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From: "bugdal at aerifal dot cx" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug other/67812] Default-PIE patch broke building compiler as PIE and on esp toolchains
Date: Fri, 02 Oct 2015 03:18:00 -0000	[thread overview]
Message-ID: <bug-67812-4-Zt17OjyI1o@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-67812-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67812

--- Comment #3 from Rich Felker <bugdal at aerifal dot cx> ---
Further research into the PCH issue shows that it will be seriously broken when
GCC is built as PIE; this looks hard to fix, but worthwhile to fix if it can
be. There's almost certainly no way it can work on FDPIC hosts, even when run
with MMU where the default load address gets used, since function descriptors
may be dynamically allocated and their addresses could vary according to ASLR.

In the mean time, would it be acceptable to just make PCH support depend on
#ifndef __PIC__? Even if the build system turns off (or attempts to turn off)
PIE like it's doing now, having #ifndef __PIC__ around the PCH code would be a
good fail-safe against random code execution if GCC somehow gets built as PIE
anyway. And users who really want/need PIE could just drop the Makefile.in
lines above and have everything work.


      parent reply	other threads:[~2015-10-02  3:18 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-02  0:06 [Bug other/67812] New: " bugdal at aerifal dot cx
2015-10-02  0:11 ` [Bug other/67812] " pinskia at gcc dot gnu.org
2015-10-02  0:20 ` bugdal at aerifal dot cx
2015-10-02  3:18 ` bugdal at aerifal dot cx [this message]

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