Re: [PATCH 1/2] perf, tools: Enable type checking for perf_evsel_config_term types

[Jiri Olsa <jolsa@redhat.com>]

On Fri, Oct 20, 2017 at 01:27:54PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Use a typed enum for the perf_evsel_config_term type enum.
> This allows gcc to do much stronger type checks, and also
> check for missing case statements.
> 
> I removed the unused _MAX member from the number.
> 
> It found one missing case. I'm not sure it's a real problem,
> so I just turned it into a BUG_ON for now.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
>  tools/perf/util/evsel.c | 2 ++
>  tools/perf/util/evsel.h | 5 ++---
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index f894893c203d..d1f63b93bf69 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -775,6 +775,8 @@ static void apply_config_terms(struct perf_evsel *evsel,
>  		case PERF_EVSEL__CONFIG_TERM_OVERWRITE:
>  			attr->write_backward = term->val.overwrite ? 1 : 0;
>  			break;
> +		case PERF_EVSEL__CONFIG_TERM_DRV_CFG:
> +			BUG_ON(1);
>  		default:
>  			break;
>  		}
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index db658785d828..6728d8d6e513 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -37,7 +37,7 @@ struct cgroup_sel;
>   * It is allocated within event parsing and attached to
>   * perf_evsel::config_terms list head.
>  */
> -enum {
> +enum period_type {

seems ok, but I'm puzzled with the 'period_type' name
I think it should be more like 'term_type' or something

jirka


>  	PERF_EVSEL__CONFIG_TERM_PERIOD,
>  	PERF_EVSEL__CONFIG_TERM_FREQ,
>  	PERF_EVSEL__CONFIG_TERM_TIME,
> @@ -48,12 +48,11 @@ enum {
>  	PERF_EVSEL__CONFIG_TERM_OVERWRITE,
>  	PERF_EVSEL__CONFIG_TERM_DRV_CFG,
>  	PERF_EVSEL__CONFIG_TERM_BRANCH,
> -	PERF_EVSEL__CONFIG_TERM_MAX,
>  };
>  
>  struct perf_evsel_config_term {
>  	struct list_head	list;
> -	int	type;
> +	enum period_type	type;
>  	union {
>  		u64	period;
>  		u64	freq;
> -- 
> 2.13.6
>