Allow specifying libcxx builder image.

[EricWF]

This change attempts to shift the libc++ builders over to new backend
infrastructure that allows running an arbitrary container for the
libc++ job.

This has been a long time in the making, and support from github
and gke is finally at the point where it's possible (hopefully).

This change should also demonstrate another important property:
No Downtime Upgrades.

If this goes well, we'll be able to test the upgrade as a part
of the PR process, and then commiting it to main should (ideally)
not break anything.

[llvmbot]

@llvm/pr-subscribers-libcxx

@llvm/pr-subscribers-github-workflow

Author: Eric (EricWF)

Changes

This change attempts to shift the libc++ builders over to new backend
infrastructure that allows running an arbitrary container for the
libc++ job.

This has been a long time in the making, and support from github
and gke is finally at the point where it's possible (hopefully).

This change should also demonstrate another important property:
No Downtime Upgrades.

If this goes well, we'll be able to test the upgrade as a part
of the PR process, and then commiting it to main should (ideally)
not break anything.

---

Full diff: https://github.com/llvm/llvm-project/pull/110303.diff

1 Files Affected:

• (modified) .github/workflows/libcxx-build-and-test.yaml (+11-8)

diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index b5e60781e00064..64855dad7197da 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -49,7 +49,8 @@ env:
 jobs:
   stage1:
     if: github.repository_owner == 'llvm'
-    runs-on: libcxx-runners-8-set
+    runs-on: libcxx-runners-set
+    container: ghcr.io/libcxx/actions-builder:testing-2024-09-21
     continue-on-error: false
     strategy:
       fail-fast: false
@@ -84,7 +85,8 @@ jobs:
             **/crash_diagnostics/*
   stage2:
     if: github.repository_owner == 'llvm'
-    runs-on: libcxx-runners-8-set
+    runs-on: libcxx-runners-set
+    container: ghcr.io/libcxx/actions-builder:testing-2024-09-21
     needs: [ stage1 ]
     continue-on-error: false
     strategy:
@@ -160,20 +162,21 @@ jobs:
           'benchmarks',
           'bootstrapping-build'
         ]
-        machine: [ 'libcxx-runners-8-set' ]
+        machine: [ 'libcxx-runners-set' ]
         include:
         - config: 'generic-cxx26'
-          machine: libcxx-runners-8-set
+          machine: libcxx-runners-set
         - config: 'generic-asan'
-          machine: libcxx-runners-8-set
+          machine: libcxx-runners-set
         - config: 'generic-tsan'
-          machine: libcxx-runners-8-set
+          machine: libcxx-runners-set
         - config: 'generic-ubsan'
-          machine: libcxx-runners-8-set
+          machine: libcxx-runners-set
         # Use a larger machine for MSAN to avoid timeout and memory allocation issues.
         - config: 'generic-msan'
-          machine: libcxx-runners-8-set
+          machine: libcxx-runners-set
     runs-on: ${{ matrix.machine }}
+    container: ghcr.io/libcxx/actions-builder:testing-2024-09-21
     steps:
       - uses: actions/checkout@v4
       - name: ${{ matrix.config }}

[ldionne]

This is amazing!

About the tests, I am not certain why the transitive includes test started failing, but I ran into something similar in #109720. I think this may be how we're running awk or something like that (I wasn't able to reproduce).

[ldionne]

@EricWF I am trying to debug and fix this CI failure in #110554

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.