From mboxrd@z Thu Jan  1 00:00:00 1970
From: Don Slutz <dslutz@verizon.com>
Subject: Re: xen 4.4.0 dependency lzo fails to build from source
 due to fPIC
Date: Tue, 29 Jul 2014 16:21:32 -0400
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To: Jan Beulich <JBeulich@suse.com>, Anthony Wright <anthony@overnetdata.com>
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On 07/29/14 02:46, Jan Beulich wrote:
>>>> On 28.07.14 at 23:02, <anthony@overnetdata.com> wrote:
>> If xen detects lzo, it tries to build tools/xclib/libxenguest.so.4.4.0
>> with lzo support but fails with the error:
>>
>> /usr/bin/ld:
>> /usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/../../../../lib64/liblzo2.a(lzo_ini
>> t.o):
>> relocation R_X86_64_PC32 against symbol '_lzo_config_check' can not be
>> used when making a shared object; recompile with -fPIC
>>
>> reading around the subject it would seem to be a problem with the lzo
>> library (2.08) which has been built without using the -fPIC option.
>> However, when I look at the lzo package there is no standard way to
>> build it with -fPIC. My workaround has been simply to remove the lzo
>> package, but I'm not sure this is a good solution, and I don't
>> understand why this problem doesn't seem to have been encountered before.
>>
>> Should I be building Xen with LZO support? (does everybody else build
>> without LZO support?)
>>
>> Should I be adding fPIC to the LZO options and rebuilding LZO?
>>
>> Is there something else I'm doing wrong that is causing the problem?

This could also be "broken toolchain" as:


  Subject: Re: [Xen-devel] [Qemu-devel] [Bug 1257099] [NEW]
  QEMU fails to build on CentOS 5.10 with relocation
  R_X86_64_PC32 error - msg#00032


On 12/14/13 15:21, Don Slutz wrote:
On 12/09/13 08:22, Paolo Bonzini wrote:

Il 09/12/2013 13:47, Don Slutz ha scritto:

On 12/05/13 22:20, Don Slutz wrote:

On 12/05/13 16:24, Richard Henderson wrote:

On 12/06/2013 04:18 AM, Paolo Bonzini wrote:

$ gcc -shared -o f.so f.c -fPIE -fPIC
/usr/bin/ld: /tmp/ccQc9els.o: relocation R_X86_64_PC32 against `f'
can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status


The bug is simply that "-fPIE -fPIC" counts as -fPIE rather than -fPIC:

$ gcc -S -o - f.c -fPIE |grep call
     call    f                      # PC32 relocation
$ gcc -S -o - f.c -fPIC |grep call
     call    f@PLT                  # PLT32 relocation

The easy workaround is to drop -fPIE when we're adding -fPIC.


r~

...

talks about.  From QEMU configure:


# check for broken gcc and libtool in RHEL5
if test -n "$libtool" -a "$pie" != "no" ; then
   cat > $TMPC <<EOF

void *f(unsigned char *buf, int len);
void *g(unsigned char *buf, int len);

void *
f(unsigned char *buf, int len)
{
     return (void*)0L;
}

void *
g(unsigned char *buf, int len)
{
     return f(buf, len);
}

EOF
   if ! libtool_prog; then
     echo "Disabling libtool due to broken toolchain support"
     libtool=
   fi
fi

    -Don Slutz

> The expectation is that there is a shared library to link against, not
> just a static one. If you want the static-only case supported, then
> you'll need to contribute patches (and imo those should then cover
> not just lzo, but all of the compression methods other than lz4).
>
> Jan
>
>
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