[SystemZ][ZOS] Remove --whole-archive & --color-diagnostics

[zibi]

Summary

We need to remove both options --whole-archive and --color-diagnostics from the link step otherwise, we get link errors when building libc++ on z/OS.

[ldionne]

libcxx/src/CMakeLists.txt

213

What's the issue with using --whole-archive on z/OS? Also, if you don't use --whole-archive, some symbols in libc++abi might not be available from the dylib you build, so you'll end up with a malfunctioning/incomplete libc++.

[zibi]

libcxx/src/CMakeLists.txt

213

Linker on z/OS does not support this option. When -Wl,--whole-archive is used the linker wants to include an object of that name and issues an error. Not sure if incomplete libc++ will apply to z/OS due to linker differences. If you know which symbol(s) might be missing let me know and I can check. Perhaps there is an existing test which will fail when those symbols are not present in libc++.

[zibi]

ping

[zibi]

After switching to a shared build we don't need these changes anymore.

libcxx/src/CMakeLists.txt

elseif (LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY AND (TARGET unwind_static OR HAVE_LIBUNWIND))
       # libunwind is already included in libc++abi
     else()
       target_link_libraries(cxx_shared PUBLIC unwind)
     endif()
   endif()
 
   # Link against libc++abi
   if (LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY)
-    if (APPLE)
+    if (ZOS)
+      target_link_libraries(cxx_shared PRIVATE "${LIBCXX_CXX_STATIC_ABI_LIBRARY}")
+    elseif (APPLE)
       target_link_libraries(cxx_shared PRIVATE "-Wl,-force_load" "${LIBCXX_CXX_STATIC_ABI_LIBRARY}")
     else()
       target_link_libraries(cxx_shared PRIVATE "-Wl,--whole-archive,-Bstatic" "${LIBCXX_CXX_STATIC_ABI_LIBRARY}" "-Wl,-Bdynamic,--no-whole-archive")
     endif()
   else()
     target_link_libraries(cxx_shared PUBLIC "${LIBCXX_CXX_SHARED_ABI_LIBRARY}")
   endif()
 

llvm/cmake/modules/HandleLLVMOptions.cmake

if (UNIX AND
     CMAKE_GENERATOR STREQUAL "Ninja" AND
     (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR
      (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND
       NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9))))
   append("-fdiagnostics-color" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
 endif()
 
 # lld doesn't print colored diagnostics when invoked from Ninja
-if (UNIX AND CMAKE_GENERATOR STREQUAL "Ninja")
+if (NOT ZOS AND UNIX AND CMAKE_GENERATOR STREQUAL "Ninja")
   include(CheckLinkerFlag)
   check_linker_flag("-Wl,--color-diagnostics" LINKER_SUPPORTS_COLOR_DIAGNOSTICS)
   append_if(LINKER_SUPPORTS_COLOR_DIAGNOSTICS "-Wl,--color-diagnostics"
     CMAKE_EXE_LINKER_FLAGS CMAKE_MODULE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS)
 endif()
 
 # Add flags for add_dead_strip().
 # FIXME: With MSVS, consider compiling with /Gy and linking with /OPT:REF?