Re: [tip:perf/core] perf probe: Support DW_OP_call_frame_cfa in debuginfo

[Masami Hiramatsu <mhiramat@redhat.com>]

Masami Hiramatsu wrote:
> Arnaldo Carvalho de Melo wrote:
>> Em Fri, May 07, 2010 at 01:16:36PM -0400, Masami Hiramatsu escreveu:
>>> Hi,
>>>
>>> Robert Richter wrote:
>>>> On 15.04.10 07:29:18, tip-bot for Masami Hiramatsu wrote:
>>>>> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
>>>>> index 2a27132..310ce89 100644
>>>>> --- a/tools/perf/util/probe-finder.h
>>>>> +++ b/tools/perf/util/probe-finder.h
>>>>> @@ -42,6 +42,7 @@ struct probe_finder {
>>>>>  	struct list_head	lcache;		/* Line cache for lazy match */
>>>>>  
>>>>>  	/* For variable searching */
>>>>> +	Dwarf_CFI		*cfi;		/* Call Frame Information */
>>>>
>>>> I get the following complile error:
>>>>
>>>> gcc -o builtin-probe.o -c -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Wformat-y2k -Wshadow -Winit-self -Wpacked -Wredundant-decls -Wstack-protector -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes -Wdeclaration-after-statement  -fstack-protector-all -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Iutil/include -I/usr/include/elfutils -DDWARF_SUPPORT -DNO_NEWT_SUPPORT -DNO_LIBPERL -DSHA1_HEADER='<openssl/sha.h>'  builtin-probe.c
>>>> In file included from builtin-probe.c:43:
>>>> util/probe-finder.h:45: error: expected specifier-qualifier-list before ‘Dwarf_CFI’
>>>> make: *** [builtin-probe.o] Error 1
>>>> build script error: 2
>>>>
>>>> git grep only finds the following:
>>>>
>>>>  $ git grep Dwarf_CFI 
>>>>  tools/perf/util/probe-finder.h: Dwarf_CFI               *cfi;           /* Call Frame Information */
>>>>
>>>> Am I missing something?
>>>
>>> Hmm, it seems that Dwarf_CFI is not defined in library.
>>> (it is defined as a type in /usr/include/elfutils/libdw.h)
>>> Could you tell me what version of elfutils you are using?
>>
>> Masami-san,
>>
>> 	If we are version dependant on that, we should disable this
>> specific feature by doing one more compile test like we have for setting
>> NO_DWARF, hopefully just a subset of DWARF support can be disabled due
>> to this version dependency, right?
> 
> Agreed. I'll check that what version can support current perf probe.

OK, I've found that the CFI support has been added at last June,
and elfutils-0.142 is released in last July.
So, I think we can check whether CFI is supported or not by checking
the version of elfutils, which can be done by _ELFUTILS_PREREQ() macro
defined in elfutils/version.h 

Thank you,

-- 
Masami Hiramatsu
e-mail: mhiramat@redhat.com