GitLab

Zubin pushed to branch wip/9.14.2-backports at Glasgow Haskell Compiler / GHC

Commits:

1aa2821e

by Simon Hengel at 2026-07-15T17:13:14+05:30

Reference correct package in error messages for reexported modules

(fixes #27417)

(cherry picked from commit a805b2a25021606b30d250e084d4beecbfac0d0a)

112110e6

by Luite Stegeman at 2026-07-15T17:13:14+05:30

rts: handle large AP closures in compacting GC

The function update_fwd_large in the compacting GC could run into
an unexpected object with the following error:

  internal error: update_fwd_large: unknown/strange object  24

Closure type 24 is the AP closure, which was not handled in
upd_fwd_large. This patch adds handling them.

fixes #27434

(cherry picked from commit cca0d58963f802a8b2e43aa2dbc58592f8ad07bb)

faf5f76d

by Cheng Shao at 2026-07-15T17:13:14+05:30

compiler: fix missing handling of CmmUnsafeForeignCall node in LayoutStack

This patch fixes missing handling of `CmmUnsafeForeignCall` middle
node in the `LayoutStack` pass.

Before proc-points splitting, this pass computes liveliness of local
registers, and spills those alive across a Cmm native call onto the
stack. It need to traverse all middle nodes in each block and check
whether a local register is an assignee, if so then the previous
mapping in `sm_regs` is invalidated and needs to be dropped. However,
it didn't handle `CmmUnsafeForeignCall` node which may also assign to
a local register. When proc-points splitting is enabled, this can
produce an invalid basic block that doesn't properly backup the
updated local register to the stack before doing a Cmm call, resulting
in completely invalid runtime behavior.

The patch also adds a `T27447` regression test. With no-TNTC or with
LLVM backend, without the fix the test case would output a stale
0x1111111111111111 value, instead of the expected 0x2222222222222222
output.

Fixes #27447.

Co-authored-by: Codex <codex@openai.com>
(cherry picked from commit 3f00f234d0d5b3b3b2a23a5dc70ce372eb9bbdb4)

2b55b40a

by Cheng Shao at 2026-07-15T17:13:14+05:30

ci: use treeless fetch for perf notes

This patch improves the ci logic for fetching perf notes by using
treeless fetch
(https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-shallow-clone),
to avoid downloading all blobs of the perf notes repo at once, and
only fetch the actually required blobs on-demand when needed. This
makes the initial `test-metrics.sh pull` operation much faster, and
also more robust, since we are seeing an increasing rate of 504 errors
in CI when fetching all perf notes at once, which is a major source of
CI flakiness at this point.

Co-authored-by: Codex <codex@openai.com>
(cherry picked from commit 3c0013778b4459c1f8e56cd0dc2600f5bb3769d2)

fcc4231f

by mangoiv at 2026-07-15T17:13:14+05:30

ci: retry fetching test metrics

Retry fetching test metrics to make the CI not fail if the services is
temporarily unavailable

(cherry picked from commit b7e24044fde064cb3f0d44c36872a86d024cd7d4)

03a35805

by Zubin Duggal at 2026-07-15T17:13:15+05:30

Bump semaphore-compat submodule to 2.0.1

This versions includes some cruicial fixes for darwin

(cherry picked from commit 4180af3f71754472dbd49b85179b25fd29bd9998)

c1c0031f

by Zubin Duggal at 2026-07-15T17:13:15+05:30

CorePrep: Don't speculatively evaluate bindings that we have already discovered to be absent

In #25924, we segfault because speculation forces a projection out of a RUBBISH dictionary
(which we generated because it absent).

Solution: Don't speculate on bindings we already know are absent.

Fixes 25924

(cherry picked from commit 9b714c4c833461c621f0a050680848d7248aa57e)

6e514e1d

by Zubin Duggal at 2026-07-15T17:13:15+05:30

Don't make absent fillers for terminating types

In #25924 we discovered that we could speculatively evaluate an absent filler
for a dictionary, and project a field (a superclass selector) out of it,
resulting in segfaults.

Solution: Never make an absent filler or rubbish literal for a terminating type
like a dictionary. mkAbsentFiller returns Nothing for isTerminatingType, so
worker/wrapper and the specialiser keep the real argument instead.

Some small metric decreases because we do a little less work in the
simplifier now.

Metric Decrease:
    T9872a
    T9872b
    T9872c
    TcPlugin_RewritePerf

(cherry picked from commit 4a59b3eece9b7106fcbe73d2d06a49755be4ea8f)

30f20fff

by Andreas Klebinger at 2026-07-15T17:13:15+05:30

Fix a profiling race condition resulting in segfaults.

StgToCmm: Don't assume tagged FUN closures in closureCodeBody.
When entering a closure the self/node pointer might not be tagged in
some situations when a thunk is evaluated by multiple threads.
So we most AND away the tag bits rather than subtracting an expected tag.

Apply.cmm: Fix a race condition occuring when a thunk is mutated during GC.

In stg_ap_0_fast when might need to run GC before entering a thunk. If this happens
another thread or the GC itself might mutate the closure making entering it no longer
valid. We now check for this.

Add test and changelog for #27123 fixes.

(cherry picked from commit ed09895d7de1ca116a561868c151fd825a16ad0c)

9f78fae4