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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Fri, 15 Jan 2021 10:25:17 +0900
Message-ID: <CAK7LNARGOwGyZMw=bfBEPRS9K6DbCOgVzhgP1K6mMfOBLHN_bA@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] kbuild: handle excessively long argument lists
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Jeff Johnson <jjohnson@codeaurora.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Prasad Sodagudi <psodagud@quicinc.com>,
        Elliot Berman <eberman@quicinc.com>,
        Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org>,
        Michal Marek <michal.lkml@markovi.net>,
        LKML <linux-kernel@vger.kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>
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On Fri, Jan 15, 2021 at 10:01 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 1:50 PM Jeff Johnson <jjohnson@codeaurora.org> wrote:
> >
> > From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org>
> >
> > Modules with a large number of compilation units may be
> > exceeding AR and LD command argument list. Handle this gracefully by
> > writing the long argument list in a file. The command line options
> > read from file are inserted in place of the original @file option.
> >
> > The usage is well documented at
> > https://www.gnu.org/software/make/manual/html_node/File-Function.html
> >
> > Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org>
> > Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org>
> > ---
> >
> > Changes in v2:
> >   - Remove spurious endif
> >
> > scripts/Makefile.build | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > index 252b7d2..787dca2 100644
> > --- a/scripts/Makefile.build
> > +++ b/scripts/Makefile.build
> > @@ -425,7 +425,10 @@ $(obj)/lib.a: $(lib-y) FORCE
> >  # module is turned into a multi object module, $^ will contain header file
> >  # dependencies recorded in the .*.cmd file.
> >  quiet_cmd_link_multi-m = LD [M]  $@
> > -      cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
> > +      cmd_link_multi-m =                                       \
> > +       $(file >$@.in,$(filter %.o,$^))                         \
> > +       $(LD) $(ld_flags) -r -o $@ @$@.in;                      \
> > +       rm -f $@.in
>
> The GNU Make docs linked above use an `@` before the invocation of
> `rm`. I don't know what that's about, but that or even this patch
> doesn't affect my ability to build negatively. LGTM


See this:

https://www.gnu.org/software/make/manual/html_node/Echoing.html#Echoing


> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
>
> >
> >  $(multi-used-m): FORCE
> >         $(call if_changed,link_multi-m)
> > --
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers


-- 
Best Regards
Masahiro Yamada