From: Ian Lance Taylor <iant@google.com>
To: Jack Howarth <howarth@bromo.med.uc.edu>
Cc: gcc@gcc.gnu.org
Subject: Re: darwin LTO broken under Xcode 3.2.6/4.0
Date: Sun, 13 Mar 2011 07:35:00 -0000 [thread overview]
Message-ID: <mcrvczn5z0q.fsf@google.com> (raw)
In-Reply-To: <20110313041719.GA17752@bromo.med.uc.edu> (Jack Howarth's message of "Sat, 12 Mar 2011 23:17:19 -0500")
Jack Howarth <howarth@bromo.med.uc.edu> writes:
> With release of Xcode 3.2.6/4.0 this week, an unfortunate change was made to
> the darwin assembler which effectively breaks LTO support for darwin. The design
> of LTO on darwin was based on the fact that mach-o object files tolerated additional
> sections as long as they didin't contain symbols. With Xcode 3.2.6/4.0, the assembler
> appears to be strictly counting sections and objecting when these exceed 255. This
> breaks huge sections of the lto testsuite and prevents larger projects like xplor-nih
> to compile if Xcode 3.2.6/4.0 is installed. I am afraid that unless Apple reverts this
> change, our only recourse would be to resort to an elf object container for the lto
> sections within the mach-o files (introducing an undesired dependency on libelf for
> FSF gcc on darwin). My understanding was that the lto design did not allow the number
> of sections required in the lto files to be reduced.
We no longer use libelf on any system.
This is largely controlled by the simple-object interface. It should be
straightforward to change the way that simple-object works with Mach-O
without changing the simple-object interface to the rest of gcc. Then
we could change the gcc output to, e.g., put all the information in a
single Mach-O section.
I suppose we should first ask Apple why they made the change and whether
it was intentional.
Ian
next prev parent reply other threads:[~2011-03-13 7:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-13 4:17 Jack Howarth
2011-03-13 7:35 ` Ian Lance Taylor [this message]
2011-03-13 7:52 ` Chris Lattner
2011-03-13 7:52 ` Jack Howarth
2011-03-13 11:39 ` Jan Hubicka
2011-03-13 15:38 ` Jack Howarth
2011-03-13 18:19 ` Chris Lattner
2011-03-13 18:26 ` Jack Howarth
2011-03-13 18:55 ` Chris Lattner
2011-03-13 18:59 ` Chris Lattner
2011-03-13 19:11 ` Jack Howarth
2011-03-13 19:05 ` Jack Howarth
2011-03-13 19:47 ` Chris Lattner
2011-03-13 19:56 ` Jack Howarth
2011-03-13 20:43 ` Jack Howarth
2011-03-13 19:07 ` Jan Hubicka
2011-03-13 19:45 ` Chris Lattner
2011-03-13 18:35 ` Jack Howarth
2011-03-13 18:54 ` Ian Lance Taylor
2011-03-14 19:48 ` Jack Howarth
2011-03-14 21:09 ` Ian Lance Taylor
2011-03-14 21:33 ` Jack Howarth
2011-03-13 19:43 Steven Bosscher
2011-03-13 19:48 ` Chris Lattner
2011-03-13 20:03 ` Jack Howarth
2011-03-13 20:38 ` Steven Bosscher
2011-03-13 20:41 ` Jack Howarth
2011-03-13 20:43 ` Steven Bosscher
2011-03-13 20:49 ` Jack Howarth
2011-03-13 20:55 ` Jack Howarth
2011-03-13 21:13 ` Jack Howarth
2011-03-14 17:20 ` Jack Howarth
2011-04-02 22:27 ` Gerald Pfeifer
2011-03-13 23:03 ` Jack Howarth
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