From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Florian Weimer <fweimer@redhat.com>,
Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>,
Richard Henderson <richard.henderson@linaro.org>
Subject: Re: [RESEND PATCH] Makeconfig: Set pie-ccflag to -fPIE by default
Date: Mon, 29 Aug 2022 15:27:36 +0000 [thread overview]
Message-ID: <AS4PR08MB7901F6D180527AC29A0A57DB83769@AS4PR08MB7901.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <87pmgj2o1d.fsf@oldenburg.str.redhat.com>
Hi Florian,
* Wilco Dijkstra via Libc-alpha:
>> However this leads to the question is why aren't all symbols marked as
>> hidden in the static PIE build? Ie. are there any symbols that must be
>> shared with a DSO loaded by a dl_open?
>
> The static main executable does not have a dynamic symbol table, so such
> sharing cannot happen (except through function pointers being passed
> around, but symbol visibility of course does not matter there).
Right, so it should be safe then to mark all symbols as hidden.
We could also teach GCC to never emit GOT indirections with -fPIE -static
(the only reason to use a GOT indirection is to avoid copy relocations in
dynamically linked binaries).
Cheers,
Wilco
WARNING: multiple messages have this Message-ID
From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Florian Weimer <fweimer@redhat.com>,
Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [RESEND PATCH] Makeconfig: Set pie-ccflag to -fPIE by default
Date: Mon, 29 Aug 2022 15:27:36 +0000 [thread overview]
Message-ID: <AS4PR08MB7901F6D180527AC29A0A57DB83769@AS4PR08MB7901.eurprd08.prod.outlook.com> (raw)
Message-ID: <20220829152736.d9YS8PYyzObCSSPJe6YDOKAkiFExsI7IcS5W48md988@z> (raw)
In-Reply-To: <87pmgj2o1d.fsf@oldenburg.str.redhat.com>
Hi Florian,
* Wilco Dijkstra via Libc-alpha:
>> However this leads to the question is why aren't all symbols marked as
>> hidden in the static PIE build? Ie. are there any symbols that must be
>> shared with a DSO loaded by a dl_open?
>
> The static main executable does not have a dynamic symbol table, so such
> sharing cannot happen (except through function pointers being passed
> around, but symbol visibility of course does not matter there).
Right, so it should be safe then to mark all symbols as hidden.
We could also teach GCC to never emit GOT indirections with -fPIE -static
(the only reason to use a GOT indirection is to avoid copy relocations in
dynamically linked binaries).
Cheers,
Wilco
next prev parent reply other threads:[~2022-08-29 15:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-26 18:39 Wilco Dijkstra
2022-08-26 19:02 ` H.J. Lu
2022-08-26 19:45 ` Richard Henderson
2022-08-26 20:11 ` H.J. Lu
2022-08-29 11:49 ` Wilco Dijkstra
2022-08-29 13:10 ` Florian Weimer
2022-08-29 15:27 ` Wilco Dijkstra [this message]
2022-08-29 15:27 ` Wilco Dijkstra
2022-08-29 19:43 ` H.J. Lu
2022-08-29 19:57 ` Fangrui Song
2022-09-05 8:58 ` Wilco Dijkstra
2022-09-15 21:45 ` Fangrui Song
2022-09-20 13:59 ` Wilco Dijkstra
2022-09-20 14:12 ` Florian Weimer
2022-09-20 16:00 ` Wilco Dijkstra
2022-09-20 22:02 ` Fangrui Song
-- strict thread matches above, loose matches on Subject: below --
2022-08-25 21:01 Richard Henderson
2022-08-26 12:32 ` Adhemerval Zanella Netto
2022-08-26 17:29 ` Richard Henderson
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