[CMake] Option to select C++ library for runtimes that use it

[phosek]

Summary

We currently have an option to select C++ ABI and C++ library for tests
but there are runtimes that use C++ library, specifically ORC and XRay,
which aren't covered by existing options. This change introduces a new
option to control the use of C++ libray for these runtimes.

Ideally, this option should become the default way to select C++ library
for all of compiler-rt replacing the existing options (the C++ ABI
option could remain as a hidden internal option).

[phosek]

I'm aware of the duplication of logic for handling of COMPILER_RT_CXX_LIBRARY and SANITIZER_TEST_CXX_LIBNAME. Right now my goal is to make the use of in-tree libc++ in compiler-rt explicit, and then cleaning up the handling logic in follow up changes.

[mstorsjo]

compiler-rt/CMakeLists.txt

534

Does this mean that if you set COMPILER_RT_CXX_LIBRARY=libcxx, it's assumed that you're actually _building_ that same libcxx in the same cmake invocation?

I'm currently building compiler-rt in a standalone cmake invocation, separate from all the others, with -DSANITIZER_CXX_ABI=libc++. Building them all at once might be something I could consider at some point, but I wouldn't want to force that situation right now, if it could be avoided?

[phosek]

compiler-rt/CMakeLists.txt

534

Yes, correct. This is modeled after https://github.com/llvm/llvm-project/blob/610139d2d9ce6746b3c617fb3e2f7886272d26ff/libcxx/CMakeLists.txt#L230 and https://github.com/llvm/llvm-project/blob/610139d2d9ce6746b3c617fb3e2f7886272d26ff/libcxx/cmake/Modules/HandleLibCXXABI.cmake#L109.

In your case you'd likely want to use -DCOMPILER_RT_CXX_LIBRARY=system-libcxx.

[mstorsjo]

LGTM

compiler-rt/CMakeLists.txt

534

Oh right, there was such an option too. Right, that'd work fine yeah - sorry for overlooking it.

clang/cmake/caches/Fuchsia-stage2.cmake

if(LINUX_${target}_SYSROOT)
     set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_C_FLAGS "--target=${target}" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_CXX_FLAGS "--target=${target}" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_ASM_FLAGS "--target=${target}" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SYSROOT ${LINUX_${target}_SYSROOT} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
+    set(RUNTIMES_${target}_COMPILER_RT_CXX_LIBRARY "libcxx" CACHE STRING "")
     set(RUNTIMES_${target}_COMPILER_RT_USE_BUILTINS_LIBRARY ON CACHE BOOL "")
     set(RUNTIMES_${target}_COMPILER_RT_USE_LLVM_UNWINDER ON CACHE BOOL "")
     set(RUNTIMES_${target}_COMPILER_RT_CAN_EXECUTE_TESTS ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
foreach(target x86_64-unknown-fuchsia;aarch64-unknown-fuchsia)
     set(RUNTIMES_${target}_CMAKE_BUILD_WITH_INSTALL_RPATH ON CACHE BOOL "")
     set(RUNTIMES_${target}_CMAKE_ASM_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_C_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_CXX_FLAGS ${FUCHSIA_${target}_COMPILER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SHARED_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_MODULE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_EXE_LINKER_FLAGS ${FUCHSIA_${target}_LINKER_FLAGS} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SYSROOT ${FUCHSIA_${target}_SYSROOT} CACHE PATH "")
+    set(RUNTIMES_${target}_COMPILER_RT_CXX_LIBRARY "libcxx" CACHE STRING "")
     set(RUNTIMES_${target}_COMPILER_RT_USE_BUILTINS_LIBRARY ON CACHE BOOL "")
     set(RUNTIMES_${target}_COMPILER_RT_USE_LLVM_UNWINDER ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_HIDE_SYMBOLS ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_HERMETIC_STATIC_LIBRARY ON CACHE BOOL "")

compiler-rt/CMakeLists.txt

macro(handle_default_cxx_lib var)
   else()
     set(${var}_LIBNAME "${${var}}")
     set(${var}_SYSTEM 1)
   endif()
 endmacro()
 
 # This is either directly the C++ ABI library or the full C++ library
 # which pulls in the ABI transitively.
+# TODO: Mark this as internal flag, most users should use COMPILER_RT_CXX_LIBRARY.
 set(SANITIZER_CXX_ABI "default" CACHE STRING
     "Specify C++ ABI library to use.")
 set(CXXABIS none default libstdc++ libc++ libcxxabi)
 set_property(CACHE SANITIZER_CXX_ABI PROPERTY STRINGS ;${CXXABIS})
 handle_default_cxx_lib(SANITIZER_CXX_ABI)
 
 # This needs to be a full C++ library for linking gtest and unit tests.
+# TODO: Mark this as internal flag, most users should use COMPILER_RT_CXX_LIBRARY.
 set(SANITIZER_TEST_CXX "default" CACHE STRING
     "Specify C++ library to use for tests.")
 set(CXXLIBS none default libstdc++ libc++)
 set_property(CACHE SANITIZER_TEST_CXX PROPERTY STRINGS ;${CXXLIBS})
 handle_default_cxx_lib(SANITIZER_TEST_CXX)
 
 option(COMPILER_RT_USE_LLVM_UNWINDER "Use the LLVM unwinder." OFF)
 cmake_dependent_option(COMPILER_RT_ENABLE_STATIC_UNWINDER

 if (DEFINED LIBCXX_ENABLE_SHARED AND NOT LIBCXX_ENABLE_SHARED)
   set(DEFAULT_SANITIZER_USE_STATIC_TEST_CXX ON)
 endif()
 
 option(SANITIZER_USE_STATIC_TEST_CXX
   "Use static libc++ for tests." ${DEFAULT_SANITIZER_USE_STATIC_TEST_CXX})
 pythonize_bool(SANITIZER_USE_STATIC_TEST_CXX)
 
+set(COMPILER_RT_SUPPORTED_CXX_LIBRARIES none default libcxx)
+set(COMPILER_RT_CXX_LIBRARY "default" CACHE STRING "Specify C++ library to use. Supported values are ${COMPILER_RT_SUPPORTED_CXX_LIBRARIES}.")
+if (NOT "${COMPILER_RT_CXX_LIBRARY}" IN_LIST COMPILER_RT_SUPPORTED_CXX_LIBRARIES)
+  message(FATAL_ERROR "Unsupported C++ library: '${COMPILER_RT_CXX_LIBRARY}'. Supported values are ${COMPILER_RT_SUPPORTED_CXX_LIBRARIES}.")
+endif()
+cmake_dependent_option(COMPILER_RT_STATIC_CXX_LIBRARY
+  "Statically link the C++ library." OFF
+  "COMPILER_RT_CXX_LIBRARY" OFF)
+
 set(DEFAULT_COMPILER_RT_USE_BUILTINS_LIBRARY OFF)
 if (FUCHSIA)
   set(DEFAULT_COMPILER_RT_USE_BUILTINS_LIBRARY ON)
 endif()
 
 option(COMPILER_RT_USE_BUILTINS_LIBRARY
   "Use compiler-rt builtins instead of libgcc" ${DEFAULT_COMPILER_RT_USE_BUILTINS_LIBRARY})
 
if(COMPILER_RT_USE_LLVM_UNWINDER)
   if (COMPILER_RT_ENABLE_STATIC_UNWINDER)
     set(unwinder_target unwind_static)
   else()
     set(unwinder_target unwind_shared)
   endif()
   list(APPEND SANITIZER_CXX_ABI_LIBRARIES "$<$<TARGET_EXISTS:${unwinder_target}>:$<TARGET_LINKER_FILE:${unwinder_target}>>")
 endif()
 
+if (COMPILER_RT_CXX_LIBRARY STREQUAL "libcxx")
+  # We are using the in-tree libc++ so avoid including the default one.
+  append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ COMPILER_RT_COMMON_CFLAGS)
+  append_list_if(COMPILER_RT_HAS_NOSTDLIBXX_FLAG -nostdlib++ COMPILER_RT_COMMON_LINK_FLAGS)
+  # Use the in-tree libc++ through explicit include and library paths.
+  if (COMPILER_RT_STATIC_CXX_LIBRARY)
+    set(cxx_target cxx_static)
+  else()
+    set(cxx_target cxx_shared)
+  endif()
+  list(APPEND COMPILER_RT_CXX_CFLAGS "$<$<TARGET_EXISTS:cxx-headers>:-isystem$<JOIN:$<TARGET_PROPERTY:cxx-headers,INTERFACE_INCLUDE_DIRECTORIES>,$<SEMICOLON>-isystem>>")
+  list(APPEND COMPILER_RT_CXX_LINK_LIBS "$<$<TARGET_EXISTS:${cxx_target}>:$<TARGET_LINKER_FILE:${cxx_target}>>")
+elseif (COMPILER_RT_CXX_LIBRARY STREQUAL "none")
+  # We aren't using any C++ standard library so avoid including the default one.
+  append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ COMPILER_RT_COMMON_CFLAGS)
+  append_list_if(COMPILER_RT_HAS_NOSTDLIBXX_FLAG -nostdlib++ COMPILER_RT_COMMON_LINK_FLAGS)
+else()
+  # Nothing to be done for `default`.
+endif()
+
 macro(append_libcxx_libs var)
   if (${var}_INTREE)
     if (SANITIZER_USE_STATIC_LLVM_UNWINDER AND (TARGET unwind_static OR HAVE_LIBUNWIND))
       list(APPEND ${var}_LIBRARIES unwind_static)
     elseif (TARGET unwind_shared OR HAVE_LIBUNWIND)
       list(APPEND ${var}_LIBRARIES unwind_shared)
     endif()
 

compiler-rt/lib/fuzzer/CMakeLists.txt

 
 if(OS_NAME MATCHES "Linux|Fuchsia" AND
    COMPILER_RT_LIBCXX_PATH AND
    COMPILER_RT_LIBCXXABI_PATH)
   list(APPEND LIBFUZZER_CFLAGS -D_LIBCPP_ABI_VERSION=Fuzzer)
   append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ LIBFUZZER_CFLAGS)
 elseif(TARGET cxx-headers OR HAVE_LIBCXX)
   # libFuzzer uses C++ standard library headers.
+  list(APPEND LIBFUZZER_CFLAGS ${COMPILER_RT_CXX_CFLAGS})
   set(LIBFUZZER_DEPS cxx-headers)
 endif()
 
 append_list_if(COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG -fno-omit-frame-pointer LIBFUZZER_CFLAGS)
 
 if (CMAKE_CXX_FLAGS MATCHES "fsanitize-coverage")
   list(APPEND LIBFUZZER_CFLAGS -fsanitize-coverage=0)
 endif()

compiler-rt/lib/orc/CMakeLists.txt

set(ORC_ALL_SOURCE_FILES
   )
 
 list(REMOVE_DUPLICATES ORC_ALL_SOURCE_FILES)
 
 # Now put it all together...
 include_directories(..)
 include_directories(../../include)
 
-set(ORC_CFLAGS ${COMPILER_RT_COMMON_CFLAGS})
+set(ORC_CFLAGS
+  ${COMPILER_RT_COMMON_CFLAGS}
+  ${COMPILER_RT_CXX_CFLAGS})
+set(ORC_LINK_FLAGS ${COMPILER_RT_COMMON_LINK_FLAGS})
+set(ORC_LINK_LIBS ${COMPILER_RT_CXX_LINK_LIBS})
 
 # Allow the ORC runtime to reference LLVM headers.
 foreach (DIR ${LLVM_INCLUDE_DIR} ${LLVM_MAIN_INCLUDE_DIR})
   list(APPEND ORC_CFLAGS -I${DIR})
 endforeach()
 
 add_compiler_rt_component(orc)
 
add_compiler_rt_object_libraries(RTOrc
     DEPS ${ORC_DEPS})
 
   add_compiler_rt_runtime(clang_rt.orc
     STATIC
     OS ${ORC_SUPPORTED_OS}
     ARCHS ${ORC_SUPPORTED_ARCH}
     OBJECT_LIBS RTOrc
     CFLAGS ${ORC_CFLAGS}
-    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_FLAGS ${ORC_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
     LINK_LIBS ${ORC_LINK_LIBS}
     PARENT_TARGET orc)
 else() # not Apple
   add_asm_sources(ORC_ASM_SOURCES 
     elfnix_tls.x86-64.S
     elfnix_tls.aarch64.S
     )
 
add_compiler_rt_object_libraries(RTOrc
       CFLAGS ${ORC_CFLAGS}
       DEPS ${ORC_DEPS})
 
     # Common ORC archive for instrumented binaries.
     add_compiler_rt_runtime(clang_rt.orc
      STATIC
      ARCHS ${arch}
      CFLAGS ${ORC_CFLAGS}
+     LINK_FLAGS ${ORC_LINK_FLAGS}
+     LINK_LIBS ${ORC_LINK_LIBS}
      OBJECT_LIBS ${ORC_COMMON_RUNTIME_OBJECT_LIBS} RTOrc
      PARENT_TARGET orc)
   endforeach()
 endif() # not Apple
 
 if(COMPILER_RT_INCLUDE_TESTS)
   add_subdirectory(unittests)
 endif()

compiler-rt/lib/xray/CMakeLists.txt

list(APPEND
     "${CMAKE_CURRENT_SOURCE_DIR}/${src_file}")
 endforeach()
 
 
 # Now put it all together...
 include_directories(..)
 include_directories(../../include)
 
-set(XRAY_CFLAGS ${COMPILER_RT_COMMON_CFLAGS})
+set(XRAY_CFLAGS
+  ${COMPILER_RT_COMMON_CFLAGS}
+  ${COMPILER_RT_CXX_CFLAGS})
 set(XRAY_COMMON_DEFINITIONS XRAY_HAS_EXCEPTIONS=1)
 
 # Too many existing bugs, needs cleanup.
 append_list_if(COMPILER_RT_HAS_WNO_FORMAT -Wno-format XRAY_CFLAGS)
 
 # We don't need RTTI in XRay, so turn that off.
 append_rtti_flag(OFF XRAY_CFLAGS)
 
+set(XRAY_LINK_FLAGS ${COMPILER_RT_COMMON_LINK_FLAGS})
+set(XRAY_LINK_LIBS ${COMPILER_RT_CXX_LINK_LIBS})
+
 append_list_if(
   COMPILER_RT_HAS_XRAY_COMPILER_FLAG XRAY_SUPPORTED=1 XRAY_COMMON_DEFINITIONS)
 append_list_if(
   COMPILER_RT_BUILD_XRAY_NO_PREINIT XRAY_NO_PREINIT XRAY_COMMON_DEFINITIONS)
 
 add_compiler_rt_component(xray)
 
 set(XRAY_COMMON_RUNTIME_OBJECT_LIBS
     RTSanitizerCommon
     RTSanitizerCommonLibc)
 
 # XRay uses C++ standard library headers.
 if (TARGET cxx-headers OR HAVE_LIBCXX)
   set(XRAY_DEPS cxx-headers)
 endif()
 
 if (APPLE)
-  set(XRAY_LINK_LIBS ${SANITIZER_COMMON_LINK_LIBS})
   add_asm_sources(XRAY_ASM_SOURCES xray_trampoline_x86_64.S)
 
   add_weak_symbols("sanitizer_common" WEAK_SYMBOL_LINK_FLAGS)
   add_weak_symbols("xray" WEAK_SYMBOL_LINK_FLAGS)
 
   add_compiler_rt_object_libraries(RTXray
     OS ${XRAY_SUPPORTED_OS}
     ARCHS ${XRAY_SUPPORTED_ARCH}
add_compiler_rt_runtime(clang_rt.xray
     STATIC
     OS ${XRAY_SUPPORTED_OS}
     ARCHS ${XRAY_SUPPORTED_ARCH}
     OBJECT_LIBS RTXray
                 RTSanitizerCommon
                 RTSanitizerCommonLibc
     CFLAGS ${XRAY_CFLAGS}
     DEFS ${XRAY_COMMON_DEFINITIONS}
-    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_FLAGS ${XRAY_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
     LINK_LIBS ${XRAY_LINK_LIBS}
     PARENT_TARGET xray)
   add_compiler_rt_runtime(clang_rt.xray-fdr
     STATIC
     OS ${XRAY_SUPPORTED_OS}
     ARCHS ${XRAY_SUPPORTED_ARCH}
     OBJECT_LIBS RTXrayFDR
     CFLAGS ${XRAY_CFLAGS}
     DEFS ${XRAY_COMMON_DEFINITIONS}
-    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_FLAGS ${XRAY_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
     LINK_LIBS ${XRAY_LINK_LIBS}
     PARENT_TARGET xray)
   add_compiler_rt_runtime(clang_rt.xray-basic
     STATIC
     OS ${XRAY_SUPPORTED_OS}
     ARCHS ${XRAY_SUPPORTED_ARCH}
     OBJECT_LIBS RTXrayBASIC
     CFLAGS ${XRAY_CFLAGS}
     DEFS ${XRAY_COMMON_DEFINITIONS}
-    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_FLAGS ${XRAY_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
     LINK_LIBS ${XRAY_LINK_LIBS}
     PARENT_TARGET xray)
   add_compiler_rt_runtime(clang_rt.xray-profiling
     STATIC
     OS ${XRAY_SUPPORTED_OS}
     ARCHS ${XRAY_SUPPORTED_ARCH}
     OBJECT_LIBS RTXrayPROFILING
     CFLAGS ${XRAY_CFLAGS}
     DEFS ${XRAY_COMMON_DEFINITIONS}
-    LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
+    LINK_FLAGS ${XRAY_LINK_FLAGS} ${WEAK_SYMBOL_LINK_FLAGS}
     LINK_LIBS ${XRAY_LINK_LIBS}
     PARENT_TARGET xray)
 else() # not Apple
   foreach(arch ${XRAY_SUPPORTED_ARCH})
     if(NOT CAN_TARGET_${arch})
       continue()
     endif()
     add_compiler_rt_object_libraries(RTXray
add_compiler_rt_object_libraries(RTXrayPROFILING
       DEFS ${XRAY_COMMON_DEFINITIONS}
       DEPS ${XRAY_DEPS})
 
     # Common XRay archive for instrumented binaries.
     add_compiler_rt_runtime(clang_rt.xray
      STATIC
      ARCHS ${arch}
      CFLAGS ${XRAY_CFLAGS}
+     LINK_FLAGS ${XRAY_LINK_FLAGS}
+     LINK_LIBS ${XRAY_LINK_LIBS}
      DEFS ${XRAY_COMMON_DEFINITIONS}
      OBJECT_LIBS ${XRAY_COMMON_RUNTIME_OBJECT_LIBS} RTXray
      PARENT_TARGET xray)
     # FDR mode runtime archive (addon for clang_rt.xray)
     add_compiler_rt_runtime(clang_rt.xray-fdr
       STATIC
       ARCHS ${arch}
       CFLAGS ${XRAY_CFLAGS}
+      LINK_FLAGS ${XRAY_LINK_FLAGS}
+      LINK_LIBS ${XRAY_LINK_LIBS}
       DEFS ${XRAY_COMMON_DEFINITIONS}
       OBJECT_LIBS RTXrayFDR
       PARENT_TARGET xray)
     # Basic mode runtime archive (addon for clang_rt.xray)
     add_compiler_rt_runtime(clang_rt.xray-basic
       STATIC
       ARCHS ${arch}
       CFLAGS ${XRAY_CFLAGS}
+      LINK_FLAGS ${XRAY_LINK_FLAGS}
+      LINK_LIBS ${XRAY_LINK_LIBS}
       DEFS ${XRAY_COMMON_DEFINITIONS}
       OBJECT_LIBS RTXrayBASIC
       PARENT_TARGET xray)
    # Profiler Mode runtime
    add_compiler_rt_runtime(clang_rt.xray-profiling
      STATIC
      ARCHS ${arch}
      CFLAGS ${XRAY_CFLAGS}
+     LINK_FLAGS ${XRAY_LINK_FLAGS}
+     LINK_LIBS ${XRAY_LINK_LIBS}
      DEFS ${XRAY_COMMON_DEFINITIONS}
      OBJECT_LIBS RTXrayPROFILING
      PARENT_TARGET xray)
   endforeach()
 endif() # not Apple
 
 if(COMPILER_RT_INCLUDE_TESTS)
   add_subdirectory(tests)
 endif()