[compiler-rt] Add custom libc++ workaround for CMake < 3.26

The INSTALL_BYPRODUCTS ExternalProject_Add() argument was only added in
CMake 3.26 and the current minimum is 3.20. Work around this by using an
explicit ExternalProject_Add_Step() call for the install step with a
BYPRODUCTS argument. We can't keep using the `install` name here since that
is reserved by the CMake implementation and results in errors when used.

This commit should be reverted once LLVM depends on CMake 3.26.

Pull Request: #115677

Author: arichardson

compiler-rt/cmake/Modules/AddCompilerRT.cmake

@@ -706,18 +706,30 @@ macro(add_custom_libcxx name prefix)
                -DLLVM_INCLUDE_TESTS=OFF
                -DLLVM_INCLUDE_DOCS=OFF
                ${LIBCXX_CMAKE_ARGS}
-    STEP_TARGETS configure build install
+    STEP_TARGETS configure build
     BUILD_ALWAYS 1
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     USES_TERMINAL_INSTALL 1
     LIST_SEPARATOR |
     EXCLUDE_FROM_ALL TRUE
+    )
+
+  # Once we depend on CMake 3.26, we can use the INSTALL_BYPRODUCTS argument
+  # instead of having to fall back to ExternalProject_Add_Step()
+  # Note: We can't use the normal name "install" here since that interferes
+  # with the default ExternalProject_Add() logic and causes errors.
+  ExternalProject_Add_Step(${name} install-cmake326-workaround
     # Ensure that DESTDIR=... set in the out environment does not affect this
     # target (we always need to install to the build directory).
-    INSTALL_COMMAND env DESTDIR= ${CMAKE_COMMAND} --build ${prefix}/build --target install
-    INSTALL_BYPRODUCTS "${prefix}/lib/libc++.a" "${prefix}/lib/libc++abi.a"
-    )
+    COMMAND env DESTDIR= ${CMAKE_COMMAND} --build ${prefix}/build --target install
+    COMMENT "Installing ${name}..."
+    BYPRODUCTS "${prefix}/lib/libc++.a" "${prefix}/lib/libc++abi.a"
+    DEPENDEES build
+    EXCLUDE_FROM_MAIN 1
+    USES_TERMINAL 1
+  )
+  ExternalProject_Add_StepTargets(${name} install-cmake326-workaround)
 
   if (CMAKE_GENERATOR MATCHES "Make")
     set(run_clean "$(MAKE)" "-C" "${prefix}" "clean")

compiler-rt/lib/fuzzer/CMakeLists.txt

@@ -166,11 +166,11 @@ if(OS_NAME MATCHES "Android|Linux|Fuchsia" AND
                  -DLIBCXX_ABI_NAMESPACE=__Fuzzer
                  -DLIBCXX_ENABLE_EXCEPTIONS=OFF)
     target_compile_options(RTfuzzer.${arch} PRIVATE -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
-    add_dependencies(RTfuzzer.${arch} libcxx_fuzzer_${arch}-install)
+    add_dependencies(RTfuzzer.${arch} libcxx_fuzzer_${arch}-install-cmake326-workaround)
     target_compile_options(RTfuzzer_main.${arch} PRIVATE -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
-    add_dependencies(RTfuzzer_main.${arch} libcxx_fuzzer_${arch}-install)
+    add_dependencies(RTfuzzer_main.${arch} libcxx_fuzzer_${arch}-install-cmake326-workaround)
     target_compile_options(RTfuzzer_interceptors.${arch} PRIVATE -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
-    add_dependencies(RTfuzzer_interceptors.${arch} libcxx_fuzzer_${arch}-install)
+    add_dependencies(RTfuzzer_interceptors.${arch} libcxx_fuzzer_${arch}-install-cmake326-workaround)
     partially_link_libcxx(fuzzer_no_main ${LIBCXX_${arch}_PREFIX} ${arch})
     partially_link_libcxx(fuzzer_interceptors ${LIBCXX_${arch}_PREFIX} ${arch})
     partially_link_libcxx(fuzzer ${LIBCXX_${arch}_PREFIX} ${arch})

compiler-rt/lib/fuzzer/tests/CMakeLists.txt

@@ -64,7 +64,7 @@ if(COMPILER_RT_DEFAULT_TARGET_ARCH IN_LIST FUZZER_SUPPORTED_ARCH)
      COMPILER_RT_LIBCXX_PATH AND
      COMPILER_RT_LIBCXXABI_PATH)
     file(GLOB libfuzzer_headers ../*.h)
-    set(LIBFUZZER_TEST_RUNTIME_DEPS libcxx_fuzzer_${arch}-install ${libfuzzer_headers})
+    set(LIBFUZZER_TEST_RUNTIME_DEPS libcxx_fuzzer_${arch}-install-cmake326-workaround ${libfuzzer_headers})
     set(LIBFUZZER_TEST_RUNTIME_CFLAGS -isystem ${LIBCXX_${arch}_PREFIX}/include/c++/v1)
     set(LIBFUZZER_TEST_RUNTIME_LINK_FLAGS ${LIBCXX_${arch}_PREFIX}/lib/libc++.a)
   endif()

compiler-rt/lib/msan/tests/CMakeLists.txt

@@ -69,7 +69,7 @@ macro(msan_compile obj_list source arch kind cflags)
   sanitizer_test_compile(
     ${obj_list} ${source} ${arch}
     KIND ${kind}
-    COMPILE_DEPS ${MSAN_UNITTEST_HEADERS} libcxx_msan_${arch}-install
+    COMPILE_DEPS ${MSAN_UNITTEST_HEADERS} libcxx_msan_${arch}-install-cmake326-workaround
     DEPS msan
     CFLAGS -isystem ${MSAN_LIBCXX_DIR}/../include/c++/v1
            ${MSAN_UNITTEST_INSTRUMENTED_CFLAGS} ${cflags}
@@ -117,10 +117,10 @@ macro(add_msan_tests_for_arch arch kind cflags)
                    DEPS ${MSAN_INST_LOADABLE_OBJECTS})
 
   set(MSAN_TEST_OBJECTS ${MSAN_INST_TEST_OBJECTS} ${MSAN_INST_GTEST})
-  set(MSAN_TEST_DEPS ${MSAN_TEST_OBJECTS} libcxx_msan_${arch}-install
+  set(MSAN_TEST_DEPS ${MSAN_TEST_OBJECTS} libcxx_msan_${arch}-install-cmake326-workaround
                      ${MSAN_LOADABLE_SO}
                      "${MSAN_LIBCXX_DIR}/libc++.a" "${MSAN_LIBCXX_DIR}/libc++abi.a")
-  list(APPEND MSAN_TEST_DEPS msan libcxx_msan_${arch}-install)
+  list(APPEND MSAN_TEST_DEPS msan libcxx_msan_${arch}-install-cmake326-workaround)
   get_target_flags_for_arch(${arch} TARGET_LINK_FLAGS)
   add_compiler_rt_test(MsanUnitTests "Msan-${arch}${kind}-Test" ${arch}
     OBJECTS ${MSAN_TEST_OBJECTS} "${MSAN_LIBCXX_DIR}/libc++.a" "${MSAN_LIBCXX_DIR}/libc++abi.a"

compiler-rt/lib/tsan/CMakeLists.txt

@@ -31,7 +31,7 @@ if(COMPILER_RT_LIBCXX_PATH AND
       DEPS ${TSAN_RUNTIME_LIBRARIES}
       CFLAGS ${TARGET_CFLAGS} -fsanitize=thread
       USE_TOOLCHAIN)
-    list(APPEND libcxx_tsan_deps libcxx_tsan_${arch}-install)
+    list(APPEND libcxx_tsan_deps libcxx_tsan_${arch}-install-cmake326-workaround)
   endforeach()
 
   add_custom_target(libcxx_tsan DEPENDS ${libcxx_tsan_deps})