Re: [PATCH tracing/kprobes v3 6/7] perf: Add perf probe subcommand for kprobe-event setup helper

[Masami Hiramatsu <mhiramat@redhat.com>]

Ingo Molnar wrote:
>
> * Frederic Weisbecker<fweisbec@gmail.com>  wrote:
>
>> On Wed, Oct 07, 2009 at 06:28:23PM -0400, Masami Hiramatsu wrote:
>>> Add perf probe subcommand for kprobe-event setup helper to perf command.
>>> This allows user to define kprobe events by C expressions (C line numbers,
>>> C function names, and C local variables).
>>>
>>
>>
>> My libdwarf.h and dwarf.h are available through<libdwarf.h>  and
>> <dwarf.h>, these are in /usr/include
>>
>> But even by fixing the include path in the makefile and probe-finder.h,
>> I get the following build error:
>>
>> util/probe-finder.c: In function ‘die_get_entrypc’:
>> util/probe-finder.c:222: erreur: ‘Dwarf_Ranges’ undeclared (first use in this function)
>> util/probe-finder.c:222: erreur: (Each undeclared identifier is reported only once
>> util/probe-finder.c:222: erreur: for each function it appears in.)
>> util/probe-finder.c:222: erreur: ‘ranges’ undeclared (first use in this function)
>> cc1: warnings being treated as errors
>> util/probe-finder.c:223: erreur: ISO C90 forbids mixed declarations and code
>> util/probe-finder.c:247: erreur: implicit declaration of function ‘dwarf_get_ranges’
>> util/probe-finder.c:247: erreur: nested extern declaration of ‘dwarf_get_ranges’
>> util/probe-finder.c:251: erreur: implicit declaration of function ‘dwarf_ranges_dealloc’
>> util/probe-finder.c:251: erreur: nested extern declaration of ‘dwarf_ranges_dealloc’
>> make: *** [util/probe-finder.o] Erreur 1
>>
>>
>> I remember we talked about that before, but I don't remember well why it happened.
>> This is because of a libdwarf version or something, right?

Yeah, you may use an old version.

>>
>> Which one should I pick? Mine is:
>>
>>      libdwarf.h
>>
>>      $Revision: #9 $ $Date: 2008/01/17 $

AFAICS, the revision tag is not updated :(
I'm usually using libdwarf later than 20090324, and dwarf_get_ranges()
was introduced from 20081231.

>
> if it's possible to still have a single set of APIs it would be nice to
> auto-detect and massage all these libdwarf versions into a single
> backend within perf.

Sure, it's not so hard to check APIs.

Thank you,

-- 
Masami Hiramatsu

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

e-mail: mhiramat@redhat.com