From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1030814AbdADP4D (ORCPT <rfc822;w@1wt.eu>);
        Wed, 4 Jan 2017 10:56:03 -0500
Received: from foss.arm.com ([217.140.101.70]:53826 "EHLO foss.arm.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S968586AbdADP4C (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 4 Jan 2017 10:56:02 -0500
Subject: Re: [PATCH] tools: perf: fix linker error when libelf config is
 disabled
To: Jiri Olsa <jolsa@redhat.com>
References: <1483537960-14499-1-git-send-email-sudeep.holla@arm.com>
 <20170104144537.GB4908@krava>
Cc: Sudeep Holla <sudeep.holla@arm.com>, linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
        Jiri Olsa <jolsa@kernel.org>
From: Sudeep Holla <sudeep.holla@arm.com>
Organization: ARM
Message-ID: <5aa63b9b-1479-8dc9-d505-56a73e7fd9ee@arm.com>
Date: Wed, 4 Jan 2017 15:45:13 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.5.1
MIME-Version: 1.0
In-Reply-To: <20170104144537.GB4908@krava>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org



On 04/01/17 14:45, Jiri Olsa wrote:
> On Wed, Jan 04, 2017 at 01:52:40PM +0000, Sudeep Holla wrote:
>> When libelf is disabled in the configuration, we get the following
>> linker error:
>>   LINK     libperf-jvmti.so
>>   ld: cannot find -lelf
>>   Makefile.perf:515: recipe for target 'libperf-jvmti.so' failed
>>
>> This patch fixes the error by using the configuration macro EXTLIBS.
>>
>> Fixes: d4dfdf00d43e ("perf jvmti: Plug compilation into perf build")
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Jiri Olsa <jolsa@kernel.org>
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>> ---
>>  tools/perf/Makefile.perf | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
>> index 8fc24824705e..6defd9b00bc4 100644
>> --- a/tools/perf/Makefile.perf
>> +++ b/tools/perf/Makefile.perf
>> @@ -512,7 +512,7 @@ $(LIBJVMTI_IN): FORCE
>>  	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=jvmti obj=jvmti
>>  
>>  $(OUTPUT)$(LIBJVMTI): $(LIBJVMTI_IN)
>> -	$(QUIET_LINK)$(CC) -shared -Wl,-soname -Wl,$(LIBJVMTI) -o $@ $< -lelf -lrt
>> +	$(QUIET_LINK)$(CC) -shared -Wl,-soname -Wl,$(LIBJVMTI) -o $@ $< $(EXTLIBS) -lrt
>>  endif
> 
> hm, do we need -lelf -lrt at all? can't see reason for that

I agree as it links well without libelf. I was not sure if enabling
libelf has any issue removing it, hence I retained. I will remove both
and repost. Thanks for having a look.

-- 
Regards,
Sudeep