On Wed, Mar 18, 2015 at 1:25 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Wed, Mar 18, 2015 at 5:13 AM, Ilya Enkovich <enkovich....@gmail.com> wrote:
>> 2015-03-18 15:08 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>:
>>> On Wed, Mar 18, 2015 at 5:05 AM, Ilya Enkovich <enkovich....@gmail.com>
>>> wrote:
>>>> 2015-03-18 15:02 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>:
>>>>> On Wed, Mar 18, 2015 at 4:56 AM, Ilya Enkovich <enkovich....@gmail.com>
>>>>> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> This patch fixes PR target/65444 by passing '-z bndplt' to linker when
>>>>>> appropriate. Bootstrapped and tested on x86_64-unknown-linux-gnu. Will
>>>>>> commit it to trunk in a couple of days if no objections arise.
>>>>>>
>>>>>> Thanks,
>>>>>> Ilya
>>>>>> --
>>>>>> gcc/
>>>>>>
>>>>>> 2015-03-18 Ilya Enkovich <ilya.enkov...@intel.com>
>>>>>>
>>>>>> PR driver/65444
>>>>>> * config/i386/linux-common.h (MPX_SPEC): New.
>>>>>> (CHKP_SPEC): Add MPX_SPEC.
>>>>>>
>>>>>> libmpx/
>>>>>>
>>>>>> 2015-03-18 Ilya Enkovich <ilya.enkov...@intel.com>
>>>>>>
>>>>>> PR driver/65444
>>>>>> * configure.ac: Add check for '-z bndplt' support
>>>>>> by linker. Add link_mpx output variable.
>>>>>> * libmpx.spec.in (link_mpx): New.
>>>>>> * configure: Regenerate.
>>>>>>
>>>>>>
>>>>>> diff --git a/gcc/config/i386/linux-common.h
>>>>>> b/gcc/config/i386/linux-common.h
>>>>>> index 9c6560b..dd79ec6 100644
>>>>>> --- a/gcc/config/i386/linux-common.h
>>>>>> +++ b/gcc/config/i386/linux-common.h
>>>>>> @@ -59,6 +59,11 @@ along with GCC; see the file COPYING3. If not see
>>>>>> %:include(libmpx.spec)%(link_libmpx)"
>>>>>> #endif
>>>>>>
>>>>>> +#ifndef MPX_SPEC
>>>>>> +#define MPX_SPEC "\
>>>>>> +
>>>>>> %{mmpx:%{fcheck-pointer-bounds:%{!static:%:include(libmpx.spec)%(link_mpx)}}}"
>>>>>> +#endif
>>>>>> +
>>>>>> #ifndef LIBMPX_SPEC
>>>>>> #if defined(HAVE_LD_STATIC_DYNAMIC)
>>>>>> #define LIBMPX_SPEC "\
>>>>>> @@ -89,5 +94,5 @@ along with GCC; see the file COPYING3. If not see
>>>>>>
>>>>>> #ifndef CHKP_SPEC
>>>>>> #define CHKP_SPEC "\
>>>>>> -%{!nostdlib:%{!nodefaultlibs:" LIBMPX_SPEC LIBMPXWRAPPERS_SPEC "}}"
>>>>>> +%{!nostdlib:%{!nodefaultlibs:" LIBMPX_SPEC LIBMPXWRAPPERS_SPEC "}}"
>>>>>> MPX_SPEC
>>>>>> #endif
>>>>>> diff --git a/libmpx/configure.ac b/libmpx/configure.ac
>>>>>> index fe0d3f2..3f8b50f 100644
>>>>>> --- a/libmpx/configure.ac
>>>>>> +++ b/libmpx/configure.ac
>>>>>> @@ -40,7 +40,18 @@ AC_MSG_RESULT($LIBMPX_SUPPORTED)
>>>>>> AM_CONDITIONAL(LIBMPX_SUPPORTED, [test "x$LIBMPX_SUPPORTED" = "xyes"])
>>>>>>
>>>>>> link_libmpx="-lpthread"
>>>>>> +link_mpx=""
>>>>>> +AC_MSG_CHECKING([whether ld accepts -z bndplt])
>>>>>> +echo "int main() {};" > conftest.c
>>>>>> +if AC_TRY_COMMAND([${CC} ${CFLAGS} -Wl,-z,bndplt -o conftest conftest.c
>>>>>> 1>&AS_MESSAGE_LOG_FD])
>>>>>> +then
>>>>>> + AC_MSG_RESULT([yes])
>>>>>> + link_mpx="$link_mpx -z bndplt"
>>>>>> +else
>>>>>> + AC_MSG_RESULT([no])
>>>>>> +fi
>>>>>> AC_SUBST(link_libmpx)
>>>>>> +AC_SUBST(link_mpx)
>>>>>>
>>>>>
>>>>> Without -z bndplt, MPX won't work correctly. We should always pass -z
>>>>> bndplt
>>>>> to linker. If linker doesn't support it, ld will issue a warning, not
>>>>> error and users
>>>>> will know their linker is too old. When they update linker, they don't
>>>>> have to
>>>>> rebuild GCC.
>>>>
>>>> If ld issues a warning instead of an error, then configure test passes
>>>> and we pass '-z bndplt' to linker.
>>>>
>>>
>>> Can you verify it with an older linker? The unknown XXX in -z XXX is always
>>> warned and ignored in Linux linker. If testing it on Linux always passes,
>>> it is useless.
>>
>> Old ld issues a warning:
>>
>> ld: warning: -z bndplt ignored.
>
> Does configure test pass?
>
>> But gold issues an error:
>>
>> ld.gold: bndplt: unknown -z option
>> ld.gold: use the --help option for usage information
>
> If gold is used, MPX won't work. What should we do here?
> Should we hardcode -fuse-ld=bfd for MPX?
Is MPX disabled when the host linker is gold and gld isn't available?
Richard.
> --
> H.J.
