[Bug c/116016] enhancement: add __builtin_set_counted_by(P->FAM, COUNT) or equivalent

[isanbard at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116016

--- Comment #46 from Bill Wendling <isanbard at gmail dot com> ---
(In reply to qinzhao from comment #45)
> (In reply to Jakub Jelinek from comment #42)
> > 
> > But for the kernel you'll need to have fallback code which will set the
> > actual counter manually for compilers without support for counted_by
> > attribute or the new builtin,
> The counter will not need to be set if there is no "counted_by" attribute. 
> Only when "counted_by" attribute is added into kernel, the corresponding
> counter field need to be set explicitly (that's a requirement for the
> "counted_by" attribute).

Not necessarily. The 'count' field may be used for purposes other than the
sanitizer, which is why the requirement exists.