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Re: PATCH] PR target/65612: Multiversioning doesn't work with DSO nor PIE
- From: Jack Howarth <howarth dot at dot gcc at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Ian Lance Taylor <ian at airs dot com>, Jakub Jelinek <jakub at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Uros Bizjak <ubizjak at gmail dot com>, Iain Sandoe <iain at codesourcery dot com>, Mike Stump <mikestump at comcast dot net>
- Date: Tue, 31 Mar 2015 14:33:54 -0400
- Subject: Re: PATCH] PR target/65612: Multiversioning doesn't work with DSO nor PIE
- Authentication-results: sourceware.org; auth=none
- References: <20150330022527 dot GA4148 at gmail dot com> <CAMe9rOrUpMmt8XyqO9fXZB-Bn+tRs-AKHTaQzu7jeGCZFXen8g at mail dot gmail dot com> <CAMe9rOp_LfJ8C4Xh4NoRD=rTutNCeqwN_OV=8+c5rFfnRHbV_g at mail dot gmail dot com> <CAMe9rOrGCRJhWpNT0hMJwKCG2+vaDsaRou7JV0tdjiANnmRm=g at mail dot gmail dot com> <CAJMcOU8nON6S=+be8C94F_tB8-VPCusa8VrEq_f5P2PZCdk7vg at mail dot gmail dot com> <CAMe9rOo2ORmyvndySKr3vzEQmZScpKQfnVVw7HW94BXvPFJqdQ at mail dot gmail dot com> <20150331053855 dot GB2121 at tucnak dot redhat dot com> <CAMe9rOrm=9gkqjFwEX8GVtri3t2mSmgOqfm_Q+LizCJqbLSAKQ at mail dot gmail dot com> <CAJMcOU_Pjryr7TxKx9zYKBtVEvBj8bmXDr=UBqShyE0CPr-cOA at mail dot gmail dot com> <CAMe9rOoRkeyw9SMuEev_ATE932UNhJBUPUd+Z81Qc1L+VpVkxw at mail dot gmail dot com> <CAJMcOU915GeWmwhTOvqXPQddZfYdJdVGQJUbMWXTEiz4y0QW9w at mail dot gmail dot com> <CAMe9rOp9kPZFhEE=seWX_VXC0NndYxtJ8Opt-kkCMSteeTuRuA at mail dot gmail dot com> <CAJMcOU8xHsE6ZyVSHy90AUgkSpY8FfG53xT+jGO=TALo27ViSA at mail dot gmail dot com> <CAMe9rOqAjsLAr+iVspN5XBdnaVtW_AJuMyOb3K6mVRKKh-sQXg at mail dot gmail dot com>
On Tue, Mar 31, 2015 at 1:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Mar 31, 2015 at 9:39 AM, Jack Howarth <howarth.at.gcc@gmail.com> wrote:
>> On Tue, Mar 31, 2015 at 12:14 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Tue, Mar 31, 2015 at 9:09 AM, Jack Howarth <howarth.at.gcc@gmail.com> wrote:
>>>> H.J.,
>>>> Did you attach the correct version of the patch? I don't see
>>>> anything conditional on linux.
>>>> Jack
>>>
>>> My patch will build and install libgcc_nonshared.a for all targets. If you
>>> don't link against it, nothing is changed. On Linux, it is used via the
>>> init_spec change.
>>
>> Isn't...
>>
>> diff --git a/gcc/gcc.c b/gcc/gcc.c
>> index d956c36..3fbd549 100644
>> --- a/gcc/gcc.c
>> +++ b/gcc/gcc.c
>> @@ -1566,6 +1566,7 @@ init_spec (void)
>> if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
>> {
>> init_gcc_specs (&obstack,
>> + "-lgcc_nonshared "
>> "-lgcc_s"
>> #ifdef USE_LIBUNWIND_EXCEPTIONS
>> " -lunwind"
>> @@ -1591,6 +1592,7 @@ init_spec (void)
>> /* Ug. We don't know shared library extensions. Hope that
>> systems that use this form don't do shared libraries. */
>> init_gcc_specs (&obstack,
>> + "libgcc_nonshared.a%s "
>> "-lgcc_s",
>> "libgcc.a%s",
>> "libgcc_eh.a%s"
>>
>> problematic for Solaris? I am unfamiliar with the Solaris spec
>> handling but sol2.h doesn't seem to have any instances of -lgcc which
>> might imply they use the stock compiler invocation which will now have
>> a non-existent libgcc_nonshared static library.
>
> libgcc_nonshared.a is built and installed for all targets.
>
>> Also, are you leaving the cpu symbols in libgcc.a on non-linux
>> targets? If not, the linkage failure reported in
>> https://gcc.gnu.org/ml/gcc-patches/2015-03/msg01668.html will occur,
>> no?
>
> My current patch doesn't change what are in libgcc.a. It
> adds libgcc_nonshared.a for all targets, which contains
> the same cpuinfo.o as in libgcc.a or a dummy .o if libgcc.a
> doesn't have cpuinfo.o.
I can confirm that the most current patch bootstraps on
x86_64-apple-darwin14 and that all of the new tests show up as
unsupported in the test suite.
Jack
>
> --
> H.J.