On Sat, 7 Nov 2020, Joe Perches wrote:
> On Fri, 2020-11-06 at 23:55 -0800, Nick Desaulniers wrote: > > Clang is more aggressive about -Wformat warnings when the format flag > > specifies a type smaller than the parameter. Fixes 8 instances of: > > > > warning: format specifies type 'unsigned short' but the argument has > > type 'int' [-Wformat] > > Likely clang's -Wformat message is still bogus. > Wasn't that going to be fixed? > > Integer promotions are already done on these types to int anyway. > Didn't we have this discussion last year? > > https://lore.kernel.org/lkml/CAKwvOd=mqzj2pAZEUsW-M_62xn4pijpCJmP=b1h_-web0ne...@mail.gmail.com/ > https://lore.kernel.org/lkml/CAHk-=wgoxnmsj8GEVFJSvTwdnWm8wVJthefNk2n6+4TC=20...@mail.gmail.com/ > https://lore.kernel.org/lkml/a68114afb134b8633905f5a25ae7c4e6799ce8f1.ca...@perches.com/ > > Look at commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use > of unnecessary %h[xudi] and %hh[xudi]") > > The "h" and "hh" things should never be used. The only reason for them > being used if if you have an "int", but you want to print it out as a > "char" (and honestly, that is a really bad reason, you'd be better off > just using a proper cast to make the code more obvious). > Joe, would this be a good rule to check for in checkpatch? Can Dwaipayan or Aditya give it a try to create a suitable patch to add such a rule? Dwaipayan, Aditya, if Joe thinks it is worth a rule, it is "first come, first serve" for you to take that task. Lukas > So if what you have a "char" (or unsigned char) you should always just > print it out as an "int", knowing that the compiler already did the > proper type conversion. > > > diff --git a/net/netfilter/nf_conntrack_standalone.c > > b/net/netfilter/nf_conntrack_standalone.c > [] > > @@ -50,38 +50,38 @@ print_tuple(struct seq_file *s, const struct > > nf_conntrack_tuple *tuple, > > > > > > switch (l4proto->l4proto) { > > case IPPROTO_ICMP: > > - seq_printf(s, "type=%u code=%u id=%u ", > > + seq_printf(s, "type=%u code=%u id=%hu ", > > etc... > > > -- > You received this message because you are subscribed to the Google Groups > "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clang-built-linux+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/clang-built-linux/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel%40perches.com. >
