Change how libc++ specifies the runners to use.

[EricWF]

Github actions has some quirks with how you use runner groups, labels,
names, etc... One of them is that groups can't "group" more than one set
of builders. To do that, you use the same name. So now we're specifying
the name.

[llvmbot]

@llvm/pr-subscribers-github-workflow

Author: Eric (EricWF)

Changes

Github actions has some quirks with how you use runner groups, labels,
names, etc... One of them is that groups can't "group" more than one set
of builders. To do that, you use the same name. So now we're specifying
the name.

---

Full diff: https://github.com/llvm/llvm-project/pull/74188.diff

1 Files Affected:

• (modified) .github/workflows/libcxx-build-and-test.yaml (+9-12)

diff --git a/.github/workflows/libcxx-build-and-test.yaml b/.github/workflows/libcxx-build-and-test.yaml
index 018f0e45a2441ef..83786052a539106 100644
--- a/.github/workflows/libcxx-build-and-test.yaml
+++ b/.github/workflows/libcxx-build-and-test.yaml
@@ -50,8 +50,7 @@ env:
 jobs:
   stage1:
     if: github.repository_owner == 'llvm'
-    runs-on:
-      group: libcxx-runners-8
+    runs-on: libcxx-runners-8-set
     continue-on-error: false
     strategy:
       fail-fast: true
@@ -89,8 +88,7 @@ jobs:
             **/crash_diagnostics/*
   stage2:
     if: github.repository_owner == 'llvm'
-    runs-on:
-      group: libcxx-runners-8
+    runs-on: libcxx-runners-8-set
     needs: [ stage1 ]
     continue-on-error: false
     strategy:
@@ -169,27 +167,26 @@ jobs:
           'benchmarks',
           'bootstrapping-build'
         ]
-        machine: [ 'libcxx-runners-8' ]
+        machine: [ 'libcxx-runners-8-set' ]
         std_modules: [ 'OFF' ]
         include:
         - config: 'generic-cxx26'
-          machine: libcxx-runners-8
+          machine: libcxx-runners-8-set
           std_modules: 'ON'
         - config: 'generic-asan'
-          machine: libcxx-runners-8
+          machine: libcxx-runners-8-set
           std_modules: 'OFF'
         - config: 'generic-tsan'
-          machine: libcxx-runners-8
+          machine: libcxx-runners-8-set
           std_modules: 'OFF'
         - config: 'generic-ubsan'
-          machine: libcxx-runners-8
+          machine: libcxx-runners-8-set
           std_modules: 'OFF'
         # Use a larger machine for MSAN to avoid timeout and memory allocation issues.
         - config: 'generic-msan'
-          machine: libcxx-runners-32
+          machine: libcxx-runners-32-set
           std_modules: 'OFF'
-    runs-on:
-      group: ${{ matrix.machine }}
+    runs-on: ${{ matrix.machine }}
     steps:
       - uses: actions/checkout@v4
       - name: ${{ matrix.config }}

[EricWF]

I'm going to go ahead and merge this so I can have better failover behavior for the bots.