-
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@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@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.
-
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.
-
7f15bd15
by Samuel Thibault at 2026-01-12T07:16:25-05:00
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.
-
1db2f240
by Andrew Lelechenko at 2026-01-12T07:17:06-05:00
Add since annotation for Data.Bifoldable1
Fixes #26432
-
e038a383
by Sven Tennie at 2026-01-12T07:17:49-05:00
Ignore Windows CI tool directories in Git
Otherwise, we see thousands of changes in `git status` which is very
confusing to work with.
-
023c301c
by sheaf at 2026-01-13T04:57:30-05:00
Don't re-use stack slots for growing registers
This commit avoids re-using a stack slot for a register that has grown
but already had a stack slot.
For example, suppose we have stack slot assigments
%v1 :: FF64 |-> StackSlot 0
%v2 :: FF64 |-> StackSlot 1
Later, we start using %v1 at a larger format (e.g. F64x2) and we need
to spill it again. Then we **must not** use StackSlot 0, as a spill
at format F64x2 would clobber the data in StackSlot 1.
This can cause some fragmentation of the `StackMap`, but that's probably
OK.
Fixes #26668
-
d0966e64
by fendor at 2026-01-13T04:58:11-05:00
Remove `traceId` from ghc-pkg executable
-
20d7efec
by Simon Peyton Jones at 2026-01-13T12:41:22-05:00
Make SpecContr rules fire a bit later
See #26615 and Note [SpecConstr rule activation]
-
8bc4eb8c
by Andrew Lelechenko at 2026-01-13T12:42:03-05:00
Upgrade mtl submodule to 2.3.2
Fixes #26656
-
c94aaacd
by Cheng Shao at 2026-01-13T12:42:44-05:00
compiler: remove iserv and only use on-demand external interpreter
This patch removes `iserv` from the tree completely. Hadrian would no
longer build or distribute `iserv`, and the GHC driver would use the
on-demand external interpreter by default when invoked with
`-fexternal-interpreter`, without needing to specify `-pgmi ""`. This
has multiple benefits:
- It allows cleanup of a lot of legacy hacks in the hadrian codebase.
- It paves the way for running cross ghc's iserv via cross emulator
(#25523), fixing TH/ghci support for cross targets other than
wasm/js.
-
c1fe0097
by Peter Trommler at 2026-01-14T03:54:49-05:00
PPC NCG: Fix shift right MO code
The shift amount in shift right [arithmetic] MOs is machine word
width. Therefore remove unnecessary zero- or sign-extending of
shift amount.
It looks harmless to extend the shift amount argument because the
shift right instruction uses only the seven lowest bits (i. e. mod 128).
But now we have a conversion operation from a smaller type to word width
around a memory load at word width. The types are not matching up but
there is no check done in CodeGen. The necessary conversion from word
width down to the smaller width would be translated into a no-op on
PowerPC anyway. So all seems harmless if it was not for a small
optimisation in getRegister'.
In getRegister' a load instruction with the smaller width of the
conversion operation was generated. This loaded the most significant
bits of the word in memory on a big-endian platform. These bits were
zero and hence shift right was used with shift amount zero and not one
as required in test Sized.
Fixes #26519
-
2dafc65a
by Cheng Shao at 2026-01-14T03:55:31-05:00
Tree-wide cleanup of cygwin logic
GHC has not supported cygwin for quite a few years already, and will
not resume support in the forseeable future. The only supported
windows toolchain is clang64/clangarm64 of the msys2 project. This
patch cleans up the unused cygwin logic in the tree.
Co-authored-by: Codex <codex@openai.com>
-
66b96e2a
by Teo Camarasu at 2026-01-14T03:56:13-05:00
Set default eventlog-flush-interval to 5s
Resolves #26707
-
d0254579
by Andrew Lelechenko at 2026-01-14T03:56:53-05:00
Document when -maxN RTS option was added
-
f25e2b12
by Cheng Shao at 2026-01-14T11:10:39-05:00
testsuite: remove obsolete --ci option from the testsuite driver
This patch removes the obsolete `--ci` option from the testsuite
driver: neither the CI scripts nor hadrian ever invokes the testsuite
driver with `--ci`, and the perf notes are always fetched to the
`refs/notes/perf` local reference anyway.
-
7964763b
by Julian Ospald at 2026-01-14T11:11:31-05:00
Fix fetch_cabal
* download cabal if the existing one is of an older version
* fix FreeBSD download url
* fix unpacking on FreeBSD
-
6b0129c1
by Julian Ospald at 2026-01-14T11:11:31-05:00
Bump toolchain in CI
-
0f53ccc6
by Julian Ospald at 2026-01-14T11:11:31-05:00
Use libffi-clib
Previously, we would build libffi via hadrian
and bundle it manually with the GHC bindist.
This now moves all that logic out of hadrian
and allows us to have a clean Haskell package
to build and link against and ship it without
extra logic.
This patch still retains the ability to link
against a system libffi.
The main reason of bundling libffi was that on
some platforms (e.g. FreeBSD and Mac), system libffi
is not visible to the C toolchain by default,
so users would require settings in e.g. cabal
to be able to compile anything.
This adds the submodule libffi-clib to the repository.
-
5e1cd595
by Peng Fan at 2026-01-14T11:12:26-05:00
NCG/LA64: add support for la664 micro architecture
Add '-mla664' flag to LA664, which has some new features:
atomic instructions, dbar hints, etc.
'LA464' is the default so that unrecognized instructions are not
generated.
-
c56567ec
by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Add evals for strict data-con args in worker-functions
This fixes #26722, by adding an eval in a worker for
arguments of strict data constructors, even if the
function body uses them strictly.
See (WIS1) in Note [Which Ids should be strictified]
I took the opportunity to make substantial improvements in the
documentation for call-by-value functions. See especially
Note [CBV Function Ids: overview] in GHC.Types.Id.Info
Note [Which Ids should be CBV candidates?] ditto
Note [EPT enforcement] in GHC.Stg.EnforceEpt
among others.
-
9719ce5d
by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Improve `interestingArg`
This function analyses a function's argument to see if it is
interesting enough to deserve an inlining discount. Improvements
for
* LitRubbish arguments
* exprIsExpandable arguments
See Note [Interesting arguments] which is substantially rewritten.
-
7b616b9f
by Cheng Shao at 2026-01-16T06:45:00-05:00
compiler: fix regression when compiling foreign stubs in the rts unit
This patch fixes a regression when compiling foreign stubs in the rts
unit introduced in 05e25647f72bc102061af3f20478aa72bff6ff6e. A simple
revert would fix it, but it's better to implement a proper fix with
comment for better understanding of the underlying problem, see the
added comment for explanation.
Co-authored-by: Codex <codex@openai.com>
-
c343ef64
by Sylvain Henry at 2026-01-16T06:45:51-05:00
base: remove GHC.JS.Prim.Internal.Build (#23432)
See accepted CLC proposal https://github.com/haskell/core-libraries-committee/issues/329
-
29c0aceb
by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
-
8b59e62c
by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
-
9e5e0234
by mangoiv at 2026-01-17T06:03:03-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
-
b18b2c42
by Cheng Shao at 2026-01-17T06:03:44-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `@llvm.compiler.used` instead of `@llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex@openai.com>
-
ebf66f67
by Cheng Shao at 2026-01-17T13:16:50-05:00
Update autoconf scripts
Scripts taken from autoconf a2287c3041a3f2a204eb942e09c015eab00dc7dd
-
598624b9
by Andreas Klebinger at 2026-01-17T13:17:32-05:00
CString.hs: Update incorrect comment.
Fixes #26322
-
eea2036b
by Cheng Shao at 2026-01-18T10:00:49-05:00
libraries: bump haskeline submodule to 0.8.4.1
This patch bumps the haskeline submodule to 0.8.4.1 which includes an
important fix for an ANSI handling bug on Windows
(https://github.com/haskell/haskeline/pull/126).
-
87d8f6c2
by Cheng Shao at 2026-01-18T10:01:30-05:00
hadrian: replace default -H32m/-H64m with -O64M to improve mutator productivity
Most hadrian build flavours pass `-H32m`/`-H64m` to GHC as
conventional wisdom to improve mutator productivity and reduce GC
overhead. They were inherited from the legacy Make build system, and
there used to be make flags to instrument a build process with
`-Rghc-timing` option to collect GC stats of each GHC run from stderr.
It's time to revisit whether there are better defaults for
`-H32m`/`-H64m`, and this patch changes it to `-O64M` which indeed
improves mutator productivity based on real statistics. `-O64M` is
more aggressive than `-H64m`; it allows the old generation to grow to
at least 64M before triggering major GC and reduces major GC runs.
The stats of a clean build with `validate` flavour and `-H64m`:
```
h64m.log
matched RTS stat lines: 5499
sum MUT cpu : 2400.808 s
sum GC cpu : 1378.292 s
sum MUT elapsed : 2788.253 s
sum GC elapsed : 1389.233 s
GC/MUT cpu ratio : 0.574 (GC is 57.4% of MUT)
GC/MUT elapsed ratio : 0.498 (GC is 49.8% of MUT)
GC fraction of (MUT+GC) cpu : 36.5%
GC fraction of (MUT+GC) elapsed : 33.3%
per-line GC/MUT cpu ratio: median 0.691, p90 1.777
per-line GC/MUT elapsed ratio: median 0.519, p90 1.081
```
The stats of a clean build with `validate` flavour and `-O64M`:
```
o64m.log
matched RTS stat lines: 5499
sum MUT cpu : 2377.383 s
sum GC cpu : 1127.146 s
sum MUT elapsed : 2758.857 s
sum GC elapsed : 1135.587 s
GC/MUT cpu ratio : 0.474 (GC is 47.4% of MUT)
GC/MUT elapsed ratio : 0.412 (GC is 41.2% of MUT)
GC fraction of (MUT+GC) cpu : 32.2%
GC fraction of (MUT+GC) elapsed : 29.2%
per-line GC/MUT cpu ratio: median 0.489, p90 1.099
per-line GC/MUT elapsed ratio: median 0.367, p90 0.806
```
Mutator time is roughly in the same ballpark, but GC CPU time has
reduced by 18.22%, and mutator productivity has increased from 63.5%
to 67.8%.
-
8372e13d
by Cheng Shao at 2026-01-18T10:02:12-05:00
rts: remove unused .def files from rts/win32
This patch removes unused .def files from `rts/win32`, given we don't
build .dll files for rts/ghc-internal/ghc-prim at all. Even when we
resurrect win32 dll support at some point in the future, these .def
files still contain incorrect symbols anyway and won't be of any use.
-
f6af485d
by Cheng Shao at 2026-01-18T10:03:19-05:00
.gitmodules: use gitlab mirror for the libffi-clib submodule
This patch fixes .gitmodules to use the gitlab mirror for the
libffi-clib submodule, to make it coherent with other submodules that
allow ghc developers to experiment with wip branches in submodules for
ghc patches. Fixes #26783.
-
41432d25
by Cheng Shao at 2026-01-18T10:05:13-05:00
hadrian: remove the horrible i386 speedHack
When hadrian builds certain rts objects for i386, there's a horrible
speedHack that forces -fno-PIC even for dynamic ways of those objects.
This is not compatible with newer versions of gcc/binutils as well as
clang/lld, and this patch removes it. Fixes #26792.
-
323eb8f0
by Cheng Shao at 2026-01-18T21:48:19-05:00
hadrian: enable split sections for cross stage0
This patch fixes a minor issue with `splitSectionsArgs` in hadrian:
previously, it's unconditionally disabled for stage0 libraries because
it's not going to be shipped in the final bindists. But it's only true
when not cross compiling. So for now we also need to enable it for
cross stage0 as well.
-
3fadfefe
by Andreas Klebinger at 2026-01-18T21:49:01-05:00
RTS: Document -K behaviour better
-
22304cd2
by Cheng Shao at 2026-01-20T10:57:39+01:00
WIP