-
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@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@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@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@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@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
-
3888f0d9
by Simon Peyton Jones at 2026-01-09T17:42:50+00:00
Make SpecContr rules fire a bit later
See #26615 and Note [SpecConstr rule activation]