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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/81708] The x86 stack canary location should be
 customizable
Date: Tue, 19 Jul 2022 16:44:20 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D81708

--- Comment #16 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
(In reply to Alexandre Oliva from comment #15)
> Uro=C5=A1,
>=20
> stack-prot-sym.c fails on ia32 with PIC/PIE: the address/value of my_guard
> is loaded from the GOT, instead of appearing as %gs:my_guard.
>=20
> After being confused by the expectation that my_guard should be a LE TLS
> symbol, I'm coming to the conclusion that my expectation was incorrect, a=
nd
> it is indeed supposed to be a plain offset, so the code is correct, if not
> as efficient as on PDC.  Does that sound right?
>=20
> I'm undecided as to whether avoiding the GOT reference, and requiring the
> symbol to be usable as a link-time constant, would be desirable/doable.=20
> Thoughts?

The current implementation was implemented specifically for linux, as reque=
sted
in Comment #0, without any other usages in mind. Also, I'm not deeply famil=
iar
with the details of symbol linking, so perhaps HJ can help here.=