Re: [PATCH 2/4] perf_event: fix getting point

Frederic Weisbecker
2009-12-15T13:59:08Z

On Tue, Dec 15, 2009 at 07:20:26PM +0800, Xiao Guangrong wrote:
> The point that got by raw_field_ptr() is point to @data offset not
> tracepoint saved.
>
> Introduce raw_field_arry() to get arry data is tracepoint save
> arry to it.

Could you please rename it into raw_field_array()?
I feel like...a kind of loss there :)

>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
> tools/perf/builtin-sched.c | 3 +--
> tools/perf/util/trace-event-parse.c | 25 ++++++++++++++++++++++---
> tools/perf/util/trace-event.h | 3 +++
> 3 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index d67f274..8df982e 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -630,8 +630,7 @@ static void test_calibrations(void)
>
> #define FILL_ARRAY(ptr, array, event, data) \
> do { \
> - void *__array = raw_field_ptr(event, #array, data); \
> - memcpy(ptr.array, __array, sizeof(ptr.array)); \
> + raw_field_arry(event, #array, data, ptr.array, sizeof(ptr.array));\
> } while(0)
>
> #define FILL_COMMON_FIELDS(ptr, event, data) \
> diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> index c5c32be..b0ee64f 100644
> --- a/tools/perf/util/trace-event-parse.c
> +++ b/tools/perf/util/trace-event-parse.c
> @@ -840,7 +840,7 @@ static int event_read_fields(struct event *event, struct format_field **fields)
> field->flags |= FIELD_IS_ARRAY;
>
> type = read_token(&token);
> - while (strcmp(token, "]") != 0) {
> + while (strcmp(token, "]") != 0) {
> if (last_type == EVENT_ITEM &&
> type == EVENT_ITEM)
> len = 2;
> @@ -1919,13 +1919,32 @@ raw_field_value(struct event *event, const char *name, void *data)
>
> void *raw_field_ptr(struct event *event, const char *name, void *data)
> {
> + void *ptr;
> + unsigned long long value;
> +
> + value = raw_field_value(event, name, data);
> +
> + if (!value)
> + return NULL;
> +
> + memcpy(&ptr, &value, sizeof(ptr));

Could you perhaps just do

ptr = (void *)value; ?

This memcpy suggest we are dereferencing some field while
actually just copy a pointer.

Thanks!