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[Git][ghc/ghc][wip/fendor/27835] 13 commits: Add regression test for #7803
by Hannes Siebenhandl (＠fendor) 05 Oct '26

05 Oct '26

Hannes Siebenhandl pushed to branch wip/fendor/27835 at Glasgow Haskell Compiler / GHC Commits: 234bab08 by Vladislav Zavialov at 2026-09-29T17:22:54-04:00 Add regression test for #7803 Commit 2effe18ab5, first shipped with GHC 8.2.1, fixed #7803 "Superclass methods are left unspecialized". This change turns the example from the ticket description into a regression test, checking that foo1 is fully specialised at Double, with no calls to the overloaded exp5Tail. Closes #7803 Assisted-by: Claude Opus 5 - - - - - c406135c by Andreas Klebinger at 2026-10-01T06:57:28-04:00 RTS: Update flag parsing/handling: Using 0 as argument to any of these flags now resets the flags setting to default: - ``-n0`` disables nursery chunking. - ``-K0`` (or a bare ``-K``) removes the stack size limit. - ``-M0`` removes the heap size limit. - ``-H0`` resets the suggested heap size, including the nursery scaling set by ``-H``. - ``-AL0`` makes the large object allocation limit follow ``-A`` again. GC Generations are now limited to 64. -n larger than -A now emits a warning and disables chunking. Fixes #27830 #27829 - - - - - 984ee82b by Andreas Klebinger at 2026-10-01T06:58:10-04:00 Fix MultiLayerModules timeout multiplier. We accidentally used the compile multiplier for ghci commands which use the run timeout setting to set the timeout. Fixes #26263 and #27796. - - - - - 50a9cf26 by Andreas Klebinger at 2026-10-01T06:58:10-04:00 testsuite: Include runtime in JUnit report. - - - - - e358619f by Alan Zimmerman at 2026-10-01T06:59:01-04:00 EPA: Use EpaLocation in EpVirtualBraces Haddock processing uses EpLayout.EpVirtualBraces to record the current layout column, for allocating haddock comments correctly. For exact printing, we need the line as well as the col, so we know how many lines to skip when the indented code block starts. This commit updates EpLayout.EpVirtualBraces so that it carries an EpaLocation instead of just the Int column, to allow it to be used for both purposes. It is a simple mechanical change, with no other impact, but it allows us to use EpLayout instead of AnnListLayout in AnnList, in the next commit in this series. - - - - - 1d2a26ee by Andrew Lelechenko at 2026-10-01T20:22:04-04:00 Remove bitSize from MINIMAL pragma of class Bits Cf. https://github.com/haskell/core-libraries-committee/issues/441 The function is deprecated for 12 years and has a default implementation, yet it was never removed from the MINIMAL pragma, putting library authors in a very awkward position. Let's finally remove bitSize from MINIMAL. - - - - - 3cc21e4c by Hannes Siebenhandl at 2026-10-01T20:22:59-04:00 Add regression test for #27641 - - - - - c35096f5 by Hannes Siebenhandl at 2026-10-01T20:23:00-04:00 Don't `:add` modules the loader will reject Only home modules can be actually added to the loader context, thus we only accept the module if it belongs to a home unit. - - - - - a563cb27 by Simon Jakobi at 2026-10-02T17:37:36-04:00 ci: accept modified changelog.d entries in lint-changelog The changelog guide says to extend an existing entry rather than add a new one when the feature is already documented. lint_changelog only counted added files, so such MRs failed before the validator ran. Fixes #27779. Assisted-by: Claude Fable 5.1 - - - - - 03082cd4 by Simon Jakobi at 2026-10-02T17:38:17-04:00 changelog.d: Fix warning flag name in the semaphore-v2 entry The entry refers to -Wsemaphore-version-mismatch, which does not exist. The warning GHC emits when it cannot use a -jsem semaphore, including on a protocol version mismatch, is -Wsemaphore-open-failure. Context: !15729, #25087 Assisted-by: Claude Fable 5.1 - - - - - a93705ee by Simon Jakobi at 2026-10-02T17:38:17-04:00 changelog.d: Fix the CLC proposal link in the T27455 entry The entry used the Sphinx :ref: role with a URL as its target. :ref: resolves only internal labels, so the generated release notes would show the proposal name without a link. Use the plain hyperlink form like the other entries. Context: !16274, #27455 Assisted-by: Claude Fable 5.1 - - - - - 54381079 by Hannes Siebenhandl at 2026-10-02T17:39:01-04:00 Extend the `TrustOverlay` for wired-in units The TrustOverlay only contained the `UnitId` of all on-disk units. However, wired-in units are referred to by their wired-in unit id, which is not the same as the on-disk unit id. Thus, trust checks for wired-in units failed because the lookup was using the wired-in unit, which wasn't present in the `TrustOverlay`. We fix #27834, by copying the trust info for wired-in unit ids. - - - - - ef692859 by Hannes Siebenhandl at 2026-10-05T10:55:39+02:00 Prepend in-memory unit database for backpack The packageDbFlags are stored in reverse order. Thus, prepending will ensure that the in-memory unit database is the last item on the unit database stack. Further, the in-memory unit database needs to be able to shadow units from earlier unit databases in the unit database stack. Moreover, a `-clear-package-db` would remove the in-memory database if it weren't the last item on the stack. Closes #27835 - - - - - 66 changed files: - .gitlab/ci.sh - + changelog.d/27641 - changelog.d/T27455 - + changelog.d/T27830-rts-flag-bounds - changelog.d/semaphore-v2 - changelog.d/unit-index - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess/Haddock.hs - compiler/GHC/Unit/External/Wired.hs - compiler/GHC/Unit/State.hs - docs/users_guide/runtime_control.rst - ghc/GHCi/UI.hs - libraries/base/changelog.md - libraries/ghc-internal/src/GHC/Internal/Bits.hs - rts/RtsFlags.c - rts/include/rts/Flags.h - rts/include/rts/storage/GC.h - rts/sm/GC.c - rts/sm/Storage.c - testsuite/driver/junit.py - testsuite/driver/testglobals.py - testsuite/driver/testlib.py - + testsuite/tests/backpack/should_compile/T27835.bkp - + testsuite/tests/backpack/should_compile/T27835.stderr - testsuite/tests/backpack/should_compile/all.T - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - + testsuite/tests/ghci/scripts/T27641.script - + testsuite/tests/ghci/scripts/T27641.stderr - + testsuite/tests/ghci/scripts/T27641.stdout - + testsuite/tests/ghci/scripts/T27834.hs - + testsuite/tests/ghci/scripts/T27834.script - + testsuite/tests/ghci/scripts/T27834.stdout - testsuite/tests/ghci/scripts/all.T - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/perf/compiler/all.T - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/rts/all.T - testsuite/tests/rts/rtsflags001.stderr-ws-32 - testsuite/tests/rts/rtsflags001.stderr-ws-64 - + testsuite/tests/simplCore/should_compile/T7803.hs - + testsuite/tests/simplCore/should_compile/T7803.stderr - + testsuite/tests/simplCore/should_compile/T7803a.hs - testsuite/tests/simplCore/should_compile/all.T The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5305cbc104bbb820badda5b9d2653f… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5305cbc104bbb820badda5b9d2653f… 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/marge_bot_batch_merge_job] 2 commits: [CLC 341] Strict variants of mutable types
by Marge Bot (＠marge-bot) 05 Oct '26

05 Oct '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: f8cfb1a5 by Hécate Kleidukos at 2026-10-04T19:36:39+02:00 [CLC 341] Strict variants of mutable types This commit is the implementation of CLC Proposal 341 https://github.com/haskell/core-libraries-committee/issues/341 - - - - - 485dea82 by Rodrigo Mesquita at 2026-10-05T03:32:22-04:00 ttg: HsModuleName in the AST, ModuleName in GHC This commit makes the AST fully independent from GHC by parsing a "module name" as an `HsModuleName (= HText)` rather than constructing an `ModuleName (= FastString)` straight away. In the GHC side, everything remains as a `ModuleName`. We turn AST `HsModuleName`s into fast strings with the cheap `mkFastStringShortText` when we process the AST for manipulation within the compiler. There are no performance regressions introduced by this approach. This is the final piece of #21592 Alternative plans were discussed in gitlab.haskell.org/ghc/ghc/-/merge_requests/16546#note_694647, but the Simon suggested one won in simplicity and performance when compared against my attempt at implementing my original plan of having a family `ModuleNameP`. - - - - - 102 changed files: - + changelog.d/clc-341-strict-mutable-data-types - compiler/GHC.hs - compiler/GHC/Builtin/Modules.hs - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Show.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/Opt/CallerCC/Types.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Driver/Pipeline.hs-boot - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Driver/Pipeline/Phases.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Lit.hs - compiler/GHC/HsToCore/Docs.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Debug.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/Header.hs - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Env.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Unbound.hs - compiler/GHC/StgToJS/Linker/Linker.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/Types.hs - compiler/GHC/Tc/Types/ErrCtxt.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Unique.hs - compiler/GHC/Types/UnresolvedImport.hs - compiler/GHC/Unit/Home.hs - compiler/GHC/Unit/Module.hs - compiler/GHC/Unit/Module/Env.hs - + compiler/GHC/Unit/Module/Name.hs - compiler/GHC/Unit/Parser.hs - compiler/GHC/Unit/Types.hs - compiler/GHC/Unit/Types.hs-boot - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - compiler/Language/Haskell/Syntax/Lit.hs - compiler/Language/Haskell/Syntax/Module/Name.hs - compiler/Language/Haskell/Syntax/Text.hs - compiler/ghc.cabal.in - ghc/GHCi/UI.hs - ghc/GHCi/UI/Info.hs - libraries/base/base.cabal.in - libraries/base/changelog.md - libraries/base/src/Control/Concurrent/Chan.hs - + libraries/base/src/Control/Concurrent/Chan/Strict.hs - libraries/base/src/Control/Concurrent/MVar.hs - + libraries/base/src/Control/Concurrent/MVar/Strict.hs - libraries/base/src/Data/IORef.hs - + libraries/base/src/Data/IORef/Strict.hs - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/ghc-api/downsweep/IncrementalDownsweep.hs - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/hiefile/should_run/T24544.hs - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/profiling/should_run/caller-cc/CallerCcParser.hs - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6c5685ea96dc2e2a44ffb3a110c9c0… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6c5685ea96dc2e2a44ffb3a110c9c0… 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/T27368-cbe-expand-subst] Cmm: keep the CBE substitution idempotent
by Simon Jakobi (＠sjakobi) 05 Oct '26

05 Oct '26

Simon Jakobi pushed to branch wip/sjakobi/T27368-cbe-expand-subst at Glasgow Haskell Compiler / GHC Commits: 64604b2c by Simon Jakobi at 2026-10-05T09:14:06+02:00 Cmm: keep the CBE substitution idempotent When blocks are merged over multiple rounds during common block elimination, a block that won a merge in an earlier round can still lose a merge in a later round. The substitution used to record this as a chain: the earlier loser mapped to a block that was itself eliminated. Applying such a substitution left edges to eliminated blocks in the Cmm graph, eventually leading to a setInfoTableStackMap panic (#27368). Now each round's substitutions are applied to the existing ones as they are added (extendSubst), keeping the substitution idempotent: every label maps directly to a surviving block. Fixes #27368. Assisted-by: Claude Fable 5.1 - - - - - 4 changed files: - + changelog.d/27368 - compiler/GHC/Cmm/CommonBlockElim.hs - + testsuite/tests/codeGen/should_compile/T27368.hs - testsuite/tests/codeGen/should_compile/all.T Changes: ===================================== changelog.d/27368 ===================================== @@ -0,0 +1,5 @@ +section: compiler +synopsis: Fix a ``setInfoTableStackMap`` panic caused by common block elimination + leaving references to eliminated blocks. +issues: #27368 +mrs: !16765 ===================================== compiler/GHC/Cmm/CommonBlockElim.hs ===================================== @@ -90,6 +90,10 @@ elimCommonBlocks g = -- (so avoid comparing them again) type DistinctBlocks = [CmmBlock] type Key = [Label] + +-- | A substitution maps each eliminated block to its replacement. +-- +-- Invariant: the substitution is idempotent, i.e. no value is a key. type Subst = LabelMap BlockId -- The outer list groups by hash. We retain this grouping throughout. @@ -108,9 +112,19 @@ iterate subst blocks where (new_subst2, db) = mergeBlockList subst dbs - subst' = subst `mapUnion` new_substs + subst' = extendSubst subst new_substs updated_blocks = map (map (first (map (lookupBid subst')))) merged_blocks +-- | Add the substitutions of one round of 'iterate'. +-- +-- A block that won a merge in an earlier round may have lost one in this +-- round, so the older substitutions are updated to keep the result idempotent. +extendSubst :: Subst -> Subst -> Subst +extendSubst subst new = assert (idempotent subst') subst' + where + subst' = mapMap (lookupBid new) subst `mapUnion` new + idempotent s = not (any (`mapMember` s) s) + -- Combine two lists of blocks. -- While they are internally distinct they can still share common blocks. mergeBlocks :: Subst -> DistinctBlocks -> DistinctBlocks -> (Subst, DistinctBlocks) @@ -218,9 +232,7 @@ dont_care _other = False eqBid :: LabelMap BlockId -> BlockId -> BlockId -> Bool eqBid subst bid bid' = lookupBid subst bid == lookupBid subst bid' lookupBid :: LabelMap BlockId -> BlockId -> BlockId -lookupBid subst bid = case mapLookup bid subst of - Just bid -> lookupBid subst bid - Nothing -> bid +lookupBid subst bid = mapFindWithDefault bid bid subst -- Middle nodes and expressions can contain BlockIds, in particular in -- CmmStackSlot and CmmBlock, so we have to use a special equality for ===================================== testsuite/tests/codeGen/should_compile/T27368.hs ===================================== @@ -0,0 +1,17 @@ +-- Common block elimination merges the duplicated blocks over several +-- rounds. Compiling this at -O panicked in setInfoTableStackMap (#27368). + +module T27368 (f) where + +{-# NOINLINE put #-} +put :: Int -> Int -> IO () +put h x = if h + x == 12345 then errorWithoutStackTrace "boom" else pure () + +data T = N | J Int | K + +f :: Int -> Bool -> T -> IO () +f h a t = do + if a + then do put h 1; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + else do put h 2; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + put h 0 ===================================== testsuite/tests/codeGen/should_compile/all.T ===================================== @@ -150,3 +150,5 @@ test('T16351', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppres test('T20298a', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298b', normal, compile, ['-O2 -dno-bignum-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298c', normal, compile, ['-O2 -dno-builtin-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) + +test('T27368', normal, compile, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/64604b2c898eacffdb63bbc9ceee1c4… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/64604b2c898eacffdb63bbc9ceee1c4… 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/T27368-cbe-expand-subst] Cmm: keep the CBE substitution chain-free
by Simon Jakobi (＠sjakobi) 04 Oct '26

04 Oct '26

Simon Jakobi pushed to branch wip/sjakobi/T27368-cbe-expand-subst at Glasgow Haskell Compiler / GHC Commits: c02fe2c9 by Simon Jakobi at 2026-10-05T01:18:46+02:00 Cmm: keep the CBE substitution chain-free When blocks are merged over multiple rounds during common block elimination, a block that won a merge in an earlier round can still lose a merge in a later round. The substitution used to record this as a chain: the earlier loser mapped to a block that was itself eliminated. Applying such a substitution left edges to eliminated blocks in the Cmm graph, eventually leading to a setInfoTableStackMap panic (#27368). Now each round's substitutions are applied to the existing ones as they are added (extendSubst), so every label maps directly to a surviving block and lookupBid no longer needs to chase chains. Fixes #27368. Assisted-by: Claude Fable 5.1 - - - - - 4 changed files: - + changelog.d/27368 - compiler/GHC/Cmm/CommonBlockElim.hs - + testsuite/tests/codeGen/should_compile/T27368.hs - testsuite/tests/codeGen/should_compile/all.T Changes: ===================================== changelog.d/27368 ===================================== @@ -0,0 +1,5 @@ +section: compiler +synopsis: Fix a ``setInfoTableStackMap`` panic caused by common block elimination + leaving references to eliminated blocks. +issues: #27368 +mrs: !16765 ===================================== compiler/GHC/Cmm/CommonBlockElim.hs ===================================== @@ -90,6 +90,10 @@ elimCommonBlocks g = -- (so avoid comparing them again) type DistinctBlocks = [CmmBlock] type Key = [Label] + +-- | A substitution maps each eliminated block to its replacement. +-- +-- Invariant: no value is a key, i.e. there are no chains @x->y->z@. type Subst = LabelMap BlockId -- The outer list groups by hash. We retain this grouping throughout. @@ -108,9 +112,19 @@ iterate subst blocks where (new_subst2, db) = mergeBlockList subst dbs - subst' = subst `mapUnion` new_substs + subst' = extendSubst subst new_substs updated_blocks = map (map (first (map (lookupBid subst')))) merged_blocks +-- | Add the substitutions of one round of 'iterate'. +-- +-- A block that won a merge in an earlier round may have lost one in this +-- round, so the older substitutions are updated to keep the result chain-free. +extendSubst :: Subst -> Subst -> Subst +extendSubst subst new = assert (chainFree subst') subst' + where + subst' = mapMap (lookupBid new) subst `mapUnion` new + chainFree s = not (any (`mapMember` s) s) + -- Combine two lists of blocks. -- While they are internally distinct they can still share common blocks. mergeBlocks :: Subst -> DistinctBlocks -> DistinctBlocks -> (Subst, DistinctBlocks) @@ -218,9 +232,7 @@ dont_care _other = False eqBid :: LabelMap BlockId -> BlockId -> BlockId -> Bool eqBid subst bid bid' = lookupBid subst bid == lookupBid subst bid' lookupBid :: LabelMap BlockId -> BlockId -> BlockId -lookupBid subst bid = case mapLookup bid subst of - Just bid -> lookupBid subst bid - Nothing -> bid +lookupBid subst bid = mapFindWithDefault bid bid subst -- Middle nodes and expressions can contain BlockIds, in particular in -- CmmStackSlot and CmmBlock, so we have to use a special equality for ===================================== testsuite/tests/codeGen/should_compile/T27368.hs ===================================== @@ -0,0 +1,17 @@ +-- Common block elimination merges the duplicated blocks over several +-- rounds. Compiling this at -O panicked in setInfoTableStackMap (#27368). + +module T27368 (f) where + +{-# NOINLINE put #-} +put :: Int -> Int -> IO () +put h x = if h + x == 12345 then errorWithoutStackTrace "boom" else pure () + +data T = N | J Int | K + +f :: Int -> Bool -> T -> IO () +f h a t = do + if a + then do put h 1; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + else do put h 2; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + put h 0 ===================================== testsuite/tests/codeGen/should_compile/all.T ===================================== @@ -150,3 +150,5 @@ test('T16351', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppres test('T20298a', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298b', normal, compile, ['-O2 -dno-bignum-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298c', normal, compile, ['-O2 -dno-builtin-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) + +test('T27368', normal, compile, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c02fe2c90bf92db5c30468bd1dfae44… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c02fe2c90bf92db5c30468bd1dfae44… 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/T27368-cbe-expand-subst] Cmm: keep the CBE substitution chain-free
by Simon Jakobi (＠sjakobi) 04 Oct '26

04 Oct '26

Simon Jakobi pushed to branch wip/sjakobi/T27368-cbe-expand-subst at Glasgow Haskell Compiler / GHC Commits: 63c9eb84 by Simon Jakobi at 2026-10-05T00:58:03+02:00 Cmm: keep the CBE substitution chain-free When blocks are merged over multiple rounds during common block elimination, a block that won a merge in an earlier round can still lose a merge in a later round. The substitution used to record this as a chain: the earlier loser mapped to a block that was itself eliminated. Applying such a substitution left edges to eliminated blocks in the Cmm graph, eventually leading to a setInfoTableStackMap panic (#27368). Now each round's substitutions are applied to the existing ones as they are added (extendSubst), so every label maps directly to a surviving block and lookupBid no longer needs to chase chains. Fixes #27368. Assisted-by: Claude Fable 5.1 - - - - - 4 changed files: - + changelog.d/27368 - compiler/GHC/Cmm/CommonBlockElim.hs - + testsuite/tests/codeGen/should_compile/T27368.hs - testsuite/tests/codeGen/should_compile/all.T Changes: ===================================== changelog.d/27368 ===================================== @@ -0,0 +1,5 @@ +section: compiler +synopsis: Fix a ``setInfoTableStackMap`` panic caused by common block elimination + leaving references to eliminated blocks. +issues: #27368 +mrs: !16543 ===================================== compiler/GHC/Cmm/CommonBlockElim.hs ===================================== @@ -90,6 +90,10 @@ elimCommonBlocks g = -- (so avoid comparing them again) type DistinctBlocks = [CmmBlock] type Key = [Label] + +-- | A substitution maps each eliminated block to its replacement. +-- +-- Invariant: no value is a key, i.e. there are no chains @x->y->z@. type Subst = LabelMap BlockId -- The outer list groups by hash. We retain this grouping throughout. @@ -108,9 +112,19 @@ iterate subst blocks where (new_subst2, db) = mergeBlockList subst dbs - subst' = subst `mapUnion` new_substs + subst' = extendSubst subst new_substs updated_blocks = map (map (first (map (lookupBid subst')))) merged_blocks +-- | Add the substitutions of one round of 'iterate'. +-- +-- A block that won a merge in an earlier round may have lost one in this +-- round, so the older substitutions are updated to keep the result chain-free. +extendSubst :: Subst -> Subst -> Subst +extendSubst subst new = assert (chainFree subst') subst' + where + subst' = mapMap (lookupBid new) subst `mapUnion` new + chainFree s = not (any (`mapMember` s) s) + -- Combine two lists of blocks. -- While they are internally distinct they can still share common blocks. mergeBlocks :: Subst -> DistinctBlocks -> DistinctBlocks -> (Subst, DistinctBlocks) @@ -218,9 +232,7 @@ dont_care _other = False eqBid :: LabelMap BlockId -> BlockId -> BlockId -> Bool eqBid subst bid bid' = lookupBid subst bid == lookupBid subst bid' lookupBid :: LabelMap BlockId -> BlockId -> BlockId -lookupBid subst bid = case mapLookup bid subst of - Just bid -> lookupBid subst bid - Nothing -> bid +lookupBid subst bid = mapFindWithDefault bid bid subst -- Middle nodes and expressions can contain BlockIds, in particular in -- CmmStackSlot and CmmBlock, so we have to use a special equality for ===================================== testsuite/tests/codeGen/should_compile/T27368.hs ===================================== @@ -0,0 +1,17 @@ +-- Common block elimination merges the duplicated blocks over several +-- rounds. Compiling this at -O panicked in setInfoTableStackMap (#27368). + +module T27368 (f) where + +{-# NOINLINE put #-} +put :: Int -> Int -> IO () +put h x = if h + x == 12345 then errorWithoutStackTrace "boom" else pure () + +data T = N | J Int | K + +f :: Int -> Bool -> T -> IO () +f h a t = do + if a + then do put h 1; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + else do put h 2; case t of { N -> pure (); J _ -> put h 3; K -> put h 4 }; put h 0; put h 0; put h 0; put h 0 + put h 0 ===================================== testsuite/tests/codeGen/should_compile/all.T ===================================== @@ -150,3 +150,5 @@ test('T16351', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppres test('T20298a', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298b', normal, compile, ['-O2 -dno-bignum-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298c', normal, compile, ['-O2 -dno-builtin-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) + +test('T27368', normal, compile, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/63c9eb8459bfab4d6829763d06f72c7… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/63c9eb8459bfab4d6829763d06f72c7… 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/T27368-cbe-expand-subst] 2 commits: Cmm: keep the common block elimination substitution chain-free
by Simon Jakobi (＠sjakobi) 03 Oct '26

03 Oct '26

Simon Jakobi pushed to branch wip/sjakobi/T27368-cbe-expand-subst at Glasgow Haskell Compiler / GHC Commits: b4fc993b by Simon Jakobi at 2026-10-04T04:49:43+02:00 Cmm: keep the common block elimination substitution chain-free A block that won a merge in one round of elimCommonBlocks can lose one in a later round, so the substitution could map a label to another eliminated label. replaceLabels looks up each label only once and so left edges to eliminated blocks in the graph, which later made setInfoTableStackMap panic (#27368). Now each round's substitutions are applied to the existing ones as they are added (extendSubst), so every label maps directly to a surviving block and lookupBid no longer needs to chase chains. Fixes #27368. Assisted-by: Claude Fable 5.1 - - - - - 4774e648 by Simon Jakobi at 2026-10-04T05:40:08+02:00 Cmm: exclude the entry block from common block elimination toBlockListEntryFirst only made the entry block win merges in the first round of elimCommonBlocks. Later rounds regroup the blocks by their substituted successors in an order unrelated to the entry, so the entry block could still lose a merge, leaving the proc's info table keyed by an eliminated label (#27722). Instead, the entry block is no longer a candidate for elimination at all. The downside is that blocks identical to the entry block are no longer merged into it. Only hand-written Cmm is affected, as the entry block of every Haskell-generated proc contains the proc's stack check, which no other block of the graph can contain. Fixes #27722. Assisted-by: Claude Fable 5.1 - - - - - 9 changed files: - + changelog.d/27368 - compiler/GHC/Cmm/CommonBlockElim.hs - + testsuite/tests/cmm/should_run/T27722.hs - + testsuite/tests/cmm/should_run/T27722.stdout - + testsuite/tests/cmm/should_run/T27722_c.c - + testsuite/tests/cmm/should_run/T27722_cmm.cmm - testsuite/tests/cmm/should_run/all.T - + testsuite/tests/codeGen/should_compile/T27368.hs - testsuite/tests/codeGen/should_compile/all.T Changes: ===================================== changelog.d/27368 ===================================== @@ -0,0 +1,5 @@ +section: compiler +synopsis: Fix a ``setInfoTableStackMap`` panic caused by common block elimination + leaving references to eliminated blocks. +issues: #27368 +mrs: !16543 ===================================== compiler/GHC/Cmm/CommonBlockElim.hs ===================================== @@ -66,30 +66,20 @@ elimCommonBlocks g = where g' = replaceLabels env $ copyTicks env g env = iterate mapEmpty blocks_with_key - -- The order of blocks doesn't matter here. While we could use - -- revPostorder which drops unreachable blocks this is done in - -- ContFlowOpt already which runs before this pass. So we use - -- toBlockList since it is faster. - -- One exception: The entry block most come first or we risk eliminating it - -- in favour of another block. See Note [Retain entry block during common block elimination.] - groups = groupByInt hash_block (toBlockListEntryFirst g) :: [[CmmBlock]] blocks_with_key = [ [ (successors b, [b]) | b <- bs] | bs <- groups] - --- Note [Retain entry block during common block elimination.] --- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ --- At the stage we run common block elimination (CBE) we only have one info --- table for the entry label. Which means we can get away without applying the --- block label substitution to the info table *as long as we keep the first block*. --- When combining blocks the first block in the list of blocks is kept, and the later --- one eliminated, so we can achieve this by simply using toBlockListEntryFirst. --- --- If we don't we end up with #27722 where the entry block was eliminated in favour --- of another block. + groups = groupByInt hash_block candidates :: [[CmmBlock]] + -- The entry block must not be eliminated: #27722 + candidates = filter ((/= g_entry g) . entryLabel) (toBlockList g) -- Invariant: The blocks in the list are pairwise distinct -- (so avoid comparing them again) type DistinctBlocks = [CmmBlock] type Key = [Label] + +-- | Maps each eliminated block to the block that replaces it. +-- +-- Invariant: no value is a key, so a single lookup resolves any label. +-- See 'extendSubst'. type Subst = LabelMap BlockId -- The outer list groups by hash. We retain this grouping throughout. @@ -108,9 +98,20 @@ iterate subst blocks where (new_subst2, db) = mergeBlockList subst dbs - subst' = subst `mapUnion` new_substs + subst' = extendSubst subst new_substs updated_blocks = map (map (first (map (lookupBid subst')))) merged_blocks +-- | Add the substitutions of one round of 'iterate'. +-- +-- A block that won a merge in an earlier round may have lost one in this +-- round, so the older substitutions are rewritten through the new ones to +-- keep the result chain-free. +extendSubst :: Subst -> Subst -> Subst +extendSubst subst new = assert (chainFree subst') subst' + where + subst' = mapMap (lookupBid new) subst `mapUnion` new + chainFree s = not (any (`mapMember` s) s) + -- Combine two lists of blocks. -- While they are internally distinct they can still share common blocks. mergeBlocks :: Subst -> DistinctBlocks -> DistinctBlocks -> (Subst, DistinctBlocks) @@ -218,9 +219,7 @@ dont_care _other = False eqBid :: LabelMap BlockId -> BlockId -> BlockId -> Bool eqBid subst bid bid' = lookupBid subst bid == lookupBid subst bid' lookupBid :: LabelMap BlockId -> BlockId -> BlockId -lookupBid subst bid = case mapLookup bid subst of - Just bid -> lookupBid subst bid - Nothing -> bid +lookupBid subst bid = mapFindWithDefault bid bid subst -- Middle nodes and expressions can contain BlockIds, in particular in -- CmmStackSlot and CmmBlock, so we have to use a special equality for ===================================== testsuite/tests/cmm/should_run/T27722.hs ===================================== @@ -0,0 +1,6 @@ +foreign import ccall "zork_info_addr" zork_info_addr :: IO Word + +main :: IO () +main = do + addr <- zork_info_addr + putStrLn (if addr /= 0 then "ok" else "no info table") ===================================== testsuite/tests/cmm/should_run/T27722.stdout ===================================== @@ -0,0 +1 @@ +ok ===================================== testsuite/tests/cmm/should_run/T27722_c.c ===================================== @@ -0,0 +1,7 @@ +#include <stdint.h> + +// Common block elimination used to drop the entry block together with +// its info table, so that this symbol went missing. +extern char zork_info[]; + +uintptr_t zork_info_addr(void) { return (uintptr_t) zork_info; } ===================================== testsuite/tests/cmm/should_run/T27722_cmm.cmm ===================================== @@ -0,0 +1,22 @@ +#include "Cmm.h" + +// The then-blocks of E1 and E2 are duplicates of the entry block: they +// carry the same number of source notes (block and statement) as the +// entry block (proc and statement), which matters for the block hash. +// They get merged with each other in the first round of common block +// elimination, E1 and E2 in the second, and only then does the entry +// block have a duplicate. +INFO_TABLE_RET (zork, RET_SMALL) + return () +{ + bits64 x; + x = 1 :: bits64; + goto E1; +E1: + if (x > 0 :: bits64) { x = 1 :: bits64; goto E2; } else { goto D; } +E2: + if (x > 0 :: bits64) { x = 1 :: bits64; goto E2; } else { goto D; } +D: + if (x > 1 :: bits64) goto E1; + goto E2; +} ===================================== testsuite/tests/cmm/should_run/all.T ===================================== @@ -60,3 +60,6 @@ test('T27447', ], multi_compile_and_run, ['T27447', [('T27447_cmm.cmm', '')], '']) + +test('T27722', [req_cmm], multi_compile_and_run, + ['T27722', [('T27722_cmm.cmm', ''), ('T27722_c.c', '')], '-O']) ===================================== testsuite/tests/codeGen/should_compile/T27368.hs ===================================== @@ -0,0 +1,17 @@ +-- Common block elimination merges the duplicated blocks over several +-- rounds. Compiling this at -O panicked in setInfoTableStackMap (#27368). + +module T27368 (f) where + +{-# NOINLINE put #-} +put :: Int -> Int -> IO () +put h x = if h + x == 12345 then errorWithoutStackTrace "boom" else pure () + +data T = J Int | K + +f :: Int -> Bool -> T -> IO () +f h a t = do + if a + then do put h 1; case t of { J _ -> put h 3; K -> put h 4 }; put h 0; put h 0 + else do put h 2; case t of { J _ -> put h 3; K -> put h 4 }; put h 0; put h 0 + put h 0 ===================================== testsuite/tests/codeGen/should_compile/all.T ===================================== @@ -150,3 +150,5 @@ test('T16351', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppres test('T20298a', normal, compile, ['-O2 -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298b', normal, compile, ['-O2 -dno-bignum-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) test('T20298c', normal, compile, ['-O2 -dno-builtin-rules -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques']) + +test('T27368', normal, compile, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/883000905d0b87b1bbe7722ef99c91… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/883000905d0b87b1bbe7722ef99c91… 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/marge_bot_batch_merge_job] ttg: HsModuleName in the AST, ModuleName in GHC
by Marge Bot (＠marge-bot) 03 Oct '26

03 Oct '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 6c5685ea by Rodrigo Mesquita at 2026-10-03T19:51:13-04:00 ttg: HsModuleName in the AST, ModuleName in GHC This commit makes the AST fully independent from GHC by parsing a "module name" as an `HsModuleName (= HText)` rather than constructing an `ModuleName (= FastString)` straight away. In the GHC side, everything remains as a `ModuleName`. We turn AST `HsModuleName`s into fast strings with the cheap `mkFastStringShortText` when we process the AST for manipulation within the compiler. There are no performance regressions introduced by this approach. This is the final piece of #21592 Alternative plans were discussed in gitlab.haskell.org/ghc/ghc/-/merge_requests/16546#note_694647, but the Simon suggested one won in simplicity and performance when compared against my attempt at implementing my original plan of having a family `ModuleNameP`. - - - - - 90 changed files: - compiler/GHC.hs - compiler/GHC/Builtin/Modules.hs - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Show.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/Opt/CallerCC/Types.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Driver/Pipeline.hs-boot - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Driver/Pipeline/Phases.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Lit.hs - compiler/GHC/HsToCore/Docs.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Debug.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/Header.hs - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Env.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Unbound.hs - compiler/GHC/StgToJS/Linker/Linker.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/Types.hs - compiler/GHC/Tc/Types/ErrCtxt.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Unique.hs - compiler/GHC/Types/UnresolvedImport.hs - compiler/GHC/Unit/Home.hs - compiler/GHC/Unit/Module.hs - compiler/GHC/Unit/Module/Env.hs - + compiler/GHC/Unit/Module/Name.hs - compiler/GHC/Unit/Parser.hs - compiler/GHC/Unit/Types.hs - compiler/GHC/Unit/Types.hs-boot - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - compiler/Language/Haskell/Syntax/Lit.hs - compiler/Language/Haskell/Syntax/Module/Name.hs - compiler/Language/Haskell/Syntax/Text.hs - compiler/ghc.cabal.in - ghc/GHCi/UI.hs - ghc/GHCi/UI/Info.hs - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/ghc-api/downsweep/IncrementalDownsweep.hs - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/hiefile/should_run/T24544.hs - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/profiling/should_run/caller-cc/CallerCcParser.hs - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/6c5685ea96dc2e2a44ffb3a110c9c0f… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/6c5685ea96dc2e2a44ffb3a110c9c0f… 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/marge_bot_batch_merge_job] ttg: HsModuleName in the AST, ModuleName in GHC
by Marge Bot (＠marge-bot) 03 Oct '26

03 Oct '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 1c2338b4 by Rodrigo Mesquita at 2026-10-03T17:27:00-04:00 ttg: HsModuleName in the AST, ModuleName in GHC This commit makes the AST fully independent from GHC by parsing a "module name" as an `HsModuleName (= HText)` rather than constructing an `ModuleName (= FastString)` straight away. In the GHC side, everything remains as a `ModuleName`. We turn AST `HsModuleName`s into fast strings with the cheap `mkFastStringShortText` when we process the AST for manipulation within the compiler. There are no performance regressions introduced by this approach. This is the final piece of #21592 Alternative plans were discussed in gitlab.haskell.org/ghc/ghc/-/merge_requests/16546#note_694647, but the Simon suggested one won in simplicity and performance when compared against my attempt at implementing my original plan of having a family `ModuleNameP`. - - - - - 90 changed files: - compiler/GHC.hs - compiler/GHC/Builtin/Modules.hs - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Show.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/Opt/CallerCC/Types.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Driver/Pipeline.hs-boot - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Driver/Pipeline/Phases.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Lit.hs - compiler/GHC/HsToCore/Docs.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Debug.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/Header.hs - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Env.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Unbound.hs - compiler/GHC/StgToJS/Linker/Linker.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/Types.hs - compiler/GHC/Tc/Types/ErrCtxt.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Unique.hs - compiler/GHC/Types/UnresolvedImport.hs - compiler/GHC/Unit/Home.hs - compiler/GHC/Unit/Module.hs - compiler/GHC/Unit/Module/Env.hs - + compiler/GHC/Unit/Module/Name.hs - compiler/GHC/Unit/Parser.hs - compiler/GHC/Unit/Types.hs - compiler/GHC/Unit/Types.hs-boot - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - compiler/Language/Haskell/Syntax/Lit.hs - compiler/Language/Haskell/Syntax/Module/Name.hs - compiler/Language/Haskell/Syntax/Text.hs - compiler/ghc.cabal.in - ghc/GHCi/UI.hs - ghc/GHCi/UI/Info.hs - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/ghc-api/downsweep/IncrementalDownsweep.hs - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/hiefile/should_run/T24544.hs - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/profiling/should_run/caller-cc/CallerCcParser.hs - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1c2338b4056ab95a9846a087aecc8c0… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1c2338b4056ab95a9846a087aecc8c0… 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/marge_bot_batch_merge_job] 6 commits: ci: accept modified changelog.d entries in lint-changelog
by Marge Bot (＠marge-bot) 03 Oct '26

03 Oct '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: a563cb27 by Simon Jakobi at 2026-10-02T17:37:36-04:00 ci: accept modified changelog.d entries in lint-changelog The changelog guide says to extend an existing entry rather than add a new one when the feature is already documented. lint_changelog only counted added files, so such MRs failed before the validator ran. Fixes #27779. Assisted-by: Claude Fable 5.1 - - - - - 03082cd4 by Simon Jakobi at 2026-10-02T17:38:17-04:00 changelog.d: Fix warning flag name in the semaphore-v2 entry The entry refers to -Wsemaphore-version-mismatch, which does not exist. The warning GHC emits when it cannot use a -jsem semaphore, including on a protocol version mismatch, is -Wsemaphore-open-failure. Context: !15729, #25087 Assisted-by: Claude Fable 5.1 - - - - - a93705ee by Simon Jakobi at 2026-10-02T17:38:17-04:00 changelog.d: Fix the CLC proposal link in the T27455 entry The entry used the Sphinx :ref: role with a URL as its target. :ref: resolves only internal labels, so the generated release notes would show the proposal name without a link. Use the plain hyperlink form like the other entries. Context: !16274, #27455 Assisted-by: Claude Fable 5.1 - - - - - 54381079 by Hannes Siebenhandl at 2026-10-02T17:39:01-04:00 Extend the `TrustOverlay` for wired-in units The TrustOverlay only contained the `UnitId` of all on-disk units. However, wired-in units are referred to by their wired-in unit id, which is not the same as the on-disk unit id. Thus, trust checks for wired-in units failed because the lookup was using the wired-in unit, which wasn't present in the `TrustOverlay`. We fix #27834, by copying the trust info for wired-in unit ids. - - - - - 575482d2 by Hécate Kleidukos at 2026-10-03T14:18:13+02:00 [CLC 341] Strict variants of mutable types This commit is the implementation of CLC Proposal 341 https://github.com/haskell/core-libraries-committee/issues/341 - - - - - fc286656 by Rodrigo Mesquita at 2026-10-03T12:31:32-04:00 ttg: HsModuleName in the AST, ModuleName in GHC This commit makes the AST fully independent from GHC by parsing a "module name" as an `HsModuleName (= HText)` rather than constructing an `ModuleName (= FastString)` straight away. In the GHC side, everything remains as a `ModuleName`. We turn AST `HsModuleName`s into fast strings with the cheap `mkFastStringShortText` when we process the AST for manipulation within the compiler. There are no performance regressions introduced by this approach. This is the final piece of #21592 Alternative plans were discussed in gitlab.haskell.org/ghc/ghc/-/merge_requests/16546#note_694647, but the Simon suggested one won in simplicity and performance when compared against my attempt at implementing my original plan of having a family `ModuleNameP`. - - - - - 112 changed files: - .gitlab/ci.sh - changelog.d/T27455 - + changelog.d/clc-341-strict-mutable-data-types - changelog.d/semaphore-v2 - changelog.d/unit-index - compiler/GHC.hs - compiler/GHC/Builtin/Modules.hs - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Show.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/Opt/CallerCC/Types.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Driver/Pipeline.hs-boot - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Driver/Pipeline/Phases.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Lit.hs - compiler/GHC/HsToCore/Docs.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Debug.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/Header.hs - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Env.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Unbound.hs - compiler/GHC/StgToJS/Linker/Linker.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/Types.hs - compiler/GHC/Tc/Types/ErrCtxt.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Unique.hs - compiler/GHC/Types/UnresolvedImport.hs - compiler/GHC/Unit/External/Wired.hs - compiler/GHC/Unit/Home.hs - compiler/GHC/Unit/Module.hs - compiler/GHC/Unit/Module/Env.hs - + compiler/GHC/Unit/Module/Name.hs - compiler/GHC/Unit/Parser.hs - compiler/GHC/Unit/State.hs - compiler/GHC/Unit/Types.hs - compiler/GHC/Unit/Types.hs-boot - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - compiler/Language/Haskell/Syntax/Lit.hs - compiler/Language/Haskell/Syntax/Module/Name.hs - compiler/Language/Haskell/Syntax/Text.hs - compiler/ghc.cabal.in - ghc/GHCi/UI.hs - ghc/GHCi/UI/Info.hs - libraries/base/base.cabal.in - libraries/base/changelog.md - libraries/base/src/Control/Concurrent/Chan.hs - + libraries/base/src/Control/Concurrent/Chan/Strict.hs - libraries/base/src/Control/Concurrent/MVar.hs - + libraries/base/src/Control/Concurrent/MVar/Strict.hs - libraries/base/src/Data/IORef.hs - + libraries/base/src/Data/IORef/Strict.hs - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/ghc-api/downsweep/IncrementalDownsweep.hs - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - + testsuite/tests/ghci/scripts/T27834.hs - + testsuite/tests/ghci/scripts/T27834.script - + testsuite/tests/ghci/scripts/T27834.stdout - testsuite/tests/ghci/scripts/all.T - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/hiefile/should_run/T24544.hs - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/profiling/should_run/caller-cc/CallerCcParser.hs - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dcf52c444f83204cfe37029c87f7d2… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dcf52c444f83204cfe37029c87f7d2… 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/T27891] wip: move Generics into base
by Teo Camarasu (＠teo) 03 Oct '26

03 Oct '26

Teo Camarasu pushed to branch wip/T27891 at Glasgow Haskell Compiler / GHC Commits: 9602a7aa by Teo Camarasu at 2026-10-03T13:08:49+01:00 wip: move Generics into base - - - - - 17 changed files: - libraries/base/src/GHC/Essentials.hs - libraries/base/src/GHC/Generics.hs - libraries/ghc-internal/ghc-internal.cabal.in - libraries/ghc-internal/src/GHC/Internal/ClosureTypes.hs - libraries/ghc-internal/src/GHC/Internal/Control/Arrow.hs - libraries/ghc-internal/src/GHC/Internal/Control/Monad/Fix.hs - libraries/ghc-internal/src/GHC/Internal/Control/Monad/Zip.hs - libraries/ghc-internal/src/GHC/Internal/Data/Data.hs - libraries/ghc-internal/src/GHC/Internal/ForeignSrcLang.hs - − libraries/ghc-internal/src/GHC/Internal/Generics.hs - libraries/ghc-internal/src/GHC/Internal/Heap/Closures.hs - libraries/ghc-internal/src/GHC/Internal/Heap/InfoTable/Types.hsc - libraries/ghc-internal/src/GHC/Internal/Heap/ProfInfo/Types.hs - libraries/ghc-internal/src/GHC/Internal/LanguageExtensions.hs - libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc - libraries/ghc-internal/src/GHC/Internal/Stats.hsc - libraries/ghc-internal/src/GHC/Internal/TH/Syntax.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/9602a7aa65204125d13531f2698d835… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/9602a7aa65204125d13531f2698d835… 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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