From: Masahiro Yamada <masahiroy@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Ilie Halip <ilie.halip@gmail.com>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [RFC PATCH] lib: move memcat_p.o to obj-y
Date: Sat, 18 Jan 2020 03:00:44 +0900 [thread overview]
Message-ID: <CAK7LNAQ1pS0nK7JoUbgOn0aMtaYH69XukjNELZNxTtV_iMmR1Q@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOdkdD9VF1k==G4vMeo4bBLarYz8gPvWfv6+N2kejeoXfjA@mail.gmail.com>
On Fri, Jan 17, 2020 at 7:30 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Wed, Jan 15, 2020 at 3:53 AM Ilie Halip <ilie.halip@gmail.com> wrote:
> >
> > The semantics of `--undefined` differ between ld.bfd and ld.lld:
> > $ echo | gcc -x c -c - -o a.o
> > $ echo "EXTERN(test)" > a.lds
> > $ ld.bfd a.o -t a.lds -o - 2>/dev/null && objdump -t | grep test
> > 0000000000000000 *UND* 0000000000000000 test
> > $ ld.lld a.o -t a.lds -o - 2>/dev/null && objdump -t | grep test
> > $
> >
> > When building with CONFIG_STM=m, there are no in-kernel users of memcat_p()
> > and ld.lld discards this symbol because it's linked in via --no-whole-archive.
> > It's marked as undefined by a linker script but ld.lld discards it anyway (as
> > seen in the above snippet).
> >
> > Work around the ld.lld behavior by moving the object file to obj-y.
> >
> > Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
> > Link: https://github.com/ClangBuiltLinux/linux/issues/515
>
> Thanks for the patch. This solves the observed linkage failure.
> Maybe Masahiro has more input based on the discussion in the above
> Link?
Sorry, I did not notice that thread until now.
I will take a look at it when I have time.
This patch does not seem to be a proper fix.
If this fix-up were acceptable, theoretically,
all objects that contain EXPORTED_SYMBOL
would need to be turned into obj-y from lib-y ?
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2020-01-17 18:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 11:52 [RFC PATCH] lib: move memcat_p.o to obj-y Ilie Halip
2020-01-16 22:30 ` Nick Desaulniers
2020-01-17 18:00 ` Masahiro Yamada [this message]
2020-03-04 5:00 ` Fāng-ruì Sòng
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