[clangd][cmake] Provide libatomic when there is no native support for 64bit atomics

[sdardis]

Summary

This addresses a persistent failure on clang-cmake-mips buildbot.

[sdardis]

Ping?

[ioeric]

lgtm

(Please add reviewers to your patch if you intend it to be reviewed.)

clangd/CMakeLists.txt

7 ↗

(On Diff #137555)

nit: s/atomic/"atomic"/

[sdardis]

Thanks, I wasn't sure who to add as a reviewer.

[ioeric]

In D44248#1041531, @sdardis wrote:

Thanks, I wasn't sure who to add as a reviewer.

Authors/reviewers of recent patches for the same files are usually good approximations :)

[matthewbauer]

This appears to be adding atomic on macOS builds, which shouldn't be happening:

https://hydra.nixos.org/build/88290234/

HAVE_CXX_ATOMICS64_WITHOUT_LIB is never being set.

[jfb]

In D44248#1391798, @matthewbauer wrote:

This appears to be adding atomic on macOS builds, which shouldn't be happening:

https://hydra.nixos.org/build/88290234/

HAVE_CXX_ATOMICS64_WITHOUT_LIB is never being set.

Odd. macOS should always have 64-bit atomic support on x86-64 as well as ARM64.

clang-tools-extra/trunk/clangd/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
+set(CLANGD_ATOMIC_LIB "")
+if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
+  list(APPEND CLANGD_ATOMIC_LIB "atomic")
+endif()
+
 add_clang_library(clangDaemon
   AST.cpp
   ClangdLSPServer.cpp
   ClangdServer.cpp
   ClangdUnit.cpp
   CodeComplete.cpp
   CodeCompletionStrings.cpp
   CompileArgsCache.cpp
add_clang_library(clangDaemon
   clangIndex
   clangLex
   clangSema
   clangSerialization
   clangTooling
   clangToolingCore
   clangToolingRefactor
   ${LLVM_PTHREAD_LIB}
+  ${CLANGD_ATOMIC_LIB}
   )
 
 if( LLVM_LIB_FUZZING_ENGINE OR LLVM_USE_SANITIZE_COVERAGE )
   add_subdirectory(fuzzer)
 endif()
 add_subdirectory(tool)
 add_subdirectory(global-symbol-builder)