Don't build tests for compiler-rt libs that aren't supported

[rnk]

Summary

This silences lots of CMake warnings about adding dependencies on
non-existing targets.

[rnk]

ping

[rnk]

ping

[samsonov]

What CMake invocation produces such errors?

Anyway, this patch brings up a valid issue, but I think we should better determine which sanitizers are actually going to be built in the top-level CMakeLists.txt (or move this logic to some helper module). Let me know if you will update the patch, otherwise I'll make this change myself.

[rnk]

On Windows, only ASan is built. However, we add the test suites for profile, tsan, and msan, all of which reference non-existing targets. This prevents us from doing that. If you want to hoist the logic for these decisions out of lib/CMakeLists, go for it, I'll close this.

[samsonov]

Hopefully, this patch won't be needed after r215247.

[rnk]

Thanks! The warnings are fixed now.

lib/CMakeLists.txt

elseif(CMAKE_SYSTEM_NAME MATCHES "Windows"
     set(SUPPORTS_BUILDING_ASAN TRUE)
   else()
     set(SUPPORTS_BUILDING_ASAN FALSE)
   endif()
   if(SUPPORTS_BUILDING_ASAN)
     add_subdirectory(asan)
     add_subdirectory(interception)
     add_subdirectory(sanitizer_common)
+  else()
+    # If we don't support the OS, clear the arch list to disable the tests.
+    set(ASAN_SUPPORTED_ARCH PARENT_SCOPE)
   endif()
   if(CMAKE_SYSTEM_NAME MATCHES "Darwin|Linux|FreeBSD" AND NOT ANDROID)
     # LSan, UBsan and profile can be built on Mac OS, FreeBSD and Linux.
     add_subdirectory(lsan)
     add_subdirectory(profile)
     add_subdirectory(ubsan)
+  else()
+    # If we don't support the OS, clear the arch list to disable the tests.
+    set(LSAN_SUPPORTED_ARCH PARENT_SCOPE)
+    set(PROFILE_SUPPORTED_ARCH PARENT_SCOPE)
+    set(UBSAN_SUPPORTED_ARCH PARENT_SCOPE)
   endif()
   if(CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID)
     # ThreadSanitizer and MemorySanitizer are supported on Linux only.
     add_subdirectory(tsan)
     add_subdirectory(tsan/dd)
     add_subdirectory(msan)
     add_subdirectory(msandr)
     add_subdirectory(dfsan)
+  else()
+    # If we don't support the OS, clear the arch list to disable the tests.
+    set(TSAN_SUPPORTED_ARCH PARENT_SCOPE)
+    set(DFSAN_SUPPORTED_ARCH PARENT_SCOPE)
+    set(MSAN_SUPPORTED_ARCH PARENT_SCOPE)
   endif()
 endif()
 
 add_subdirectory(builtins)