[compiler-rt][Sanitizer] Link sanitizer libs with -latomic on SPARC

[ro]

Summary

When building on Linux/sparc64, the 32-bit libclang_rt.asan.so, libclang_rt.ubsan_minimal.so, and libclang_rt.ubsan_standalone.so failed to link with undefined references to 64-bit atomics, which clang cannot inline. Even D130569 didn't help because those libraries are linked with -nodefaultlibs, so dependent libraries need to be added explicitly.

That's what this patch does.

Tested on sparc64-unknown-linux-gnu and sparcv9-sun-solaris2.11.

[glaubitz]

Great. I think that should fix the CI!

compiler-rt/CMakeLists.txt

 append_list_if(MINGW -fms-extensions SANITIZER_COMMON_CFLAGS)
 
 # Set common link flags.
 # TODO: We should consider using the same model as libc++, that is use either
 # -nostdlib++ and --unwindlib=none if supported, or -nodefaultlibs otherwise.
 append_list_if(C_SUPPORTS_NODEFAULTLIBS_FLAG -nodefaultlibs SANITIZER_COMMON_LINK_FLAGS)
 append_list_if(COMPILER_RT_HAS_Z_TEXT -Wl,-z,text SANITIZER_COMMON_LINK_FLAGS)
 
+# Only necessary for 32-bit SPARC.  Solaris 11.2+ ld uses -z ignore/-z record
+# natively, but supports --as-needed/--no-as-needed for GNU ld compatibility.
+if("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "sparc")
+  list(APPEND SANITIZER_COMMON_LINK_LIBS -Wl,--as-needed atomic -Wl,--no-as-needed)
+endif()
+
 if (COMPILER_RT_USE_BUILTINS_LIBRARY)
   string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
 else()
   if (ANDROID)
     append_list_if(COMPILER_RT_HAS_GCC_LIB gcc SANITIZER_COMMON_LINK_LIBS)
   else()
     append_list_if(COMPILER_RT_HAS_GCC_S_LIB gcc_s SANITIZER_COMMON_LINK_LIBS)
   endif()