7. Release notes for version 8.10.5¶
The significant changes to the various parts of the compiler are listed in the following sections.
Like previous releases in the 8.10 series, the LLVM backend
of this release is to be used with LLVM 9.
7.1. General bug fixes¶
- First-class support for Apple M1 hardware using GHC’s LLVM ARM backend
- Fix a bug where code may be unloaded prematurely when using the parallel garbage collector (see #%s19417)
- Fix a bug where the linker may during shutdown unload code before
libraries’
atexithandlers have a chance to run (#%s19297). - Improve code layout by distiguishing conditional and unconditional branches (#%s18053).
- Add
hs-bootfile support for-ddump-minimal-imports(#%s18497). - Ensure
hs-bootfiles are built before source files in GHCs-Mmode (#%s14482) - Fix a long standing GHC API bug affecting clients like HLS where async exceptions used to cancel threads during typechecking would be caught by the Template Haskell evaluator and reported as compile errors (#%s19410).
- Improve error messages when looking up packages fails (#%s19370).
- Fix a number of quirks in GC accounting (#%s19147)
- Fix a code generation bug which could result in entry of unlifted objects in some programs using unboxed sums (#%s19645).
- Ensure that POSIX signals are not delivered to the ticker thread when using the pthread itimer implementation.
- Fix a specialiser bug which could result in the construction of recursive dictionaries in some programs (#%s17151).
- Bump
containersto 0.6.4.1 - Do not treat
-Winferred-safe-importswarnings as errors. - Fix a bug where typechecker plugins could be run with an inconsistent typechecker environment (#%s19191).
- Fix a simplifier bug which lead to an exponential blow up and excessive memory usage in certain cases (#%s18923, #%s18140, #%s10421, #%s18282, #%s13253)
7.2. Portability fixes¶
- Fix a number of linking portability issues affecting Apple’s macOS Big Sur.
- Use the pthread-based itimer implemention under FreeBSD by default
- Enable large-file support in
base’s the OFD file locking implementation, avoiding #%s17950. - Ensure that Darwin binary distributions do not depend upon
utimensat(#%s17895). - Remove a number of older autoconf idioms from the
configurescript, improving support in newer environments.
7.3. Known issues¶
A long-standing bug (#%s16893) which can cause some applications of
unsafeCoerceto segmentation fault is only partially fixed in this release. This release only avoids this issue in the uses ofunsafeCoerceinData.Typeable.Internal, which was the proximate cause of #%s16893.However, it is possible that this bug could manifest in user-code using
unsafeCoerceto perform dynamic type checks. See the ticket for details.We expect that this issue will be fixed in the next major release of GHC.
A long-standing bug (#%s17760) where some uses of the
touch#primop can be dropped by the simplifier is present in this release. This bug will be fixed in GHC 9.0.1. In the meantime, see the ticket for mitigations.
7.4. Included libraries¶
The package database provided with this distribution also contains a number of packages other than GHC itself. See the changelogs provided with these packages for further change information.
| Package | Version | Reason for inclusion |
|---|---|---|
| ghc | 8.10.7 | The compiler itself |
| Cabal | 3.2.1.0 | Dependency of ghc-pkg utility |
| Win32 | 2.6.2.1 | Dependency of ghc library |
| array | 0.5.4.0 | Dependency of ghc library |
| base | 4.14.3.0 | Core library |
| binary | 0.8.8.0 | Dependency of ghc library |
| bytestring | 0.10.12.0 | Dependency of ghc library |
| containers | 0.6.5.1 | Dependency of ghc library |
| deepseq | 1.4.4.0 | Dependency of ghc library |
| directory | 1.3.6.0 | Dependency of ghc library |
| exceptions | 0.10.4 | Dependency of haskeline library |
| filepath | 1.4.2.1 | Dependency of ghc library |
| ghc-boot-th | 8.10.7 | Internal compiler library |
| ghc-boot | 8.10.7 | Internal compiler library |
| ghc-compact | 0.1.0.0 | Core library |
| ghc-heap | 8.10.7 | GHC heap-walking library |
| ghc-prim | 0.6.1 | Core library |
| ghci | 8.10.7 | The REPL interface |
| haskeline | 0.8.2 | Dependency of ghci executable |
| hpc | 0.6.1.0 | Dependency of hpc executable |
| integer-gmp | 1.0.3.0 | Core library |
| libiserv | 8.10.7 | Internal compiler library |
| mtl | 2.2.2 | Dependency of Cabal library |
| parsec | 3.1.14.0 | Dependency of Cabal library |
| pretty | 1.1.3.6 | Dependency of ghc library |
| process | 1.6.13.2 | Dependency of ghc library |
| stm | 2.5.0.1 | Dependency of haskeline library |
| template-haskell | 2.16.0.0 | Core library |
| terminfo | 0.4.1.4 | Dependency of haskeline library |
| text | 1.2.4.1 | Dependency of Cabal library |
| time | 1.9.3 | Dependency of ghc library |
| transformers | 0.5.6.2 | Dependency of ghc library |
| unix | 2.7.2.2 | Dependency of ghc library |
| xhtml | 3000.2.2.1 | Dependency of haddock executable |