-
96fce8d0
by Cheng Shao at 2025-12-12T01:17:51+01:00
hadrian: add support for building with UndefinedBehaviorSanitizer
This patch adds a +ubsan flavour transformer to hadrian to build all
stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is
particularly useful to catch potential undefined behavior in the RTS
codebase.
-
f7a06d8c
by Cheng Shao at 2025-12-12T01:17:51+01:00
ci: update alpine/fedora & add ubsan job
This patch updates alpine image to 3.23, fedora image to 43, and adds
a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in
validate/nightly pipelines to catch undefined behavior in the RTS
codebase.
-
2ccd11ca
by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix zero-length VLA undefined behavior in interpretBCO
This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0
```
-
4156ed19
by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix unaligned ReadSpB in interpretBCO
This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment
```
To perform proper unaligned read, we define StgUnalignedWord as a type
alias of StgWord with aligned(1) attribute, and load StgUnalignedWord
instead of StgWord in ReadSpB, so the C compiler is aware that we're
not loading with natural alignment.
-
fef89fb9
by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix signed integer overflow in subword arithmetic in interpretBCO
This commit fixes signed integer overflow in subword arithmetic in
interpretBCO, see added note for detailed explanation.
-
3c001377
by Cheng Shao at 2025-12-13T05:03:15-05:00
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>
-
123a8d77
by Peter Trommler at 2025-12-13T05:03:57-05:00
Cmm: remove restriction in MachOp folding
-
0b54b5fd
by Andreas Klebinger at 2025-12-13T05:04:38-05:00
Remove explicit Typeable deriviations.
-
08b13f7b
by Cheng Shao at 2025-12-13T05:05:18-05:00
ci: set gc.auto=0 during setup stage
This patch sets `gc.auto=0` during `setup` stage of CI, see added
comment for detailed explanation.
-
3b5aecb5
by Ben Gamari at 2025-12-13T23:43:10+01:00
Bump exceptions submodule to 0.10.11
-
c32de3b0
by Johan Förberg at 2025-12-15T02:36:03-05:00
base: Define Semigroup and Monoid instances for lazy ST
CLC proposal:
https://github.com/haskell/core-libraries-committee/issues/374
Fixes #26581
-
4f8b660c
by mangoiv at 2025-12-15T02:37:05-05:00
ci: do not require nightly cabal-reinstall job to succeed
-
2c2a3ef3
by Cheng Shao at 2025-12-15T11:51:53-05:00
docs: drop obsolete warning about -fexternal-interpreter on windows
This patch drops an obsolete warning about -fexternal-interpreter not
supported on windows; it is supported since a long time ago, including
the profiled way.
-
68573aa5
by Marc Scholten at 2025-12-15T11:53:00-05:00
haddock: Drop Haddock.Backends.HaddockDB as it's unused
-
b230d549
by mangoiv at 2025-12-16T15:17:45-05:00
base: generalize delete{Firsts,}By
When we delete{Firsts,}By we should not require the
lists to be the same type. This is an especially useful
generalisation in the case of deleteFirstsBy because we
can skip an invocation of the map function.
This change was discussed on the core-libraries-committee's bug
tracker at https://github.com/haskell/core-libraries-committee/issues/372.
-
6a2b43e3
by Cheng Shao at 2025-12-16T15:18:30-05:00
compiler: clean up redundant LANGUAGE pragmas
This patch bumps `default-language` of `ghc`/`ghc-bin` from `GHC2021`
to `GHC2024` (which is supported in ghc 9.10, current boot ghc lower
version bound), and also cleans up redundant `LANGUAGE` pragmas (as
well as `default-extensions`/`other-extensions`) that are already
implied by `GHC2024`.
Co-authored-by: Codex <codex@openai.com>
-
fca9cd7c
by sheaf at 2025-12-18T13:18:18-05:00
X86 CodeGen: fix assign_eax_sse_regs
We must set %al to the number of SSE2 registers that contain arguments
(in case we are dealing with a varargs function). The logic for counting
how many arguments reside in SSE2 registers was incorrect, as it used
'isFloatFormat', which incorrectly ignores vector registers.
We now instead do case analysis on the register class:
is_sse_reg r =
case targetClassOfReg platform r of
RcFloatOrVector -> True
RcInteger -> False
This change is necessary to prevent segfaults in T20030_test1j, because
subsequent commits change the format calculations, resulting in vector
formats more often.
-
53150617
by sheaf at 2025-12-18T13:18:19-05:00
X86 regUsageOfInstr: fix format for IMUL
When used with 8-bit operands, the IMUL instruction returns the result
in the lower 16 bits of %rax (also known as %ax). This is different
than for the other sizes, where an input at 16, 32 or 64 bits will
result in 16, 32 or 64 bits of output in both %rax and %rdx.
This doesn't affect the behaviour of the compiler, because we don't
allow partial writes at sub-word sizes. The rationale is explained
in Wrinkle [Don't allow scalar partial writes] in Note [Register formats in liveness analysis],
in GHC.CmmToAsm.Reg.Liveness.
-
c7a56dd1
by sheaf at 2025-12-18T13:18:19-05:00
Liveness analysis: consider register formats
This commit updates the register allocator to be a bit more careful in
situations in which a single register is used at multiple different
formats, e.g. when xmm1 is used both to store a Double# and a DoubleX2#.
This is done by introducing the 'Regs' newtype around 'UniqSet RegWithFormat',
for which the combining operations take the larger of the two formats
instead of overriding the format.
Operations on 'Regs' are defined in 'GHC.CmmToAsm.Reg.Regs'. There is
a modest compile-time cost for the additional overhead for tracking
register formats, which causes the metric increases of this commit.
The subtle aspects of the implementation are outlined in
Note [Register formats in liveness analysis] in GHC.CmmToAsm.Reg.Liveness.
Fixes #26411 #26611
-------------------------
Metric Increase:
T12707
T26425
T3294
-------------------------
-
c2e83339
by sheaf at 2025-12-18T13:18:19-05:00
Register allocator: reload at same format as spill
This commit ensures that if we spill a register onto the stack at a
given format, we then always reload the register at this same format.
This ensures we don't end up in a situation where we spill F64x2 but end
up only reloading the lower F64. This first reload would make us believe
the whole data is in a register, thus silently losing the upper 64 bits
of the spilled register's contents.
Fixes #26526
-
55ab583b
by sheaf at 2025-12-18T13:18:19-05:00
Register allocation: writes redefine format
As explained in Note [Allocated register formats] in GHC.CmmToAsm.Reg.Linear,
we consider all writes to redefine the format of the register.
This ensures that in a situation such as
movsd .Ln6m(%rip),%v1
shufpd $0,%v1,%v1
we properly consider the broadcast operation to change the format of %v1
from F64 to F64x2.
This completes the fix to #26411 (test in T26411b).
-
951402ed
by Vladislav Zavialov at 2025-12-18T13:19:05-05:00
Parser: improve mkModuleImpExp, remove checkImportSpec
1. The `mkModuleImpExp` helper now knows whether it is processing an import or
export list item, and uses this information to produce a more accurate error
message for `import M (T(..,x))` with PatternSynonyms disabled.
The old message incorrectly referred to this case as an export form.
2. The `checkImportSpec` helper is removed in favor of more comprehensive error
checking in `mkModuleImpExp`.
3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been
made more explicit in the comments and assertions (calls to 'panic').
Test case: import-syntax-no-ext
-
47d83d96
by Vladislav Zavialov at 2025-12-18T13:19:06-05:00
Subordinate namespace-specified wildcards (#25901)
Add support for subordinate namespace-specified wildcards
`X(type ..)` and `X(data ..)` to import and export lists.
Examples:
import M (Cls(type ..)) -- imports Cls and all its associated types
import M (Cls(data ..)) -- imports Cls and all its methods
module M (R(data ..), C(type ..)) where
-- exports R and all its data constructors and record fields;
-- exports C and all its associated types, but not its methods
The scope of this change is limited to the case where the wildcard is the only
subordinate import/export item, whereas the more complex forms `X(type .., f)`
or `X(type .., data ..)` are unsupported and raise the newly introduced
PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later.
Summary of the changes:
1. Refactor IEThingAll to store its extension field XIEThingAll as a record
IEThingAllExt instead of a tuple.
2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt,
representing an optional namespace specifier `type` or `data` in front
of a subordinate wildcard `X(..)`.
3. Extend the grammar in Parser.y with productions for `type ..` and `data ..`
in subordinate import/export items.
4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a
NamespaceSpecifier; use it in `filterImports` and `exports_from_avail`
to account for the namespace specifier in IEThingAll.
5. Improve diagnostics by storing more information in DodgyImportsEmptyParent
and DodgyExportsEmptyParent.
Test cases:
T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a
T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w
DodgyImports02 DodgyImports03 DodgyImports04
-
eac418bb
by Recursion Ninja at 2025-12-18T13:19:48-05:00
Removing the 'Data' instance for 'InstEnv'.
The 'Data' instance is blocking work on Trees that Grow, and the
'Data' instance seem to have been added without a clear purpose.
-
e920e038
by Recursion Ninja at 2025-12-18T13:19:48-05:00
'Decouple Language.Haskell.Syntax.Decls' from 'GHC.Unit.Module.Warnings'
-
bd38b76c
by Cheng Shao at 2025-12-18T13:20:31-05:00
testsuite: improve coverage of foundation test
This patch refactors the `foundation` test a bit to improve coverage:
- Instead of using a hard-coded seed, a random seed is now taken from
the command line, and printed upon test failure. This improves test
coverage over many future CI runs, and shall a failure occur, the
seed is available in the CI log for local reproduction.
- The iterations count is bumped to 1000 instead of 100, similar to
the bump in `test-primops`. Runtime timeout is bumped 2x just to be
safe.
- Improve `newLCGGen` by using non-atomic loads/stores on a
`MutableByteArray#` for storing mutable `Word64`, this test doesn't
use parallelism in the first place
- Fixed a few compiler warnings and removed redundant pragmas and
imports
Co-authored-by: Codex <codex@openai.com>
-
3995187c
by Sylvain Henry at 2025-12-18T13:21:45-05:00
Doc: document -pgmi "" (#26634)
-
5729418c
by Cheng Shao at 2025-12-18T13:22:29-05:00
rts: use __builtin_mul_overflow for hs_mulIntMayOflo
This patch uses `__builtin_mul_overflow` to implement
`hs_mulIntMayOflo`. This is a GNU C checked arithmetic builtin
function supported by gcc/clang, is type-generic so works for both
32-bit/64-bit, and makes the code both more efficient and easier to
read/maintain than the previous hand rolled logic.
-
1ca4b49a
by Cheng Shao at 2025-12-18T13:23:11-05:00
compiler/rts: fix ABI mismatch in barf() invocations
This patch fixes a long-standing issue of ABI mismatch in `barf()`
invocations, both in compiler-emitted code and in hand written Cmm
code:
- In RTS, we have `barf()` which reports a fatal internal error
message and exits the program.
- `barf()` is a variadic C function! When used as a callee of a
foreign call with `ccall` calling convention instead of `capi`,
there is an ABI mismatch between the caller and the callee!
- Unfortunately, both the compiler and the Cmm sources contain many
places where we call `barf()` via `ccall` convention!! Like, when
you write `foreign "C" barf("foo object (%p) entered!", R1)`, it
totally doesn't do what you think it'll do at all!! The second
argument `R1` is not properly passed in `va_list`, and the behavior
is completely undefined!!
- Even more unfortunately, this issue has been sitting around long
enough because the ABI mismatch is subtle enough on normie platforms
like x64 and arm64.
- But there are platforms like wasm32 that are stricter about ABI, and
the broken `barf()` invocations already causes trouble for wasm
backend: we had to use ugly hacks like `barf(errmsg, NULL)` to make
`wasm-ld` happy, and even with this band-aid, compiler-generated
`barf()` invocations are still broken, resulting in regressions in
certain debug-related functionality, e.g. `-dtag-inference-checks`
is broken on wasm32 (#22882).
This patch properly fixes the issue:
- We add non-variadic `barf` wrappers in the RTS that can be used as
`ccall` callees
- Both the compiler `emitBarf` logic and the hand-written Cmm are
changed to call these wrappers
- `emitBarf` now also properly annotates the foreign call as
`CmmNeverReturns` to indicate it's a noreturn call to enable more
efficient code generation
`-dtag-inference-checks` now works on wasm. Closes #22882.
Co-authored-by: Codex <codex@openai.com>
-
b3dd23b9
by Vilim Lendvaj at 2025-12-18T13:23:57-05:00
Remove outdated comment
The Traversable instance for ZipList is no longer in
GHC.Internal.Data.Traversable. In fact, it is right below this very comment.
-
9a9c2f03
by Cheng Shao at 2025-12-18T13:24:39-05:00
compiler: remove unused OtherSection logic
This patch removes the OtherSection logic in Cmm, given it's never
actually used by any of our backends.
-
91edd292
by Wolfgang Jeltsch at 2025-12-19T03:18:19-05:00
Remove unused known-key and name variables for generics
This removes the known-key and corresponding name variables for `K1`,
`M1`, `R`, `D`, `C`, `S`, and `URec` from `GHC.Generics`, as they are
apparently nowhere used in GHC’s source code.
-
73ee7e38
by Wolfgang Jeltsch at 2025-12-19T03:19:02-05:00
Remove unused known keys and names for generics classes
This removes the known-key and corresponding name variables for
`Datatype`, `Constructor`, and `Selector` from `GHC.Generics`, as they
are apparently nowhere used in GHC’s source code.
-
f69c5f14
by Cheng Shao at 2025-12-19T03:19:45-05:00
wasm: fix handling of ByteArray#/MutableByteArray# arguments in JSFFI imports
This patch fixes the handling of ByteArray#/MutableByteArray#
arguments in JSFFI imports, see the amended note and manual for
explanation. Also adds a test to witness the fix.
Co-authored-by: Codex <codex@openai.com>
-
224446a2
by Cheng Shao at 2025-12-20T07:49:54-05:00
rts: workaround -Werror=maybe-uninitialized false positives
In some cases gcc might report -Werror=maybe-uninitialized that we
know are false positives, but need to workaround it to make validate
builds with -Werror pass.
-
251ec087
by Cheng Shao at 2025-12-20T07:49:54-05:00
hadrian: use -Og as C/C++ optimization level when debugging
This commit enables -Og as optimization level when compiling the debug
ways of rts. According to gcc documentation
(https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og),
-Og is a better choice than -O0 for producing debuggable code. It's
also supported by clang as well, so it makes sense to use it as a
default for debugging. Also add missing -g3 flag to C++ compilation
flags in +debug_info flavour transformer.
-
fb586c67
by Cheng Shao at 2025-12-20T07:50:36-05:00
compiler: replace DList with OrdList
This patch removes `DList` logic from the compiler and replaces it
with `OrdList` which also supports O(1) concatenation and should be
more memory efficient than the church-encoded `DList`.
-
8149c987
by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: add with_profiled_libs flavour transformer
This patch adds a `with_profiled_libs` flavour transformer to hadrian
which is the exact opposite of `no_profiled_libs`. It adds profiling
ways to stage1+ rts/library ways, and doesn't alter other flavour
settings. It is useful when needing to test profiling logic locally
with a quick flavour.
-
746b18cd
by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: fix missing profiled dynamic libraries in profiled_ghc
This commit fixes the profiled_ghc flavour transformer to include
profiled dynamic libraries as well, since they're supported by GHC
since !12595.
-
4dd7e3b9
by Cheng Shao at 2025-12-20T17:07:33-05:00
ci: set http.postBuffer to mitigate perf notes timeout on some runners
This patch sets http.postBuffer to mitigate the timeout when fetching
perf notes on some runners with slow internet connection. Fixes #26684.
-
bc36268a
by Wolfgang Jeltsch at 2025-12-21T16:23:24-05:00
Remove unused known keys and names for type representations
This removes the known-key and corresponding name variables for
`TrName`, `TrNameD`, `TypeRep`, `KindRepTypeLitD`, `TypeLitSort`, and
`mkTrType`, as they are apparently nowhere used in GHC’s source code.
-
ff5050e9
by Wolfgang Jeltsch at 2025-12-21T16:24:04-05:00
Remove unused known keys and names for natural operations
This removes the known-key and corresponding name variables for
`naturalAndNot`, `naturalLog2`, `naturalLogBaseWord`, `naturalLogBase`,
`naturalPowMod`, `naturalSizeInBase`, `naturalToFloat`, and
`naturalToDouble`, as they are apparently nowhere used in GHC’s source
code.
-
424388c2
by Wolfgang Jeltsch at 2025-12-21T16:24:45-05:00
Remove the unused known key and name for `Fingerprint`
This removes the variables for the known key and the name of the
`Fingerprint` data constructor, as they are apparently nowhere used in
GHC’s source code.
-
a1ed86fe
by Wolfgang Jeltsch at 2025-12-21T16:25:26-05:00
Remove the unused known key and name for `failIO`
This removes the variables for the known key and the name of the
`failIO` operation, as they are apparently nowhere used in GHC’s source
code.
-
b8220daf
by Wolfgang Jeltsch at 2025-12-21T16:26:07-05:00
Remove the unused known key and name for `liftM`
This removes the variables for the known key and the name of the `liftM`
operation, as they are apparently nowhere used in GHC’s source code.
-
eb0628b1
by Wolfgang Jeltsch at 2025-12-21T16:26:47-05:00
Fix the documentation of `hIsClosed`
-
b1ab6928
by Cheng Shao at 2025-12-22T07:53:11+01:00
rts: replace initMutex/closeMutex with static initializer
This patch drops all `initMutex`/`closeMutex` logic from the RTS, and
instead define and use a static initializer `MUTEX_INIT` to initialize
a `Mutex`. For both pthreads/win32 cases, a mutex is just a
process-private cheap resource that doesn't really need to be freed
upon RTS exit; it can be statically initialized inplace using either
`PTHREAD_MUTEX_INITIALIZER` or `SRWLOCK_INIT`, hence we define
`MUTEX_INIT` and prefer to use it to initialize a `Mutex`.
All `closeMutex` invocations are dropped. Most `initMutex` invocations
are dropped, except non-global ones, and the ones that need to be
re-initialized in the child process after `forkProcess`, these are
replaced by assigning `MUTEX_INIT`. The patch also drops
`initIpe`/`exitIpe`/`stat_exit` since they are now no-ops. Also cleans
up legacy wasm32 stub definitions, since wasi-libc started shipping
basic pthread stubs in wasip1 sysroot.
Sadly, we can't do the same for condition variables, since
`PTHREAD_COND_INITIALIZER` defaults to real-time but we want monotonic
time.
The main motivation of this patch is not just housecleaning: it is to
make it easier to acquire/release a global Mutex in C initializer
functions generated by GHC (some custom instrumentation for debugging
purpose). Now that a global Mutex can be statically initialized
in-place using `MUTEX_INIT`, the initializer code can acquire/release
it without worrying about Mutex initialization, otherwise it needs to
be initialized in another initializer function with higher priority,
which complicates the implementation.
Co-authored-by: Codex <codex@openai.com>