linux/tools/build
Ian Rogers 7e1f74bbbe tools build: Fix feature checks to touch target files on success
In tools/build/feature/Makefile, test-clang-bpf-co-re.bin and
test-bpftool-skeletons.bin redirected grep output but never touched or
created the $@ target file upon success.

Because the target file was never created on disk, Kbuild could never cache
the result of the check. Consequently, Make treated the prerequisite as
missing and continuously re-executed the Clang BPF backend and bpftool
feature checks on every single sub-make evaluation during build startup, or
on every incremental build.

Refactor both feature check recipes to touch $@ on success. For
test-clang-bpf-co-re.bin, group the shell pipeline within curly braces
and redirect both stdout and stderr to .make.output to allow errors to
be inspected and not appear in build output.

List test-clang-bpf-co-re.bin's input C file as a dependency so
modification triggers a rebuild. For test-bpftool-skeletons.bin, add it
to the FILES list so that it will be cleaned.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Yuzhuo Jing <yuzhuo@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
History 2026-06-04 10:58:47 -03:00
..
Documentation tools build: Add CFLAGS_REMOVE_* support 2016-11-14 11:37:25 -03:00
feature tools build: Fix feature checks to touch target files on success 2026-06-04 10:58:47 -03:00
tests License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Build tools build: Fix fixdep dependencies 2025-10-14 14:45:20 -07:00
Build.include tools build: Fix rust cross compilation 2026-03-04 11:37:30 -03:00
fixdep.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile perf build: Fix perf build issues with fixdep 2025-10-23 09:53:49 +02:00
Makefile.build tools build: Make in-target rule robust against too long argument error 2026-03-04 11:21:48 -03:00
Makefile.feature tools build: Deduplicate test-libunwind for different architectures 2026-05-15 08:26:11 -03:00
Makefile.include tools build: Correct bpf fixdep dependencies 2024-08-05 12:19:48 -03:00