Date: Thu, 13 Apr 2017 14:02:19 -0700 From: Mark Millard <markmi@dsl-only.net> To: svn-src-stable-11@freebsd.org, Pedro Giffuni <pfg@FreeBSD.org> Subject: Re: svn commit: r316779 - stable/11/sys/sys Message-ID: <7B482BAF-6ACA-4303-88FF-4F3E3EDFB440@dsl-only.net>
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> Author: pfg > Date: Thu Apr 13 18:28:40 2017 > New Revision: 316779 > URL:=20 > https://svnweb.freebsd.org/changeset/base/316779 >=20 >=20 > Log: > Temporarily revert r315602. > Bring back the definition for the GCC __nonnull() attribute. > =20 > Old versions of GCC, including the version installed the latest = 11-stable > snapshot with pkg(8), still carry the old attributes. > =20 > The issue is easily fixed by rebuilding GCC but there is no need to = cause > havoc in our user base. The definition by itself is harmless but it = should > be removed again in the near future. >=20 > Modified: > stable/11/sys/sys/cdefs.h > Directory Properties: > stable/11/ (props changed) >=20 > Modified: stable/11/sys/sys/cdefs.h > = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D > --- stable/11/sys/sys/cdefs.h Thu Apr 13 18:13:10 2017 = (r316778) > +++ stable/11/sys/sys/cdefs.h Thu Apr 13 18:28:40 2017 = (r316779) > @@ -376,6 +376,14 @@ > #define __noinline > #endif > =20 > +#if __GNUC_PREREQ__(3, 3) > +#define __nonnull(x) __attribute__((__nonnull__(x))) > +#define __nonnull_all __attribute__((__nonnull__)) > +#else > +#define __nonnull(x) > +#define __nonnull_all > +#endif > + > #if __GNUC_PREREQ__(3, 4) > #define __fastcall __attribute__((__fastcall__)) > #define __result_use_check = __attribute__((__warn_unused_result__)) My understanding was that __attribute__((__nonnull__(x))) and __attribute__((__nonnull__)) were causing some problems because of optimization consequences (code removal). The goal of converting to the new technique (involving lack of __nonnull and lack of __nonnull_all ) was to still have warning notices but without such removal of code if I understand right. If avoiding code removal was the intent behind the removal of __nonnull (and __nonnull_all) use (and use of the __nonull__ attributes) then just having the two lines: +#define __nonnull(x) +#define __nonnull_all=20 might be better for maintaining compatibility with existing older sources that reference __nonnull and/or __nonnull_all . Of course I could be wrong about why the changes were made in the first place or in other details about the alternatives. =3D=3D=3D Mark Millard markmi at dsl-only.net
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