[CMake] Support runtimes and monorepo layouts when looking for libc++

[phosek]

Summary

This also slightly refactors the code that's checking the directory
presence which allows eliminating one unnecessary variable.

[phosek]

ping

[beanz]

LGTM

compiler-rt/trunk/CMakeLists.txt

if (CMAKE_LINKER MATCHES "link.exe$")
   # it, but CMake doesn't seem to have a way to set linker flags for
   # individual static libraries, so we enable the suppression flag for
   # the whole compiler-rt project.
   append("/IGNORE:4221" CMAKE_STATIC_LINKER_FLAGS)
 endif()
 
 add_subdirectory(include)
 
-set(COMPILER_RT_LIBCXX_PATH ${LLVM_MAIN_SRC_DIR}/projects/libcxx)
-if(EXISTS ${COMPILER_RT_LIBCXX_PATH}/)
-  set(COMPILER_RT_HAS_LIBCXX_SOURCES TRUE)
-else()
-  set(COMPILER_RT_LIBCXX_PATH ${LLVM_MAIN_SRC_DIR}/../libcxx)
-  if(EXISTS ${COMPILER_RT_LIBCXX_PATH}/)
-    set(COMPILER_RT_HAS_LIBCXX_SOURCES TRUE)
-  else()
-    set(COMPILER_RT_HAS_LIBCXX_SOURCES FALSE)
-  endif()
+foreach(path IN ITEMS ${LLVM_MAIN_SRC_DIR}/projects/libcxx
+                      ${LLVM_MAIN_SRC_DIR}/runtimes/libcxx
+                      ${LLVM_MAIN_SRC_DIR}/../libcxx
+                      ${LLVM_EXTERNAL_LIBCXX_SOURCE_DIR})
+  if(IS_DIRECTORY ${path})
+    set(COMPILER_RT_LIBCXX_PATH ${path})
+    break()
   endif()
+endforeach()
 
 set(COMPILER_RT_LLD_PATH ${LLVM_MAIN_SRC_DIR}/tools/lld)
 if(EXISTS ${COMPILER_RT_LLD_PATH}/ AND LLVM_TOOL_LLD_BUILD)
   set(COMPILER_RT_HAS_LLD TRUE)
 else()
   set(COMPILER_RT_LLD_PATH ${LLVM_MAIN_SRC_DIR}/../lld)
   if(EXISTS ${COMPILER_RT_LLD_PATH}/ AND LLVM_TOOL_LLD_BUILD)
     set(COMPILER_RT_HAS_LLD TRUE)

compiler-rt/trunk/cmake/Modules/AddCompilerRT.cmake

 endmacro(add_compiler_rt_script src name)
 
 # Builds custom version of libc++ and installs it in <prefix>.
 # Can be used to build sanitized versions of libc++ for running unit tests.
 # add_custom_libcxx(<name> <prefix>
 #                   DEPS <list of build deps>
 #                   CFLAGS <list of compile flags>)
 macro(add_custom_libcxx name prefix)
-  if(NOT COMPILER_RT_HAS_LIBCXX_SOURCES)
+  if(NOT COMPILER_RT_LIBCXX_PATH)
     message(FATAL_ERROR "libcxx not found!")
   endif()
 
   cmake_parse_arguments(LIBCXX "" "" "DEPS;CFLAGS" ${ARGN})
   foreach(flag ${LIBCXX_CFLAGS})
     set(flagstr "${flagstr} ${flag}")
   endforeach()
   set(LIBCXX_CFLAGS ${flagstr})

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

add_compiler_rt_test(MsanUnitTests "Msan-${arch}${kind}-Test" ${arch}
     DEPS ${MSAN_TEST_DEPS}
     LINK_FLAGS ${MSAN_UNITTEST_LINK_FLAGS}
                ${TARGET_LINK_FLAGS}
                "-Wl,-rpath=${CMAKE_CURRENT_BINARY_DIR}"
                "-Wl,-rpath=${LIBCXX_PREFIX}/lib")
 endmacro()
 
 # We should only build MSan unit tests if we can build instrumented libcxx.
-if(COMPILER_RT_CAN_EXECUTE_TESTS AND COMPILER_RT_HAS_LIBCXX_SOURCES)
+if(COMPILER_RT_CAN_EXECUTE_TESTS AND COMPILER_RT_LIBCXX_PATH)
   foreach(arch ${MSAN_SUPPORTED_ARCH})
     get_target_flags_for_arch(${arch} TARGET_CFLAGS)
     set(LIBCXX_PREFIX ${CMAKE_CURRENT_BINARY_DIR}/../libcxx_msan_${arch})
     add_custom_libcxx(libcxx_msan_${arch} ${LIBCXX_PREFIX}
       DEPS ${MSAN_RUNTIME_LIBRARIES}
       CFLAGS ${MSAN_LIBCXX_CFLAGS} ${TARGET_CFLAGS})
     set(MSAN_LIBCXX_SO ${LIBCXX_PREFIX}/lib/libc++.so)
 
     add_msan_tests_for_arch(${arch} "" "")
     add_msan_tests_for_arch(${arch} "-with-call"
                             "-mllvm;-msan-instrumentation-with-call-threshold=0")
   endforeach()
 endif()

compiler-rt/trunk/lib/tsan/CMakeLists.txt

if(COMPILER_RT_HAS_SYSROOT_FLAG AND NOT CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
   file(GLOB _tsan_platform_sources rtl/tsan*posix* rtl/tsan*mac*
                                    rtl/tsan*linux*)
   list(REMOVE_ITEM _tsan_generic_sources ${_tsan_platform_sources})
   set_source_files_properties(${_tsan_generic_sources}
     PROPERTIES COMPILE_FLAGS "--sysroot=.")
 endif()
 
 # Build libcxx instrumented with TSan.
-if(COMPILER_RT_HAS_LIBCXX_SOURCES AND
+if(COMPILER_RT_LIBCXX_PATH AND
    COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang" AND
    NOT ANDROID)
   set(libcxx_tsan_deps)
   foreach(arch ${TSAN_SUPPORTED_ARCH})
     get_target_flags_for_arch(${arch} TARGET_CFLAGS)
     set(LIBCXX_PREFIX ${CMAKE_CURRENT_BINARY_DIR}/libcxx_tsan_${arch})
     add_custom_libcxx(libcxx_tsan_${arch} ${LIBCXX_PREFIX}
       DEPS ${TSAN_RUNTIME_LIBRARIES}

compiler-rt/trunk/test/msan/CMakeLists.txt

foreach(arch ${MSAN_TEST_ARCH})
   list(APPEND MSAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
 endforeach()
 
 set(MSAN_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 if(NOT COMPILER_RT_STANDALONE_BUILD)
   list(APPEND MSAN_TEST_DEPS msan)
 endif()
 
-if(COMPILER_RT_INCLUDE_TESTS AND COMPILER_RT_HAS_LIBCXX_SOURCES)
+if(COMPILER_RT_INCLUDE_TESTS AND COMPILER_RT_LIBCXX_PATH)
   configure_lit_site_cfg(
     ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg)
   list(APPEND MSAN_TEST_DEPS MsanUnitTests)
   list(APPEND MSAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/Unit)
 endif()
 
 add_lit_testsuite(check-msan "Running the MemorySanitizer tests"
   ${MSAN_TESTSUITES}
   DEPENDS ${MSAN_TEST_DEPS}
   )
 set_target_properties(check-msan PROPERTIES FOLDER "Compiler-RT Misc")

compiler-rt/trunk/test/tsan/CMakeLists.txt

 set(TSAN_LIT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 set(TSAN_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 if(${COMPILER_RT_DEFAULT_TARGET_ARCH} MATCHES "x86_64")
   list(APPEND TSAN_TEST_DEPS GotsanRuntimeCheck)
 endif()
 if(NOT COMPILER_RT_STANDALONE_BUILD)
   list(APPEND TSAN_TEST_DEPS tsan)
 endif()
-if(COMPILER_RT_HAS_LIBCXX_SOURCES AND
+if(COMPILER_RT_LIBCXX_PATH AND
    COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang"
    AND NOT APPLE AND NOT ANDROID)
   list(APPEND TSAN_TEST_DEPS libcxx_tsan)
   set(TSAN_HAS_LIBCXX True)
 else()
   set(TSAN_HAS_LIBCXX False)
 endif()