Magnus pushed to branch ghc-9.12 at Glasgow Haskell Compiler / GHC Commits: 12988118 by Cheng Shao at 2026-05-13T13:47:34+02:00 testsuite: mark T22159 as fragile This patch marks T22159 as fragile on Windows for issue described in #27248. Before we get to the bottom of those failures, this unblocks newer Windows runners. (cherry picked from commit 4392aa200fcd336154f58764488a798ba3f57701) - - - - - c0b9c162 by Zubin Duggal at 2026-05-13T18:51:34+02:00 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. (cherry picked from commit 870243e4f2a24730539f01ee8e3f3949c42ff312) - - - - - 5b5aac16 by Simon Jakobi at 2026-05-14T16:19:04+02:00 Fix -dsuppress-uniques for free variables in demand signatures Before: Str=b{sXyZ->S} With this patch: Str=b{S} T13143.stderr is updated accordingly. Fixes #27106. (cherry picked from commit 5b82080a3f3dd476e198130218d4da729fb5334a) - - - - - 2aacc599 by Andreas Klebinger at 2026-05-20T11:51:11+02:00 Fix missing profiling header for origin_thunk frame. Fixes #27007 (cherry picked from commit 63ae8eb38c54eaba77949b048a3621a5f4ca76e3) - - - - - 0acea5fa by Luite Stegeman at 2026-05-20T11:51:13+02:00 bytecode: Carefully SLIDE off the end of a stack chunk The SLIDE bytecode instruction was not checking for stack chunk boundaries and could corrupt the stack underflow frame, leading to crashes. We add a check to use safe writes if we cross the chunk boundary and also handle stack underflow if Sp is advanced past the underflow frame. fix #27001 (cherry picked from commit 72b20fc0ad4b6ad12c67f686af5cb42700656886) - - - - - b2e91dc8 by Andreas Klebinger at 2026-05-20T11:51:13+02:00 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 (cherry picked from commit 43638643adbe999de8d2288a40bdd15c602f6481) - - - - - 682654f0 by Ian Duncan at 2026-05-20T11:51:14+02:00 AArch64: fix MOVK regUsageOfInstr to mark dst as both read and written MOVK (move with keep) modifies only a 16-bit slice of the destination register, so the destination is both read and written. The register allocator must know this to avoid clobbering live values. Update regUsageOfInstr to list the destination in both src and dst sets. No regression test: triggering the misallocation requires specific register pressure around a MOVK sequence, which is difficult to reliably provoke from Haskell source. (cherry picked from commit 2823b03966e495581f4695f07649c5885306b656) - - - - - a50fabdf by Zubin Duggal at 2026-05-20T11:51:14+02:00 compiler/ffi: Collapse void pointer chains in capi wrappers New gcc/clang treat -Wincompatible-pointer-types as an error by default. Since C only allows implicit conversion from void*, not void**, capi wrappers for functions taking e.g. abstract** would fail to compile when the Haskell type Ptr (Ptr Abstract) was naively translated to void**. Collapse nested void pointers to a single void* when the pointee type has no known C representation. Fixes #26852 (cherry picked from commit 80e2dd4f084eff9cc857b31daf9ea2e9e460c727) - - - - - b62022a9 by Zubin Duggal at 2026-05-20T11:51:14+02:00 hadrian: Don't include the package hash in the haddock directory Since GHC 9.8 and hash_unit_ids, haddock urls have looked like`ghc-9.10.3/doc/html/libraries/base-4.20.2.0-39f9/**/*.html` The inclusion of the hash makes it hard for downstream non-boot packages to properly link to these files, as the hash is not part of a standard cabal substitution. Since we only build one version of each package, we don't need the hash to disambiguate anything, we can just remove it. Fixes #26635 (cherry picked from commit 07267f79d91169f474cacc8bcd38d76a6e97887d) - - - - - 0f95ad43 by ARATA Mizuki at 2026-05-20T11:51:14+02:00 rts: Align stack to 64-byte boundary in StgRun on x86 When LLVM spills AVX/AVX-512 vector registers to the stack, it requires 32-byte (__m256) or 64-byte (__m512) alignment. If the stack is not sufficiently aligned, LLVM inserts a realignment prologue that reserves %rbp as a frame pointer, conflicting with GHC's use of %rbp as an STG callee-saved register and breaking the tail-call-based calling convention. Previously, GHC worked around this by lying to LLVM about the stack alignment and rewriting aligned vector loads/stores (VMOVDQA, VMOVAPS) to unaligned ones (VMOVDQU, VMOVUPS) in the LLVM Mangler. This had two problems: - It did not extend to AVX-512, which requires 64-byte alignment. (#26595) - When Haskell calls a C function that takes __m256/__m512 arguments on the stack, the callee requires genuine alignment, which could cause a segfault. (#26822) This patch genuinely aligns the stack to 64 bytes in StgRun by saving the original stack pointer before alignment and restoring it in StgReturn. We now unconditionally advertise 64-byte stack alignment to LLVM for all x86 targets, making rewriteAVX in the LLVM Mangler unnecessary. STG_RUN_STACK_FRAME_SIZE is increased from 48 to 56 bytes on non-Windows x86-64 to store the saved stack pointer. Closes #26595 and #26822 Co-Authored-By: Claude Opus 4.5 (cherry picked from commit a5ec467ee3d4e77c026437a545981269acde3434) - - - - - 6726c914 by Wen Kokke at 2026-05-20T11:51:14+02:00 Fix race condition between flushEventLog and start/endEventLogging. This commit changes `flushEventLog` to acquire/release the `state_change` mutex to prevent interleaving with `startEventLogging` and `endEventLogging`. In the current RTS, `flushEventLog` _does not_ acquire this mutex, which may lead to eventlog corruption on the following interleaving: - `startEventLogging` writes the new `EventLogWriter` to `event_log_writer`. - `flushEventLog` flushes some events to `event_log_writer`. - `startEventLogging` writes the eventlog header to `event_log_writer`. This causes the eventlog to be written out in an unreadable state, with one or more events preceding the eventlog header. This commit renames the old function to `flushEventLog_` and defines `flushEventLog` simply as: ```c void flushEventLog(Capability **cap USED_IF_THREADS) { ACQUIRE_LOCK(&state_change_mutex); flushEventLog_(cap); RELEASE_LOCK(&state_change_mutex); } ``` The old function is still needed internally within the compilation unit, where it is used in `endEventLogging` in a context where the `state_change` mutex has already been acquired. I've chosen to mark `flushEventLog_` as static and let other uses of `flushEventLog` within the RTS refer to the new version. There is one use in `hs_init_ghc` via `flushTrace`, where the new locking behaviour should be harmless, and one use in `handle_tick`, which I believe was likely vulnerable to the same race condition, so the new locking behaviour is desirable. I have not added a test. The behaviour is highly non-deterministic and requires a program that concurrently calls `flushEventLog` and `startEventLogging`/`endEventLogging`. I encountered the issue while developing `eventlog-socket` and within that context have verified that my patch likely addresses the issue: a test that used to fail within the first dozen or so runs now has been running on repeat for several hours. (cherry picked from commit 3d6492ce311611707e80b2594103ddbe93fc6c76) - - - - - d99bb8e1 by mangoiv at 2026-05-20T14:52:56+02:00 rts: cast Sp_plusW to StgPtr to appease gcc - - - - - 8fde70d7 by mangoiv at 2026-05-20T14:52:56+02:00 rts: disable out of bounds array warning for sometimes inlined rts function - - - - - 1957e964 by Duncan Coutts at 2026-05-22T15:48:38+02:00 Handle heap allocation failure in I/O primops The current I/O managers do not use allocateMightFail, but future ones will. To support this properly we need to be able to return to the primop with a failure. We simply use a bool return value. Currently however, we will just throw an exception rather than calling the GC because that's what all the other primops do too. For the general issue of primops invoking GC and retrying, see https://gitlab.haskell.org/ghc/ghc/-/issues/24105 (cherry picked from commit 62ae97de67f8cc59fc702e26a9e29eda1f84d461) - - - - - 789790d2 by Luite Stegeman at 2026-05-22T15:48:38+02:00 Windows: remove StgAsyncIOResult and fix crash/leaks In stg_block_async{_void}, a stack slot was reserved for an StgAsyncIOResult. This slot would be filled by the IO manager upon completion of the async call. However, if the blocked thread was interrupted by an async exception, we would end up in an invalid state: - If the blocked computation was never re-entered, the StgAsyncIOResult would never be freed. - If the blocked computation was re-entered, the thread would find an unitialized stack slot for the StgAsyncIOResult, leading to a crash reading its fields, or freeing the pointer. We fix this by removing the StgAsyncIOResult altogether and writing the result directly to the stack. Fixes #26341 (cherry picked from commit fcf092dda534cc38637d1f7920aa0dae58fe5273) - - - - - 716a1340 by Brian J. Cardiff at 2026-05-22T15:48:38+02:00 configure: Accept happy-2.2 In Jan 2026 happy-2.2 was released. The most sensible change is https://github.com/haskell/happy/issues/335 which didn't trigger in a fresh build (cherry picked from commit 4f2840f2bb729ef1a6660f9f5c46906b7b838147) - - - - - 1cbf9aed by sheaf at 2026-05-22T15:48:38+02:00 Careful with ticked join points in mergeCaseAlts This commit backports the fix to GHC.Core.Utils.mergeCaseAlts that was carried out in f726fcc4fb0b59f8ad2e2fa80f1b03efdaf73c30. That is, this commit addresses the regression that was introduced by e026bdf275e287005f2c2e534d3ba034ebf11c01, which allowed mergeCaseAlts to move ticks in between a join point and one of its jumps, which results in disaster (see #26929 but also #26642, #26693). See (MC6) in Note [Merge Nested Cases] for a detailed explanation. (cherry picked from commit 08bc245be70d95801bc1138804ed1de9474fbdc0) (cherry picked from commit 974586eb5b6a924e8ce3ea8c4b2180ea9c0f3801) - - - - - 30d967d8 by Zubin Duggal at 2026-05-22T15:48:38+02:00 driver: recognise .dyn_o as a valid object file to link if passed on the command line. This allows plugins compiled with this suffix to run. Fixes #24486 (cherry picked from commit bc4b44870d096d43e8cbc530da1fd613d9e4514f) - - - - - 0ccecfc5 by mangoiv at 2026-05-22T15:48:38+02:00 profiling: partial backport of 2dadf3b0 to fix #27121 This backports fix and test for #27121 from 2dadf3b0 since the entirety of the patch is not backportable without also backporting two larger refactorings. - - - - - 26da4dd4 by sheaf at 2026-05-22T15:48:38+02:00 Deal with 'noSpec' in 'coreExprToPmLit' This commit makes two separate changes relating to 'GHC.HsToCore.Pmc.Solver.Types.coreExprAsPmLit': 1. Commit 7124e4ad mistakenly marked deferred errors as non-canonical, which led to the introduction of 'nospec' wrappers in the generated Core. This reverts that accident by declaring deferred errors as being canonical, avoiding spurious 'nospec' wrapping. 2. Look through magic identity-like Ids such as 'nospec', 'inline' and 'lazy' in 'coreExprAsPmLit', just like Core Prep does. There might genuinely be incoherent evidence, but that shouldn't obstruct the pattern match checker. See test T27124a. Fixes #25926 #27124 ------------------------- Metric Decrease: T3294 ------------------------- (cherry picked from commit e8a196c65cee32f06c3d99b74af33457511408c7) - - - - - ba7b8b5d by Luite Stegeman at 2026-05-22T15:48:38+02:00 CodeOutput: Fix finalizers on multiple platforms - ELF platforms: emit .fini_array section - wasm32/Darwin: emit initializer with __cxa_atexit call - Windows: use -Wl,--whole-archive to prevent dropping finalizer symbols - rts linker: fix crash/assertion failure unloading objects with finalizers fixes #27072 (cherry picked from commit 014087e7a5753687161a24a1b2bc55c7bf7273fd) - - - - - c18b40a6 by Luite Stegeman at 2026-05-22T15:48:38+02:00 rts: add a few missing i386 relocations in the rts linker (cherry picked from commit 04d143c02e82e9ca03eb75849959d369d07fb81a) - - - - - 110 changed files: - + changelog.d/T27124.md - + changelog.d/fix-finalizers-27072 - compiler/GHC/CmmToAsm/AArch64/Instr.hs - compiler/GHC/CmmToLlvm.hs - compiler/GHC/CmmToLlvm/Config.hs - compiler/GHC/CmmToLlvm/Mangler.hs - compiler/GHC/Core/Opt/DmdAnal.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToStg/Prep.hs - compiler/GHC/Driver/CodeOutput.hs - compiler/GHC/Driver/Config/CmmToLlvm.hs - compiler/GHC/Driver/Phases.hs - compiler/GHC/HsToCore/Foreign/C.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/Linker/Static.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Types/Demand.hs - compiler/GHC/Types/ForeignStubs.hs - hadrian/bindist/Makefile - hadrian/src/CommandLine.hs - hadrian/src/Context.hs - hadrian/src/Settings/Builders/Cabal.hs - m4/fp_prog_cc_linker_target.m4 - m4/fptools_happy.m4 - rts/HeapStackCheck.cmm - rts/IOManager.c - rts/IOManager.h - rts/Interpreter.c - rts/Linker.c - rts/LinkerInternals.h - rts/PrimOps.cmm - rts/RtsSymbols.c - rts/StgCRun.c - rts/StgMiscClosures.cmm - rts/Threads.c - rts/eventlog/EventLog.c - rts/include/rts/Constants.h - rts/include/rts/storage/ClosureMacros.h - rts/include/rts/storage/TSO.h - rts/include/stg/MiscClosures.h - rts/linker/Elf.c - rts/win32/AsyncMIO.c - rts/win32/AsyncMIO.h - + testsuite/tests/bytecode/T27001.hs - + testsuite/tests/bytecode/T27001.stdout - testsuite/tests/bytecode/all.T - + testsuite/tests/codeGen/should_run/T27072d.hs - + testsuite/tests/codeGen/should_run/T27072d.stdout - + testsuite/tests/codeGen/should_run/T27072d_c.c - + testsuite/tests/codeGen/should_run/T27072d_check.c - + testsuite/tests/codeGen/should_run/T27072w.hs - + testsuite/tests/codeGen/should_run/T27072w.stdout - + testsuite/tests/codeGen/should_run/T27072w_c.c - testsuite/tests/codeGen/should_run/all.T - + testsuite/tests/concurrent/should_run/T26341.hs - + testsuite/tests/concurrent/should_run/T26341.stdout - + testsuite/tests/concurrent/should_run/T26341a.hs - + testsuite/tests/concurrent/should_run/T26341a.stdout - + testsuite/tests/concurrent/should_run/T26341b.hs - + testsuite/tests/concurrent/should_run/T26341b.stdout - testsuite/tests/concurrent/should_run/all.T - testsuite/tests/dmdanal/should_compile/T13143.stderr - testsuite/tests/dmdanal/should_compile/T18894.stderr - + testsuite/tests/dmdanal/should_compile/T27106.hs - + testsuite/tests/dmdanal/should_compile/T27106.stderr - testsuite/tests/dmdanal/should_compile/all.T - + testsuite/tests/dmdanal/should_run/M1.hs - + testsuite/tests/dmdanal/should_run/T26416.hs - + testsuite/tests/dmdanal/should_run/T26416.stdout - testsuite/tests/dmdanal/should_run/all.T - testsuite/tests/dmdanal/sigs/T21081.stderr - + testsuite/tests/ffi/should_compile/T26852.h - + testsuite/tests/ffi/should_compile/T26852.hs - + testsuite/tests/ffi/should_compile/T26852.stderr - testsuite/tests/ffi/should_compile/all.T - testsuite/tests/ffi/should_run/all.T - + testsuite/tests/overloadedstrings/should_fail/T25926.hs - + testsuite/tests/overloadedstrings/should_fail/T25926.stderr - + testsuite/tests/overloadedstrings/should_fail/T27124.hs - + testsuite/tests/overloadedstrings/should_fail/T27124.stderr - + testsuite/tests/overloadedstrings/should_fail/all.T - + testsuite/tests/overloadedstrings/should_run/T27124a.hs - testsuite/tests/overloadedstrings/should_run/all.T - testsuite/tests/plugins/Makefile - + testsuite/tests/plugins/T24486-plugin/Makefile - + testsuite/tests/plugins/T24486-plugin/Setup.hs - + testsuite/tests/plugins/T24486-plugin/T24486-plugin.cabal - + testsuite/tests/plugins/T24486-plugin/T24486_Plugin.hs - + testsuite/tests/plugins/T24486.hs - + testsuite/tests/plugins/T24486_Helper.hs - testsuite/tests/plugins/all.T - + testsuite/tests/profiling/should_compile/T27121.hs - + testsuite/tests/profiling/should_compile/T27121_aux.hs - testsuite/tests/profiling/should_compile/all.T - + testsuite/tests/rts/linker/T27072/Lib.c - + testsuite/tests/rts/linker/T27072/Makefile - + testsuite/tests/rts/linker/T27072/T27072.stdout - + testsuite/tests/rts/linker/T27072/all.T - + testsuite/tests/rts/linker/T27072/main.c - + testsuite/tests/simd/should_run/StackAlignment32.hs - + testsuite/tests/simd/should_run/StackAlignment32.stdout - + testsuite/tests/simd/should_run/StackAlignment32_main.c - + testsuite/tests/simd/should_run/StackAlignment64.hs - + testsuite/tests/simd/should_run/StackAlignment64.stdout - + testsuite/tests/simd/should_run/StackAlignment64_main.c - testsuite/tests/simd/should_run/all.T - + testsuite/tests/simplCore/should_compile/T26642.hs - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/th/all.T - utils/deriveConstants/Main.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5846d4f91f85b0776f6fb71f62d2527... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5846d4f91f85b0776f6fb71f62d2527... You're receiving this email because of your account on gitlab.haskell.org.