Re: [PATCH tracing/kprobes v2 1/5] tracing/kprobes: Rename special variables syntax

[Masami Hiramatsu <mhiramat@redhat.com>]

Frederic Weisbecker wrote:
> On Tue, Oct 06, 2009 at 10:23:50AM -0400, Masami Hiramatsu wrote:
>> OK, so here are syntax ideas
>>
>> * current syntax
>> <Ftrace>
>> - $sp_var
>> - %regs
>> - @symbol
>> <Perf>
>> - local_var
> 
> 
> This one looks good.
> And why not turning @symbol into symbol?
> Then it's up to perf probe to find the right
> target.

Hmm, one big reason for separating local_vars
and others is that I'd like to check whether
perf-probe needs debuginfo or not.
If there is no local_vars, we don't need to
parse debuginfo. Sometimes, it is useful just
for setting up probe points.

> And @ can be used for raw addresses?

Yeah, but @ can be shared with symbols and raw addresses.
If the first char is digit, it's not a symbol.:-)

And also, @symbol actually has its syntax rule.:-)
its real syntax is:
@[MODULE:]SYMBOL[+OFFSET]
or
@ADDRESS (0xNN (base 16) or NN (base 10))

Perhaps, since perf-probe has another syntax rule,
I don't want to confuse users. :-P

Thank you,

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com