PING.
On Tue, Jan 13, 2015 at 3:25 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Tue, Jan 13, 2015 at 5:03 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> On Mon, Jan 12, 2015 at 11:50:41PM +0000, Joseph Myers wrote:
>>> On Mon, 12 Jan 2015, H.J. Lu wrote:
>>>
>>> > +if test x$enable_default_pie = xyes; then
>>> > + AC_MSG_CHECKING(if $target supports default PIE)
>>> > + enable_default_pie=no
>>> > + case $target in
>>> > + i?86*-*-linux* | x86_64*-*-linux*)
>>> > + saved_LDFLAGS="$LDFLAGS"
>>> > + saved_CFLAGS="$CFLAGS"
>>> > + CFLAGS="$CFLAGS -fPIE"
>>> > + LDFLAGS="$LDFLAGS -fPIE -pie"
>>> > + AC_TRY_LINK(,,[enable_default_pie=yes],)
>>> > + LDFLAGS="$saved_LDFLAGS"
>>> > + CFLAGS="$saved_CFLAGS"
>>> > + ;;
>>> > + *)
>>> > + ;;
>>> > + esac
>>>
>>> There should not be any such hardcoding of targets here without concrete
>>> evidence that the targets for which this sets enable_default_pie=no really
>>> cannot support PIE. In particular, there is no reason at all for this to
>>> be architecture-specific; all GNU/Linux architectures should support PIE.
>>>
>>> I believe AC_TRY_LINK here will test for the host, whereas what you want
>>> to know is what's supported for the target (but it's not possible to run
>>> link tests for the target at this point; the compiler for the target
>>> hasn't even been built).
>>>
>>> So: just presume that if the user passes --enable-default-pie then they
>>> know what they are doing, and don't try to override their choice.
>>>
>>> > diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
>>> > index c9e3bf1..89fc305 100644
>>> > --- a/gcc/doc/install.texi
>>> > +++ b/gcc/doc/install.texi
>>> > @@ -1583,6 +1583,10 @@ not be built.
>>> > Specify that the run-time libraries for stack smashing protection
>>> > should not be built.
>>> >
>>> > +@item --enable-default-pie
>>> > +Turn on @option{-fPIE} and @option{-pie} by default if supported.
>>> > +Currently supported targets are i?86-*-linux* and x86-64-*-linux*.
>>>
>>> The "if supported" and target list can then be removed here.
>>>
>>
>> Here is the updated patch. To support --enable-default-pie, each target
>> must update STARTFILE_SPEC to support PIE_SPEC and NO_PIE_SPEC. I can
>> provide STARTFILE_SPEC patch if needed.
>>
>> Thanks.
>>
>>
>> H.J.
>> ---
>> gcc/
>>
>> 2015-01-12 Magnus Granberg <zo...@gentoo.org>
>> H.J. Lu <hongjiu...@intel.com>
>>
>> * Makefile.in (COMPILER): Add @NO_PIE_CFLAGS@.
>> (LINKER): Add @NO_PIE_FLAG@.
>> (libgcc.mvars): Set NO_PIE_CFLAGS to -fno-PIE for
>> --enable-default-pie.
>> * common.opt (fPIE): Initialize to -1.
>> (fpie): Likewise.
>> (static): Add "RejectNegative Negative(shared)".
>> (no-pie): New option.
>> (pie): Replace "Negative(shared)" with "Negative(no-pie)".
>> * configure.ac: Add --enable-default-pie.
>> (NO_PIE_CFLAGS): New. Check if -fno-PIE works. AC_SUBST.
>> (NO_PIE_FLAG): New. Check if -no-pie works. AC_SUBST.
>> * defaults.h (DEFAULT_FLAG_PIE): New. Default PIE to -fPIE.
>> * gcc.c (NO_PIE_SPEC): New.
>> (PIE_SPEC): Likewise.
>> (LD_PIE_SPEC): Likewise.
>> (LINK_PIE_SPEC): Handle -no-pie. Use PIE_SPEC and LD_PIE_SPEC.
>> * opts.c (DEFAULT_FLAG_PIE): New. Set to 0 if ENABLE_DEFAULT_PIE
>> is undefined.
>> (finish_options): Update opts->x_flag_pie if it is -1.
>> * config/gnu-user.h (FVTABLE_VERIFY_SPEC): New.
>> (GNU_USER_TARGET_STARTFILE_SPEC): Use FVTABLE_VERIFY_SPEC. Use
>> NO_PIE_SPEC and NO_PIE_SPEC if ENABLE_DEFAULT_PIE is defined.
>> (GNU_USER_TARGET_STARTFILE_SPEC): Use FVTABLE_VERIFY_SPEC.
>> * doc/install.texi: Document --enable-default-pie.
>> * doc/invoke.texi: Document -no-pie.
>> * config.in: Regenerated.
>> * configure: Likewise.
>>
>> gcc/ada/
>>
>> 2015-01-12 H.J. Lu <hongjiu...@intel.com>
>>
>> * gcc-interface/Makefile.in (TOOLS_LIBS): Add @NO_PIE_FLAG@.
>>
>> libgcc/
>>
>> 2015-01-12 H.J. Lu <hongjiu...@intel.com>
>>
>> * Makefile.in (CRTSTUFF_CFLAGS): Add $(NO_PIE_CFLAGS).
>>
>
> This is the updated patch. I fixed the -r regression. LTO tests
> pass now.
>
> --
> H.J.
--
H.J.
