[libc++][CI] Moves modules build to C++23.

[Mordante]

Summary

The std module can be tested in the generic C++23 build. This removes the
special module build.

Note it is possible to enable modules automatically in CMake, but that
would fail in the "parts disabled" builds; they have not been properly
been converted to modules yet.

Depends on D157625

[Mordante]

CI fixes.

[ldionne]

libcxx/cmake/caches/Generic-cxx23-no-modules.cmake

1 ↗

(On Diff #549586)

Instead of adding a new job with std modules disabled, I would instead do this:

diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
index bda040285bb2..bd24a8429686 100644
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -308,6 +308,7 @@ steps:
         CC: "clang-15"
         CXX: "clang++-15"
         ENABLE_CLANG_TIDY: "On"
+        ENABLE_STD_MODULES: "Off"
     agents:
       queue: "libcxx-builders"
       os: "linux"
@@ -326,6 +327,7 @@ steps:
         CC: "clang-16"
         CXX: "clang++-16"
         ENABLE_CLANG_TIDY: "On"
+        ENABLE_STD_MODULES: "Off"
     agents:
       queue: "libcxx-builders"
       os: "linux"
@@ -1108,6 +1110,7 @@ steps:
       env:
           CC: "clang15"
           CXX: "clang++15"
+          ENABLE_STD_MODULES: "Off"
       agents:
         queue: "libcxx-builders"
         os: "freebsd"

Then it becomes more clear that this is a temporary option until it can be enabled by default everywhere (also, please document that env var as such so that we eventually clean it up).

libcxx/utils/ci/buildkite-pipeline.yml

199–205

Everywhere

libcxx/utils/ci/run-buildbot

473

Not needed anymore.

[Mordante]

Addresses review comments.

[Mordante]

Fixes building modules in C++23 mode.

[ldionne]

LGTM w/ comments, thanks!

libcxx/utils/ci/buildkite-pipeline.yml

144

Commit message typo: wouls fail

libcxx/utils/ci/run-buildbot

55–58

Tabs/space conflict?

144

Also a tab!

libcxx/cmake/caches/Generic-module-std-cxx23.cmake

-set(LIBCXX_ENABLE_STD_MODULES ON CACHE BOOL "")
-set(LIBCXX_TEST_PARAMS "std=c++23" CACHE STRING "")
-set(LIBCXXABI_TEST_PARAMS "std=c++23" CACHE STRING "")
-

libcxx/utils/ci/buildkite-pipeline.yml

- label: "Modular build"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
         CC: "clang-${LLVM_HEAD_VERSION}"
         CXX: "clang++-${LLVM_HEAD_VERSION}"
         ENABLE_CLANG_TIDY: "On"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
 
-  - label: "C++23 Module std"
-    command: "libcxx/utils/ci/run-buildbot generic-module-std-cxx23"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    env:
-        # Note modules require and absolute path for clang-scan-deps
-        # https://github.com/llvm/llvm-project/issues/61006
-        CC: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang"
-        CXX: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang++"
-        CMAKE: "/opt/bin/cmake"
-        ENABLE_CLANG_TIDY: "On"
-    agents:
-      queue: "libcxx-builders"
-      os: "linux"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-    timeout_in_minutes: 120
-
   - label: "C++11"
     command: "libcxx/utils/ci/run-buildbot generic-cxx11"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
         CC: "clang-${LLVM_HEAD_VERSION}"
         CXX: "clang++-${LLVM_HEAD_VERSION}"
steps:
   - wait
 
   - label: "C++23"
     command: "libcxx/utils/ci/run-buildbot generic-cxx23"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
-        CC: "clang-${LLVM_HEAD_VERSION}"
-        CXX: "clang++-${LLVM_HEAD_VERSION}"
+        # Note: Modules require and absolute path for clang-scan-deps
+        # https://github.com/llvm/llvm-project/issues/61006
+        CC: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang"
+        CXX: "/usr/lib/llvm-${LLVM_HEAD_VERSION}/bin/clang++"
+        CMAKE: "/opt/bin/cmake"
         ENABLE_CLANG_TIDY: "On"
+        ENABLE_STD_MODULES: "On"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
- label: "Clang 15"
     command: "libcxx/utils/ci/run-buildbot generic-cxx23"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
         CC: "clang-15"
         CXX: "clang++-15"
         ENABLE_CLANG_TIDY: "On"
+        ENABLE_STD_MODULES: "Off"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
 
   - label: "Clang 16"
     command: "libcxx/utils/ci/run-buildbot generic-cxx23"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
         CC: "clang-16"
         CXX: "clang++-16"
         ENABLE_CLANG_TIDY: "On"
+        ENABLE_STD_MODULES: "Off"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
 
   - label: "Clang 17"
     command: "libcxx/utils/ci/run-buildbot generic-cxx23"
     artifact_paths:
       - "**/test-results.xml"
       - "**/*.abilist"
     env:
-        CC: "clang-17"
-        CXX: "clang++-17"
+        # Note: Modules require and absolute path for clang-scan-deps
+        # https://github.com/llvm/llvm-project/issues/61006
+        CC: "/usr/lib/llvm-17/bin/clang"
+        CXX: "/usr/lib/llvm-17/bin/clang++"
+        CMAKE: "/opt/bin/cmake"
         ENABLE_CLANG_TIDY: "On"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
- group: ":freebsd: FreeBSD"
     - label: "FreeBSD 13 amd64"
       command: "libcxx/utils/ci/run-buildbot generic-cxx23"
       artifact_paths:
         - "**/test-results.xml"
         - "**/*.abilist"
       env:
           CC: "clang15"
           CXX: "clang++15"
+          ENABLE_STD_MODULES: "Off"
       agents:
         queue: "libcxx-builders"
         os: "freebsd"
       retry:
         automatic:
           - exit_status: -1  # Agent was lost
             limit: 2
       timeout_in_minutes: 120

libcxx/utils/ci/run-buildbot

 
 GIT_CLANG_FORMAT    The git-clang-format binary to use in the 'format' builder.
                     When the value is omitted, it defaults to
                     'git-clang-format'. This variable or its fallback must work
                     when running the 'format' builder.
 
 ENABLE_CLANG_TIDY   Whether to compile and run clang-tidy checks. This variable
                     is optional.
+
+ENABLE_STD_MODULES  Whether to enable or disable building the C++23 std
+                    modules. This variable is optional.
+                    TODO MODULES remove when all supported compilers support
+                    modules.
+
 EOF
 }
 
 if [[ $# == 0 ]]; then
    usage
    exit 0
 fi
 

 function clean() {
     rm -rf "${BUILD_DIR}"
 }
 
 if [ -z "${ENABLE_CLANG_TIDY}" ]; then
     ENABLE_CLANG_TIDY=Off
 fi
 
+if [ -n "${ENABLE_STD_MODULES}" ]; then
+    ENABLE_STD_MODULES="-DLIBCXX_ENABLE_STD_MODULES=${ENABLE_STD_MODULES}"
+fi
+
 function generate-cmake-base() {
     echo "--- Generating CMake"
     ${CMAKE} \
           -S "${MONOREPO_ROOT}/runtimes" \
           -B "${BUILD_DIR}" \
           -GNinja -DCMAKE_MAKE_PROGRAM="${NINJA}" \
           -DCMAKE_BUILD_TYPE=RelWithDebInfo \
           -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
           -DLIBCXX_ENABLE_WERROR=YES \
           -DLIBCXXABI_ENABLE_WERROR=YES \
           -DLIBUNWIND_ENABLE_WERROR=YES \
           -DLIBCXX_ENABLE_CLANG_TIDY=${ENABLE_CLANG_TIDY} \
+          ${ENABLE_STD_MODULES} \
           -DLLVM_LIT_ARGS="-sv --show-unsupported --xunit-xml-output test-results.xml --timeout=1500 --time-tests" \
           "${@}"
 }
 
 function generate-cmake() {
     generate-cmake-base \
           -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" \
           -DLIBCXX_CXX_ABI=libcxxabi \
generic-modules)
     check-abi-list
 ;;
 generic-modules-lsv)
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-modules-lsv.cmake"
     check-runtimes
     check-abi-list
 ;;
-generic-module-std-cxx23)
-    clean
-    generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-module-std-cxx23.cmake"
-    check-runtimes
-    check-abi-list
-;;
 #
 # Parts removed
 #
 generic-no-threads)
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-no-threads.cmake"
     check-runtimes
 ;;
generic-no-experimental)
     check-abi-list
 ;;
 generic-no-exceptions)
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-no-exceptions.cmake"
     check-runtimes
     check-abi-list
 ;;
 #
 # Other miscellaneous jobs
 #
 generic-abi-unstable)
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-abi-unstable.cmake"
     check-runtimes
 ;;
 apple-system)