[Bug sanitizer/58411] no_sanitize_undefined function attribute

[jan.smets@alcatel-lucent.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58411

--- Comment #3 from Jan Smets <jan.smets@alcatel-lucent.com> ---
Eg, these attributes are useful too I think:

no_sanitize => disable ALL sanitize checks
sanitize -> enable ALL sanitize checks

no_sanitize_{address,undefined,vla...} => disable the specific check
sanitize_{address,undefined,vla...} => enable the specific check

Perhaps the enablers will not be used as much, but it might be useful for
people who want to instrument just one specific function.

The no_sanitize attribute could be used for sensitive code, eg, task scheduler
code, interrupt handlers where someone might choose to never instrument.

Thanks
- Jan