Re: [PATCH v2 06/13] rust: modernize link_section usage for ELF platforms

[Zhao Liu <zhao1.liu@intel.com>]

On Mon, Oct 21, 2024 at 06:35:31PM +0200, Paolo Bonzini wrote:
> Date: Mon, 21 Oct 2024 18:35:31 +0200
> From: Paolo Bonzini <pbonzini@redhat.com>
> Subject: [PATCH v2 06/13] rust: modernize link_section usage for ELF
>  platforms
> X-Mailer: git-send-email 2.46.2
> 
> Some newer ABI implementations do not provide .ctors; and while
> some linkers rewrite .ctors into .init_array, not all of them do.
> Use the newer .init_array ABI, which works more reliably, and
> apply it to all non-Apple, non-Windows platforms.
> 
> This is similar to how the ctor crate operates; without this change,
> "#[derive(Object)]" does not work on Fedora 41.
> 
> Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  rust/qemu-api-macros/src/lib.rs  |  7 +++++--
>  rust/qemu-api/src/definitions.rs | 14 ++++++++++----
>  2 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs
> index 59aba592d9a..70e3f920460 100644
> --- a/rust/qemu-api-macros/src/lib.rs
> +++ b/rust/qemu-api-macros/src/lib.rs
> @@ -16,8 +16,11 @@ pub fn derive_object(input: TokenStream) -> TokenStream {
>      let expanded = quote! {
>          #[allow(non_upper_case_globals)]
>          #[used]
> -        #[cfg_attr(target_os = "linux", link_section = ".ctors")]
> -        #[cfg_attr(target_os = "macos", link_section = "__DATA,__mod_init_func")]
> +        #[cfg_attr(
> +            not(any(target_vendor = "apple", target_os = "windows")),

EMM, "apple" vendor contains macOS, iOS and other variations of iOS.
Do we need to consider other OSs besides macOS for now?

And it seems that the Rust people don't like "target_vendor = 'apple'".
(https://github.com/rust-lang/rust/issues/100343). :-)


Otherwise,

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>