After upgrading to XCode 13, I cannot debug my shader on iOS anymore.
I enabled the cvars in ConsoleVariables.ini, such as r.Shaders.Optimize=0, r.Shaders.KeepDebugInfo=1.
Also I check the shader compiler did add -gline-tables-only and -MO as the metal frontend args. (According to xcode commandline tools, -MO is deprecated by -frecord-sources, so I also try the latter instead of -MO, but it dose not help).