11:12 a.m.
https://fedoraproject.org/wiki/Changes/LLVM-17
This document represents a proposed Change. As part of the Changes
process, proposals are publicly announced in order to receive
community feedback. This proposal will only be implemented if approved
by the Fedora Engineering Steering Committee.
== Summary ==
Update all llvm sub-projects in Fedora Linux to version 17.
== Owner ==
* Name: [[User:tstellar| Tom Stellard]]
* Email: <tstellar(a)redhat.com>
== Detailed Description ==
All llvm sub-projects in Fedora will be updated to version 17, and
there will be a soname version change for the llvm libraries.
Compatibility packages clang16, llvm16, and lld16 will be added to
ensure that packages that currently depend on clang and llvm version
16 libraries will continue to work.
Other notable changes:
* The Clang Resource Directory will be moved from /usr/lib64/clang/17/
to /usr/lib/clang/17/ this is the location of clang's internal headers
and runtime libraries like libomp and compiler-rt. Package owners of
packages that read or write this directory will need to update their
packages when rebuilding against/with LLVM 17. The
%clang_resource_dir helper macro can be used to make this transition
smoother, and packages are encouraged to update to use this macro even
before the LLVM 17 update.
* Along with the Clang Resource Directory change, compiler-rt will now
install its libraries into /usr/lib/clang/17/lib/$TRIPLE/ instead of
/usr/lib64/clang/17/lib/
* The macros.clang file with RPM macros will be moved from the
clang-devel package to the clang-resource-filesystem package.
===LLVM Build Schedule===
We will be changing our build schedule slightly from previous Fedora
releases. We will now plan to ship a release candidate in Fedora
build prior to the Beta Freeze rather than waiting until after.
====Important Dates====
* July 28: Upstream: 17.0.0-rc1 Release
* Aug 8: Fedora: f39 branch created
* Aug 11: Upstream: 17.0.0-rc2 Release
* Aug 22: Fedora: f39 Beta Freeze
* Aug 25: Upstream: 17.0.0-rc3 Release
* Sep 8: Upstream: 17.0.0 Release
* Oct 10: Fedora: f39 Final Freeze
====Plan====
# Build LLVM 17.0.0-rc1 in COPR.
# Build LLVM 17.0.0-rc1 into a rawhide side-tag in Koji.
# Build LLVM 17.0.0-rc1 into a f39 side-tag in Koji.
# Build LLVM 17.0.0-rc2 into a rawhide side-tag in Koji.
# Build LLVM 17.0.0-rc2 into a f39 side-tag in Koji.
# Push F39 Bodhi Update with 17.0.0-rc2 (or 17.0.0-rc1 if -rc2 is not
ready) prior to the Beta Freeze.
# Continue building new release candidates and pushing them to stable
until the Final Freeze.
We are not planning to push 17.0.0-rc1 into rawhide because the
library ABI is not stabilized at that point. Typically, the ABI
stabilizes after -rc2, but there are no guarantees from upstream about
this. Given the history of minimal ABI changes after -rc2, we feel
like it's safe to push -rc2 into rawhide. The worst case scenario
would be an ABI change -rc3 that we force us to patch LLVM to maintain
compatibility with the -rc2 ABI. This scenario would not require
rebuilding LLVM library uses in Fedora, so this would not require much
extra work from our team.
Updates after 17.0.0-rc2 will generally be very small and can be done
after the Final Freeze is over. If we are late packaging -rc3 or the
final release, we will not ask for a Final Freeze exception, unless
they contain a fix for a critical release blocking bug.
== Feedback ==
== Benefit to Fedora ==
New features and bug fixes provided by the latest version of LLVM.
== Scope ==
* Proposal owners:
** Review existing llvm and clang compatibility packages and orphan
any packages that are no longer used.
** Do scratch builds of Fedora packages that depend on llvm and report
issues to package maintainer.
* Other developers:
** Fix build issues found with LLVM-17 or switch their package to use
the llvm16 compat libs. The LLVM team no longer plans to block Bodhi
updates on dependent packages that fail to build or run with LLVM-17.
There should be around 6-8 weeks between when -rc1 lands in koji and
the Final Freeze for package maintainers to fix issues uncovered with
the LLVM-17 update.
* Release engineering: [https://pagure.io/releng/issues/11455]
* Policies and guidelines: N/A (not needed for this Change)
* Trademark approval: N/A (not needed for this Change)
* Alignment with Community Initiatives:
== Upgrade/compatibility impact ==
This change should not impact upgradeability.
== How To Test ==
The CI tests for the llvm sub-packages in Fedora will be used to catch
regressions that might be potentially introduced by the update to LLVM
17.
== User Experience ==
== Dependencies ==
Packages that depend on one of the llvm packages will need to be
updated to work with LLVM17 or will need to switch to using one of the
llvm16 compat packages.
== Contingency Plan ==
* Contingency mechanism: If there are major problems with LLVM 17,
the compatibility package provide a way for other packages to continue
using LLVM 16.
* Contingency deadline: Beta Freeze
== Documentation ==
Release notes will be added for this change.
== Release Notes ==
LLVM sub-projects in Fedora have been updated to version 17:
*llvm
*clang
*lld
*lldb
*compiler-rt
*libomp
*llvm-test-suite
*libcxx
*python-lit
*flang
*mlir
*polly
*libclc
*llvm-bolt
--
Aoife Moloney
Product Owner
Community Platform Engineering Team
Red Hat EMEA
Communications House
Cork Road
Waterford