Re: [PATCH v2 04/11] perf annotate-data: Count flexible array accesses for the whole struct

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] perf annotate-data: missing stub for
  annotated_member_extent() without libdw
--

commit 08cc9872c27cbef64cf4ff8273d106d1700fd31c
Author: Arnaldo Carvalho de Melo <acme@redhat.com>

perf annotate-data: Count flexible array accesses for the whole struct

This commit introduces annotated_member_extent() to include children such as
flexible array members when computing the sample range of a struct or union
member in both stdio and TUI data-type annotation outputs.

> diff --git a/tools/perf/ui/browsers/annotate-data.c b/tools/perf/ui/browsers/annotate-data.c
> index 0f778788df4a9..0e1e06acf2b23 100644
> --- a/tools/perf/ui/browsers/annotate-data.c
> +++ b/tools/perf/ui/browsers/annotate-data.c
> @@ -53,12 +53,11 @@ static int get_member_overhead(struct annotated_data_type *adt,
>  			       struct evsel *leader)
>  {
>  	struct annotated_member *member = entry->data;
> -	int i, k;
> +	int i, k, end = annotated_member_extent(member);

[ ... ]

> diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h
> index 184262c735621..880b11849a932 100644
> --- a/tools/perf/util/annotate-data.h
> +++ b/tools/perf/util/annotate-data.h
> @@ -260,6 +260,9 @@ void global_var_type__tree_delete(struct rb_root *root);
>  /* Print data type annotation (including members) on stdout */
>  int hist_entry__annotate_data_tty(struct hist_entry *he, struct evsel *evsel);
>  
> +/* End offset of a member, including a flexible array's children */
> +int annotated_member_extent(struct annotated_member *member);
> +
>  /* Get name of member field at the given offset in the data type */
>  int annotated_data_type__get_member_name(struct annotated_data_type *adt,
>  					 char *buf, size_t sz, int member_offset);

[Severity: Medium]
Does annotated_member_extent() need a fallback stub in the
#else /* HAVE_LIBDW_SUPPORT */ block (or to be defined outside the guard)?

This declaration sits inside #ifdef HAVE_LIBDW_SUPPORT and
tools/perf/util/annotate-data.c is only built when CONFIG_LIBDW is enabled,
whereas tools/perf/ui/browsers/annotate-data.c is built whenever
CONFIG_SLANG is enabled.  Building perf with TUI enabled and libdw disabled
(e.g. make NO_LIBDW=1) fails in get_member_overhead() with an implicit
declaration and undefined reference to annotated_member_extent().

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261113200850.2803460-1-acme@kernel.org?part=4