[libc++] Add a CI job for the LLDB data formatters

[ldionne]

Summary

This patch adds a CI job running the LLDB data formatters in the libc++
CI. This should avoid breaking the LLDB data formatters when e.g. the
layout of libc++ data structures is changed.

[ldionne]

For watchers -- this is kind of a RFC patch:

1. The Dockerfile change will have to be landed separately (first).
2. I'd like to quantify how slow this job is before we add it. We should avoid adding a lot of latency to the libc++ CI pipeline.

Also, this is not a hard commitment to start maintaining LLDB's data formatters. I spoke to @aprantl and @JDevlieghere and we agreed that this should be used as a way to avoid disruption on both the libc++ and the LLDB side. If we run into LLDB data formatters issues with a libc++ patch, we should work with the LLDB folks (and they agreed to be responsive) to resolve the issue and unblock the libc++ patch. That way, everyone's happy. Let's just hope the turnaround time for this job isn't prohibitive.

[Mordante]

Thanks a lot for working on this!

libcxx/utils/ci/run-buildbot

475

When this is too slow we could consider merging it with the bootstrapping build. They have quite a bit of overlap.

That isn't a great solution, but it may help us. I didn't find a way a in Buildkite to re-use the build from an other step as basis for a new step

[ldionne]

Rebase onto main -- this should run the new CI job now.

[JDevlieghere]

Thanks for working on this, Louis. Looks good from the LLDB perspective.

[ldionne]

Since I probably won't have time to pick this up and finish it this week, I am closing this and I moved it over to GitHub here: https://github.com/llvm/llvm-project/pull/65174

libcxx/utils/ci/buildkite-pipeline.yml

agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
 
+  - label: "LLDB Data Formatters"
+    command: "libcxx/utils/ci/run-buildbot check-lldb-data-formatters"
+    artifact_paths:
+      - "**/test-results.xml"
+    env:
+        CC: "clang-${LLVM_HEAD_VERSION}"
+        CXX: "clang++-${LLVM_HEAD_VERSION}"
+    agents:
+      queue: "libcxx-builders"
+      os: "linux"
+    retry:
+      automatic:
+        - exit_status: -1  # Agent was lost
+          limit: 2
+    timeout_in_minutes: 120
+
   # Tests on non-Unix platforms
   - group: ":windows: Windows"
     steps:
     - label: "Clang-cl (DLL)"
       command: "bash libcxx/utils/ci/run-buildbot clang-cl-dll"
       artifact_paths:
         - "**/test-results.xml"
         - "**/*.abilist"

libcxx/utils/ci/run-buildbot

apple-system-backdeployment-*)
 
     check-runtimes
 ;;
 benchmarks)
     clean
     generate-cmake
     check-cxx-benchmarks
 ;;
+check-lldb-data-formatters)
+    clean
+    ${CMAKE} \
+        -S "${MONOREPO_ROOT}/llvm" \
+        -B "${BUILD_DIR}" \
+        -GNinja -DCMAKE_MAKE_PROGRAM="${NINJA}" \
+        -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+        -DLLVM_ENABLE_ASSERTIONS=ON \
+        -DLLDB_ENABLE_PYTHON=ON \
+        -DLLVM_ENABLE_PROJECTS='llvm;clang;lldb' \
+        -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi'
+
+    ${NINJA} -C "${BUILD_DIR}" check-lldb-api-functionalities-data-formatter-data-formatter-stl-libcxx
+;;
 documentation)
     clean
     generate-cmake -DLLVM_ENABLE_SPHINX=ON
 
     echo "+++ Generating documentation"
     ${NINJA} -vC "${BUILD_DIR}" docs-libcxx-html
 ;;
 bootstrapping-build)