From: Jeffrey Walton <noloader@gmail.com>
To: musl@lists.openwall.com
Subject: Re: max_align_t mess on i386
Date: Sun, 15 Dec 2019 16:51:27 -0500 [thread overview]
Message-ID: <CAH8yC8kBrp+XMgGZvV_Rquq8Aac0WRn04th-wAVcShNH-vxODg@mail.gmail.com> (raw)
In-Reply-To: <alpine.LNX.2.20.13.1912152232580.29076@monopod.intra.ispras.ru>
On Sun, Dec 15, 2019 at 3:03 PM Alexander Monakov <amonakov@ispras.ru> wrote:
>
> ...
> [SNIP] Which makes those bit positions available for flags
> associated with the pointer, if you can arrange for them to be masked off
> to use the pointer itself.
Be careful of those tricks. I believe they are called Tagged Pointers.
Aarch64 was doing it for a while. It caused a lot of problems in
practice. It was breaking diagnostic tools. It was also holding up the
porting of some libraries.
See, for example,
https://releases.llvm.org/6.0.0/tools/clang/docs/HardwareAssistedAddressSanitizerDesign.html
and https://bugzilla.mozilla.org/show_bug.cgi?id=1143022 .
Jeff
prev parent reply other threads:[~2019-12-15 21:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-14 15:19 Rich Felker
2019-12-14 17:51 ` Florian Weimer
2019-12-14 18:17 ` Rich Felker
2019-12-14 18:53 ` Daniel Kolesa
2019-12-15 18:04 ` Rich Felker
2019-12-15 5:47 ` Markus Wichmann
2019-12-15 18:06 ` Jeffrey Walton
2019-12-15 18:22 ` Rich Felker
2019-12-16 15:30 ` Jeffrey Walton
2019-12-16 15:56 ` Rich Felker
2019-12-16 16:36 ` Jeffrey Walton
2019-12-16 17:49 ` Rich Felker
2019-12-16 16:40 ` Florian Weimer
2019-12-16 17:45 ` Rich Felker
2019-12-16 17:49 ` Florian Weimer
2019-12-16 17:51 ` Rich Felker
2019-12-15 18:23 ` Joakim Sindholt
2019-12-15 18:51 ` Rich Felker
2019-12-15 20:03 ` Alexander Monakov
2019-12-15 20:50 ` Szabolcs Nagy
2019-12-15 21:51 ` Jeffrey Walton [this message]
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