From: "Martin Liška" <mliska@suse.cz>
To: Daniel Kiss <Daniel.Kiss@arm.com>, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Cc: Pavel Iliin <Pavel.Iliin@arm.com>
Subject: Re: [RFC] Function Multi Versioning on Arm
Date: Wed, 23 Nov 2022 13:28:33 +0100 [thread overview]
Message-ID: <ff0e5a6e-d74a-0c91-a8ad-58fd56289ebb@suse.cz> (raw)
In-Reply-To: <45073915-9D33-4097-9CFD-FFBCB9CE1A44@arm.com>
On 7/18/22 12:36, Daniel Kiss via Gcc wrote:
> Hello,
>
> We are going to add Function Multiversioning [1] support to Arm architectures.
> The specification is made public as beta[2] to ensure toolchain that follows Arm
> C Language Extension will implement it in the same way.
>
> A few tweaks considered to make the developers' life easier.
> Since the `target` attribute is used widely on Arm, we would like to introduce a
> new attribute `target_version` to avoid confusion and possible deployment
> problems. The `target_clones` attribute will be supported too. Also the “default”
> version to be made optional.
>
> We are looking for feedback on the specification (reply, github works too).
>
> Thanks so much,
> Daniel
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Function-Multiversioning.html
> [2] https://github.com/ARM-software/acle/blob/main/main/acle.md#function-multi-versioning
>
Hey.
I've just spent some time looking into https://gitlab.com/x86-psABIs/i386-ABI ABI and I noticed
you may define something similar to:
GNU 0x00000020 NT_GNU_PROPERTY_TYPE_0
Properties: x86 ISA needed: x86-64-baseline, x86-64-v2, x86-64-v3, x86-64-v4
x86 feature used: x86
Where GNU_PROPERTY_X86_FEATURE_2_NEEDED has only 4B pr_data field. In you case you have ~60 features
or so, which barely fits into 8B even. If you plan to add a something similar
(GNU_PROPERTY_AARCH64_FEATURE_NEEDED or something similar), keep that in mind.
Cheers,
Martin
prev parent reply other threads:[~2022-11-23 12:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-18 10:36 Daniel Kiss
2022-07-19 10:01 ` Martin Liška
2022-07-21 17:49 ` Daniel Kiss
2022-07-22 8:12 ` Martin Liška
2022-07-22 8:40 ` Daniel Kiss
2022-07-25 14:17 ` Martin Liška
2022-11-23 12:28 ` Martin Liška [this message]
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