Re: [PATCH 2/2] kbuild: handle excessively long argument lists

jjohnson
2021-01-14T21:33:59Z

On 2021-01-14 13:07, Nick Desaulniers 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>
>> ---
>> scripts/Makefile.build | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
>> index 252b7d2..d5ef345 100644
>> --- a/scripts/Makefile.build
>> +++ b/scripts/Makefile.build
>> @@ -425,7 +425,11 @@ $(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
>> +endif
>
> Was this build tested?
>
> $ make LLVM=1 LLVM_IAS=1 -j72 defconfig
> scripts/Makefile.build:432: *** extraneous 'endif'. Stop.
> make: *** [Makefile:535: scripts_basic] Error 2
>
> (Please cc me on v2)

blush

It was tested on a workspace that also contains the Clang LTO series
https://patchwork.kernel.org/project/linux-kbuild/patch/20201211184633.3213045-3-samitolvanen@google.com/

I messed up when trimming, will update in v2