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From: John Snow <jsnow@redhat.com>
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Date: Thu, 5 Nov 2015 15:16:09 -0500
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Subject: Re: [Qemu-devel] enable-gprof configuration option issue?
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To: Claudio Fontana <claudio.fontana@huawei.com>, Peter Maydell <peter.maydell@linaro.org>
Cc: Ajo Jose Panoor <ajo.jose.panoor@huawei.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>



On 11/04/2015 11:45 AM, Claudio Fontana wrote:
> Hello,
> 
> we are trying to use good old gprof to profile the QEMU process,
> and it seems to work when directly passing "-O0 -pg" using --extra-cflags,
> while it does not seem to work when using "--enable-gprof".
> 
> The error we get when using --enable-gprof is the following:
> 
> ld: gcrt1.o: relocation R_X86_64_32S against `__libc_csu_fini' can not be used when making a shared object; recompile with -fPIC
> gcrt1.o: could not read symbols: Bad value
> 
> We got this on a few X86 boxes with different distros, in my case I have Slackware-14.1 64bit, ld 2.23.52.0.1.20130226, gcc 4.8.2
> 
> Is the expectation that one should pass "-pg" directly?
> 
> Thanks!
> 
> Ciao,
> 
> Claudio
> 
> 

It looks like our configure script currently only prepends -p when you
specify --enable-gprof, and not -pg. It doesn't appear to set -O0
either; you probably want --enable-debug --enable-gprof.

I'm not very familiar with gprof or the flags that make the most sense
for it, so it might be in your interest to send a patch over to make
this configure option more useful.

--js