mark -f[no-]sycl-device-lib-online-link as experimental and all doc for the option

Signed-off-by: jinge90 <[email protected]>

Author: jinge90

clang/include/clang/Driver/Options.td

@@ -4856,10 +4856,10 @@ def fno_sycl_device_lib_EQ : CommaJoined<["-"], "fno-sycl-device-lib=">, Group<s
   "are libc, libm-fp32, libm-fp64, all">;
 def fsycl_device_lib_online_link : Flag<["-"], "fsycl-device-lib-online-link">,
   Group<sycl_Group>, Flags<[NoArgumentUnused, CoreOption]>, HelpText<"Enables "
-  "sycl device library online link">;
+  "sycl device library online link (experimental)">;
 def fno_sycl_device_lib_online_link : Flag<["-"], "fno-sycl-device-lib-online-link">,
   Group<sycl_Group>, Flags<[NoArgumentUnused, CoreOption]>, HelpText<"Disables "
-  "sycl device library online link">;
+  "sycl device library online link (experimental)">;
 def fsycl_fp32_prec_sqrt : Flag<["-"], "fsycl-fp32-prec-sqrt">, Group<sycl_Group>, Flags<[CC1Option]>,
   HelpText<"SYCL only. Specify that single precision floating-point sqrt is correctly rounded.">,
   MarshallingInfoFlag<CodeGenOpts<"SYCLFp32PrecSqrt">>;

sycl/doc/UsersManual.md

@@ -191,6 +191,14 @@ and not recommended to use in production environment.
     libm-fp32, libm-fp64, libc, all. Use of 'all' will enable/disable all of
     the device libraries.
 
+**`-f[no-]sycl-device-lib-online-link`** [EXPERIMENTAL]
+
+    Enables/disables online link mechanism for SYCL device library in JIT
+    compilation. If online link is enabled, all required device libraries will
+    be linked with user's device image by SYCL runtime during execution time,
+    otherwise the link will happen in build time, online link is disabled by
+    default currently and this option is ignored in AOT compilation.
+
 ## Intel FPGA specific options
 
 **`-fintelfpga`**