On Fri, Jun 8, 2018 at 1:28 PM, Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, Jun 08, 2018 at 12:04:36PM +0200, Sedat Dilek wrote: >> On Fri, Jun 8, 2018 at 9:59 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: >> > On Thu, Jun 7, 2018 at 10:49 PM, Nick Desaulniers >> > <ndesaulniers@xxxxxxxxxx> wrote: >> >> Functions marked extern inline do not emit an externally visible >> >> function when the gnu89 C standard is used. Some KBUILD Makefiles >> >> overwrite KBUILD_CFLAGS. This is an issue for GCC 5.1+ users as without >> >> an explicit C standard specified, the default is gnu11. Since c99, the >> >> semantics of extern inline have changed such that an externally visible >> >> function is always emitted. This can lead to multiple definition errors >> >> of extern inline functions at link time of compilation units whose build >> >> files have removed an explicit C standard compiler flag for users of GCC >> >> 5.1+ or Clang. >> >> >> >> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> >> >> Suggested-by: H. Peter Anvin <hpa@xxxxxxxxx> >> >> Suggested-by: Joe Perches <joe@xxxxxxxxxxx> >> > >> > I suspect this will break Geert's gcc-4.1.2, which I think doesn't have that >> > attribute yet (4.1.3 or higher have it according to the documentation. >> > >> > It wouldn't be hard to work around that if we want to keep that version >> > working, or we could decide that it's time to officially stop supporting >> > that version, but we should probably decide on one or the other. >> > >> >> Good point. >> What is the minimum requirement of GCC version currently? > > Good question ;-) (I recently had the impression that > Documentation/process/changes.rst was making fun of me ;-) > > >> AFAICS x86/asm-goto support requires GCC >= 4.5? >> >> Just FYI... >> ...saw the last days in upstream commits that kbuild/kconfig for >> 4.18-rc1 offers possibilities to check for cc-version dependencies. > > Good to know! Mind retrieving/sharing the commit id(s) > or links to the corresponding discussion on LKML? > Sorry, it is not yet in Linus upstream. see [1]. Documentation: kconfig: add recommended way to describe compiler support kconfig: add CC_IS_CLANG and CLANG_VERSION kconfig: add CC_IS_GCC and GCC_VERSION - sed@ - [1] https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/log/?h=kbuild -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
