Re: [RFC PATCH v6 1/2] tools lib traceevent: Support function __get_dynamic_array_len

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Jul 21, 2015 at 03:08:49AM +0000, He Kuang wrote:
> Support helper function __get_dynamic_array_len() in libtraceevent,
> this function is used accompany with __print_array() or __print_hex(),
> but currently it is not an available function in the function list of
> process_function().
> 
> The total allocated length of the dynamic array is embedded in the top
> half of __data_loc_##item field. This patch adds new arg type
> PRINT_DYNAMIC_ARRAY_LEN to return the length to eval_num_arg(),
> 
> Signed-off-by: He Kuang <hekuang@huawei.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  tools/lib/traceevent/event-parse.c                 | 56 +++++++++++++++++++++-
>  tools/lib/traceevent/event-parse.h                 |  1 +
>  .../perf/util/scripting-engines/trace-event-perl.c |  1 +
>  .../util/scripting-engines/trace-event-python.c    |  1 +
>  4 files changed, 57 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
> index cc25f05..3af69cf 100644
> --- a/tools/lib/traceevent/event-parse.c
> +++ b/tools/lib/traceevent/event-parse.c
> @@ -783,6 +783,7 @@ static void free_arg(struct print_arg *arg)
>  		free(arg->bitmask.bitmask);
>  		break;
>  	case PRINT_DYNAMIC_ARRAY:
> +	case PRINT_DYNAMIC_ARRAY_LEN:
>  		free(arg->dynarray.index);
>  		break;
>  	case PRINT_OP:
> @@ -2655,6 +2656,42 @@ process_dynamic_array(struct event_format *event, struct print_arg *arg, char **
>  }
>  
>  static enum event_type
> +process_dynamic_array_len(struct event_format *event, struct print_arg *arg,
> +			  char **tok)
> +{
> +	struct format_field *field;
> +	enum event_type type;
> +	char *token;
> +
> +	if (read_expect_type(EVENT_ITEM, &token) < 0)
> +		goto out_free;
> +
> +	arg->type = PRINT_DYNAMIC_ARRAY_LEN;
> +
> +	/* Find the field */
> +	field = pevent_find_field(event, token);
> +	if (!field)
> +		goto out_free;
> +
> +	arg->dynarray.field = field;
> +	arg->dynarray.index = 0;
> +
> +	if (read_expected(EVENT_DELIM, ")") < 0)
> +		goto out_err;
> +
> +	type = read_token(&token);
> +	*tok = token;
> +
> +	return type;
> +
> + out_free:
> +	free_token(token);
> + out_err:
> +	*tok = NULL;
> +	return EVENT_ERROR;
> +}
> +
> +static enum event_type
>  process_paren(struct event_format *event, struct print_arg *arg, char **tok)
>  {
>  	struct print_arg *item_arg;
> @@ -2901,6 +2938,10 @@ process_function(struct event_format *event, struct print_arg *arg,
>  		free_token(token);
>  		return process_dynamic_array(event, arg, tok);
>  	}
> +	if (strcmp(token, "__get_dynamic_array_len") == 0) {
> +		free_token(token);
> +		return process_dynamic_array_len(event, arg, tok);
> +	}
>  
>  	func = find_func_handler(event->pevent, token);
>  	if (func) {
> @@ -3581,14 +3622,25 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
>  			goto out_warning_op;
>  		}
>  		break;
> +	case PRINT_DYNAMIC_ARRAY_LEN:
> +		offset = pevent_read_number(pevent,
> +					    data + arg->dynarray.field->offset,
> +					    arg->dynarray.field->size);
> +		/*
> +		 * The total allocated length of the dynamic array is
> +		 * stored in the top half of the field, and the offset
> +		 * is in the bottom half of the 32 bit field.
> +		 */
> +		val = (unsigned long long)(offset >> 16);
> +		break;
>  	case PRINT_DYNAMIC_ARRAY:
>  		/* Without [], we pass the address to the dynamic data */
>  		offset = pevent_read_number(pevent,
>  					    data + arg->dynarray.field->offset,
>  					    arg->dynarray.field->size);
>  		/*
> -		 * The actual length of the dynamic array is stored
> -		 * in the top half of the field, and the offset
> +		 * The total allocated length of the dynamic array is
> +		 * stored in the top half of the field, and the offset
>  		 * is in the bottom half of the 32 bit field.
>  		 */
>  		offset &= 0xffff;
> diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
> index 063b197..94543aa 100644
> --- a/tools/lib/traceevent/event-parse.h
> +++ b/tools/lib/traceevent/event-parse.h
> @@ -294,6 +294,7 @@ enum print_arg_type {
>  	PRINT_OP,
>  	PRINT_FUNC,
>  	PRINT_BITMASK,
> +	PRINT_DYNAMIC_ARRAY_LEN,
>  };
>  
>  struct print_arg {
> diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
> index 1bd593b..544509c 100644
> --- a/tools/perf/util/scripting-engines/trace-event-perl.c
> +++ b/tools/perf/util/scripting-engines/trace-event-perl.c
> @@ -221,6 +221,7 @@ static void define_event_symbols(struct event_format *event,
>  		break;
>  	case PRINT_BSTRING:
>  	case PRINT_DYNAMIC_ARRAY:
> +	case PRINT_DYNAMIC_ARRAY_LEN:
>  	case PRINT_STRING:
>  	case PRINT_BITMASK:
>  		break;
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index ace2484..aa9e125 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -251,6 +251,7 @@ static void define_event_symbols(struct event_format *event,
>  		/* gcc warns for these? */
>  	case PRINT_BSTRING:
>  	case PRINT_DYNAMIC_ARRAY:
> +	case PRINT_DYNAMIC_ARRAY_LEN:
>  	case PRINT_FUNC:
>  	case PRINT_BITMASK:
>  		/* we should warn... */
> -- 
> 1.8.5.2
>