January 2026 - ghc-commits

[Git][ghc/ghc] Pushed new branch wip/remove-alloc_p_ticky
by Cheng Shao (＠TerrorJack) 12 Jan '26

12 Jan '26

Cheng Shao pushed new branch wip/remove-alloc_p_ticky at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/remove-alloc_p_ticky You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/fendor/ghc-pkg-traceid] 93 commits: X86 CodeGen: fix assign_eax_sse_regs
by Hannes Siebenhandl (＠fendor) 12 Jan '26

12 Jan '26

Hannes Siebenhandl pushed to branch wip/fendor/ghc-pkg-traceid at Glasgow Haskell Compiler / GHC Commits: fca9cd7c by sheaf at 2025-12-18T13:18:18-05:00 X86 CodeGen: fix assign_eax_sse_regs We must set %al to the number of SSE2 registers that contain arguments (in case we are dealing with a varargs function). The logic for counting how many arguments reside in SSE2 registers was incorrect, as it used 'isFloatFormat', which incorrectly ignores vector registers. We now instead do case analysis on the register class: is_sse_reg r = case targetClassOfReg platform r of RcFloatOrVector -> True RcInteger -> False This change is necessary to prevent segfaults in T20030_test1j, because subsequent commits change the format calculations, resulting in vector formats more often. - - - - - 53150617 by sheaf at 2025-12-18T13:18:19-05:00 X86 regUsageOfInstr: fix format for IMUL When used with 8-bit operands, the IMUL instruction returns the result in the lower 16 bits of %rax (also known as %ax). This is different than for the other sizes, where an input at 16, 32 or 64 bits will result in 16, 32 or 64 bits of output in both %rax and %rdx. This doesn't affect the behaviour of the compiler, because we don't allow partial writes at sub-word sizes. The rationale is explained in Wrinkle [Don't allow scalar partial writes] in Note [Register formats in liveness analysis], in GHC.CmmToAsm.Reg.Liveness. - - - - - c7a56dd1 by sheaf at 2025-12-18T13:18:19-05:00 Liveness analysis: consider register formats This commit updates the register allocator to be a bit more careful in situations in which a single register is used at multiple different formats, e.g. when xmm1 is used both to store a Double# and a DoubleX2#. This is done by introducing the 'Regs' newtype around 'UniqSet RegWithFormat', for which the combining operations take the larger of the two formats instead of overriding the format. Operations on 'Regs' are defined in 'GHC.CmmToAsm.Reg.Regs'. There is a modest compile-time cost for the additional overhead for tracking register formats, which causes the metric increases of this commit. The subtle aspects of the implementation are outlined in Note [Register formats in liveness analysis] in GHC.CmmToAsm.Reg.Liveness. Fixes #26411 #26611 ------------------------- Metric Increase: T12707 T26425 T3294 ------------------------- - - - - - c2e83339 by sheaf at 2025-12-18T13:18:19-05:00 Register allocator: reload at same format as spill This commit ensures that if we spill a register onto the stack at a given format, we then always reload the register at this same format. This ensures we don't end up in a situation where we spill F64x2 but end up only reloading the lower F64. This first reload would make us believe the whole data is in a register, thus silently losing the upper 64 bits of the spilled register's contents. Fixes #26526 - - - - - 55ab583b by sheaf at 2025-12-18T13:18:19-05:00 Register allocation: writes redefine format As explained in Note [Allocated register formats] in GHC.CmmToAsm.Reg.Linear, we consider all writes to redefine the format of the register. This ensures that in a situation such as movsd .Ln6m(%rip),%v1 shufpd $0,%v1,%v1 we properly consider the broadcast operation to change the format of %v1 from F64 to F64x2. This completes the fix to #26411 (test in T26411b). - - - - - 951402ed by Vladislav Zavialov at 2025-12-18T13:19:05-05:00 Parser: improve mkModuleImpExp, remove checkImportSpec 1. The `mkModuleImpExp` helper now knows whether it is processing an import or export list item, and uses this information to produce a more accurate error message for `import M (T(..,x))` with PatternSynonyms disabled. The old message incorrectly referred to this case as an export form. 2. The `checkImportSpec` helper is removed in favor of more comprehensive error checking in `mkModuleImpExp`. 3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been made more explicit in the comments and assertions (calls to 'panic'). Test case: import-syntax-no-ext - - - - - 47d83d96 by Vladislav Zavialov at 2025-12-18T13:19:06-05:00 Subordinate namespace-specified wildcards (#25901) Add support for subordinate namespace-specified wildcards `X(type ..)` and `X(data ..)` to import and export lists. Examples: import M (Cls(type ..)) -- imports Cls and all its associated types import M (Cls(data ..)) -- imports Cls and all its methods module M (R(data ..), C(type ..)) where -- exports R and all its data constructors and record fields; -- exports C and all its associated types, but not its methods The scope of this change is limited to the case where the wildcard is the only subordinate import/export item, whereas the more complex forms `X(type .., f)` or `X(type .., data ..)` are unsupported and raise the newly introduced PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later. Summary of the changes: 1. Refactor IEThingAll to store its extension field XIEThingAll as a record IEThingAllExt instead of a tuple. 2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt, representing an optional namespace specifier `type` or `data` in front of a subordinate wildcard `X(..)`. 3. Extend the grammar in Parser.y with productions for `type ..` and `data ..` in subordinate import/export items. 4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a NamespaceSpecifier; use it in `filterImports` and `exports_from_avail` to account for the namespace specifier in IEThingAll. 5. Improve diagnostics by storing more information in DodgyImportsEmptyParent and DodgyExportsEmptyParent. Test cases: T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w DodgyImports02 DodgyImports03 DodgyImports04 - - - - - eac418bb by Recursion Ninja at 2025-12-18T13:19:48-05:00 Removing the 'Data' instance for 'InstEnv'. The 'Data' instance is blocking work on Trees that Grow, and the 'Data' instance seem to have been added without a clear purpose. - - - - - e920e038 by Recursion Ninja at 2025-12-18T13:19:48-05:00 'Decouple Language.Haskell.Syntax.Decls' from 'GHC.Unit.Module.Warnings' - - - - - bd38b76c by Cheng Shao at 2025-12-18T13:20:31-05:00 testsuite: improve coverage of foundation test This patch refactors the `foundation` test a bit to improve coverage: - Instead of using a hard-coded seed, a random seed is now taken from the command line, and printed upon test failure. This improves test coverage over many future CI runs, and shall a failure occur, the seed is available in the CI log for local reproduction. - The iterations count is bumped to 1000 instead of 100, similar to the bump in `test-primops`. Runtime timeout is bumped 2x just to be safe. - Improve `newLCGGen` by using non-atomic loads/stores on a `MutableByteArray#` for storing mutable `Word64`, this test doesn't use parallelism in the first place - Fixed a few compiler warnings and removed redundant pragmas and imports Co-authored-by: Codex <codex(a)openai.com> - - - - - 3995187c by Sylvain Henry at 2025-12-18T13:21:45-05:00 Doc: document -pgmi "" (#26634) - - - - - 5729418c by Cheng Shao at 2025-12-18T13:22:29-05:00 rts: use __builtin_mul_overflow for hs_mulIntMayOflo This patch uses `__builtin_mul_overflow` to implement `hs_mulIntMayOflo`. This is a GNU C checked arithmetic builtin function supported by gcc/clang, is type-generic so works for both 32-bit/64-bit, and makes the code both more efficient and easier to read/maintain than the previous hand rolled logic. - - - - - 1ca4b49a by Cheng Shao at 2025-12-18T13:23:11-05:00 compiler/rts: fix ABI mismatch in barf() invocations This patch fixes a long-standing issue of ABI mismatch in `barf()` invocations, both in compiler-emitted code and in hand written Cmm code: - In RTS, we have `barf()` which reports a fatal internal error message and exits the program. - `barf()` is a variadic C function! When used as a callee of a foreign call with `ccall` calling convention instead of `capi`, there is an ABI mismatch between the caller and the callee! - Unfortunately, both the compiler and the Cmm sources contain many places where we call `barf()` via `ccall` convention!! Like, when you write `foreign "C" barf("foo object (%p) entered!", R1)`, it totally doesn't do what you think it'll do at all!! The second argument `R1` is not properly passed in `va_list`, and the behavior is completely undefined!! - Even more unfortunately, this issue has been sitting around long enough because the ABI mismatch is subtle enough on normie platforms like x64 and arm64. - But there are platforms like wasm32 that are stricter about ABI, and the broken `barf()` invocations already causes trouble for wasm backend: we had to use ugly hacks like `barf(errmsg, NULL)` to make `wasm-ld` happy, and even with this band-aid, compiler-generated `barf()` invocations are still broken, resulting in regressions in certain debug-related functionality, e.g. `-dtag-inference-checks` is broken on wasm32 (#22882). This patch properly fixes the issue: - We add non-variadic `barf` wrappers in the RTS that can be used as `ccall` callees - Both the compiler `emitBarf` logic and the hand-written Cmm are changed to call these wrappers - `emitBarf` now also properly annotates the foreign call as `CmmNeverReturns` to indicate it's a noreturn call to enable more efficient code generation `-dtag-inference-checks` now works on wasm. Closes #22882. Co-authored-by: Codex <codex(a)openai.com> - - - - - b3dd23b9 by Vilim Lendvaj at 2025-12-18T13:23:57-05:00 Remove outdated comment The Traversable instance for ZipList is no longer in GHC.Internal.Data.Traversable. In fact, it is right below this very comment. - - - - - 9a9c2f03 by Cheng Shao at 2025-12-18T13:24:39-05:00 compiler: remove unused OtherSection logic This patch removes the OtherSection logic in Cmm, given it's never actually used by any of our backends. - - - - - 91edd292 by Wolfgang Jeltsch at 2025-12-19T03:18:19-05:00 Remove unused known-key and name variables for generics This removes the known-key and corresponding name variables for `K1`, `M1`, `R`, `D`, `C`, `S`, and `URec` from `GHC.Generics`, as they are apparently nowhere used in GHC’s source code. - - - - - 73ee7e38 by Wolfgang Jeltsch at 2025-12-19T03:19:02-05:00 Remove unused known keys and names for generics classes This removes the known-key and corresponding name variables for `Datatype`, `Constructor`, and `Selector` from `GHC.Generics`, as they are apparently nowhere used in GHC’s source code. - - - - - f69c5f14 by Cheng Shao at 2025-12-19T03:19:45-05:00 wasm: fix handling of ByteArray#/MutableByteArray# arguments in JSFFI imports This patch fixes the handling of ByteArray#/MutableByteArray# arguments in JSFFI imports, see the amended note and manual for explanation. Also adds a test to witness the fix. Co-authored-by: Codex <codex(a)openai.com> - - - - - 224446a2 by Cheng Shao at 2025-12-20T07:49:54-05:00 rts: workaround -Werror=maybe-uninitialized false positives In some cases gcc might report -Werror=maybe-uninitialized that we know are false positives, but need to workaround it to make validate builds with -Werror pass. - - - - - 251ec087 by Cheng Shao at 2025-12-20T07:49:54-05:00 hadrian: use -Og as C/C++ optimization level when debugging This commit enables -Og as optimization level when compiling the debug ways of rts. According to gcc documentation (https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og) -Og is a better choice than -O0 for producing debuggable code. It's also supported by clang as well, so it makes sense to use it as a default for debugging. Also add missing -g3 flag to C++ compilation flags in +debug_info flavour transformer. - - - - - fb586c67 by Cheng Shao at 2025-12-20T07:50:36-05:00 compiler: replace DList with OrdList This patch removes `DList` logic from the compiler and replaces it with `OrdList` which also supports O(1) concatenation and should be more memory efficient than the church-encoded `DList`. - - - - - 8149c987 by Cheng Shao at 2025-12-20T17:06:51-05:00 hadrian: add with_profiled_libs flavour transformer This patch adds a `with_profiled_libs` flavour transformer to hadrian which is the exact opposite of `no_profiled_libs`. It adds profiling ways to stage1+ rts/library ways, and doesn't alter other flavour settings. It is useful when needing to test profiling logic locally with a quick flavour. - - - - - 746b18cd by Cheng Shao at 2025-12-20T17:06:51-05:00 hadrian: fix missing profiled dynamic libraries in profiled_ghc This commit fixes the profiled_ghc flavour transformer to include profiled dynamic libraries as well, since they're supported by GHC since !12595. - - - - - 4dd7e3b9 by Cheng Shao at 2025-12-20T17:07:33-05:00 ci: set http.postBuffer to mitigate perf notes timeout on some runners This patch sets http.postBuffer to mitigate the timeout when fetching perf notes on some runners with slow internet connection. Fixes #26684. - - - - - bc36268a by Wolfgang Jeltsch at 2025-12-21T16:23:24-05:00 Remove unused known keys and names for type representations This removes the known-key and corresponding name variables for `TrName`, `TrNameD`, `TypeRep`, `KindRepTypeLitD`, `TypeLitSort`, and `mkTrType`, as they are apparently nowhere used in GHC’s source code. - - - - - ff5050e9 by Wolfgang Jeltsch at 2025-12-21T16:24:04-05:00 Remove unused known keys and names for natural operations This removes the known-key and corresponding name variables for `naturalAndNot`, `naturalLog2`, `naturalLogBaseWord`, `naturalLogBase`, `naturalPowMod`, `naturalSizeInBase`, `naturalToFloat`, and `naturalToDouble`, as they are apparently nowhere used in GHC’s source code. - - - - - 424388c2 by Wolfgang Jeltsch at 2025-12-21T16:24:45-05:00 Remove the unused known key and name for `Fingerprint` This removes the variables for the known key and the name of the `Fingerprint` data constructor, as they are apparently nowhere used in GHC’s source code. - - - - - a1ed86fe by Wolfgang Jeltsch at 2025-12-21T16:25:26-05:00 Remove the unused known key and name for `failIO` This removes the variables for the known key and the name of the `failIO` operation, as they are apparently nowhere used in GHC’s source code. - - - - - b8220daf by Wolfgang Jeltsch at 2025-12-21T16:26:07-05:00 Remove the unused known key and name for `liftM` This removes the variables for the known key and the name of the `liftM` operation, as they are apparently nowhere used in GHC’s source code. - - - - - eb0628b1 by Wolfgang Jeltsch at 2025-12-21T16:26:47-05:00 Fix the documentation of `hIsClosed` - - - - - db1ce858 by sheaf at 2025-12-22T17:11:17-05:00 Do deep subsumption when computing valid hole fits This commit makes a couple of improvements to the code that computes "valid hole fits": 1. It uses deep subsumption for data constructors. This matches up the multiplicities, as per Note [Typechecking data constructors]. This fixes #26338 (test: LinearHoleFits). 2. It now suggests (non-unidirectional) pattern synonyms as valid hole fits. This fixes #26339 (test: PatSynHoleFit). 3. It uses 'stableNameCmp', to make the hole fit output deterministic. ------------------------- Metric Increase: hard_hole_fits ------------------------- - - - - - 72ee9100 by sheaf at 2025-12-22T17:11:17-05:00 Speed up hole fits with a quick pre-test This speeds up the machinery for valid hole fits by doing a small check to rule out obviously wrong hole fits, such as: 1. A hole fit identifier whose type has a different TyCon at the head, after looking through foralls and (=>) arrows, e.g.: hole_ty = Int cand_ty = Maybe a or hole_ty = forall a b. a -> b cand_ty = forall x y. Either x y 2. A hole fit identifier that is not polymorphic when the hole type is polymorphic, e.g. hole_ty = forall a. a -> a cand_ty = Int -> Int ------------------------- Metric Decrease: hard_hole_fits ------------------------- - - - - - 30e513ba by Cheng Shao at 2025-12-22T17:12:00-05:00 configure: remove unused win32-tarballs.md5sum This patch removes the unused `win32-tarballs.md5sum` file from the tree. The current mingw tarball download logic in `mk/get-win32-tarballs.py` fetches and checks against `SHA256SUM` from the same location where the tarballs are fetched, and this file has been unused for a few years. - - - - - a2d52b3b by Wolfgang Jeltsch at 2025-12-23T04:47:33-05:00 Add an operation `System.IO.hGetNewlineMode` This commit also contains some small code and documentation changes for related operations, for the sake of consistency. - - - - - b26d134a by Cheng Shao at 2025-12-23T04:48:15-05:00 rts: opportunistically reclaim slop space in shrinkMutableByteArray# Previously, `shrinkMutableByteArray#` shrinks a `MutableByteArray#` in-place by assigning the new size to it, and zeroing the extra slop space. That slop space is not reclaimed and wasted. But it's often the case that we allocate a `MutableByteArray#` upfront, then shrink it shortly after, so the `MutableByteArray#` closure sits right at the end of a nursery block; this patch identifies such chances, and also shrink `bd->free` if possible, reducing heap space fragmentation. Co-authored-by: Codex <codex(a)openai.com> ------------------------- Metric Decrease: T10678 ------------------------- - - - - - c72ddabf by Cheng Shao at 2025-12-23T16:13:23-05:00 hadrian: fix bootstrapping with ghc-9.14 This patch fixes bootstrapping GHC with ghc-9.14, tested locally with ghc-9.14.1 release as bootstrapping GHC. - - - - - 0fd6d8e4 by Cheng Shao at 2025-12-23T16:14:05-05:00 hadrian: pass -keep-tmp-files to test ghc when --keep-test-files is enabled This patch makes hadrian pass `-keep-tmp-files` to test ghc when `--keep-test-files` is enabled, so you can check the ghc intermediate files when debugging certain test failures. Closes #26688. - - - - - 81d10134 by Cheng Shao at 2025-12-24T06:11:52-05:00 configure: remove dead code in configure scripts This patch removes dead code in our configure scripts, including: - Variables and auto-detected programs that are not used - autoconf functions that are not used, or export a variable that's not used - `AC_CHECK_HEADERS` invocations that don't have actual corresponding `HAVE_XXX_H` usage - Other dead code (e.g. stray `AC_DEFUN()`) Co-authored-by: Codex <codex(a)openai.com> - - - - - fb1381c3 by Wolfgang Jeltsch at 2025-12-24T06:12:34-05:00 Remove unused known keys and names for list operations This removes the known-key and corresponding name variables for `concat`, `filter`, `zip`, and `(++)`, as they are apparently nowhere used in GHC’s source code. - - - - - 7b9c20f4 by Recursion Ninja at 2025-12-24T10:35:36-05:00 Decoupling Language.Haskell.Syntax.Binds from GHC.Types.Basic by transferring InlinePragma types between the modules. * Moved InlinePragma data-types to Language.Haskell.Syntax.Binds.InlinePragma * Partitioned of Arity type synonyms to GHC.Types.Arity * InlinePragma is now extensible via Trees That Grow * Activation is now extensible via Trees That Grow * Maybe Arity change to more descriptive InlineSaturation data-type * InlineSaturation information removed from InlinePragma during GHS parsing pass * Cleaned up the exposed module interfaces of the new modules - - - - - a3afae0c by Simon Peyton Jones at 2025-12-25T15:26:36-05:00 Check for rubbish literals in Lint Addresses #26607. See new Note [Checking for rubbish literals] in GHC.Core.Lint - - - - - 8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00 [#26183] Associated Type Iface Fix When determining "extras" for class decl interface entries, axioms for the associated types need to included so that dependent modules will be recompiled if those axioms change. resolves #26183 - - - - - ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00 testsuite: run numeric tests with optasm when available This patch adds the `optasm` extra way to nueric tests when NCG is available. Some numeric bugs only surface with optimization, omitting this can hide these bugs and even make them slip into release! (e.g. #26711) - - - - - 6213bb57 by maralorn at 2026-01-02T16:30:32+01:00 GHC.Internal.Exception.Context: Fix comment on addExceptionAnnotation - - - - - b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00 GHC.Internal.Control.Monad.replicateM: Fix comment - - - - - a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drops unused PE linker script for windows This patch drops unused PE linker script for windows in the `MergeObjects` builder of hadrian. The linker script is used for merging object files into a single `HS*.o` object file and undoing the effect of split sections, when building the "ghci library" object file. However, we don't build the ghci library on windows, and this code path is actually unreachable. - - - - - 53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drop unused logic for building ghci libraries This patch drops the unused logic for building ghci libraries in hadrian: - The term "ghci library" refers to an optional object file per library `HS*.o`, which is merged from multiple object files in that library using the `MergeObjects` builder in hadrian. - The original rationale of having a ghci library object, in addition to normal archives, was to speedup ghci loading, since the combined object is linked with a linker script to undo the effects of `-fsplit-sections` to reduce section count and make it easier for the RTS linker to handle. - However, most GHC builds enable `dynamicGhcPrograms` by default, in such cases the ghci library would already not be built. - `dynamicGhcPrograms` is disabled on Windows, but still we don't build the ghci library due to lack of functioning merge objects command. - The only case that we actually build ghci library objects, are alpine fully static bindists. However, for other reasons, split sections is already disabled for fully static builds anyway! - There will not be any regression if the ghci library objects are absent from a GHC global libdir when `dynamicGhcPrograms` is disabled. The RTS linker can already load the archives without any issue. Hence the removal. We now forcibly disable ghci libraries for all Cabal components, and rip out all logic related to `MergeObjects` and ghci libraries in hadrian. This also nicely cleans up some old todos and fixmes that are no longer relevant. Note that MergeObjects in hadrian is not the same thing as merge objects in the GHC driver. The latter is not affected by this patch. ------------------------- Metric Decrease: libdir ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00 User's guide: Fix link to language extensions Instead of linking to haddocks, it seemed more useful to link to the extension overview in the user's guide. Closes #26614. - - - - - 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - 69e0ab59 by Cheng Shao at 2026-01-06T19:37:56-05:00 compiler: add targetHasRTSWays function This commit adds a `targetHasRTSWays` util function in `GHC.Driver.Session` to query if the target RTS has a given Ways (e.g. WayThreaded). - - - - - 25a0ab94 by Cheng Shao at 2026-01-06T19:37:56-05:00 compiler: link on-demand external interpreter with threaded RTS This commit makes the compiler link the on-demand external interpreter program with threaded RTS if it is available in the target RTS ways. This is a better default than the previous single-threaded RTS, and it enables the external interpreter to benefit from parallelism when deserializing CreateBCOs messages. - - - - - 92404a2b by Cheng Shao at 2026-01-06T19:37:56-05:00 hadrian: link iserv with threaded RTS This commit makes hadrian link iserv with threaded RTS if it's available in the RTS ways. Also cleans up the iserv main C program which can be replaced by the `-fkeep-cafs` link-time option. - - - - - a20542d2 by Cheng Shao at 2026-01-06T19:38:38-05:00 ghc-internal: remove unused GMP macros This patch removes unused GMP related macros from `ghc-internal`. The in-tree GMP version was hard coded and outdated, but it was not used anywhere anyway. - - - - - 4079dcd6 by Cheng Shao at 2026-01-06T19:38:38-05:00 hadrian: fix in-tree gmp configure error on newer c compilers Building in-tree gmp on newer c compilers that default to c23 fails at configure stage, this patch fixes it, see added comment for explanation. - - - - - 414d1fe1 by Cheng Shao at 2026-01-06T19:39:20-05:00 compiler: fix LLVM backend pdep/pext handling for i386 target This patch fixes LLVM backend's pdep/pext handling for i386 target, and also removes non-existent 128/256/512 bit hs_pdep/hs_pext callees. See amended note for more explanation. Fixes #26450. Co-authored-by: Codex <codex(a)openai.com> - - - - - c7f6fba3 by Cheng Shao at 2026-01-06T19:39:20-05:00 ci: remove allow_failure flag for i386 alpine job The LLVM codegen issue for i386 has been fixed, and the i386 alpine job should pass now. This commit removes the allow_failure flag so that other i386 regressions in the future are signaled more timely. - - - - - 52d00c05 by Simon Peyton Jones at 2026-01-07T10:24:21-05:00 Add missing InVar->OutVar lookup in SetLevels As #26681 showed, the SetLevels pass was failing to map an InVar to an OutVar. Very silly! I'm amazed it hasn't broken before now. I have improved the type singatures (to mention InVar and OutVar) so it's more obvious what needs to happen. - - - - - ab0a5594 by Cheng Shao at 2026-01-07T10:25:04-05:00 hadrian: drop deprecated pkgHashSplitObjs code path This patch drops deprecated `pkgHashSplitObjs` code path from hadrian, since GHC itself has removed split objs support many versions ago and this code path is unused. - - - - - bb3a2ba1 by Cheng Shao at 2026-01-07T10:25:44-05:00 hadrian: remove linting/assertion in quick-validate flavour The `quick-validate` flavour is meant for testing ghc and passing the testsuite locally with similar settings to `validate` but faster. This patch removes the linting/assertion overhead in `quick-validate` to improve developer experience. I also took the chance to simplify redundant logic of rts/library way definition in `validate` flavour. - - - - - 7971f5dd by Cheng Shao at 2026-01-07T10:26:26-05:00 deriveConstants: clean up unused constants This patch cleans up unused constants from `deriveConstants`, they are not used by C/Cmm code in the RTS, nor compiler-generated code. Co-authored-by: Codex <codex(a)openai.com> - - - - - 4df96993 by Cheng Shao at 2026-01-07T10:27:08-05:00 hadrian: pass -fno-omit-frame-pointer with +debug_info This patch adds `-fno-omit-frame-pointer` as C/C++ compilation flag when compiling with `+debug_info` flavour transformer. It's a sane default when you care about debugging and reliable backtraces, and makes debugging/profiling with bpf easier. - - - - - 8a3900a3 by Aaron Allen at 2026-01-07T10:27:57-05:00 [26705] Include TyCl instances in data fam iface entry Ensures dependent modules are recompiled when the class instances for a data family instance change. resolves #26705 - - - - - a0b980af by Cheng Shao at 2026-01-07T10:28:38-05:00 hadrian: remove unused Hp2Ps/Hpc builders This patch removes the Hp2Ps/Hpc builders from hadrian, they are unused in the build system. Note that the hp2ps/hpc programs are still built and not affected. - - - - - 50a58757 by Cheng Shao at 2026-01-07T10:29:20-05:00 hadrian: only install js files to libdir for wasm/js targets There are certain js files required for wasm/js targets to work, and previously hadrian would install those js files to libdir unconditionally on other targets as well. This could be a minor annoyance for packagers especially when the unused js files contain shebangs that interfere with the packaging process. This patch makes hadrian only selectively install the right js files for the right targets. Co-authored-by: Codex <codex(a)openai.com> - - - - - da40e553 by Simon Peyton Jones at 2026-01-07T10:30:00-05:00 Add flavour transformer assertions_stage1 This allows us to enable -DDEBUG assertions in the stage1 compiler - - - - - ec3cf767 by Cheng Shao at 2026-01-08T06:24:31-05:00 make: remove unused Makefiles from legacy make build system This patch removes unused Makefiles from legacy make build system; now they are never used by hadrian in any way, and they already include common boilerplate mk files that are long gone in the make build system removal, hence the housecleaning. Co-authored-by: Codex <codex(a)openai.com> - - - - - 04ea3f83 by Cheng Shao at 2026-01-08T06:25:13-05:00 compiler: use -O3 as LLVM optimization level for ghc -O2 The GHC driver clamps LLVM optimization level to `-O2` due to LLVM crashes, but those were historical issues many years ago that are no longer relevant for LLVM versions we support today. This patch changes the driver to use `-O3` as LLVM optimization level when compiling with `-O2`, which is a better default when we're willing to trade compilation time for faster generated code. - - - - - 472df471 by Peter Trommler at 2026-01-08T13:28:54-05:00 Use half-word literals in info tables With this commit info tables are mapped to the same assembler code on big-endian and little-endian platforms. Fixes #26579. - - - - - 393f9c51 by Simon Peyton Jones at 2026-01-08T13:29:35-05:00 Refactor srutOkForBinderSwap This MR does a small refactor: * Moves `scrutOkForBinderSwap` and `BinderSwapDecision` to GHC.Core.Utils * Inverts the sense of the coercion it returns, which makes more sense No effect on behaviour - - - - - ad76fb0f by Simon Peyton Jones at 2026-01-08T13:29:36-05:00 Improve case merging This small MR makes case merging happen a bit more often than it otherwise could, by getting join points out of the way. See #26709 and GHC.Core.Utils Note [Floating join points out of DEFAULT alternatives] - - - - - 4c9395f5 by Cheng Shao at 2026-01-08T13:30:16-05:00 hadrian: remove broken hsc2hs flag when cross compiling to windows This patch removes the `--via-asm` hsc2hs flag when cross compiling to windows. With recent llvm-mingw toolchain, it would fail with: ``` x86_64-w64-mingw32-hsc2hs: Cannot combine instructions: [Quad 8,Long 4,Long 241,Ref ".Ltmp1-.Ltmp0"] ``` The hsc2hs default `--cross-compile` logic is slower but works. - - - - - 71fdef55 by Simon Peyton Jones at 2026-01-08T13:30:57-05:00 Try harder to keep the substitution empty Avoid unnecessary cloning of variables in the Simplifier. Addresses #26724, See Note [Keeping the substitution empty] We get some big wins in compile time Metrics: compile_time/bytes allocated ------------------------------------- Baseline Test Metric value New value Change ---------------------------------------------------------------------------- CoOpt_Singletons(normal) ghc/alloc 721,544,088 692,174,216 -4.1% GOOD LargeRecord(normal) ghc/alloc 1,268,031,157 1,265,168,448 -0.2% T14766(normal) ghc/alloc 918,218,533 688,432,296 -25.0% GOOD T15703(normal) ghc/alloc 318,103,629 306,638,016 -3.6% GOOD T17836(normal) ghc/alloc 419,174,584 418,400,824 -0.2% T18478(normal) ghc/alloc 471,042,976 470,261,376 -0.2% T20261(normal) ghc/alloc 573,387,162 563,663,336 -1.7% T24984(normal) ghc/alloc 87,832,666 87,636,168 -0.2% T25196(optasm) ghc/alloc 1,103,284,040 1,101,376,992 -0.2% hard_hole_fits(normal) ghc/alloc 224,981,413 224,608,208 -0.2% geo. mean -0.3% minimum -25.0% maximum +0.1% Metric Decrease: CoOpt_Singletons T14766 T15703 - - - - - 30341168 by Simon Peyton Jones at 2026-01-08T13:31:38-05:00 Add regression test for #24867 - - - - - 1ac1a541 by Julian Ospald at 2026-01-09T02:48:53-05:00 Support statically linking executables properly Fixes #26434 In detail, this does a number of things: * Makes GHC aware of 'extra-libraries-static' (this changes the package database format). * Adds a switch '-static-external' that will honour 'extra-libraries-static' to link external system dependencies statically. * Adds a new field to settings/targets: "ld supports verbatim namespace". This field is used by '-static-external' to conditionally use '-l:foo.a' syntax during linking, which is more robust than trying to find the absolute path to an archive on our own. * Adds a switch '-fully-static' that is meant as a high-level interface for e.g. cabal. This also honours 'extra-libraries-static'. This also attempts to clean up the confusion around library search directories. At the moment, we have 3 types of directories in the package database format: * library-dirs * library-dirs-static * dynamic-library-dirs However, we only have two types of linking: dynamic or static. Given the existing logic in 'mungeDynLibFields', this patch assumes that 'library-dirs' is really just nothing but a fallback and always prefers the more specific variants if they exist and are non-empty. Conceptually, we should be ok with even just one search dirs variant. Haskell libraries are named differently depending on whether they're static or dynamic, so GHC can conveniently pick the right one depending on the linking needs. That means we don't really need to play tricks with search paths to convince the compiler to do linking as we want it. For system C libraries, the convention has been anyway to place static and dynamic libs next to each other, so we need to deal with that issue anyway and it is outside of our control. But this is out of the scope of this patch. This patch is backwards compatible with cabal. Cabal should however be patched to use the new '-fully-static' switch. - - - - - ad3c808d by Julian Ospald at 2026-01-09T02:48:53-05:00 Warn when "-dynamic" is mixed with "-staticlib" - - - - - 322dd672 by Matthew Pickering at 2026-01-09T02:49:35-05:00 rts: Use INFO_TABLE_CONSTR for stg_dummy_ret_closure Since the closure type is CONSTR_NOCAF, we need to use INFO_TABLE_CONSTR to populate the constructor description field (this crashes ghc-debug when decoding AP_STACK frames sometimes) Fixes #26745 - - - - - 039bac4c by Ben Gamari at 2026-01-09T20:22:16-05:00 ghc-internal: Move STM utilities out of GHC.Internal.Conc.Sync This is necessary to avoid an import cycle on Windows when importing `GHC.Internal.Exception.Context` in `GHC.Internal.Conc.Sync`. On the road to address #25365. - - - - - 8c389e8c by Ben Gamari at 2026-01-09T20:22:16-05:00 base: Capture backtrace from throwSTM Implements core-libraries-committee#297. Fixes #25365. - - - - - e1ce1fc3 by Ben Gamari at 2026-01-09T20:22:16-05:00 base: Annotate rethrown exceptions in catchSTM with WhileHandling Implements core-libraries-committee#298 - - - - - c4ebdbdf by Cheng Shao at 2026-01-09T20:23:06-05:00 compiler: make getPrim eagerly evaluate its result This commit makes `GHC.Utils.Binary.getPrim` eagerly evaluate its result, to avoid accidental laziness when future patches build other binary parsers using `getPrim`. - - - - - 66a0c4f7 by Cheng Shao at 2026-01-09T20:23:06-05:00 compiler: implement fast get/put for Word16/Word32/Word64 Previously, `GHC.Utils.Binary` contains `get`/`put` functions for `Word16`/`Word32`/`Word64` which always loads and stores them as big-endian words at a potentially unaligned address. The previous implementation is based on loads/stores of individual bytes and concatenating bytes with bitwise operations, which currently cannot be fused to a single load/store operation by GHC. This patch implements fast `get`/`put` functions for `Word16`/`Word32`/`Word64` based on a single memory load/store, with an additional `byteSwap` operation on little-endian hosts. It is based on unaligned load/store primops added since GHC 9.10, and we already require booting with at least 9.10, so it's about time to switch to this faster path. - - - - - 641ec3f0 by Simon Peyton Jones at 2026-01-09T20:23:55-05:00 Fix scoping errors in specialisation Using -fspecialise-aggressively in #26682 showed up a couple of subtle errors in the type-class specialiser. * dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a call that mentioned a dictionary that was not in scope. This call has been missing since 2009! commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe Author: Simon Peyton Jones <simonpj(a)microsoft.com> Date: Fri Oct 23 16:15:51 2009 +0000 Fixed by re-combining `dumpBindUDs` and `dumpUDs`. * I think there was another bug involving the quantified type variables in polymorphic specialisation. In any case I refactored `specHeader` and `spec_call` so that the former looks for the extra quantified type variables rather than the latter. This is quite a worthwhile simplification: less code, easier to grok. Test case in simplCore/should_compile/T26682, brilliantly minimised by @sheaf. - - - - - 2433e91d by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: change sectionProtection to take SectionType argument This commit changes `sectionProtection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. - - - - - e5926fbe by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: change isInitOrFiniSection to take SectionType argument This commit changes `isInitOrFiniSection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. Also marks it as exported. - - - - - 244d57d7 by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: fix split sections on windows This patch fixes split sections on windows by emitting the right COMDAT section header in NCG, see added comment for more explanation. Fix #26696 #26494. ------------------------- Metric Decrease: LargeRecord T9675 size_hello_artifact size_hello_artifact_gzip size_hello_unicode size_hello_unicode_gzip Metric Increase: T13035 ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 182f3d0f by Cheng Shao at 2026-01-09T20:25:28-05:00 iserv: add comment about -fkeep-cafs - - - - - 49675b69 by Matthew Craven at 2026-01-09T20:26:14-05:00 Account for "stupid theta" in demand sig for DataCon wrappers Fixes #26748. - - - - - 1a709131 by fendor at 2026-01-12T10:23:13+01:00 Remove `traceId` from ghc-pkg executable - - - - - 441 changed files: - .gitattributes - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - compiler/GHC.hs - compiler/GHC/Builtin/Names.hs - compiler/GHC/Builtin/PrimOps/Ids.hs - compiler/GHC/Builtin/Utils.hs - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/Info.hs - compiler/GHC/Cmm/InitFini.hs - compiler/GHC/Cmm/Parser.y - compiler/GHC/Cmm/Utils.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/LA64/Ppr.hs - compiler/GHC/CmmToAsm/PPC/Ppr.hs - compiler/GHC/CmmToAsm/Ppr.hs - compiler/GHC/CmmToAsm/RV64/Ppr.hs - compiler/GHC/CmmToAsm/Reg/Graph.hs - compiler/GHC/CmmToAsm/Reg/Graph/Coalesce.hs - compiler/GHC/CmmToAsm/Reg/Graph/Spill.hs - compiler/GHC/CmmToAsm/Reg/Graph/SpillCost.hs - compiler/GHC/CmmToAsm/Reg/Linear.hs - compiler/GHC/CmmToAsm/Reg/Linear/Base.hs - compiler/GHC/CmmToAsm/Reg/Linear/JoinToTargets.hs - compiler/GHC/CmmToAsm/Reg/Liveness.hs - + compiler/GHC/CmmToAsm/Reg/Regs.hs - compiler/GHC/CmmToAsm/Reg/Target.hs - compiler/GHC/CmmToAsm/Wasm/FromCmm.hs - compiler/GHC/CmmToAsm/X86/CodeGen.hs - compiler/GHC/CmmToAsm/X86/Instr.hs - compiler/GHC/CmmToAsm/X86/Ppr.hs - compiler/GHC/CmmToC.hs - compiler/GHC/CmmToLlvm/CodeGen.hs - compiler/GHC/CmmToLlvm/Data.hs - compiler/GHC/Core.hs - compiler/GHC/Core/DataCon.hs - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/InstEnv.hs - compiler/GHC/Core/Lint.hs - compiler/GHC/Core/Opt/CSE.hs - compiler/GHC/Core/Opt/CprAnal.hs - compiler/GHC/Core/Opt/DmdAnal.hs - compiler/GHC/Core/Opt/OccurAnal.hs - compiler/GHC/Core/Opt/Pipeline.hs - compiler/GHC/Core/Opt/Pipeline/Types.hs - compiler/GHC/Core/Opt/SetLevels.hs - compiler/GHC/Core/Opt/Simplify.hs - compiler/GHC/Core/Opt/Simplify/Env.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Core/Ppr.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/SimpleOpt.hs - compiler/GHC/Core/Subst.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unfold/Make.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Config/Core/Lint.hs - compiler/GHC/Driver/Config/Core/Lint/Interactive.hs - compiler/GHC/Driver/Config/Core/Opt/Simplify.hs - compiler/GHC/Driver/Config/Interpreter.hs - compiler/GHC/Driver/Downsweep.hs - compiler/GHC/Driver/DynFlags.hs - compiler/GHC/Driver/Pipeline.hs - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/Hs/Binds.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Errors/Types.hs - compiler/GHC/HsToCore/Foreign/C.hs - compiler/GHC/HsToCore/Foreign/JavaScript.hs - compiler/GHC/HsToCore/Foreign/Wasm.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Make.hs - compiler/GHC/Iface/Recomp.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/Iface/Tidy.hs - compiler/GHC/Iface/Warnings.hs - compiler/GHC/IfaceToCore.hs - compiler/GHC/Linker/Dynamic.hs - compiler/GHC/Linker/Executable.hs - compiler/GHC/Linker/Loader.hs - compiler/GHC/Linker/Unit.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Ppr.hs - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Bind.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Utils.hs - compiler/GHC/Runtime/Interpreter/C.hs - compiler/GHC/Runtime/Interpreter/Init.hs - compiler/GHC/Settings.hs - compiler/GHC/Settings/IO.hs - compiler/GHC/StgToCmm/Bind.hs - compiler/GHC/StgToCmm/InfoTableProv.hs - compiler/GHC/StgToCmm/Utils.hs - compiler/GHC/StgToJS/Linker/Utils.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Deriv/Utils.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Hole.hs - compiler/GHC/Tc/Errors/Hole/FitTypes.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Arrow.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Instance/Typeable.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/TyCl/Instance.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/ThToHs.hs - + compiler/GHC/Types/Arity.hs - compiler/GHC/Types/Basic.hs - compiler/GHC/Types/DefaultEnv.hs - compiler/GHC/Types/Error/Codes.hs - compiler/GHC/Types/Hint.hs - compiler/GHC/Types/Id.hs - compiler/GHC/Types/Id/Info.hs - compiler/GHC/Types/Id/Make.hs - + compiler/GHC/Types/InlinePragma.hs - compiler/GHC/Types/Name/Reader.hs - compiler/GHC/Types/TyThing.hs - compiler/GHC/Types/Unique/FM.hs - compiler/GHC/Types/Unique/Set.hs - compiler/GHC/Unit/Info.hs - compiler/GHC/Unit/Module/Warnings.hs - compiler/GHC/Unit/State.hs - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax/Binds.hs - + compiler/Language/Haskell/Syntax/Binds/InlinePragma.hs - compiler/Language/Haskell/Syntax/Decls.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/ghc.cabal.in - configure.ac - distrib/configure.ac.in - − docs/Makefile - − docs/storage-mgt/Makefile - docs/users_guide/9.16.1-notes.rst - − docs/users_guide/Makefile - docs/users_guide/exts/pragmas.rst - docs/users_guide/exts/table.rst - docs/users_guide/phases.rst - docs/users_guide/wasm.rst - − driver/Makefile - − driver/ghc/Makefile - − driver/ghci/Makefile - − driver/haddock/Makefile - − driver/utils/merge_sections.ld - − driver/utils/merge_sections_pe.ld - ghc/Main.hs - − ghc/Makefile - hadrian/cabal.project - hadrian/cfg/default.host.target.in - hadrian/cfg/default.target.in - hadrian/doc/flavours.md - hadrian/hadrian.cabal - hadrian/src/Base.hs - hadrian/src/Builder.hs - hadrian/src/Context.hs - hadrian/src/Flavour.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Oracles/Flag.hs - hadrian/src/Oracles/Setting.hs - hadrian/src/Packages.hs - hadrian/src/Rules.hs - hadrian/src/Rules/Gmp.hs - hadrian/src/Rules/Library.hs - hadrian/src/Rules/Register.hs - hadrian/src/Settings/Builders/Cabal.hs - hadrian/src/Settings/Builders/Hsc2Hs.hs - − hadrian/src/Settings/Builders/MergeObjects.hs - hadrian/src/Settings/Builders/RunTest.hs - hadrian/src/Settings/Builders/SplitSections.hs - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Flavours/Validate.hs - hadrian/src/Settings/Packages.hs - − libraries/Makefile - libraries/base/changelog.md - libraries/base/src/GHC/Conc.hs - libraries/base/src/GHC/Conc/Sync.hs - libraries/base/src/System/IO.hs - − libraries/doc/Makefile - libraries/ghc-boot/GHC/Unit/Database.hs - libraries/ghc-internal/configure.ac - libraries/ghc-internal/ghc-internal.buildinfo.in - libraries/ghc-internal/ghc-internal.cabal.in - libraries/ghc-internal/include/HsIntegerGmp.h.in - libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs - libraries/ghc-internal/src/GHC/Internal/Conc/POSIX.hs - libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs - libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs-boot - libraries/ghc-internal/src/GHC/Internal/Conc/Windows.hs - libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs - libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs - libraries/ghc-internal/src/GHC/Internal/Event/Windows/Thread.hs - libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs - libraries/ghc-internal/src/GHC/Internal/Functor/ZipList.hs - libraries/ghc-internal/src/GHC/Internal/IO/Handle.hs - + libraries/ghc-internal/src/GHC/Internal/STM.hs - libraries/ghc-internal/src/GHC/Internal/System/IO.hs - linters/lint-codes/LintCodes/Static.hs - − linters/lint-codes/Makefile - − linters/lint-notes/Makefile - llvm-passes - − m4/find_ghc_bootstrap_prog.m4 - − m4/fp_copy_shellvar.m4 - + m4/fp_linker_supports_verbatim.m4 - − m4/fp_prog_ld_flag.m4 - − m4/fp_prog_sort.m4 - m4/prep_target_file.m4 - mk/system-cxx-std-lib-1.0.conf.in - − mk/win32-tarballs.md5sum - rts/Apply.cmm - rts/Compact.cmm - rts/ContinuationOps.cmm - rts/Exception.cmm - rts/Jumps.h - − rts/Makefile - rts/PrimOps.cmm - rts/RtsMessages.c - rts/StgMiscClosures.cmm - rts/StgStartup.cmm - rts/configure.ac - − rts/include/Makefile - rts/include/Stg.h - rts/include/rts/Messages.h - rts/linker/InitFini.c - rts/prim/mulIntMayOflo.c - rts/rts.buildinfo.in - rts/rts.cabal - rts/sm/Sanity.c - + testsuite/driver/_elffile.py - testsuite/driver/testglobals.py - testsuite/driver/testlib.py - testsuite/ghc-config/ghc-config.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/diagnostic-codes/codes.stdout - + testsuite/tests/dmdanal/should_run/T26748.hs - + testsuite/tests/dmdanal/should_run/T26748.stdout - testsuite/tests/dmdanal/should_run/all.T - + testsuite/tests/driver/fully-static/Hello.hs - + testsuite/tests/driver/fully-static/Makefile - + testsuite/tests/driver/fully-static/all.T - + testsuite/tests/driver/fully-static/fully-static.stdout - + testsuite/tests/driver/fully-static/test/Test.hs - + testsuite/tests/driver/fully-static/test/test.pkg - + testsuite/tests/driver/mostly-static/Hello.hs - + testsuite/tests/driver/mostly-static/Makefile - + testsuite/tests/driver/mostly-static/all.T - + testsuite/tests/driver/mostly-static/mostly-static.stdout - + testsuite/tests/driver/mostly-static/test/test.c - + testsuite/tests/driver/mostly-static/test/test.h - + testsuite/tests/driver/mostly-static/test/test.pkg - + testsuite/tests/driver/recomp26183/M.hs - + testsuite/tests/driver/recomp26183/M2A.hs - + testsuite/tests/driver/recomp26183/M2B.hs - + testsuite/tests/driver/recomp26183/Makefile - + testsuite/tests/driver/recomp26183/all.T - + testsuite/tests/driver/recomp26183/recomp26183.stderr - + testsuite/tests/driver/recomp26705/M.hs - + testsuite/tests/driver/recomp26705/M2A.hs - + testsuite/tests/driver/recomp26705/M2B.hs - + testsuite/tests/driver/recomp26705/Makefile - + testsuite/tests/driver/recomp26705/all.T - + testsuite/tests/driver/recomp26705/recomp26705.stderr - testsuite/tests/ghci/scripts/T8353.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.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/interface-stability/base-exports.stdout-ws-32 - testsuite/tests/jsffi/all.T - + testsuite/tests/jsffi/bytearrayarg.hs - + testsuite/tests/jsffi/bytearrayarg.mjs - + testsuite/tests/jsffi/bytearrayarg.stdout - testsuite/tests/numeric/should_run/all.T - testsuite/tests/numeric/should_run/foundation.hs - testsuite/tests/numeric/should_run/foundation.stdout - testsuite/tests/overloadedrecflds/should_fail/DRFHoleFits.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/patsyn/should_fail/all.T - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.hs - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.stderr - testsuite/tests/perf/compiler/hard_hole_fits.stderr - testsuite/tests/perf/should_run/all.T - testsuite/tests/plugins/test-hole-plugin.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - + testsuite/tests/pmcheck/should_compile/T24867.hs - + testsuite/tests/pmcheck/should_compile/T24867.stderr - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - + testsuite/tests/rename/should_compile/T25901_sub_e.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g.hs - + testsuite/tests/rename/should_compile/T25901_sub_g.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g_helper.hs - testsuite/tests/rename/should_compile/all.T - testsuite/tests/rename/should_fail/T23570b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_a.hs - + testsuite/tests/rename/should_fail/T25901_sub_a.stderr - + testsuite/tests/rename/should_fail/T25901_sub_b.hs - + testsuite/tests/rename/should_fail/T25901_sub_b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c.hs - + testsuite/tests/rename/should_fail/T25901_sub_c.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.stderr - + testsuite/tests/rename/should_fail/T25901_sub_d_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.stderr - testsuite/tests/rename/should_fail/all.T - + testsuite/tests/simd/should_run/T26411.hs - + testsuite/tests/simd/should_run/T26411.stdout - + testsuite/tests/simd/should_run/T26411b.hs - + testsuite/tests/simd/should_run/T26411b.stdout - testsuite/tests/simd/should_run/all.T - + testsuite/tests/simplCore/should_compile/T26681.hs - + testsuite/tests/simplCore/should_compile/T26682.hs - + testsuite/tests/simplCore/should_compile/T26682a.hs - + testsuite/tests/simplCore/should_compile/T26709.hs - + testsuite/tests/simplCore/should_compile/T26709.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/simplStg/should_compile/all.T - testsuite/tests/th/T15321.stderr - testsuite/tests/typecheck/should_compile/T13050.stderr - testsuite/tests/typecheck/should_compile/T14273.stderr - testsuite/tests/typecheck/should_compile/T14590.stderr - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_compile/T25180.stderr - testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr - testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr - testsuite/tests/typecheck/should_compile/free_monad_hole_fits.stderr - testsuite/tests/typecheck/should_compile/hole_constraints.stderr - testsuite/tests/typecheck/should_compile/holes.stderr - testsuite/tests/typecheck/should_compile/holes2.stderr - testsuite/tests/typecheck/should_compile/holes3.stderr - testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr - testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr - testsuite/tests/typecheck/should_compile/type_in_type_hole_fits.stderr - testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr - testsuite/tests/typecheck/should_compile/valid_hole_fits_interactions.stderr - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T14884.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - testsuite/tests/warnings/should_compile/DodgyExports03.stderr - testsuite/tests/warnings/should_compile/DodgyImports.stderr - + testsuite/tests/warnings/should_compile/DodgyImports02.hs - + testsuite/tests/warnings/should_compile/DodgyImports02.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03.hs - + testsuite/tests/warnings/should_compile/DodgyImports03.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03_helper.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.stderr - testsuite/tests/warnings/should_compile/DodgyImports_hiding.stderr - testsuite/tests/warnings/should_compile/all.T - utils/check-exact/ExactPrint.hs - utils/deriveConstants/Main.hs - utils/genapply/Main.hs - utils/ghc-pkg/Main.hs - utils/ghc-toolchain/exe/Main.hs - utils/ghc-toolchain/src/GHC/Toolchain/Tools/Link.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/haddock-api/src/Haddock/Interface/Create.hs - − utils/iserv/cbits/iservmain.c - utils/iserv/iserv.cabal.in The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e876421c95720785ff7b1dc23a91aa… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e876421c95720785ff7b1dc23a91aa… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/fendor/ghc-pkg-traceid
by Hannes Siebenhandl (＠fendor) 12 Jan '26

12 Jan '26

Hannes Siebenhandl pushed new branch wip/fendor/ghc-pkg-traceid at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/fendor/ghc-pkg-traceid You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 3 commits: Fix the OS string encoding for GNU/Hurd
by Marge Bot (＠marge-bot) 12 Jan '26

12 Jan '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 1d56d49e by Samuel Thibault at 2026-01-12T00:14:53-05:00 Fix the OS string encoding for GNU/Hurd Following https://github.com/haskell/cabal/pull/9434/files , and as seen in the various gnu_HOST_OS usages in the source code, it is expected that GNU/Hurd is advertised as "gnu", like the autotools do. - - - - - f43fec0f by Andrew Lelechenko at 2026-01-12T00:14:53-05:00 Add since annotation for Data.Bifoldable1 Fixes #26432 - - - - - 0f55a0d7 by Sven Tennie at 2026-01-12T00:14:54-05:00 Ignore Windows CI tool directories in Git Otherwise, we see thousands of changes in `git status` which is very confusing to work with. - - - - - 3 changed files: - .gitignore - libraries/base/src/Data/Bifoldable1.hs - libraries/ghc-platform/src/GHC/Platform/ArchOS.hs Changes: ===================================== .gitignore ===================================== @@ -256,3 +256,12 @@ ghc.nix/ # clangd .clangd dist-newstyle/ + +# ----------------------------------------------------------------------------- +# CI + +# Windows CI +toolchain/ +ghc-*/ +inplace/ +tmp/ ===================================== libraries/base/src/Data/Bifoldable1.hs ===================================== @@ -2,6 +2,7 @@ -- Copyright: Edward Kmett, Oleg Grenrus -- License: BSD-3-Clause -- +-- @since 4.18.0.0 {-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE Safe #-} ===================================== libraries/ghc-platform/src/GHC/Platform/ArchOS.hs ===================================== @@ -156,7 +156,7 @@ stringEncodeOS = \case OSHaiku -> "haiku" OSQNXNTO -> "nto-qnx" OSAIX -> "aix" - OSHurd -> "hurd" + OSHurd -> "gnu" OSWasi -> "wasi" OSGhcjs -> "ghcjs" View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8e07437ab6bc90a07c5871504f967a… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8e07437ab6bc90a07c5871504f967a… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/int-index/iethingwith-subwc
by Vladislav Zavialov (＠int-index) 12 Jan '26

12 Jan '26

Vladislav Zavialov pushed new branch wip/int-index/iethingwith-subwc at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/int-index/iethingwith-subwc You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 4 commits: hurd: Fix getExecutablePath build
by Marge Bot (＠marge-bot) 12 Jan '26

12 Jan '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: f3c18890 by Samuel Thibault at 2026-01-10T15:48:22+01:00 hurd: Fix getExecutablePath build 3939a8bf93e27 ("GNU/Hurd: Add getExecutablePath support") added using /proc/self/exe for GNU/Hurd but missed adding the required imports for the corresponding code. - - - - - 4b02820e by Samuel Thibault at 2026-01-11T20:04:23-05:00 Fix the OS string encoding for GNU/Hurd Following https://github.com/haskell/cabal/pull/9434/files , and as seen in the various gnu_HOST_OS usages in the source code, it is expected that GNU/Hurd is advertised as "gnu", like the autotools do. - - - - - 5a797c1b by Andrew Lelechenko at 2026-01-11T20:04:23-05:00 Add since annotation for Data.Bifoldable1 Fixes #26432 - - - - - 8e07437a by Sven Tennie at 2026-01-11T20:04:24-05:00 Ignore Windows CI tool directories in Git Otherwise, we see thousands of changes in `git status` which is very confusing to work with. - - - - - 4 changed files: - .gitignore - libraries/base/src/Data/Bifoldable1.hs - libraries/ghc-internal/src/GHC/Internal/System/Environment/ExecutablePath.hsc - libraries/ghc-platform/src/GHC/Platform/ArchOS.hs Changes: ===================================== .gitignore ===================================== @@ -256,3 +256,12 @@ ghc.nix/ # clangd .clangd dist-newstyle/ + +# ----------------------------------------------------------------------------- +# CI + +# Windows CI +toolchain/ +ghc-*/ +inplace/ +tmp/ ===================================== libraries/base/src/Data/Bifoldable1.hs ===================================== @@ -2,6 +2,7 @@ -- Copyright: Edward Kmett, Oleg Grenrus -- License: BSD-3-Clause -- +-- @since 4.18.0.0 {-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE Safe #-} ===================================== libraries/ghc-internal/src/GHC/Internal/System/Environment/ExecutablePath.hsc ===================================== @@ -51,7 +51,7 @@ import GHC.Internal.Foreign.Ptr import GHC.Internal.Foreign.Storable import GHC.Internal.System.IO.Error (isDoesNotExistError) import GHC.Internal.System.Posix.Internals -#elif defined(linux_HOST_OS) +#elif defined(linux_HOST_OS) || defined(gnu_HOST_OS) import GHC.Internal.Data.Functor import GHC.Internal.Data.List (isSuffixOf) import GHC.Internal.Foreign.C.Types ===================================== libraries/ghc-platform/src/GHC/Platform/ArchOS.hs ===================================== @@ -156,7 +156,7 @@ stringEncodeOS = \case OSHaiku -> "haiku" OSQNXNTO -> "nto-qnx" OSAIX -> "aix" - OSHurd -> "hurd" + OSHurd -> "gnu" OSWasi -> "wasi" OSGhcjs -> "ghcjs" View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/41e3903a0ec8f29e94334865d8e140… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/41e3903a0ec8f29e94334865d8e140… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26615] Wibbles
by Simon Peyton Jones (＠simonpj) 12 Jan '26

12 Jan '26

Simon Peyton Jones pushed to branch wip/T26615 at Glasgow Haskell Compiler / GHC Commits: a47e6e22 by Simon Peyton Jones at 2026-01-11T23:22:44+00:00 Wibbles - - - - - 5 changed files: - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Core/Rules.hs - testsuite/tests/simplCore/should_compile/spec-inline.stderr Changes: ===================================== compiler/GHC/Core/Opt/SpecConstr.hs ===================================== @@ -1864,7 +1864,7 @@ specialise env bind_calls (RI { ri_fn = fn, ri_lam_bndrs = arg_bndrs return (nullUsage, spec_info, []) | not (isNeverActive (idInlineActivation fn)) - -- See Note [Transfer activation] + -- See (SCRA1) in Note [SpecConstr: rule activation] -- Don't specialise OPAQUE things, see Note [OPAQUE pragma]. -- Since OPAQUE things are always never-active (see -- GHC.Parser.PostProcess.mkOpaquePragma) this guard never fires for @@ -2075,7 +2075,7 @@ mkSeqs seqees res_ty rhs = = rhs specConstrRuleActivation :: InlinePragmaInfo -> ActivationGhc --- See Note [SpecConstr rule activation] +-- See Note [SpecConstr: rule activation] specConstrRuleActivation fn_prag = activeAfter $ nextPhase $ beginPhase $ inlinePragmaActivation fn_prag @@ -2129,7 +2129,7 @@ The void argument must follow the foralls, lest the forall be ill-kinded. See Note [Worker/wrapper needs to add void arg last] in GHC.Core.Opt.WorkWrap.Utils. -Note [SpecConstr rule activation] +Note [SpecConstr: rule activation] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When should the RULE generated by SpecConstr be activated? See the function `specConstrRuleActivation`. @@ -2163,15 +2163,13 @@ Goal 1: "SC:1" won't fire in f's unfolding; see Note [What is active in the RHS of a RULE or unfolding?] Goal 2: "SPEC:f" has the same activation as `f`; - see Note [Auto-specialisation and RULES]). So "SPEC:f" will fire + see Note [Specialise: rule activation]. So "SPEC:f" will fire before "SC:1" -Other points: - -* c.f. Note [Auto-specialisation and RULES] in GHC.Core.Opt.Specialise. -* his in turn means there is no point in specialising NOINLINE things, -so we test for that. +Wrinkles +(SCRA1) If `f` is NOINLINE we arguably don't want a specialisation at all. + See (SRA1) in GHC.Core.Opt.Specialise. At least that's the choice for now. Note [generaliseDictPats] ~~~~~~~~~~~~~~~~~~~~~~~~~ ===================================== compiler/GHC/Core/Opt/Specialise.hs ===================================== @@ -1588,7 +1588,7 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs | notNull calls_for_me -- And there are some calls to specialise && not (isNeverActive (idInlineActivation fn)) -- Don't specialise NOINLINE things - -- See Note [Auto-specialisation and RULES] + -- See (SRA1) in Note [Specialise: rule activation] -- -- Don't specialise OPAQUE things, see Note [OPAQUE pragma]. -- Since OPAQUE things are always never-active (see @@ -1619,7 +1619,7 @@ specCalls spec_imp env existing_rules calls_for_me fn rhs fn_unf = realIdUnfolding fn -- Ignore loop-breaker-ness here fn_prag = idInlinePragma fn rule_act = inlinePragmaActivation fn_prag - -- rule_act: see Note [Auto-specialisation and RULES] + -- rule_act: see Note [Specialise: rule activation] is_active :: ActivationGhc -> Bool is_active = isActive (SimplPhaseRange (beginPhase rule_act) (endPhase rule_act)) -- is_active: rule_act is the activation we are going to put in the new @@ -2361,8 +2361,8 @@ argument pattern. Wrinkles (SC3) Annoyingly, we /also/ eliminate duplicates in `filterCalls`. See (MP3) in Note [Specialising polymorphic dictionaries] -Note [Auto-specialisation and RULES] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Note [Specialise: rule activation] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider: g :: Num a => a -> a g = ... @@ -2383,15 +2383,22 @@ also add RULE f g_spec = 0 But that's a bit complicated. For now we lean on the programmer: - * Set the activation of the RULE is the same as the activation of the Id, + + * Make the activation of the RULE be the same as the activation of the Id, i.e. (idInlineActivation g) So if `g` says {-# NOINLINE[2] g #-}, then the auto-spec rule will also not be active until phase 2. And that's what programmers should jolly well do anyway, even aside from specialisation, to ensure that `g` doesn't inline too early. -This in turn means that the RULE would never fire for a NOINLINE -thing so not much point in generating a specialisation at all. +Wrinkles + +(SRA1) This in turn means that the RULE would never fire for a NOINLINE thing + so not much point in generating a specialisation at all. This is a + bit moot: it's not unreasonable to have a (NOINLINE) specialisation for a + NOINLINE function. But currently we don't. And hence we don't create + a specialisation for an OPAQUE function either (see Note [OPAQUE pragma] + in Language.Haskell.Syntax.Binds.InlinePragma. Note [Specialisation shape] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ===================================== compiler/GHC/Core/Opt/WorkWrap.hs ===================================== @@ -499,7 +499,7 @@ When should the wrapper inlining be active? {-# SPECIALISE foo :: (Int,Int) -> Bool -> Int #-} {-# NOINLINE [n] foo #-} then specialisation will generate a SPEC rule active from Phase n. - See Note [Auto-specialisation and RULES] in GHC.Core.Opt.Specialise + See Note [Specialise: rule activation] in GHC.Core.Opt.Specialise This SPEC specialisation rule will compete with inlining, but we don't mind that, because if inlining succeeds, it should be better. ===================================== compiler/GHC/Core/Rules.hs ===================================== @@ -231,7 +231,7 @@ mkSpecRule dflags this_mod is_auto inl_act herald fn bndrs args rhs where rule = mkRule this_mod is_auto is_local rule_name - inl_act -- Note [Auto-specialisation and RULES] + inl_act -- Note [Specialise: rule activation] (idName fn) bndrs args rhs ===================================== testsuite/tests/simplCore/should_compile/spec-inline.stderr ===================================== @@ -17,7 +17,7 @@ Roman.foo3 Rec { -- RHS size: {terms: 40, types: 5, coercions: 0, joins: 0/0} -Roman.foo_$s$wgo [Occ=LoopBreaker] +Roman.foo_$s$wgo [InlPrag=[2], Occ=LoopBreaker] :: GHC.Internal.Prim.Int# -> GHC.Internal.Prim.Int# -> GHC.Internal.Prim.Int# [GblId, Arity=2, Str=<A><L>, Unf=OtherCon []] @@ -141,7 +141,7 @@ foo ------ Local rules for imported ids -------- -"SC:$wgo0" [2] +"SC:$wgo0" [1] forall (sc :: GHC.Internal.Prim.Int#) (sc1 :: GHC.Internal.Prim.Int#). Roman.$wgo (GHC.Internal.Maybe.Just View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a47e6e2285bc44eb3d5fbbd1fc21b97… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a47e6e2285bc44eb3d5fbbd1fc21b97… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/mtl-2.3.2
by Bodigrim (＠Bodigrim) 12 Jan '26

12 Jan '26

Bodigrim pushed new branch wip/mtl-2.3.2 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/mtl-2.3.2 You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/romes/hadrian-cross-stage2-rebase_SVEN_FINAL] WIP: Dirty hack
by Sven Tennie (＠supersven) 12 Jan '26

12 Jan '26

Sven Tennie pushed to branch wip/romes/hadrian-cross-stage2-rebase_SVEN_FINAL at Glasgow Haskell Compiler / GHC Commits: 51ad7c99 by Sven Tennie at 2026-01-11T20:17:52+01:00 WIP: Dirty hack Let Stage0 build with the default.host.target file and decide for other stages if default.target cannot be used. Acutally, I don't like this logic on this level. - - - - - 8 changed files: - hadrian/src/Hadrian/Oracles/TextFile.hs - hadrian/src/Oracles/Setting.hs - hadrian/src/Rules/BinaryDist.hs - hadrian/src/Rules/Generate.hs - hadrian/src/Rules/Lint.hs - hadrian/src/Settings.hs - hadrian/src/Settings/Builders/Hsc2Hs.hs - hadrian/src/Settings/Builders/RunTest.hs Changes: ===================================== hadrian/src/Hadrian/Oracles/TextFile.hs ===================================== @@ -124,8 +124,8 @@ getBuildTarget :: Action Toolchain.Target getBuildTarget = getTargetConfig buildTargetFile -- | Get the host target configuration through 'getTargetConfig' -getHostTarget :: Action Toolchain.Target -getHostTarget = do +getHostTarget :: Stage -> Action Toolchain.Target +getHostTarget stage | stage >= Stage1 = do -- MP: If we are not cross compiling then we should use the target file in order to -- build things for the host, in particular we want to use the configured values for the -- target for building the RTS (ie are we using Libffi for adjustors, and the wordsize) @@ -135,8 +135,7 @@ getHostTarget = do if (Toolchain.targetPlatformTriple ht) == (Toolchain.targetPlatformTriple tt) then return tt else return ht - -- where - -- msg = "The host's target configuration file " ++ quote hostTargetFile ++ " does not exist! ghc-toolchain might have failed to generate it." +getHostTarget _stage {- stage0 -} = getTargetConfig hostTargetFile -- | Get the target target configuration through 'getTargetConfig' getTargetTarget :: Action Toolchain.Target @@ -145,9 +144,8 @@ getTargetTarget = getTargetConfig targetTargetFile queryBuildTarget :: (Toolchain.Target -> a) -> Action a queryBuildTarget f = f <$> getBuildTarget -queryHostTarget :: (Toolchain.Target -> a) -> Action a -queryHostTarget f = f <$> getHostTarget - +queryHostTarget :: Stage -> (Toolchain.Target -> a) -> Action a +queryHostTarget stage f = f <$> getHostTarget stage newtype KeyValue = KeyValue (FilePath, String) deriving (Binary, Eq, Hashable, NFData, Show) ===================================== hadrian/src/Oracles/Setting.hs ===================================== @@ -137,7 +137,7 @@ getSetting = expr . setting bashPath :: Action FilePath bashPath = setting BourneShell -isWinHost :: Action Bool +isWinHost :: Stage -> Action Bool isWinHost = anyHostOs [OSMinGW32] isWinTarget :: Stage -> Action Bool @@ -153,8 +153,8 @@ isArmTarget :: Stage -> Action Bool isArmTarget stage = queryTargetTarget stage (isARM . archOS_arch . tgtArchOs) -- | Check whether the host OS setting matches one of the given strings. -anyHostOs :: [OS] -> Action Bool -anyHostOs oss = (`elem` oss) <$> queryHostTarget (archOS_OS . tgtArchOs) +anyHostOs :: [OS] -> Stage -> Action Bool +anyHostOs oss stage = (`elem` oss) <$> queryHostTarget stage (archOS_OS . tgtArchOs) -- | Check whether the target architecture setting matches one of the given -- strings. @@ -233,7 +233,7 @@ libsuf st way -- For example, we want to build RTS with stage1 for the host target as we -- produce a host executable with stage1 (which cross-compiles to stage2). targetStage :: Stage -> Action Target -targetStage stage | isHostStage stage = getHostTarget +targetStage stage | isHostStage stage = getHostTarget stage targetStage _ = getTargetTarget isHostStage :: Stage -> Bool ===================================== hadrian/src/Rules/BinaryDist.hs ===================================== @@ -326,7 +326,7 @@ bindistRules = do -- phony "binary-dist-dir-stage3" $ buildBinDistDir root targetBindist let buildBinDist compressor = do - win_host <- isWinHost + win_host <- isWinHost Stage1 win_target <- isWinTarget Stage2 when (win_target && win_host) (error "normal binary-dist does not work for windows targets, use `reloc-binary-dist-*` target instead.") buildBinDistX "binary-dist-dir" "bindist" compressor ===================================== hadrian/src/Rules/Generate.hs ===================================== @@ -409,7 +409,7 @@ bindistRules = do , interpolateSetting "ProjectPatchLevel2" ProjectPatchLevel2 , interpolateSetting "ProjectGitCommitId" ProjectGitCommitId - , interpolateVar "HostOS_CPP" $ fmap cppify $ interp $ queryHost queryOS + , interpolateVar "HostOS_CPP" $ fmap cppify $ interp $ queryHost queryOS Stage1 , interpolateVar "TargetPlatform" $ getTarget targetPlatformTriple , interpolateVar "TargetPlatform_CPP" $ cppify <$> getTarget targetPlatformTriple @@ -433,7 +433,7 @@ bindistRules = do , interpolateVar "TargetHasLibm" $ yesNo <$> interp (staged (buildFlag TargetHasLibm)) , interpolateVar "TargetPlatform" $ getTarget targetPlatformTriple , interpolateVar "BuildPlatform" $ interp $ queryBuild targetPlatformTriple - , interpolateVar "HostPlatform" $ interp $ queryHost targetPlatformTriple + , interpolateVar "HostPlatform" $ interp $ queryHost targetPlatformTriple Stage1 , interpolateVar "TargetWordBigEndian" $ getTarget isBigEndian , interpolateVar "TargetWordSize" $ getTarget wordSize , interpolateVar "Unregisterised" $ yesNo <$> getTarget tgtUnregisterised @@ -523,7 +523,7 @@ generateConfigHs = do let chooseSetting x y = case stage of { Stage0 {} -> x; _ -> y } let queryTarget f = f <$> expr (targetStage stage) -- Not right for stage3 - buildPlatform <- chooseSetting (queryBuild targetPlatformTriple) (queryHost targetPlatformTriple) + buildPlatform <- chooseSetting (queryBuild targetPlatformTriple) (queryHost targetPlatformTriple stage) hostPlatform <- queryTarget targetPlatformTriple trackGenerateHs cProjectName <- getSetting ProjectName @@ -626,9 +626,9 @@ generatePlatformHostHs = do stage <- getStage let chooseHostQuery = case stage of Stage0 {} -> queryHost - _ -> queryTarget stage - cHostPlatformArch <- chooseHostQuery (archOS_arch . tgtArchOs) - cHostPlatformOS <- chooseHostQuery (archOS_OS . tgtArchOs) + _ -> flip queryTarget + cHostPlatformArch <- chooseHostQuery (archOS_arch . tgtArchOs) stage + cHostPlatformOS <- chooseHostQuery (archOS_OS . tgtArchOs) stage return $ unlines [ "module GHC.Platform.Host where" , "" ===================================== hadrian/src/Rules/Lint.hs ===================================== @@ -42,7 +42,7 @@ runHLint :: [FilePath] -- ^ include directories -> Action () runHLint includeDirs defines dir = do threads <- shakeThreads <$> getShakeOptions - hostArch <- (<> "_HOST_ARCH") <$> queryHostTarget queryArch + hostArch <- (<> "_HOST_ARCH") <$> queryHostTarget Stage1 queryArch let hlintYaml = dir </> ".hlint.yaml" defines' = hostArch : defines cmdLine = unwords $ ===================================== hadrian/src/Settings.hs ===================================== @@ -119,9 +119,11 @@ unsafeFindPackageByPath path = err $ find (\pkg -> pkgPath pkg == path) knownPac -- Be careful querying values from the HOST and BUILD targets until the targets -- are only generated by ghc-toolchain: -- See Note [The dummy values in the HOST target description] -queryBuild, queryHost :: (Target -> a) -> Expr a +queryBuild :: (Target -> a) -> Expr a queryBuild f = expr $ queryBuildTarget f -queryHost f = expr $ queryHostTarget f + +queryHost :: (Target -> a) -> Stage -> Expr a +queryHost f stage = expr $ queryHostTarget stage f queryArch, queryOS, queryVendor :: Target -> String queryArch = stringEncodeArch . archOS_arch . tgtArchOs ===================================== hadrian/src/Settings/Builders/Hsc2Hs.hs ===================================== @@ -13,8 +13,8 @@ hsc2hsBuilderArgs = builder Hsc2Hs ? do ccPath <- getBuilderPath $ Cc CompileC stage gmpDir <- staged (buildSetting GmpIncludeDir) top <- expr topDirectory - hArch <- queryHost queryArch - hOs <- queryHost queryOS + hArch <- queryHost queryArch stage + hOs <- queryHost queryOS stage tArch <- queryTarget stage queryArch tOs <- queryTarget stage queryOS version <- case stage of ===================================== hadrian/src/Settings/Builders/RunTest.hs ===================================== @@ -124,7 +124,7 @@ inTreeCompilerArgs stg = do debugged <- ghcDebugged <$> flavour <*> pure ghcStage profiled <- ghcProfiled <$> flavour <*> pure ghcStage - os <- queryHostTarget queryOS + os <- queryHostTarget ghcStage queryOS arch <- queryTargetTarget ghcStage queryArch let codegen_arches = ["x86_64", "i386", "powerpc", "powerpc64", "powerpc64le", "aarch64", "wasm32", "riscv64", "loongarch64"] let withNativeCodeGen View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/51ad7c997c1c36db4727d4f3b8a2c73… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/51ad7c997c1c36db4727d4f3b8a2c73… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 13 commits: ghc-internal: Move STM utilities out of GHC.Internal.Conc.Sync
by Marge Bot (＠marge-bot) 12 Jan '26

12 Jan '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 039bac4c by Ben Gamari at 2026-01-09T20:22:16-05:00 ghc-internal: Move STM utilities out of GHC.Internal.Conc.Sync This is necessary to avoid an import cycle on Windows when importing `GHC.Internal.Exception.Context` in `GHC.Internal.Conc.Sync`. On the road to address #25365. - - - - - 8c389e8c by Ben Gamari at 2026-01-09T20:22:16-05:00 base: Capture backtrace from throwSTM Implements core-libraries-committee#297. Fixes #25365. - - - - - e1ce1fc3 by Ben Gamari at 2026-01-09T20:22:16-05:00 base: Annotate rethrown exceptions in catchSTM with WhileHandling Implements core-libraries-committee#298 - - - - - c4ebdbdf by Cheng Shao at 2026-01-09T20:23:06-05:00 compiler: make getPrim eagerly evaluate its result This commit makes `GHC.Utils.Binary.getPrim` eagerly evaluate its result, to avoid accidental laziness when future patches build other binary parsers using `getPrim`. - - - - - 66a0c4f7 by Cheng Shao at 2026-01-09T20:23:06-05:00 compiler: implement fast get/put for Word16/Word32/Word64 Previously, `GHC.Utils.Binary` contains `get`/`put` functions for `Word16`/`Word32`/`Word64` which always loads and stores them as big-endian words at a potentially unaligned address. The previous implementation is based on loads/stores of individual bytes and concatenating bytes with bitwise operations, which currently cannot be fused to a single load/store operation by GHC. This patch implements fast `get`/`put` functions for `Word16`/`Word32`/`Word64` based on a single memory load/store, with an additional `byteSwap` operation on little-endian hosts. It is based on unaligned load/store primops added since GHC 9.10, and we already require booting with at least 9.10, so it's about time to switch to this faster path. - - - - - 641ec3f0 by Simon Peyton Jones at 2026-01-09T20:23:55-05:00 Fix scoping errors in specialisation Using -fspecialise-aggressively in #26682 showed up a couple of subtle errors in the type-class specialiser. * dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a call that mentioned a dictionary that was not in scope. This call has been missing since 2009! commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe Author: Simon Peyton Jones <simonpj(a)microsoft.com> Date: Fri Oct 23 16:15:51 2009 +0000 Fixed by re-combining `dumpBindUDs` and `dumpUDs`. * I think there was another bug involving the quantified type variables in polymorphic specialisation. In any case I refactored `specHeader` and `spec_call` so that the former looks for the extra quantified type variables rather than the latter. This is quite a worthwhile simplification: less code, easier to grok. Test case in simplCore/should_compile/T26682, brilliantly minimised by @sheaf. - - - - - 2433e91d by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: change sectionProtection to take SectionType argument This commit changes `sectionProtection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. - - - - - e5926fbe by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: change isInitOrFiniSection to take SectionType argument This commit changes `isInitOrFiniSection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. Also marks it as exported. - - - - - 244d57d7 by Cheng Shao at 2026-01-09T20:24:43-05:00 compiler: fix split sections on windows This patch fixes split sections on windows by emitting the right COMDAT section header in NCG, see added comment for more explanation. Fix #26696 #26494. ------------------------- Metric Decrease: LargeRecord T9675 size_hello_artifact size_hello_artifact_gzip size_hello_unicode size_hello_unicode_gzip Metric Increase: T13035 ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 182f3d0f by Cheng Shao at 2026-01-09T20:25:28-05:00 iserv: add comment about -fkeep-cafs - - - - - 49675b69 by Matthew Craven at 2026-01-09T20:26:14-05:00 Account for "stupid theta" in demand sig for DataCon wrappers Fixes #26748. - - - - - 95773d28 by Samuel Thibault at 2026-01-10T16:03:18+01:00 Fix the OS string encoding for GNU/Hurd Following https://github.com/haskell/cabal/pull/9434/files , and as seen in the various gnu_HOST_OS usages in the source code, it is expected that GNU/Hurd is advertised as "gnu", like the autotools do. - - - - - 41e3903a by Sven Tennie at 2026-01-11T13:31:18-05:00 Ignore Windows CI tool directories in Git Otherwise, we see thousands of changes in `git status` which is very confusing to work with. - - - - - 36 changed files: - .gitignore - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/InitFini.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/Ppr.hs - compiler/GHC/CmmToAsm/Wasm/FromCmm.hs - compiler/GHC/CmmToAsm/X86/Ppr.hs - compiler/GHC/CmmToC.hs - compiler/GHC/CmmToLlvm/Data.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Types/Id/Make.hs - compiler/GHC/Utils/Binary.hs - libraries/base/changelog.md - libraries/base/src/GHC/Conc.hs - libraries/base/src/GHC/Conc/Sync.hs - libraries/ghc-internal/ghc-internal.cabal.in - libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs - libraries/ghc-internal/src/GHC/Internal/Conc/POSIX.hs - libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs - libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs-boot - libraries/ghc-internal/src/GHC/Internal/Conc/Windows.hs - libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs - libraries/ghc-internal/src/GHC/Internal/Event/Windows/Thread.hs - + libraries/ghc-internal/src/GHC/Internal/STM.hs - libraries/ghc-platform/src/GHC/Platform/ArchOS.hs - + testsuite/tests/dmdanal/should_run/T26748.hs - + testsuite/tests/dmdanal/should_run/T26748.stdout - testsuite/tests/dmdanal/should_run/all.T - 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/interface-stability/base-exports.stdout-ws-32 - + testsuite/tests/simplCore/should_compile/T26682.hs - + testsuite/tests/simplCore/should_compile/T26682a.hs - testsuite/tests/simplCore/should_compile/all.T - utils/iserv/iserv.cabal.in The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/f2077450a58c4911e119c7cbb01c1e… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/f2077450a58c4911e119c7cbb01c1e… You're receiving this email because of your account on gitlab.haskell.org.

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