On Thu, May 9, 2019 at 4:06 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > On Thu, May 9, 2019 at 8:45 AM Masahiro Yamada > <yamada.masahiro@xxxxxxxxxxxxx> wrote: > > > > We do not support old Clang versions. Upgrade your clang version > > if any of these flags is unsupported. > > > > Let's add flags within ifdef CONFIG_CC_IS_CLANG unconditionally, > > except -fcatch-undefined-behavior. > > > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > > Looks good to me. > > Reviewed-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> > > Just as sidenote: > I experimented with a snapshot version of clang-9 and lld-9 and could > build, link and boot on bare-metal with '-mglobal-merge' on > Debian/buster AMD64. The comment says # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the # source of a reference will be _MergedGlobals and not on of the whitelisted names. # See modpost pattern 2 So, it seems it is just a matter of modpost, but I am not sure enough. This flag has been here since the initial support. (61163efae02040f66a95c8ed17f4407951ba58fa) Perhaps, we should review clang flags one by one again? > But forgot to document in [1]. > > [1] https://github.com/ClangBuiltLinux/linux/issues/431 -- Best Regards Masahiro Yamada
