Re: [PATCH v1 05/10] perf build: Enable additional Clang thread-safety flags

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] build: broken feature test using -E for parser flag
--

commit 0e33ca477acb734d0166b74d7f9ee83ae4860cb6
Author: Ian Rogers <irogers@google.com>

perf build: Enable additional Clang thread-safety flags

This commit adds additional Clang thread-safety flags (-Wthread-safety-pointer,
-Wthread-safety-beta, and -fexperimental-late-parse-attributes) to the perf
build to align with the kernel's context analysis.

> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 39442577418ea..d536203ff42f2 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -64,7 +64,10 @@ ifeq ($(CC_NO_CLANG), 0)
>    endif
>  
>    # Enabled Wthread-safety analysis for clang builds.
> -  CFLAGS += -Wthread-safety -DWARN_CONTEXT_ANALYSIS
> +  CFLAGS += -DWARN_CONTEXT_ANALYSIS -Wthread-safety -Wthread-safety-pointer -Wthread-safety-beta
> +  ifeq ($(shell $(CC) -Werror -fexperimental-late-parse-attributes -E -x c /dev/null >/dev/null 2>&1 && echo 1), 1)

[Severity: Medium]
Since -fexperimental-late-parse-attributes is a parsing flag, does passing it
with -E (preprocess only) cause Clang to emit a -Wunused-command-line-argument
warning? Due to -Werror, this warning gets promoted to a fatal error, which
forces the shell command to exit with a non-zero status regardless of whether
the compiler actually supports the flag.

As a result, the flag is never added to CFLAGS, preventing Clang from correctly
parsing thread-safety annotations that reference struct members declared later
in the same struct.

Should this feature test use -c rather than -E to avoid this issue?

> +    CFLAGS += -fexperimental-late-parse-attributes
> +  endif
>  endif
>  
>  include $(srctree)/tools/scripts/Makefile.arch

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261013182458.1234616-1-irogers@google.com?part=5