On Tue, Aug 25, 2020 at 09:29:09PM -0700, Ian Rogers wrote:
> This patch resolves some undefined behavior where variables in
> expr_id_data were accessed (for debugging) without being defined. To
> better enforce the tagged union behavior, the struct is moved into
> expr.c and accessors provided. Tag values (kinds) are explicitly
> identified.
>
> Signed-off-by: Ian Rogers <irog...@google.com>
> ---
> tools/perf/util/expr.c | 64 ++++++++++++++++++++++++++++++-----
> tools/perf/util/expr.h | 17 +++-------
> tools/perf/util/expr.y | 2 +-
> tools/perf/util/metricgroup.c | 4 +--
> 4 files changed, 62 insertions(+), 25 deletions(-)
>
> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index 53482ef53c41..1ca0992db86b 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -17,6 +17,25 @@
> extern int expr_debug;
> #endif
>
> +struct expr_id_data {
> + union {
> + double val;
> + struct {
> + double val;
> + const char *metric_name;
> + const char *metric_expr;
> + } ref;
> + struct expr_id *parent;
> + };
> +
> + enum {
> + EXPR_ID_DATA__VALUE,
> + EXPR_ID_DATA__REF,
> + EXPR_ID_DATA__REF_VALUE,
> + EXPR_ID_DATA__PARENT,
> + } kind;
I like that, it's more clear than current state ;-)
could you still put a small comment for each enum above,
as a hint what it's used for?
thanks,
jirka
