Sven Tennie pushed to branch wip/romes/hadrian-cross-stage2-rebase_SVEN_FINAL at Glasgow Haskell Compiler / GHC Commits: 5ac9ce7d by Zubin Duggal at 2026-06-10T21:26:32+05:30 hadrian: Remove old package.conf files when generating new ones Old package.conf files might exists with different hashes, causing issues like #26661 Fixes #26661 - - - - - c9015f09 by sheaf at 2026-06-11T12:40:28-04:00 Fix AArch64 clobbering bug for MUL2 On AArch64, the code generator could clobber one of the input operands when computing the lower bits of a MUL2 operation. This rendered invalid the subsequent computation of the high bits. This commit fixes that by using a temporary register. The register allocator can remove the redundant move in the common case when the registers do not conflict. Fixes #27046 - - - - - 7ab90288 by Rodrigo Mesquita at 2026-06-11T12:41:11-04:00 fix: make T27131 less flaky It seems that T27131 fails flakily in a race where we check the flag before the capability had the chance to process the mailbox which sets the flag. This seemingly should only happen if the capability ends up being the same for setting and checking the flag. - - - - - 8965cb76 by Marc Scholten at 2026-06-12T04:53:22-04:00 haddock: render modules concurrently - - - - - 8cc0b64a by Duncan Coutts at 2026-06-12T04:54:06-04:00 Promote HAVE_PREEMPTION from Timer.c to OSThreads.h We will want to know about HAVE_PREEMPTION in more places. HAVE_PREEMPTION tells us that we do have OS threads available, irrespective of whether THREADED is defined. In particular, HAVE_PREEMPTION is defined on all proper OSs, but not on WASM (and hyopthetically may not be true on some other platforms like micro-controllers, RTOSs, VM hypervisors etc). - - - - - cce574ed by Duncan Coutts at 2026-06-12T04:54:06-04:00 Define ACQUIRE_LOCK_ALWAYS and friends Fix issue #27335 Like the atomic _ALWAYS variants, these lock actions are always defined, rather than being dependent on whether we are in the THREADED case. All the "normal" LOCK macros are defined to be no-ops when !THREADED. The use case for the _ALWAYS variants is where we are using OS threads even in the non-threaded RTS. This includes everything to do with the timer/ticker thread, which is used in the non-threaded RTS too. In particular, we will want to use this for eventlog things, because the timer thread performs eventlogging concurrently with the main capability, even in the non-threaded RTS. - - - - - 1f28d1f6 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Use ACQUIRE/RELEASE_LOCK_ALWAYS with eventBufMutex Even in the non-threaded RTS the eventBufMutex is needed by both the main capability and the timer/ticker thread, so always use the mutex. This should fix #25165 which is about the main capability and the timer thread posting events to the eventlog buffer concurrently and thereby corrupting the buffer data. - - - - - 0ff29782 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Expose eventBufMutex in the EventLog interface/header We will need it in forkProcess to ensure we don't write to the global eventlog buffer concurrently with trying to flush eventlog buffers and do the fork(). - - - - - 7a688395 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Split flushAllCapsEventsBufs into safe and unlocked version Following the convention that unlocked versions have a trailing _ underscore in their name. This one requires the caller to hold the eventlog global buffer mutex. We will need this in forkProcess. - - - - - 341ed474 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in setNumCapabilities Historically, the comment here was: We must stop the interval timer while we are changing the capabilities array lest handle_tick may try to context switch an old capability. See #17289. and We must disable the timer while we do this since the tick handler may call contextSwitchAllCapabilities, which may see the capabilities array as we free it. What this refers to is that historically, when changing the number of capabilities, the array of capabilities was reallocated to a new size, allocating new ones and freeing the old ones, thus invalidating all existing capbility pointers. Strangely, for good measure the code used to call stopTimer twice (hence the two similar comments above). However, since commit a3eccf06292dd666b24606251a52da2b466a9612, the capabilities array is no longer reallocated. Instead the array is allcoated once on RTS startup to the maximum size it could ever be allowed to be, and then capabilities get enabled/disabled at runtime. So the capability pointers never become invalid anymore. At worst, they may point to capabilities that are disabled. Thus we no longer need to stop the timer (twice) while we change the number of enabled capabilities. This also partially solves issue #27105, which notes that stopTimer is being used as if it were synchronous, when it is not. At least for this case, the solution is that stopTimer is not needed at all! - - - - - 674858e3 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in forkProcess but replace it with taking the eventlog buffer lock during the fork. Fixes issue #27105 The original reason to block the timer during a fork was that historically the timer was implemented using a periodic timer signal, and the signal itself would interrupt the fork system call (returning EINTR). For large processes (where fork() takes a while) this could permanently livelock: the timer always would go off before the fork could complete, which got retried in a loop forever. The timer is no longer implemented as a unix signal, but uses threads. Thus the original problem no longer exists. The only remaining reason to block the timer tick is to prevent actions taken by the tick from interfering with the delicate process involved in fork (taking a load of locks and pausing everything). The only thing we need to do is to prevent the eventlog from being written to or flushed while the fork is taking place. To achieve this all we need to do is hold the mutex for the global eventlog buffer. This removes the last use of stopTimer that expects stopTimer to work synchronously (which it was not) and thus solves issue #27105. To be clear, we solve issue #27105 not by making stopTimer synchronous, but by eliminating the use sites that expected it to be synchronous. - - - - - 40764930 by sheaf at 2026-06-12T14:54:43-04:00 Add type family performance test for #26426 Some GHC versions produced large numbers of coercions after typechecking and desugaring when compiling the program in #26426: Version | Typechecker time | Typechecker allocations | Coercions -------:|-----------------:|------------------------:|---------: 9.6 | 47 ms | 48 MB | 110k 9.8 | 1000 ms | 486 MB | 10,437k 9.10 | 922 ms | 489 MB | 10,436k 9.12 | 906 ms | 482 MB | 10,437k 9.14 | 63 ms | 55 MB | 333k 10.0 | 47 ms | 64 MB | 35k The improvement 9.12 -> 9.14 was due to commit 22d11fa818fae2c95c494fc0fac1f8cb4c6e7cb6, while the improvement 9.14 -> 10.0 was due to commit 0b7df6db9e46df40e86fbff1a66dc10440b99db5. As the behaviour of GHC seems better than it's ever been on this program, we declare victory, adding this performance test to ensure we don't regress on this program. On the way, we update Note [Combining equalities] in GHC.Tc.SolveR.Equality with the explanation of the 9.12 -> 9.14 improvement (getting rid of an exponential blowup in coercion sizes), and we update Note [Exploiting closed type families] in GHC.Tc.Solver.FunDeps with the explanation of the 9.14 -> 10.0 improvement (bringing down coercion size growth from cubic to quadratic). - - - - - 0f3d0a71 by Zubin Duggal at 2026-06-12T14:55:30-04:00 compiler: mark tool messages as errors/warnings depending on the exit code Fixes #27370 - - - - - d9ea2d76 by mangoiv at 2026-06-13T04:41:51-04:00 libraries/process: bump submodule to v1.6.30.0 - bump the submodule to the appropriate tag - suppress benign warning resulting from the change - - - - - 6ebaaba3 by David Eichmann at 2026-06-13T04:42:37-04:00 ghc-toolchain: don't throw when candidate executables are not found Fixes #27369 - - - - - 6c65e1e1 by David Eichmann at 2026-06-13T04:43:23-04:00 CI: lint-changelog checks for no-changelog label in script instead of rules - - - - - 4cfcdc5d by Matthew Pickering at 2026-06-14T11:39:13+02:00 Add missing req_interp modifier to T18441fail3 and T18441fail19 These tests require the interpreter but they were failing in a different way with the javascript backend because the interpreter was disabled and stderr is ignored by the test. - - - - - a9d868b7 by Matthew Pickering at 2026-06-14T11:39:13+02:00 hadrian: Fill in more of the default.host toolchain file When you are building a cross compiler this file will be used to build stage1 and it's libraries, so we need enough information here to work accurately. There is still more work to be done (see for example, word size is still fixed). - - - - - 59b15623 by Matthew Pickering at 2026-06-14T11:39:13+02:00 hadrian: Build stage 2 cross compilers * Most of hadrian is abstracted over the stage in order to remove the assumption that the target of all stages is the same platform. This allows the RTS to be built for two different targets for example. * Abstracts the bindist creation logic to allow building either normal or cross bindists. Normal bindists use stage 1 libraries and a stage 2 compiler. Cross bindists use stage 2 libararies and a stage 2 compiler. * hadrian: Make binary-dist-dir the default build target. This allows us to have the logic in one place about which libraries/stages to build with cross compilers. Fixes #24192 New hadrian target: * `binary-dist-dir-cross`: Build a cross compiler bindist (compiler = stage 1, libraries = stage 2) This commit also contains various changes to make stage2 compilers feasible. ------------------------- Metric Decrease: LinkableUsage02 ManyAlternatives ManyConstructors MultiComponentModulesRecomp MultiLayerModulesRecomp RecordUpdPerf T10421 T12150 T12227 T12425 T12707 T13035 T13379 T13820 T15703 T16577 T18140 T18282 T18698a T18698b T18923 T1969 T20049 T21839c T3294 T4801 T5030 T5321FD T5321Fun T5631 T5642 T6048 T783 T9020 T9198 T9233 T9630 T9872d T9961 parsing001 T3064 Metric Increase: T26989 hard_hole_fits ------------------------- Co-authored-by: Sven Tennie - - - - - e98029d5 by Matthew Pickering at 2026-06-14T11:39:13+02:00 ci: Test cross bindists We remove the special logic for testing in-tree cross compilers and instead test cross compiler bindists, like we do for all other platforms. - - - - - 25b52761 by Matthew Pickering at 2026-06-14T11:39:13+02:00 ci: Introduce CROSS_STAGE variable In preparation for building and testing stage3 bindists we introduce the CROSS_STAGE variable which is used by a CI job to determine what kind of bindist the CI job should produce. At the moment we are only using CROSS_STAGE=2 but in the future we will have some jobs which set CROSS_STAGE=3 to produce native bindists for a target, but produced by a cross compiler, which can be tested on by another CI job on the native platform. CROSS_STAGE=2: Build a normal cross compiler bindist CROSS_STAGE=3: Build a stage 3 bindist, one which is a native compiler and library for the target - - - - - 61366700 by Sven Tennie at 2026-06-14T11:39:13+02:00 ci: Increase timeout for emulators Test runs with emulators naturally take longer than on native machines. Generate jobs.yml - - - - - 12362d0e by Matthew Pickering at 2026-06-14T11:39:13+02:00 ci: Javascript don't set CROSS_EMULATOR There is no CROSS_EMULATOR needed to run javascript binaries, so we don't set the CROSS_EMULATOR to some dummy value. - - - - - 43713b0c by Sven Tennie at 2026-06-14T11:39:14+02:00 Javascript skip T23697 See #22355 about how HSC2HS and the Javascript target don't play well together. - - - - - fab848a0 by Sven Tennie at 2026-06-14T11:39:14+02:00 Mark T24602 as fragile It was skipped before (due to CROSS_EMULATOR being set, which changed for JS), so we don't make things worse by marking it as fragile. - - - - - a38c291b by Sven Tennie at 2026-06-14T11:39:14+02:00 Fix T22744 for GHCJS In fact, this test needs Template Haskell, not necessarily an interpreter. - - - - - 101 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - + changelog.d/T27046 - + changelog.d/hadrian-stale-package-confs-26661 - + changelog.d/stage2-cross-compilers - + changelog.d/tool-messages-27370 - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/SysTools/Process.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - configure.ac - distrib/configure.ac.in - hadrian/README.md - hadrian/bindist/config.mk.in - hadrian/cfg/default.host.target.in - + hadrian/cfg/system.config.host.in - hadrian/cfg/system.config.in - + hadrian/cfg/system.config.target.in - hadrian/hadrian.cabal - hadrian/src/Base.hs - + hadrian/src/BindistConfig.hs - hadrian/src/Builder.hs - hadrian/src/Context.hs - hadrian/src/Expression.hs - hadrian/src/Flavour.hs - hadrian/src/Flavour/Type.hs - hadrian/src/Hadrian/Builder.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Hadrian/Oracles/TextFile.hs - hadrian/src/Main.hs - hadrian/src/Oracles/Flag.hs - hadrian/src/Oracles/Flavour.hs - hadrian/src/Oracles/Setting.hs - hadrian/src/Oracles/TestSettings.hs - hadrian/src/Packages.hs - hadrian/src/Rules.hs - hadrian/src/Rules/BinaryDist.hs - hadrian/src/Rules/CabalReinstall.hs - hadrian/src/Rules/Changelog.hs - hadrian/src/Rules/Compile.hs - hadrian/src/Rules/Documentation.hs - hadrian/src/Rules/Generate.hs - hadrian/src/Rules/Gmp.hs - hadrian/src/Rules/Library.hs - hadrian/src/Rules/Program.hs - hadrian/src/Rules/Register.hs - hadrian/src/Rules/Rts.hs - hadrian/src/Rules/Test.hs - hadrian/src/Settings.hs - hadrian/src/Settings/Builders/Cabal.hs - hadrian/src/Settings/Builders/Common.hs - hadrian/src/Settings/Builders/Configure.hs - hadrian/src/Settings/Builders/DeriveConstants.hs - hadrian/src/Settings/Builders/Ghc.hs - hadrian/src/Settings/Builders/Hsc2Hs.hs - hadrian/src/Settings/Builders/RunTest.hs - hadrian/src/Settings/Builders/SplitSections.hs - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Flavours/GhcInGhci.hs - hadrian/src/Settings/Flavours/Performance.hs - hadrian/src/Settings/Flavours/QuickCross.hs - hadrian/src/Settings/Packages.hs - hadrian/src/Settings/Program.hs - hadrian/src/Settings/Warnings.hs - libraries/base/tests/all.T - libraries/process - m4/fp_find_nm.m4 - m4/prep_target_file.m4 - rts/Capability.c - rts/Schedule.c - rts/Timer.c - rts/eventlog/EventLog.c - rts/eventlog/EventLog.h - rts/include/rts/OSThreads.h - testsuite/driver/testlib.py - testsuite/ghc-config/ghc-config.hs - + testsuite/tests/codeGen/should_run/T27046.hs - + testsuite/tests/codeGen/should_run/T27046_cmm.cmm - testsuite/tests/codeGen/should_run/all.T - + testsuite/tests/driver/T27370/Makefile - + testsuite/tests/driver/T27370/T27370.hs - + testsuite/tests/driver/T27370/T27370.pp - + testsuite/tests/driver/T27370/T27370.stderr - + testsuite/tests/driver/T27370/all.T - testsuite/tests/ghc-e/should_fail/all.T - testsuite/tests/javascript/closure/all.T - + testsuite/tests/perf/compiler/T26426.hs - testsuite/tests/perf/compiler/all.T - testsuite/tests/rts/T27131.hs - testsuite/tests/rts/T27131.stdout - utils/ghc-toolchain/src/GHC/Toolchain/Program.hs - utils/ghc-toolchain/src/GHC/Toolchain/Utils.hs - utils/haddock/haddock-api/haddock-api.cabal - utils/haddock/haddock-api/src/Haddock.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml.hs - utils/haddock/haddock-api/src/Haddock/Options.hs - utils/haddock/haddock-api/src/Haddock/Utils.hs The diff was not included because it is too large. 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