Messages in this thread | | | From | Linus Torvalds <> | Date | Sat, 22 Oct 2022 11:16:33 -0700 | Subject | Re: [PATCH] kbuild: treat char as always signed |
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On Fri, Oct 21, 2022 at 11:06 PM Gabriel Paubert <paubert@iram.es> wrote: > > Ok, I´ve just tried it, except that I had something slightly different in > mind, but perhaps should have been clearer in my first post. > > I have change your code to the following:
I actually tested that, but using a slightly different version, and my non-union test case ended up like
size_t strlen(const char *p) { return __builtin_strlen(p); }
and then gcc actually complains about
warning: infinite recursion detected
and I (incorrectly) thought this was unworkable. But your version seems to work fine.
So yeah, for the kernel I think we could do something like this. It's ugly, but it gets rid of the crazy warning.
Practically speaking this might be a bit painful, because we've got several different variations of this all due to all the things like our debugging versions (see <linux/fortify-string.h> for example), so some of our code is this crazy jungle of "with this config, use this wrapper".
But if somebody wants to deal with the '-Wpointer-sign' warnings, there does seem to be a way out. Maybe with another set of helper macros, creating those odd __transparent_union__ wrappers might even end up reasonable.
It's not like we don't have crazy macros for function wrappers elsewhere (the SYSCALL macros come to mind - shudder). The macros themselves may be a nasty horror, but when done right the _use_ point of said macros can be nice and clean.
Linus
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