FW: GCC-plugin maintainers On Mon, Apr 20, 2020 at 7:04 AM David Lamparter <equinox@xxxxxxxxxx> wrote: > > Hello kernel build hackers, > > > in case it is of interest to anyone, we've recently added an extended > format string checking plugin in the FRRouting project. We took > inspiration from the Linux kernel and modified a printf (funnily enough, > the one from FreeBSD) to support things like %pI4, and we wanted better > warnings for this. Since the scheme is the same as in the Linux kernel, > it may or may not be worth someone's time to take a look. > > The plugin is found here: > https://github.com/FRRouting/frr/tree/master/tools/gcc-plugins > > It's derived from gcc's "c-format.c", as such it may make sense to look > at the diff instead of the straight source. The original GCC code is in > the git history there. It's tested against gcc 9.3.0, YMMV on other > versions. > > Note that the plugin needs a single-line GCC source code modification: > https://github.com/FRRouting/frr/blob/master/tools/gcc-plugins/gcc-retain-typeinfo.patch > this is to stop GCC from prematurely stripping information, specifically > from casts in function parameters. It does work without the change, but > it may produce false-positive/negative warnings. > > Aside from %pXX suffix support, the plugin also contains two other > changes that are probably irrelevant to kernel land: > - it makes some typedefs "final" types since these are not guaranteed to > be consistent in size across platforms and therefore can't be > printf'd without a cast (e.g. pid_t, uid_t, time_t, etc.) > - it reserves %Lu for uint64_t > > Please don't expect too much on its code quality, I'm not a GCC > developer and essentially wrote this by trial and error ;) > > Cheers, > > > -David -- Best Regards Masahiro Yamada
