On Mon, Nov 15, 2021 at 9:30 AM Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> wrote: > > On Sun, Nov 14, 2021 at 05:17:51PM -0700, Nathan Chancellor wrote: > > On Sun, Nov 14, 2021 at 02:18:41PM -0700, Nathan Chancellor wrote: > > > On Sat, Nov 13, 2021 at 06:57:25PM -0600, Gustavo A. R. Silva wrote: > > > > Add Kconfig support for -Wimplicit-fallthrough for both GCC and Clang. > > > > > > > > The compiler option is under configuration CC_IMPLICIT_FALLTHROUGH, > > > > which is enabled by default. > > > > > > > > Special thanks to Nathan Chancellor who fixed the Clang bug[1][2]. This > > > > bugfix only appears in Clang 14.0.0, so older versions still contain > > > > the bug and -Wimplicit-fallthrough won't be enabled for them, for now. > > > > > > > > This concludes a long journey and now we are finally getting rid > > > > of the unintentional fallthrough bug-class in the kernel, entirely. :) > > > > > > > > [1] https://github.com/llvm/llvm-project/commit/9ed4a94d6451046a51ef393cd62f00710820a7e8 > > > > [2] https://bugs.llvm.org/show_bug.cgi?id=51094 > > > > > > > > Link: https://github.com/KSPP/linux/issues/115 > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/236 > > > > Co-developed-by: Kees Cook <keescook@xxxxxxxxxxxx> > > > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > > > Co-developed-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > > > > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > > > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > > > > > > This appears to do the right thing with both clang-13 and clang-14. > > > > Now that I gave this a look for the GCC side, I think it is wrong. > > > > -Wimplicit-fallthrough=5 was under cc-option because it was only > > available in GCC 7.x and newer so the build is now broken for GCC 5.x > > and 6.x: > > > > gcc: error: unrecognized command line option '-Wimplicit-fallthrough=5'; > > did you mean '-Wno-fallthrough'? > > I'll send a patch for this right away. Thanks for the report, Nathan! :) Please use a subject prefix different than "kconfig:" I want to see "kconfig:' only for changes in scripts/kconfig/. -- Best Regards Masahiro Yamada
