[libcxx] Add a CI configuration for standalone building in llvm-project/runtimes

Generate the llvm-lit script in runtimes/CmakeFiles.txt unless invoked
from llvm/runtimes.

Differential Revision: https://reviews.llvm.org/D109593

libcxx/utils/ci/buildkite-pipeline.yml

@@ -479,6 +479,19 @@ steps:
           limit: 2
     timeout_in_minutes: 120
 
+  - label: "New standalone runtimes build"
+    command: "libcxx/utils/ci/run-buildbot new-standalone"
+    artifact_paths:
+      - "**/test-results.xml"
+    agents:
+      queue: "libcxx-builders"
+      os: "linux"
+    retry:
+      automatic:
+        - exit_status: -1  # Agent was lost
+          limit: 2
+    timeout_in_minutes: 120
+
   - label: "Runtimes build"
     command: "libcxx/utils/ci/run-buildbot runtimes-build"
     artifact_paths:

libcxx/utils/ci/run-buildbot

@@ -430,6 +430,22 @@ unified-standalone)
 
     check-cxx-cxxabi
 ;;
+new-standalone)
+
+    clean
+
+    echo "--- Generating CMake"
+    ${CMAKE} \
+          -S "${MONOREPO_ROOT}/runtimes" \
+          -B "${BUILD_DIR}" \
+          -GNinja -DCMAKE_MAKE_PROGRAM="${NINJA}" \
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+          -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
+          -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" \
+          -DLIBCXX_TEST_CONFIG="${MONOREPO_ROOT}/libcxx/test/configs/libcxx-trunk-shared.cfg.in"
+
+    check-cxx-cxxabi
+;;
 runtimes-build)
     clean
 

llvm/runtimes/CMakeLists.txt

@@ -13,6 +13,7 @@ set(LLVM_ENABLE_RUNTIMES "" CACHE STRING
 if(LLVM_ENABLE_RUNTIMES STREQUAL "all" )
   set(LLVM_ENABLE_RUNTIMES ${LLVM_ALL_RUNTIMES})
 endif()
+set(COMMON_CMAKE_ARGS "-DHAVE_LLVM_LIT=ON")
 foreach(proj ${LLVM_ENABLE_RUNTIMES})
   set(proj_dir "${CMAKE_CURRENT_SOURCE_DIR}/../../${proj}")
   if(IS_DIRECTORY ${proj_dir} AND EXISTS ${proj_dir}/CMakeLists.txt)
@@ -87,6 +88,7 @@ function(builtin_default_target compiler_rt_path)
                                       -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=${LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_default}
                                       -DCMAKE_C_COMPILER_WORKS=ON
                                       -DCMAKE_ASM_COMPILER_WORKS=ON
+                                      ${COMMON_CMAKE_ARGS}
                                       ${BUILTINS_CMAKE_ARGS}
                            PASSTHROUGH_PREFIXES COMPILER_RT
                            USE_TOOLCHAIN
@@ -119,6 +121,7 @@ function(builtin_register_target compiler_rt_path target)
                                       -DCMAKE_C_COMPILER_WORKS=ON
                                       -DCMAKE_ASM_COMPILER_WORKS=ON
                                       -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+                                      ${COMMON_CMAKE_ARGS}
                                       ${${target}_extra_args}
                            USE_TOOLCHAIN
                            TARGET_TRIPLE ${target}
@@ -236,6 +239,7 @@ function(runtime_default_target)
                                       -DCMAKE_C_COMPILER_WORKS=ON
                                       -DCMAKE_CXX_COMPILER_WORKS=ON
                                       -DCMAKE_ASM_COMPILER_WORKS=ON
+                                      ${COMMON_CMAKE_ARGS}
                                       ${RUNTIMES_CMAKE_ARGS}
                            PASSTHROUGH_PREFIXES LLVM_ENABLE_RUNTIMES
                                                 ${ARG_PREFIXES}
@@ -338,6 +342,7 @@ function(runtime_register_target name target)
                                       -DCMAKE_ASM_COMPILER_WORKS=ON
                                       -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
                                       -DLLVM_RUNTIMES_TARGET=${name}
+                                      ${COMMON_CMAKE_ARGS}
                                       ${${name}_extra_args}
                            EXTRA_TARGETS ${${name}_extra_targets}
                                          ${${name}_test_targets}

runtimes/CMakeLists.txt

@@ -116,6 +116,8 @@ if (NOT LLVM_DEFAULT_TARGET_TRIPLE)
   get_host_triple(LLVM_DEFAULT_TARGET_TRIPLE)
 endif()
 
+option(LLVM_INCLUDE_TESTS "Generate build targets for the runtimes unit tests." ON)
+
 # Use libtool instead of ar if you are both on an Apple host, and targeting Apple.
 if(CMAKE_HOST_APPLE AND APPLE)
   include(UseLibtool)
@@ -184,6 +186,14 @@ if(LLVM_INCLUDE_TESTS)
     ARGS ${RUNTIMES_LIT_EXTRA_ARGS}
     )
   add_custom_target(runtimes-test-depends DEPENDS ${RUNTIMES_LIT_DEPENDS})
+
+  if (NOT HAVE_LLVM_LIT)
+    # If built by manually invoking cmake on this directory, we don't have
+    # llvm-lit. If invoked via llvm/runtimes, the toplevel llvm cmake
+    # invocation already generated the llvm-lit script.
+    add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit
+                     ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit)
+  endif()
 endif()
 
 get_property(SUB_COMPONENTS GLOBAL PROPERTY SUB_COMPONENTS)