LLVM stdenvs lack a set of `__atomic_*` routines that compilers
sometimes rely on, making it impossible to build certain C programs in
them. The reason we lack these routines is that we're using neither
compiler-rt's implementation of them (which was disabled by default a
long time ago) nor gcc's implementation (libatomic). See #391740 for a
more detailed explanation and an example of program that cannot be built.
Since no particular preference was expressed as to which approach
should be used to solve this, I'm going with LLVM's implementation
and recommended setup, which seems to be used also in AIX, Fuchsia
and Apple platforms. This consists of enabling a CMake flag,
`COMPILER_RT_BUILD_STANDALONE_LIBATOMIC`, which causes the routines to
be built and shipped in a separate DSO (placing them in a DSO instead
of `builtins.a` is needed for correctness, as it ensures the lock
section is unique in memory).
As with the other builtins, I'm symlinking this DSO to `libatomic.so` so
that downstream packages don't need specific/complicated logic for LLVM.
Other details:
- For static platforms, since no dynamic linking is expected at all, it
should be correct to ship the symbols in `builtins.a`.
So, that's what I'm doing in those cases.
- Since v19, compiler-rt allows using pthread locks rather than ad-hoc
ones for the atomic routines. Since this plays better with
instrumentation, I'm enabling this whenever libc is available.
- It would be nice to put the DSO in a separate output / derivation, so
that the rest of compiler-rt isn't pulled into the runtime closure,
but it isn't high prio since compiler-rt doesn't pull in dependencies
other than libc, libc++ and unwinder.
Fixes: https://github.com/NixOS/nixpkgs/issues/311930
This is unnecessary since LLVM commit d7bead833631 ("[sanitizer]
Remove crypt and crypt_r interceptors"), included in LLVM 18, the
oldest version we still have in Nixpkgs.
The commit 01e8f570c6 unpinned the
LLVM version, which led to the following warnings whenever Scudo
is loaded (basically whenever a command is started when used
system-wide):
Scudo WARNING: found 3 unrecognized flag(s):
DeleteSizeMismatch=0:DeallocationTypeMismatch=0
DeallocationTypeMismatch=0
ZeroContents=1
According to the current Scudo documentation [1] the options are
now spelled differently. This commit keeps all existing options
and only updates the spelling.
[1] https://llvm.org/docs/ScudoHardenedAllocator.html
Reported-by: CUB3D <callumthom11@gmail.com>
aarch64 FMV (Function MultiVersioning) is not available before the libc
is available. This causes issues while building with compiler-rt on
aarch64. By disabling FMV before the libc is available resolves missing
symbol errors.
Rationale: --replace is deprecated and emits warnings. If these
replacements fail it is probably better to know about it early and come
up with better fixes than the alternative of letting them silently fail
and discover some distal brokenness.
Signed-off-by: Peter Waller <p@pwaller.net>
All LLVM versions < 12 have been removed, so this patch can live in the
versioned directory, simplifying the patch list in the process.
(cherry picked from commit 8408b91e8d)
(cherry picked from commit e33308016c10e2c67551e448b420bed634907c62)
As mentioned in #305146, keeping LLVM 12 is a source of pain because it
is the only version to be built from individual release tarball instead
of the LLVM monorepo. This commit makes LLVM 12 start from the monorepo
as well, simplifying all common LLVM expressions in the process.
With #347887, some quirks in the expressions for LLVM <14 were ironed
out, so building LLVM through from the monorepo is quite simple now.
- Most expressions only required minor changes, mostly removing the
special casing for `sourceRoot`.
- The patch lists from llvm/12/default.nix were ported to
common/default.nix. This only required a few extra conditionals which
could be reduced via a rebuild also involving other LLVM versions.
Outstanding tasks of little urgency have been noted in TODO comments.
I have verified that the patch lists stay the same for all packages
except LLVM where merely the order changes. An extra set of eyes
is appreciated, of course.
- clang: The expression was reworked to use the same symlink location
for clang-tools-extra for all versions including LLVM 12. This
required adjusting the ad hoc patching of the clangd cmake files
slightly.
- libunwind: We no longer need to make the libcxx sources available
manually. We can rely on the monorepo source instead.
- lld: We no longer need to make the libunwind sources available manually.
- llvm: We no longer need to make the polly sources available manually
- On Darwin, we need to bypass CMake's C++ compiler for libcxx and
libunwind now. It isn't a 100% clear why, probably because we've
started to use Darwin's bootstrapStdenv for libcxx in the common
expression compared to LLVM 12 on master [1].
The reordering of flags for wasm causes a rebuild for some packages
like firefox, but this should be tolerable on staging.
[1]: https://github.com/NixOS/nixpkgs/blob/665ebfb253caba7b85c2affefe2a92b305def4e6/pkgs/development/compilers/llvm/12/default.nix#L392-L430
(cherry picked from commit ee9eacf23e)
(cherry picked from commit c4e9f17ef944bb7ce0d3d1226d7f922f28e46b02)
Also exposes owner, repo, and other attributes available on the original
monorepoSrc. These attributes were previously hidden behind a
runCommand that consumes monorepoSrc and hides this information away.
```
$ nix eval --raw .#llvmPackages_18.llvm.src.rev
llvmorg-18.1.8
$ nix eval --raw .#llvmPackages_git.llvm.src.rev
0e8555d4dbfdfeddc01dc2ecf9a9b6e804f7b645
```
Signed-off-by: Peter Waller <p@pwaller.net>
As mentioned in #305146, keeping LLVM 12 is a source of pain because it
is the only version to be built from individual release tarball instead
of the LLVM monorepo. This commit makes LLVM 12 start from the monorepo
as well, simplifying all common LLVM expressions in the process.
With #347887, some quirks in the expressions for LLVM <14 were ironed
out, so building LLVM through from the monorepo is quite simple now.
- Most expressions only required minor changes, mostly removing the
special casing for `sourceRoot`.
- The patch lists from llvm/12/default.nix were ported to
common/default.nix. This only required a few extra conditionals which
could be reduced via a rebuild also involving other LLVM versions.
Outstanding tasks of little urgency have been noted in TODO comments.
I have verified that the patch lists stay the same for all packages
except LLVM where merely the order changes. An extra set of eyes
is appreciated, of course.
- clang: The expression was reworked to use the same symlink location
for clang-tools-extra for all versions including LLVM 12. This
required adjusting the ad hoc patching of the clangd cmake files
slightly.
- libunwind: We no longer need to make the libcxx sources available
manually. We can rely on the monorepo source instead.
- lld: We no longer need to make the libunwind sources available manually.
- llvm: We no longer need to make the polly sources available manually
- On Darwin, we need to bypass CMake's C++ compiler for libcxx and
libunwind now. It isn't a 100% clear why, probably because we've
started to use Darwin's bootstrapStdenv for libcxx in the common
expression compared to LLVM 12 on master [1].
The reordering of flags for wasm causes a rebuild for some packages
like firefox, but this should be tolerable on staging.
[1]: https://github.com/NixOS/nixpkgs/blob/665ebfb253caba7b85c2affefe2a92b305def4e6/pkgs/development/compilers/llvm/12/default.nix#L392-L430
Without these fixes, the git build currently fails because the tests are
out of date.
One is updated since it was fixed upstream, the other is still needed
for the git build, but testing `version` resulted in a test against the
`unstable-*` string and not the one with the version number in it.
Signed-off-by: Peter Waller <p@pwaller.net>
Alba Mendez