Changes/LLVM-14

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LLVM 14

Summary

Update all llvm sub-projects in Fedora Linux to version 14.

Owner

• Name: Tom Stellard
• Email: <tstellar@redhat.com>

Current status

• Targeted release: Fedora Linux 36
• Last updated: 2021-12-02
• FESCo issue: <will be assigned by the Wrangler>
• Tracker bug: <will be assigned by the Wrangler>
• Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

All llvm sub-projects in Fedora will be updated to version 14, and there will be a soname version change for the llvm libraries. Compatibility packages clang13 and llvm13 will be added to ensure that packages that currently depend on clang and llvm version 13 libraries will continue to work.

Unlike previous releases, we will no longer be packaging release candidate builds in Rawhide or F36. Release candidates are not guaranteed to be ABI compatible with each other, so upgrading from one release candidate to another (or to the final release) requires rebuilding all the clang/LLVM library users and this has become very difficult to coordinate given the increased number of packages using the clang/LLVM libraries.

We do plan to build release candidate versions into a side-tag for testing. We will also create an llvm-14 branch in dist-git, so that we can build the release candidate versions while still being able to fix bugs and make changes to LLVM 13 in the rawhide branch.

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.
 * Request an llvm-14 branch in dist-git for each llvm sub-project.
 * Request a side-tag.
 * Build llvm13 and clang13 compat packages into the side-tag.
 * When upstream LLVM project releases version 14.0.0-rc1 (Late January 2021), package this using the llvm-14 branches and build it into the side-tag.
   * Repeat process for each release candidate.
 * When upstream LLVM project releases version 14.0.0-final (March 2021), package this using the rawhide and f36 branches.

• Other developers:

 * Maintainers of packages that depend on clang-libs or llvm-libs will need to update their spec files to depend on the clang13 and llvm13 compatibility packages if they want to rebuild their package and it does not work with LLVM 14 yet. The key point here is that spec file changes are only needed if a package is going to be rebuilt after LLVM 14 is added to Fedora. The compatibility packages will ensure that already built packages continue to work.

• Release engineering: #Releng issue number

• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

• Alignment with Objectives:

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 14.

Contingency Plan

• Contingency mechanism: (What to do? Who will do it?) N/A (not a System Wide Change)
• Contingency deadline: N/A (not a System Wide Change)
• Blocks release? N/A (not a System Wide Change), Yes/No

Documentation

N/A (not a System Wide Change)