d/fix-cmm-atomic-load-store - + changelog.d/fix-make-install-j - + changelog.d/fix-use-std-ap-thunk - + changelog.d/inter-module-far-jumps-aarch64-default - + changelog.d/unit-index - compiler/GHC.hs - compiler/GHC/ByteCode/Breakpoints.hs - compiler/GHC/ByteCode/Types.hs - compiler/GHC/Cmm/Parser.y - compiler/GHC/Core/Coercion/Axiom.hs - compiler/GHC/Core/Coercion/Opt.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Config/StgToCmm.hs - compiler/GHC/Driver/DynFlags.hs - compiler/GHC/Driver/Env.hs - compiler/GHC/Driver/Flags.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Driver/Main/Hsc.hs - compiler/GHC/Driver/Main/Interactive.hs - 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