Cheng Shao pushed to branch wip/26737 at Glasgow Haskell Compiler / GHC
Commits:
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.
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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
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ebf66f67 by Cheng Shao at 2026-01-17T13:16:50-05:00
Update autoconf scripts
Scripts taken from autoconf a2287c3041a3f2a204eb942e09c015eab00dc7dd
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598624b9 by Andreas Klebinger at 2026-01-17T13:17:32-05:00
CString.hs: Update incorrect comment.
Fixes #26322
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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).
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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%.
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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.
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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.
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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.
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708ad5ca by Simon Peyton Jones at 2026-01-18T17:49:11+01:00
Make the implicit-parameter class have representational role
This MR addresses #26737, by making the built-in class IP
have a representational role for its second parameter.
See Note [IP: implicit parameter class] in
ghc-internal:GHC.Internal.Classes.IP
In fact, IP is (unfortunately, currently) exposed by
base:GHC.Base, so we ran a quick CLC proposal to
agree the change:
https://github.com/haskell/core-libraries-committee/issues/385
Some (small) compilations get faster because they only need to
load (small) interface file GHC.Internal.Classes.IP.hi,
rather than (large) GHC.Internal.Classes.hi.
Metric Decrease:
T10421
T12150
T12425
T24582
T5837
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37 changed files:
- + .gitlab/issue_templates/get-verified.md
- .gitmodules
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- config.guess
- config.sub
- docs/users_guide/9.16.1-notes.rst
- hadrian/doc/flavours.md
- hadrian/src/Settings/Default.hs
- hadrian/src/Settings/Flavours/Benchmark.hs
- hadrian/src/Settings/Flavours/Development.hs
- hadrian/src/Settings/Flavours/GhcInGhci.hs
- hadrian/src/Settings/Flavours/Performance.hs
- hadrian/src/Settings/Flavours/Quick.hs
- hadrian/src/Settings/Flavours/QuickCross.hs
- hadrian/src/Settings/Flavours/Quickest.hs
- hadrian/src/Settings/Flavours/Validate.hs
- hadrian/src/Settings/Packages.hs
- libraries/ghc-internal/ghc-internal.cabal.in
- libraries/ghc-internal/src/GHC/Internal/CString.hs
- libraries/ghc-internal/src/GHC/Internal/Classes.hs
- + libraries/ghc-internal/src/GHC/Internal/Classes/IP.hs
- libraries/haskeline
- − rts/win32/libHSffi.def
- − rts/win32/libHSghc-internal.def
- − rts/win32/libHSghc-prim.def
- 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/interface-stability/ghc-prim-exports.stdout
- testsuite/tests/interface-stability/ghc-prim-exports.stdout-mingw32
- testsuite/tests/th/TH_implicitParams.stdout
- + testsuite/tests/typecheck/should_compile/T26737.hs
- testsuite/tests/typecheck/should_compile/all.T
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/22fb0ced78a19b3e23ab6eb9f1192fb...
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/22fb0ced78a19b3e23ab6eb9f1192fb...
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