[opt-remark] Add support for emitting opt-remark bitstream artifacts when building benchmarks with cmake.

I didn't do this for swiftpm as well since when I tried passing this via
unsafeFlags to swiftpm, swiftpm just created the opt-remarks in my source
directory instead of next to the .o in the build directory. A problem for
another time.

Author: gottesmm

benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake

@@ -367,12 +367,17 @@ function (swift_benchmark_compile_archopts)
       "-F" "${sdk}/../../../Developer/Library/Frameworks"
       "-sdk" "${sdk}"
       "-no-link-objc-runtime")
+
+    # If we are not compiling at -Onone and are performing WMO, always emit
+    # optimization-records.
+    if(NOT ${optflag} STREQUAL "Onone" AND "${bench_flags}" MATCHES "-whole-module.*")
+      list(APPEND common_options "-save-optimization-record=bitstream")
+    endif()
   endif()
 
   set(opt_view_main_dir)
   if(SWIFT_BENCHMARK_GENERATE_OPT_VIEW AND LLVM_HAVE_OPT_VIEWER_MODULES)
     if(NOT ${optflag} STREQUAL "Onone" AND "${bench_flags}" MATCHES "-whole-module.*")
-      list(APPEND common_options "-save-optimization-record")
       set(opt_view_main_dir "${objdir}/opt-view")
     endif()
   endif()