[Bug driver/103398] New: configure: Enable --enable-default-pie by default for Linux

[Bug driver/103398] New: configure: Enable --enable-default-pie by default for Linux

[i at maskray dot me]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103398

            Bug ID: 103398
           Summary: configure: Enable --enable-default-pie by default for
                    Linux
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
          Assignee: unassigned at gcc dot gnu.org
          Reporter: i at maskray dot me
  Target Milestone: ---

Many Linux distros configure GCC with --enable-default-pie (at least
Arch/Debian/Fedora/Gentoo/Ubuntu). I think it makes sense to default to
--enable-default-pie for Linux.

[Bug driver/103398] configure: Enable --enable-default-pie by default for Linux

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103398

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |WONTFIX
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
No. The whole reason why there is an option is because it is optional.

[Bug driver/103398] configure: Enable --enable-default-pie by default for Linux

[i at maskray dot me]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103398

--- Comment #2 from Fangrui Song <i at maskray dot me> ---
I want to switch the default because:

* It seems to me that every Linux distro uses --enable-default-pie GCC. I use
"many", but it is likely "most" at this point (2021).
* When a user builds GCC on Linux, the generated GCC does not default PIE. This
almost certainly does not match the behavior of their host GCC. 

On the libc-alpha mailing list, I have seen that contributors waste time
because they don't notice that scripts/build-many-glibcs.py built GCC uses the
implicit --disable-default-pie, which has a behavior different from the host
GCC or cross compiler provided by system packages.

[Bug driver/103398] configure: Enable --enable-default-pie by default for Linux

[sam at gentoo dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103398

--- Comment #3 from Sam James <sam at gentoo dot org> ---
(In reply to Andrew Pinski from comment #1)
> No. The whole reason why there is an option is because it is optional.

A fair amount of future-new-defaults start off as optional and eventually
become it. This isn't a particularly strong reason to reject it.

The alternative would be that there was.. never a configure option? And one day
it just flipped without any chance of changing it? I think this would probably
benefit from more discussion.

As meowray noted, this has been set by every major Linux distro for quite some
time. It would make sense to re-evaluate GCC's defaults in that context and
whether the reasons for them still make sense.

[Bug driver/103398] configure: Enable --enable-default-pie by default for Linux

[mark.esler at canonical dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103398

Mark Esler <mark.esler at canonical dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mark.esler at canonical dot com

--- Comment #4 from Mark Esler <mark.esler at canonical dot com> ---
(In reply to Andrew Pinski from comment #1)
> No. The whole reason why there is an option is because it is optional.

Could this issue be re-considered?

Or should -fhardened and related endeavors all re-suggest the specific flags
that --enable-default-pie provides?