From: "H.J. Lu" <hjl.tools@gmail.com>
To: Joe Groff <jgroff@apple.com>
Cc: Alan Modra <amodra@gmail.com>, Cary Coutant <ccoutant@gmail.com>,
Binutils <binutils@sourceware.org>
Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26
Date: Tue, 29 Mar 2016 19:54:00 -0000 [thread overview]
Message-ID: <CAMe9rOqNcYnm1YocG-m7XNDE0g68YQAGe=ULP-G98gaatpxSeA@mail.gmail.com> (raw)
In-Reply-To: <6AAD87D2-90F9-4AD7-A195-AC91B76EA6AE@apple.com>
On Tue, Mar 29, 2016 at 12:51 PM, Joe Groff <jgroff@apple.com> wrote:
>
>> On Mar 29, 2016, at 12:43 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>> The link-time shared library may be very different from the run-time
>> shared library. Since copy relocation works correctly against protected
>> symbol with the current gcc, binutils and glibc, we can't simply disallow
>> copy relocation against protected symbol at link-time.
>
> However, protected doesn't work this way in older binutils, or with alternative tools like llvm or gold, and it sounds like protected was never intended to work this way either. Rather If gcc is interested in pursuing this optimization, it seems more responsible to me they could investigate introducing language-level annotations that let libraries opt into the optimization, instead of unilaterally breaking things for other binutils clients and introducing new complexity to get back to the original behavior.
>
Protected symbol never worked correctly on x86 before. My
change closed a few long-standing bugs. There is no going-back.
--
H.J.
next prev parent reply other threads:[~2016-03-29 19:54 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AB592ABD-D6D7-4D2F-A0D6-45738F168DC4@apple.com>
2016-03-29 19:31 ` Fwd: " Joe Groff
2016-03-29 19:33 ` H.J. Lu
2016-03-29 19:36 ` Joe Groff
2016-03-29 19:43 ` H.J. Lu
2016-03-29 19:51 ` Joe Groff
2016-03-29 19:54 ` H.J. Lu [this message]
2016-03-29 22:05 ` H.J. Lu
2016-03-30 1:44 ` Alan Modra
2016-03-30 1:46 ` Cary Coutant
2016-03-30 4:04 ` Jeff Law
2016-03-30 7:20 ` Cary Coutant
2016-03-30 7:34 ` Cary Coutant
2016-03-30 14:44 ` Alan Modra
2016-03-31 0:45 ` Cary Coutant
2016-04-15 21:49 ` Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248] Jeff Law
2016-04-15 21:56 ` H.J. Lu
2016-04-18 9:02 ` Richard Biener
2016-04-18 14:49 ` Alan Modra
2016-04-18 14:59 ` H.J. Lu
2016-04-18 17:04 ` Maciej W. Rozycki
2016-04-18 17:09 ` H.J. Lu
2016-04-18 17:24 ` Michael Matz
2016-04-18 17:27 ` H.J. Lu
2016-04-18 18:52 ` Jakub Jelinek
2016-04-18 19:28 ` H.J. Lu
2016-04-18 17:55 ` Cary Coutant
2016-04-25 17:24 ` Jeff Law
2016-04-25 17:31 ` H.J. Lu
2016-04-18 17:57 ` Maciej W. Rozycki
2016-04-19 5:08 ` Alan Modra
2016-04-19 8:20 ` Richard Biener
2016-04-19 9:53 ` Szabolcs Nagy
2016-04-19 14:06 ` Michael Matz
2016-04-19 15:37 ` Cary Coutant
2016-04-19 15:44 ` H.J. Lu
2016-04-19 15:52 ` H.J. Lu
2016-04-19 15:54 ` H.J. Lu
2016-04-19 15:58 ` Cary Coutant
2016-04-19 16:00 ` H.J. Lu
2016-04-19 15:54 ` Cary Coutant
2016-04-19 19:11 ` H.J. Lu
2016-04-19 20:17 ` Rich Felker
2016-04-19 21:03 ` Cary Coutant
2016-04-20 17:45 ` anonymous
2016-04-19 15:46 ` Alan Modra
2016-04-25 17:35 ` Jeff Law
2016-04-26 5:55 ` Alan Modra
2016-04-26 8:13 ` Jakub Jelinek
2016-04-18 17:05 ` Cary Coutant
2016-03-31 0:40 ` Preventing preemption of 'protected' symbols in GNU ld 2.26 Cary Coutant
2016-03-31 0:53 ` Jeff Law
2016-03-31 13:27 ` Ramana Radhakrishnan
2016-03-31 15:05 ` H.J. Lu
2016-04-15 16:10 ` Szabolcs Nagy
2016-04-01 19:51 ` Jeff Law
2016-04-02 2:53 ` Alan Modra
2016-04-19 19:47 ` Fwd: " Rich Felker
2016-04-15 16:16 H.J. Lu
2016-04-15 16:36 ` Jeff Law
2016-04-15 16:45 ` H.J. Lu
2016-04-15 16:43 ` Szabolcs Nagy
2016-04-15 23:59 ` Maciej W. Rozycki
2016-04-16 1:08 ` Szabolcs Nagy
-- strict thread matches above, loose matches on Subject: below --
2016-03-24 0:00 Joe Groff
2016-03-24 0:45 ` H.J. Lu
2016-03-24 0:52 ` Joe Groff
2016-03-24 1:25 ` H.J. Lu
2016-03-24 15:01 ` Cary Coutant
2016-03-24 15:07 ` H.J. Lu
2016-03-24 16:06 ` Cary Coutant
2016-03-24 16:42 ` H.J. Lu
2016-03-24 16:56 ` Cary Coutant
2016-03-24 17:05 ` H.J. Lu
2016-03-24 17:06 ` Joe Groff
2016-03-24 17:09 ` H.J. Lu
2016-03-24 18:31 ` Cary Coutant
2016-03-27 16:26 ` Rafael Espíndola
2016-03-28 12:12 ` H.J. Lu
2016-03-28 22:12 ` Cary Coutant
[not found] ` <BC969B3B-87A2-4238-90C8-DA2E166707AF@apple.com>
2016-03-28 17:03 ` Joe Groff
2016-03-28 17:17 ` H.J. Lu
2016-03-28 22:22 ` Cary Coutant
2016-03-28 22:24 ` Joe Groff
2016-03-28 22:38 ` Cary Coutant
2016-03-28 22:41 ` Joe Groff
2016-03-28 23:21 ` Alan Modra
2016-03-29 0:29 ` Cary Coutant
2016-03-29 15:44 ` H.J. Lu
2016-03-29 12:40 ` Maciej W. Rozycki
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