On Mon, Jan 26, 2015 at 06:38:24PM +0800, Wang Nan wrote:
> (If Steven Rostedt accept the previous patch which introduce a priv
> field to 'struct format_field', we can use a relative simple method
> for name conversion. If not , perf must track name conversion by
> itself.)
Sorry for coming in so late here.
>
> Some parameters of syscall tracepoints named as 'nr', 'event', etc.
> When dealing with them, perf convert to ctf meets some problem:
>
> 1. If a parameter with name 'nr', it will duplicate syscall's
> common field 'nr'. One such syscall is io_submit().
>
> 2. If a parameter with name 'event', it is denied to be inserted
> because 'event' is a babeltrace keywork. One such syscall is
> epoll_ctl.
>
> This patch appends '_dupl_X' suffix to avoid problem 1, prepend a '_'
> prefix to avoid problem 2.
Actually, I don't like this approach. That is, to have this private
data structure. Why not just add an "alias" to format_field. In other
words, instead of hiding this interaction behind a void pointer and
needing to create a function pointer to free it, just add another
field to format field and be done with it. I think it would make
the code a hell of a lot simpler and easier to understand.
struct format_field {
struct format_field *next;
struct event_format *event;
char *type;
char *name;
+ char *alias;
int offset;
int size;
unsigned int arraylen;
unsigned int elementsize;
unsigned long flags;
};
And put the logic in event parse to free alias if need be.
Heck, you could even add a pevent_*() func to assign the alias
using strdup, or what not.
-- Steve
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