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From: "kees at outflux dot net" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/101836] __builtin_object_size(P->M, 1) where M is an
 array and the last member of a struct fails
Date: Tue, 14 Jun 2022 00:00:31 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101836

--- Comment #21 from Kees Cook <kees at outflux dot net> ---
(In reply to Martin Sebor from comment #20)
> Well, I just "asked" for such an option the same way you asked for
> -fstrict-flex-arrays in comment #3, because I believe it would be useful =
to
> make the BOS improvements you're looking for available even to code that
> can't do a whole-hog replacement of all trailing arrays with flexible arr=
ay

Right, sorry, I meant, "I have a project waiting to use this feature right
now", where as other projects might, upon discovering this feature, decide =
they
also only need "-fstrict-flex-arrays". e.g. what option would GCC itself us=
e?

> members.  The spelling of the option names doesn't seem important to me
> (they could be separate options, or the same one with an argument).

How about "-fnot-flex-arrays=3DN" to mean "trailing arrays with N or more
elements will NOT be treated like a flex array"?

Then code with sockaddr can use "-fnot-flex-arrays=3D15", code with "[1]" a=
rrays
can use "-fnot-flex-arrays=3D2", code with only "[0]" arrays can use
"-fnot-flex-arrays=3D1", and "-fstrict-flex-arrays" can be an alias for
"-fnot-flex-arrays=3D0", which Linux would use.=