Re: [PATCH v4 0/4] tools/build: Allow versioning of all LLVM tools

[Kumar Kartikeya Dwivedi]

On Thu Jul 16, 2026 at 1:46 AM CEST, Namhyung Kim wrote:
> Hello BPF folks,
>
> On Wed, Jul 15, 2026 at 03:53:47PM +0100, James Clark wrote:
>> I ran into the build issue mentioned in the first commit, because using
>> an option like LLVM=-15 is a documented way to build [1], but only
>> some of the LLVM tools defined in tools/ support this.
>>
>> After fixing that, a lot of other tidyups fell out. I didn't go too far,
>> for example some selftests include tools/testing/selftests/lib.mk which
>> reimplements some of the LLVM_SUFFIX stuff, but other selftests include
>> tools/scripts/Makefile.include and I stopped before touching the former.
>> Some other non build scripts hard code toolchains and I didn't touch
>> those either, this change is only focused on things that already
>> include Makefile.include.
>>
>> [1]: Documentation/kbuild/llvm.rst
>>
>> Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
>> ---
>> Changes in v4:
>> - Drop "tools/build: selftests: Allow versioning LLVM lld", clang
>>   already picks the correct sibling lld version. (Sashiko)
>> - Link to v3: https://lore.kernel.org/r/20260715-james-perf-llvm-version-v3-0-8854bfe5af7e@xxxxxxxxxx
>>
>> Changes in v3:
>> - Add warning for empty $USE_LD
>> - Use $HOSTREADELF in bpf Makefile
>> - Rebase on v7.2-rc3
>> - Link to v2: https://lore.kernel.org/r/20260518-james-perf-llvm-version-v2-0-f12cc4f031d8@xxxxxxxxxx
>>
>> Changes in v2:
>> - Fix selftests/bpf build. LLD needs to take the full path to be used
>>   with -fuse-ld=
>> - Link to v1: https://lore.kernel.org/r/20260514-james-perf-llvm-version-v1-0-6cac1a9a4c8d@xxxxxxxxxx
>>
>> ---
>> James Clark (4):
>>       tools/build: Allow versioning of all LLVM tools defined in Makefile.include
>>       tools/build: Indent if else blocks
>>       tools/build: Allow versioning LLVM readelf
>>       tools/build: selftests: Remove some duplicate toolchain definitions
>>
>>  tools/bpf/resolve_btfids/Makefile    |  3 --
>>  tools/lib/api/Makefile               |  4 --
>>  tools/lib/bpf/Makefile               |  8 ++--
>>  tools/lib/subcmd/Makefile            |  4 --
>>  tools/lib/symbol/Makefile            |  4 --
>>  tools/perf/Makefile.perf             |  7 ----
>>  tools/scripts/Makefile.include       | 77 ++++++++++++++++++++----------------
>>  tools/testing/selftests/bpf/Makefile |  1 -
>>  8 files changed, 46 insertions(+), 62 deletions(-)
>
> Are you ok with this change and going through perf tree?
>

Sorry for the delay, yes, feel free to take it through your tree.

> Thanks,
> Namhyung
>
>> ---
>> base-commit: a13c140cc289c0b7b3770bce5b3ad42ab35074aa
>> change-id: 20260511-james-perf-llvm-version-43ab1cb5bc7d
>>
>> Best regards,
>> --
>> James Clark <james.clark@xxxxxxxxxx>
>>