[Docs] Added -fomit-frame-pointer and -fno-omit-frame-pointer flag documentation

[MaskRay]

Summary

Fix #61322

[vitalybuka]

clang/include/clang/Driver/Options.td

2539

2643

[MaskRay]

Sorry for my belated response as I was on a trip for quite a few days.

We don't need to document the negative form. "Produce better stack traces," is not necessarily correct. See https://maskray.me/blog/2020-11-08-stack-unwinding

I created D146603 for a different wording.

clang/include/clang/Driver/Options.td

 def fno_module_file_deps : Flag <["-"], "fno-module-file-deps">, Group<f_Group>,
   Flags<[NoXarchOption]>;
 def fno_ms_extensions : Flag<["-"], "fno-ms-extensions">, Group<f_Group>,
   Flags<[CoreOption]>;
 def fno_ms_compatibility : Flag<["-"], "fno-ms-compatibility">, Group<f_Group>,
   Flags<[CoreOption]>;
 def fno_objc_legacy_dispatch : Flag<["-"], "fno-objc-legacy-dispatch">, Group<f_Group>;
 def fno_objc_weak : Flag<["-"], "fno-objc-weak">, Group<f_Group>, Flags<[CC1Option]>;
-def fno_omit_frame_pointer : Flag<["-"], "fno-omit-frame-pointer">, Group<f_Group>;
+def fno_omit_frame_pointer : Flag<["-"], "fno-omit-frame-pointer">, Group<f_Group>,
+  HelpText<"Help to produce better stack traces during debugging">;
 defm operator_names : BoolFOption<"operator-names",
   LangOpts<"CXXOperatorNames">, Default<cplusplus.KeyPath>,
   NegFlag<SetFalse, [CC1Option], "Do not treat C++ operator name keywords as synonyms for operators">,
   PosFlag<SetTrue>>;
 def fdiagnostics_absolute_paths : Flag<["-"], "fdiagnostics-absolute-paths">, Group<f_Group>,
   Flags<[CC1Option, CoreOption]>, HelpText<"Print absolute paths in diagnostics">,
   MarshallingInfoFlag<DiagnosticOpts<"AbsolutePath">>;
 def fno_stack_protector : Flag<["-"], "fno-stack-protector">, Group<f_Group>,
def fobjc_disable_direct_methods_for_testing :
   HelpText<"Ignore attribute objc_direct so that direct methods can be tested">,
   MarshallingInfoFlag<LangOpts<"ObjCDisableDirectMethodsForTesting">>;
 defm objc_avoid_heapify_local_blocks : BoolFOption<"objc-avoid-heapify-local-blocks",
   CodeGenOpts<"ObjCAvoidHeapifyLocalBlocks">, DefaultFalse,
   PosFlag<SetTrue, [], "Try">,
   NegFlag<SetFalse, [], "Don't try">,
   BothFlags<[CC1Option, NoDriverOption], " to avoid heapifying local blocks">>;
 
-def fomit_frame_pointer : Flag<["-"], "fomit-frame-pointer">, Group<f_Group>;
+def fomit_frame_pointer : Flag<["-"], "fomit-frame-pointer">, Group<f_Group>,
+  HelpText<"Used to instruct the compiler to omit the frame pointer which leads to smaller code size and faster execution.">;
 def fopenmp : Flag<["-"], "fopenmp">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused, FlangOption, FC1Option]>,
   HelpText<"Parse OpenMP pragmas and generate parallel code.">;
 def fno_openmp : Flag<["-"], "fno-openmp">, Group<f_Group>, Flags<[NoArgumentUnused]>;
 def fopenmp_version_EQ : Joined<["-"], "fopenmp-version=">, Group<f_Group>, Flags<[CC1Option, NoArgumentUnused]>,
   HelpText<"Set OpenMP version (e.g. 45 for OpenMP 4.5, 50 for OpenMP 5.0). Default value is 50.">;
 defm openmp_extensions: BoolFOption<"openmp-extensions",
   LangOpts<"OpenMPExtensions">, DefaultTrue,
   PosFlag<SetTrue, [CC1Option, NoArgumentUnused],