2015-03-18 15:42 GMT+03:00 Richard Biener <richard.guent...@gmail.com>:
> 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?
No. You may use MPX with gold and old ld but you would loose passed
bounds when make a call via plt.
Ilya
>
> Richard.
>
>> --
>> H.J.
