Re: [PATCH v2 05/10] perf trace: Add a new argument to trace__btf_scnprintf()

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, Aug 15, 2024 at 09:36:21AM +0800, Howard Chu wrote:
> Pass the struct syscall_arg, so that we can use the augmented_arg later
> in the struct augmentation.

Breaks the build with:

builtin-trace.c: In function ‘trace__btf_scnprintf’:
builtin-trace.c:1011:78: error: unused parameter ‘arg’ [-Werror=unused-parameter]
 1011 |                                    size_t size, int val, struct syscall_arg *arg, char *type)
      |                                                          ~~~~~~~~~~~~~~~~~~~~^~~
  LD      /tmp/build/perf-tools-next/util/perf-util-in.o
  LD      /tmp/build/perf-tools-next/perf-util-in.o
  AR      /tmp/build/perf-tools-next/libperf-util.a
  GEN     /tmp/build/perf-tools-next/python/perf.cpython-312-x86_64-linux-gnu.so
cc1: all warnings being treated as errors

So we either use __maybe_unused at this point or combine it with the
patch where it really gets used. I think the later is better, will do.

- Arnaldo
 
> Signed-off-by: Howard Chu <howardchu95@gmail.com>
> ---
>  tools/perf/builtin-trace.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 84c7398312d8..4bde40f91531 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -1007,7 +1007,7 @@ static size_t btf_enum_scnprintf(const struct btf_type *type, struct btf *btf, c
>  }
>  
>  static size_t trace__btf_scnprintf(struct trace *trace, struct syscall_arg_fmt *arg_fmt, char *bf,
> -				   size_t size, int val, char *type)
> +				   size_t size, int val, struct syscall_arg *arg, char *type)
>  {
>  	if (trace->btf == NULL)
>  		return 0;
> @@ -1030,7 +1030,7 @@ static size_t trace__btf_scnprintf(struct trace *trace, struct syscall_arg_fmt *
>  #else // HAVE_LIBBPF_SUPPORT
>  static size_t trace__btf_scnprintf(struct trace *trace __maybe_unused, struct syscall_arg_fmt *arg_fmt __maybe_unused,
>  				   char *bf __maybe_unused, size_t size __maybe_unused, int val __maybe_unused,
> -				   char *type __maybe_unused)
> +				   struct syscall_arg *arg __maybe_unused, char *type __maybe_unused)
>  {
>  	return 0;
>  }
> @@ -2284,7 +2284,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
>  				printed += scnprintf(bf + printed, size - printed, "%s: ", field->name);
>  
>  			btf_printed = trace__btf_scnprintf(trace, &sc->arg_fmt[arg.idx], bf + printed,
> -							   size - printed, val, field->type);
> +							   size - printed, val, &arg, field->type);
>  			if (btf_printed) {
>  				printed += btf_printed;
>  				continue;
> @@ -2986,7 +2986,7 @@ static size_t trace__fprintf_tp_fields(struct trace *trace, struct evsel *evsel,
>  		if (trace->show_arg_names)
>  			printed += scnprintf(bf + printed, size - printed, "%s: ", field->name);
>  
> -		btf_printed = trace__btf_scnprintf(trace, arg, bf + printed, size - printed, val, field->type);
> +		btf_printed = trace__btf_scnprintf(trace, arg, bf + printed, size - printed, val, NULL, field->type);
>  		if (btf_printed) {
>  			printed += btf_printed;
>  			continue;
> -- 
> 2.45.2