5. Release notes for version 8.10.3¶
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.
5.1. Highlights¶
Numerous stability improvements on Windows.
GHC now has far more robust support for architectures with weak memory ordering guarantees.
GHC can split up dynamic objects to mitigate the macOS
RPATH
size limitation when building large projects (#14444).Several significant correctness bugs in the low-latency garbage collector have been fixed. Users of
--nonmoving-gc
are strongly encouraged to upgrade promptly.
5.2. Full details¶
5.2.1. Compiler¶
A compiler crash triggered by a
SPECIALISE
pragma on a binding with no unfolding has been fixed (#18118).GHC now supports a command-line flag,
-pgmc-supports-no-pie
, allowing the user to indicate that the C compiler supplied via-pgmc ⟨cmd⟩
supports-no-pie
.A pair of flags,
-pgmlm ⟨cmd⟩
and-optlm ⟨option⟩
, allowing the user to override the linker used to be join GHCi object files has been added.A regression in the treatment of the
-fbyte-code
flag has been fixed (#18955).
A bug in the determination of source spans of post-qualified imports has been fixed #19014.
5.2.2. Runtime system¶
GHC is now more careful to respect address space limits set via ulimit` when allocating its heap (#18623).
Numerous fixes on Windows. These include a bug in stack allocation triggering Windows’ stack verifier (#18601), various linker bugs (#15808, #18991), and a bug where
libc
may be called during image initialization resulting in undefined behavior (#18548).GHC’s linker is now able to load macOS frameworks on Big Sur (#18446).
A soundness bug affecting programs relying on heavy mutation of
MVar
s has been fixed (#18919).The internal linker’s code unloading logic has been reenabled and now tracks object file dependencies, fixing a soundness bug (#16525).
A linker bug relying in the misalignment of loaded
.rodata
sections has been fixed.
5.3. Known issues¶
A long-standing bug (#16893) which can cause some applications of
unsafeCoerce
to segmentation fault is only partially fixed in this release. This release only avoids this issue in the uses ofunsafeCoerce
inData.Typeable.Internal
, which was the proximate cause of #16893.However, it is possible that this bug could manifest in user-code using
unsafeCoerce
to 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 (#17760) 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.
5.4. 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 |
8.10.6 | The compiler itself |
Cabal |
3.2.1.0 | Dependency of |
Win32 |
2.6.2.1 | Dependency of |
array |
0.5.4.0 | Dependency of |
base |
4.14.3.0 | Core library |
binary |
0.8.8.0 | Dependency of |
bytestring |
0.10.12.0 | Dependency of |
containers |
0.6.5.1 | Dependency of |
deepseq |
1.4.4.0 | Dependency of |
directory |
1.3.6.0 | Dependency of |
exceptions |
0.10.4 | Dependency of |
filepath |
1.4.2.1 | Dependency of |
ghc-boot-th |
8.10.6 | Internal compiler library |
ghc-boot |
8.10.6 | Internal compiler library |
ghc-compact |
0.1.0.0 | Core library |
ghc-heap |
8.10.6 | GHC heap-walking library |
ghc-prim |
0.6.1 | Core library |
ghci |
8.10.6 | The REPL interface |
haskeline |
0.8.2 | Dependency of |
hpc |
0.6.1.0 | Dependency of |
integer-gmp |
1.0.3.0 | Core library |
libiserv |
8.10.6 | Internal compiler library |
mtl |
2.2.2 | Dependency of |
parsec |
3.1.14.0 | Dependency of |
pretty |
1.1.3.6 | Dependency of |
process |
1.6.13.2 | Dependency of |
stm |
2.5.0.1 | Dependency of |
template-haskell |
2.16.0.0 | Core library |
terminfo |
0.4.1.4 | Dependency of |
text |
1.2.4.1 | Dependency of |
time |
1.9.3 | Dependency of |
transformers |
0.5.6.2 | Dependency of |
unix |
2.7.2.2 | Dependency of |
xhtml |
3000.2.2.1 | Dependency of |