-
870243e4
by Zubin Duggal at 2026-03-12T17:33:28+05:30
DmdAnal: Take stable unfoldings into account when determining argument demands
Previously, demand analysis only looked at the RHS to compute argument demands.
If the optimised RHS discarded uses of an argument that the stable unfolding
still needed, it would be incorrectly marked absent. Worker/wrapper would then
replace it with LitRubbish, and inlining the stable unfolding would use the
rubbish value, causing a segfault.
To fix, we introduce addUnfoldingDemands which analyses the stable unfolding
with dmdAnal and combines its DmdType with the RHS's via the new `maxDmdType`
which combines the demands of the stable unfolding with the rhs, so we can avoid
any situation where we give an absent demand to something which is still used
by the stable unfolding.
Fixes #26416.
-
669d09f9
by Cheng Shao at 2026-03-13T15:06:07-04:00
hadrian: remove redundant library/rts ways definitions from stock flavours
This patch removes redundant library/rts ways definitions from stock
flavours in hadrian; they can be replaced by applying appropriate
filters on `defaultFlavour`.
-
a27dc081
by Teo Camarasu at 2026-03-13T15:06:51-04:00
ghc-internal: move bits Weak of finalizer interface to base
We move parts of the Weak finalizer interface to `base` only the parts
that the RTS needs to know about are kept in `ghc-internal`.
This lets us then prune our imports somewhat and get rid of some SOURCE imports.
Resolves #26985
-
6eef855b
by Sylvain Henry at 2026-03-13T15:08:18-04:00
Stg/Unarise: constant-folding during unarisation (#25650)
When building an unboxed sum from a literal argument, mkUbxSum
previously emitted a runtime cast via `case primop [lit] of var -> ...`.
This wrapper prevented GHC from recognising the result as a static
StgRhsCon, causing top-level closures to be allocated as thunks instead
of being statically allocated.
Fix: try to perform the numeric literal cast at compile time using
mkLitNumberWrap (wrapping semantics). If successful, return the cast
literal directly with an identity wrapper (no case expression). The
runtime cast path is kept as fallback for non-literal arguments.
Test: codeGen/should_compile/T25650
-
905f8723
by Simon Jakobi at 2026-03-13T15:09:09-04:00
Add regression test for #2057
Test that GHC stops after an interface-file error instead of
continuing into the linker.
The test constructs a stale package dependency on purpose. `pkgB` is compiled
against one version of package `A`, then the same unit id is replaced by an
incompatible build of `A`. When `Main` imports `B`, GHC has to read `B.hi`,
finds an unfolding that still mentions the old `A`, and should fail while
loading interfaces.
Closes #2057.
Assisted-by: Codex
-
a13245a9
by Sylvain Henry at 2026-03-13T15:10:06-04:00
JS: fix recompilation avoidance (#23013)
- we were checking the mtime of the *.jsexe directory, not of a file
- we were not computing the PkgsLoaded at all
-
07442653
by Cheng Shao at 2026-03-13T15:10:51-04:00
hadrian: bump index state & bootstrap plans
This patch bumps hadrian index state & bootstrap plans:
- The updated index state allows bootstrapping from 9.14 without cabal
allow-newer hacks
- The updated bootstrap plans all contain shake-0.19.9 containing
important bugfix, allowing a subsequent patch to bump shake bound to
ensure the bugfix is included
- ghc 9.14.1 bootstrap plan is added
-
fdc1dbad
by Cheng Shao at 2026-03-13T15:10:51-04:00
ci: add ghc 9.14.1 to bootstrap matrix
This patch adds ghc 9.14.1 to bootstrap matrix, so that we test
bootstrapping from ghc 9.14.1.
-
91916079
by Sylvain Henry at 2026-03-13T15:11:43-04:00
T17912: wait for opener thread to block before killing it (#24739)
Instead of a fixed 1000ms delay, poll threadStatus until the opener
thread is in BlockedOnForeignCall, ensuring killThread only fires once
the thread is provably inside the blocking open() syscall. This prevents
the test from accidentally passing on Windows due to scheduling races.
-
baa4ebb4
by Cheng Shao at 2026-03-13T15:12:26-04:00
template-haskell: fix redundant import in Language.Haskell.TH.Quote
This patch fixes a redundant import in `Language.Haskell.TH.Quote`
that causes a ghc build failure when bootstrapping from 9.14 with
validate flavours. Fixes #27014.
-
02e68a86
by Brandon Simmons at 2026-03-13T15:13:19-04:00
Add a cumulative gc_sync_elapsed_ns counter to GHC.Internal.Stats
This makes it possible to get an accurate view of time spent in sync
phase when using prometheus-style sampling. Previously this was only
available for the most recent GC.
This intentionally leaves GHC.Stats API unchanged since it is marked as
deprecated, and API changes there require CLC approval.
Fixes #26944
-
a18fa3c1
by Cheng Shao at 2026-03-14T05:12:14-04:00
configure: make $LLVMAS default to $CC when $CcLlvmBackend is YES
This patch changes the $LLVMAS detection logic in configure so that
when it's not manually specified by the user, it defaults to $CC if
$CcLlvmBackend is YES. It's a more sensible default than auto-detected
clang from the environment, especially when cross-compiling, $CC as
the cross target's LLVM assembler is more compatible with the use case
than the system-wide clang. Fixes #26769.
-
3774086e
by Matthew Pickering at 2026-03-14T05:13:00-04:00
exceptions: annotate onException continuation with WhileHandling
Before this patch, an exception thrown in the `onException` handler
would loose track of where the original exception was thrown.
```
import Control.Exception
main :: IO ()
main = failingAction `onException` failingCleanup
where
failingAction = throwIO (ErrorCall "outer failure")
failingCleanup = throwIO (ErrorCall "cleanup failure")
```
would report
```
T28399: Uncaught exception ghc-internal:GHC.Internal.Exception.ErrorCall:
cleanup failure
HasCallStack backtrace:
throwIO, called at T28399.hs:<line>:<column> in <package-id>:Main
```
notice that the "outer failure" exception is not present in the error
message.
With this patch, any exception thrown is in the handler is annotated
with WhileHandling. The resulting message looks like
```
T28399: Uncaught exception ghc-internal:GHC.Internal.Exception.ErrorCall:
cleanup failure
While handling outer failure
HasCallStack backtrace:
throwIO, called at T28399.hs:7:22 in main:Main
```
CLC Proposal: https://github.com/haskell/core-libraries-committee/issues/397
Fixes #26759
-
63ae8eb3
by Andreas Klebinger at 2026-03-14T05:13:43-04:00
Fix missing profiling header for origin_thunk frame.
Fixes #27007
-
213d2c0e
by Cheng Shao at 2026-03-14T05:14:28-04:00
ci: fix ci-images revision
The current ci-images revision was a commit on the WIP branch of
https://gitlab.haskell.org/ghc/ci-images/-/merge_requests/183, and
it's not on the current ci-images master branch. This patch fixes the
image revision to use the current tip of ci-images master.
-
fc2b083f
by Andreas Klebinger at 2026-03-14T05:15:14-04:00
Revert "hadrian/build-cabal: Better respect and utilize -j"
This reverts commit eab3dbba79650e6046efca79133b4c0a5257613d.
While it's neat this currently isn't well supported on all platforms.
It's time will come, but for now I'm reverting this to avoid issues for
users on slightly unconvential platforms.
This will be tracked at #26977.
-
12a706cf
by Cheng Shao at 2026-03-14T16:37:54-04:00
base: fix redundant imports in GHC.Internal.Weak.Finalize
This patch fixes redundant imports in GHC.Internal.Weak.Finalize that
causes a regression in bootstrapping head from 9.14 with validate
flavours. Fixes #27026.
-
b5d39cad
by Matthew Pickering at 2026-03-14T16:38:37-04:00
Use explicit syntax rather than pure
-
43638643
by Andreas Klebinger at 2026-03-15T18:15:48-04:00
Configure: Fix check for --target support in stage0 CC
The check FP_PROG_CC_LINKER_TARGET used $CC unconditionally to check for
--target support. However this fails for the stage0 config where the C
compiler used is not $CC but $CC_STAGE0.
Since we already pass the compiler under test into the macro I simply
changed it to use that instead.
Fixes #26999
-
18fd0df6
by Simon Hengel at 2026-03-15T18:16:33-04:00
Fix typo in recursive_do.rst
-
a71e5dad
by fendor at 2026-03-17T11:43:12+01:00
Add linkable testsuite
-
85d6f070
by fendor at 2026-03-17T11:43:12+01:00
Record `LinkableUsage` instead of `Linkable` in `LoaderState`
Retaining a ByteCode `Linkable` after it has been loaded retains its
`UnlinkedBCO`, keeping it alive for the remainder of the program.
This starts accumulating a lot of `UnlinkedBCO` and memory over time.
However, the `Linkable` is merely used to later record its usage in
`mkObjectUsage`, which is used for recompilation checking.
However, this is incorrect, as the interface file and bytecode objects
could be in different states, e.g. the interface changes, but the
bytecode library hasn't changed so we don't need to recompile and vice
versa.
By computing a `Fingerprint` for the `ModuleByteCode`, and recording it
in the `LinkableUsage`, we know precisely whether the `ByteCode` object
on disk is outdated.
Thus, parts of this commit just makes sure that we efficiently compute a
`Fingerprint` for `ModuleByteCode` and store it in the on-disk
representation of `ModuleByteCode`.
We change the `LoaderState` to retain `LinkableUsage`, which is smaller
representation of a `Linkable`. This allows us to free the unneeded
fields of `Linkable` after linking them.
We declare the following memory invariants that this commit implements:
* No `LinkablePart` should be retained from `LoaderState`.
* `Linkable`s should be unloaded after they have been loaded.
These invariants are unfortunately tricky to automatically uphold, so we
are simply documenting our assumptions for now.
-------------------------
Metric Increase:
MultiLayerModulesTH_OneShot
-------------------------
We allocate a bit more, but the peak number of bytes doesn't change.
While a bit unfortunate, accepting the metric increase.
We add multiple new performance measurements where we were able to
observe the desired memory invariants. Further, we add regression tests
to validate that the recompilation checker behaves more correct than
before.
-
c2564c99
by fendor at 2026-03-17T11:43:12+01:00
Avoid `panic` during `hscRecompStatus`