Zubin pushed to branch wip/backports-9.12.4 at Glasgow Haskell Compiler / GHC Commits: a3f7ffef by Matthew Pickering at 2026-03-03T10:49:47+05:30 Evaluate backtraces for "error" exceptions at the moment they are thrown See Note [Capturing the backtrace in throw] and Note [Hiding precise exception signature in throw] which explain the implementation. This commit makes `error` and `throw` behave the same with regard to backtraces. Previously, exceptions raised by `error` would not contain useful IPE backtraces. I did try and implement `error` in terms of `throw` but it started to involve putting diverging functions into hs-boot files, which seemed to risky if the compiler wouldn't be able to see if applying a function would diverge. CLC proposal: https://github.com/haskell/core-libraries-committee/issues/383 Fixes #26751 (cherry picked from commit 94dcd15e54146abecf9b4f5e47d258ca3cd40f1b) - - - - - 5839b832 by fendor at 2026-03-03T10:49:47+05:30 Remove `traceId` from ghc-pkg executable (cherry picked from commit d0966e64880e9fa30ce07c0fa5ea28108c6e8ad9) - - - - - 79bc27f8 by sheaf at 2026-03-03T10:49:47+05:30 Don't re-use stack slots for growing registers This commit avoids re-using a stack slot for a register that has grown but already had a stack slot. For example, suppose we have stack slot assigments %v1 :: FF64 |-> StackSlot 0 %v2 :: FF64 |-> StackSlot 1 Later, we start using %v1 at a larger format (e.g. F64x2) and we need to spill it again. Then we **must not** use StackSlot 0, as a spill at format F64x2 would clobber the data in StackSlot 1. This can cause some fragmentation of the `StackMap`, but that's probably OK. Fixes #26668 (cherry picked from commit 023c301c51e7346af3d4d773c448277ad3645ad2) - - - - - 8e964b00 by Cheng Shao at 2026-03-03T10:49:47+05:30 llvm: fix split sections for llvm backend This patch fixes split sections for llvm backend: - Pass missing `--data-sections`/`--function-sections` flags to llc/opt. - Use `@llvm.compiler.used` instead of `@llvm.used` to avoid sections being unnecessarily retained at link-time. Fixes #26770. ------------------------- Metric Decrease: libdir size_hello_artifact size_hello_unicode ------------------------- Co-authored-by: Codex (cherry picked from commit b18b2c42c32488ad6d3480a56a1fcd753cad2023) - - - - - e9f0c76e by Matthew Pickering at 2026-03-03T10:49:47+05:30 Fix ghc-experimental GHC.Exception.Backtrace.Experimental module This module wasn't added to the cabal file so it was never compiled or included in the library. (cherry picked from commit ee937134aa0ddf35c1a9dc7334c0aec0de13b719) - - - - - 43715212 by Sylvain Henry at 2026-03-03T10:49:47+05:30 GC: don't use CAS without PARALLEL_GC on If we're not using the parallel GC, there is no reason to do a costly CAS. This was flagged as taking time in a perf profile. (cherry picked from commit 0491f08a965df0d6448bd9cd940d2b86fca2db5d) - - - - - e98afd59 by Sylvain Henry at 2026-03-03T10:49:48+05:30 GC: suffix parallel GC with "par" instead of "thr" Avoid some potential confusion (see discussion in !15351). (cherry picked from commit 211a8f5633f0a5069c0689171f60b57719a242be) - - - - - 8aea6d74 by Cheng Shao at 2026-03-03T10:49:48+05:30 testsuite: avoid re.sub in favor of simple string replacements This patch refactors the testsuite driver and avoids the usage of re.sub in favor of simple string replacements when possible. The changes are not comprehensive, and there are still a lot of re.sub usages lingering around the tree, but this already addresses a major performance bottleneck in the testsuite driver that might has to do with quadratic or worse slowdown in cpython's regular expression engine when handling certain regex patterns with large strings. Especially on i386, and i386 jobs are the bottlenecks of all full-ci validate pipelines! Here are the elapsed times of testing x86_64/i386 with -j48 before this patch: x86_64: `Build completed in 6m06s` i386: `Build completed in 1h36m` And with this patch: x86_64: `Build completed in 4m55s` i386: `Build completed in 4m23s` Fixes #26786. Co-authored-by: Codex (cherry picked from commit ca79475f6b4dfba991e2c933bac9c22d54a4950d) - - - - - 22e6dda8 by Zubin Duggal at 2026-03-03T10:49:48+05:30 hadrian: Add ghc-{experimental,internal}.cabal to the list of dependencies of the doc target We need these files to detect the version of these libraries Fixes #26738 (cherry picked from commit 1b490f5a7bbdb1441948241e6089b31efba9db45) - - - - - c2322fcc by Jessica Clarke at 2026-03-03T10:49:48+05:30 PPC NCG: Use libcall for 64-bit cmpxchg on 32-bit PowerPC There is no native instruction for this, and even if there were a register pair version we could use, the implementation here is assuming the values fit in a single register, and we end up only using / defining the low halves of the registers. Fixes: b4d39adbb5 ("PrimOps: Add CAS op for all int sizes") Fixes: #23969 (cherry picked from commit ce2d62fba69d2ea0c74c46c50628feb8b81719d2) - - - - - 546506f5 by John Paul Adrian Glaubitz at 2026-03-03T10:49:48+05:30 rts: Switch prim to use modern atomic compiler builtins The __sync_*() atomic compiler builtins have been deprecated in GCC for a while now and also don't provide variants for 64-bit values such as __sync_fetch_and_add_8(). Thus, replace them with the modern __atomic_*() compiler builtins and while we're at it, also drop the helper macro CAS_NAND() which is now no longer needed since we stopped using the __sync_*() compiler builtins altogether. Co-authored-by: Ilias Tsitsimpis Fixes #26729 (cherry picked from commit 7c52c4f9bc8d6ae6404039ec02efe48fbf7a4778) - - - - - 1b75850a by sterni at 2026-03-03T10:49:48+05:30 users_guide: fix runtime error during build with Sphinx 9.1.0 Appears that pathto is stricter about what it accepts now. Tested Sphinx 8.2.3 and 9.1.0 on the ghc-9.10 branch. Resolves #26810. Co-authored-by: Martin Weinelt (cherry picked from commit e8f5a45de561ec80c88cd3da2c66502deb32d4c3) - - - - - 8103c4f4 by Michael Karcher at 2026-03-03T10:49:48+05:30 NCG for PPC: add pattern for CmmRegOff to iselExpr64 Closes #26828 (cherry picked from commit 43d977619de65c0cf87695fa5d86f1a3ff3176c3) - - - - - 777a7b5a by Matthew Pickering at 2026-03-03T10:49:48+05:30 determinism: Use deterministic map for Strings in TyLitMap When generating typeable evidence the types we need evidence for all cached in a TypeMap, the order terms are retrieved from a type map determines the order the bindings appear in the program. A TypeMap is quite diligent to use deterministic maps, apart from in the TyLitMap, which uses a UniqFM for storing strings, whose ordering depends on the Unique of the FastString. This can cause non-deterministic .hi and .o files. An unexpected side-effect is the error message but RecordDotSyntaxFail8 changing. I looked into this with Sam and this change caused the constraints to be solved in a different order which results in a slightly different error message. I have accepted the new test, since the output before was non-deterministic and the new output is consistent with the other messages in that file. Fixes #26846 (cherry picked from commit aeeb4a2034e80e26503eb88f5abde85e87a82f7b) - - - - - 293ded1d by Andrew Lelechenko at 2026-03-03T10:49:48+05:30 Upgrade text submodule to 2.1.4 (cherry picked from commit 9e4d70c2764d117c5cf753127f93056d66e4f0d7) - - - - - bced716b by Zubin Duggal at 2026-03-03T10:49:48+05:30 Bump transformers submodule to 0.6.3.0 Fixes #26790 (cherry picked from commit ea0d1317a630799a6b7bea12b24ef7e1ea6ed512) - - - - - 5e9a99fb by Matthew Pickering at 2026-03-03T10:49:48+05:30 determinism: Use a stable sort in WithHsDocIdentifiers binary instance `WithHsDocIdentifiers` is defined as ``` 71 data WithHsDocIdentifiers a pass = WithHsDocIdentifiers 72 { hsDocString :: !a 73 , hsDocIdentifiers :: ![Located (IdP pass)] 74 } ``` This list of names is populated from `rnHsDocIdentifiers`, which calls `lookupGRE`, which calls `lookupOccEnv_AllNameSpaces`, which calls `nonDetEltsUFM` and returns the results in an order depending on uniques. Sorting the list with a stable sort before returning the interface makes the output deterministic and follows the approach taken by other fields in `Docs`. Fixes #26858 (cherry picked from commit 0020e38a021b5f0371c48fe73cddf8987acb1eb1) - - - - - f6e481a3 by Simon Peyton Jones at 2026-03-03T10:49:48+05:30 Fix subtle bug in cast worker/wrapper See (CWw4) in Note [Cast worker/wrapper]. The true payload is in the change to the definition of GHC.Types.Id.Info.hasInlineUnfolding Everthing else is just documentation. There is a 2% compile time decrease for T13056; I'll take the win! Metric Decrease: T13056 (cherry picked from commit 99d8c146c12146e1e21b1f2d31809845d4afe9d4) - - - - - 39783f42 by Cheng Shao at 2026-03-03T10:49:48+05:30 wasm: use import.meta.main for proper distinction of nodejs main modules This patch uses `import.meta.main` for proper distinction of nodejs main modules, especially when the main module might be installed as a symlink. Fixes #26916. (cherry picked from commit 039f19778e35b193af0de2a2c6ed89556038627a) - - - - - 519601bc by Zubin Duggal at 2026-03-03T10:49:48+05:30 Prepare release 9.12.4 - - - - - 49 changed files: - compiler/GHC/CmmToAsm/PPC/CodeGen.hs - compiler/GHC/CmmToAsm/Reg/Linear.hs - compiler/GHC/CmmToAsm/Reg/Linear/StackMap.hs - compiler/GHC/CmmToLlvm.hs - compiler/GHC/CmmToLlvm/Base.hs - compiler/GHC/Core/Map/Type.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Driver/Config/Core/Lint.hs - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Types/Id/Info.hs - docs/users_guide/release-notes.rst - docs/users_guide/rtd-theme/layout.html - hadrian/src/Rules/Documentation.hs - libraries/base/base.cabal.in - libraries/base/changelog.md - libraries/ghc-experimental/ghc-experimental.cabal.in - libraries/ghc-experimental/src/GHC/Exception/Backtrace/Experimental.hs - libraries/ghc-internal/src/GHC/Internal/Err.hs - + libraries/ghc-internal/tests/stack-annotation/ann_frame005.hs - + libraries/ghc-internal/tests/stack-annotation/ann_frame005.stdout - libraries/text - libraries/transformers - rts/prim/atomic.c - rts/rts.cabal - rts/sm/Evac.c - rts/sm/Evac_thr.c → rts/sm/Evac_par.c - rts/sm/Scav_thr.c → rts/sm/Scav_par.c - testsuite/driver/runtests.py - testsuite/driver/testlib.py - testsuite/driver/testutil.py - + testsuite/tests/ghc-api/TypeMapStringLiteral.hs - testsuite/tests/ghc-api/all.T - testsuite/tests/ghci.debugger/scripts/T8487.stdout - testsuite/tests/ghci.debugger/scripts/break011.stdout - testsuite/tests/ghci.debugger/scripts/break017.stdout - testsuite/tests/ghci.debugger/scripts/break025.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout-mingw32 - testsuite/tests/showIface/DocsInHiFile1.stdout - testsuite/tests/showIface/HaddockSpanIssueT24378.stdout - testsuite/tests/showIface/MagicHashInHaddocks.stdout - + testsuite/tests/simplCore/should_compile/T26903.hs - + testsuite/tests/simplCore/should_compile/T26903.stderr - testsuite/tests/simplCore/should_compile/all.T - utils/ghc-pkg/Main.hs - utils/jsffi/dyld.mjs - utils/jsffi/post-link.mjs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/45bc79ab3c196a90297cad2368983da... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/45bc79ab3c196a90297cad2368983da... You're receiving this email because of your account on gitlab.haskell.org.