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.
--
H.J.
