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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.263, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 10/23/24 12:38, Manos Pitsidianakis wrote: > Hello Paolo, > > On Mon, 21 Oct 2024 19:35, Paolo Bonzini wrote: >> Use the "struct update" syntax to initialize most of the fields to zero, >> and simplify the handmade type-checking of $name. > > Note: It wasn't meant for type checking but for making sure the linker > doesn't strip the symbol (hence the #[used] attribute). These were left > over when I was debugging linker issues and slapped #[used] everywhere > but they are not needed in this case indeed. Well, it does do type checking as well, :) otherwise you end up duck-typing on whether $name as as_ptr(). I guess you are okay with the change below and the comment: >> - name: { >> - #[used] >> - static _TEMP: &::core::ffi::CStr = $name; >> - _TEMP.as_ptr() >> - }, >> + // use associated function syntax for type checking >> + name: ::core::ffi::CStr::as_ptr($name), ? >> info: $prop, >> offset: ::core::mem::offset_of!($state, $field) >> .try_into() >> .expect("Could not fit offset value to type"), >> - bitnr: 0, >> - bitmask: 0, >> set_default: true, >> defval: $crate::bindings::Property__bindgen_ty_1 { u: $defval.into() }, >> - arrayoffset: 0, >> - arrayinfo: ::core::ptr::null(), >> - arrayfieldsize: 0, >> - link_type: ::core::ptr::null(), >> + ..unsafe { ::core::mem::MaybeUninit::<$crate::bindings::Property>::zeroed().assume_init() } > > Call it personal taste but I don't like emulating C's zero initializer > syntax in Rust :) Is it that much trouble to explicitly write down every > field in a macro, anyway? No strong preference here though. Rust does make generous use of "..Default::default()", so I think it's more idiomatic to use the struct update syntax. We just cannot use it here because it's not const-ified. I'm okay with switching from Zeroable::ZERO to something like ConstDefault::CONST_DEFAULT; it's basically just a rename. On the other hand you do rely on "zero-ness" in PL011State::init()... so I thought I was actually following your style. :) Paolo