[PATCH 1/3] Compiler attributes: Introduce the __preserve_most function attribute
Miguel Ojeda
miguel.ojeda.sandonis at gmail.com
Wed Aug 2 10:08:51 PDT 2023
On Wed, Aug 2, 2023 at 6:51 PM Marco Elver <elver at google.com> wrote:
>
> Mark says that there may be an issue with using this in combination
> with ftrace because arm64 tracing relies on AAPCS. Probably not just
> arm64, but also other architectures (x86?).
>
> To make this safe, I'm going to move __preserve_most to
> compiler_types.h and always pair it with notrace and some comments in
> v2.
Sounds good, thanks! The patch here was otherwise good in terms of
`compiler_attributes.h`.
I was also thinking about the implications for Rust. I guess if we
need to call them, we will go through a C helper for the moment, and
later on if we get cross-language LTO (or the LLVM IR hacks), it will
hopefully not be a performance penalty.
Cheers,
Miguel
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