Hi! On Wed, Oct 19, 2022 at 10:14:20AM -0700, Linus Torvalds wrote: > On Wed, Oct 19, 2022 at 9:57 AM Segher Boessenkool > <segher@xxxxxxxxxxxxxxxxxxx> wrote: > > > > This is an ABI change. It is also hugely detrimental to generated > > code quality on architectures that make the saner choice (that is, have > > most instructions zero-extend byte quantities). > > Yeah, I agree. We should just accept the standard wording, and be > aware that 'char' has indeterminate signedness. And plain "char" is a separate type from "signed char" and "unsigned char" both. > But: > > > Instead, don't actively disable the compiler warnings that catch such > > cases? So start with removing footguns like > > > > # disable pointer signed / unsigned warnings in gcc 4.0 > > KBUILD_CFLAGS += -Wno-pointer-sign > > Nope, that won't fly. > > The pointer-sign thing doesn't actually help (ie it won't find places > where you actually compare a char), and it causes untold damage in > doing completely insane things. When I did this more than a decade ago there indeed was a LOT of noise, mostly caused by dubious code. I do agree many cases detected are not very important, but it also revealed cases where a filesystem's disk format changed (atarifs or amigafs or such iirc) -- many cases it is annoying to be reminded of sloppy code, but in some cases it detects crucial problems. > Seriously, -Wpointer-sign is not just useless, it's actively _evil_. Then suggest something better? Or suggest improvements to the existing warning? This warning is part of -Wall, most people must not have problems with it (or people are so apathetic about this that they have not complained about it). It is easy to improve your code when the compiler detects problems like this. Of course after such a long time of lax code sanity enforcement you get all warnings at once :-/ > The fact that you suggest that clearly means that you've never used > it. Ah, ad hominems. Great. Segher
