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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Thu, 14 Jan 2021 17:00:56 -0800
Message-ID: <CAKwvOdnfm9XvKsgn30HSUYoCSibHND-JSTqNH0yU7bfpYog_3w@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] kbuild: handle excessively long argument lists
To:     Jeff Johnson <jjohnson@codeaurora.org>
Cc:     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>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        LKML <linux-kernel@vger.kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>
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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

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