1 // Copyright 2024, Linaro Limited 2 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> 3 // SPDX-License-Identifier: GPL-2.0-or-later 4 5 use proc_macro::TokenStream; 6 use proc_macro2::Span; 7 use quote::{quote, quote_spanned}; 8 use syn::{ 9 parse_macro_input, parse_quote, punctuated::Punctuated, token::Comma, Data, DeriveInput, Field, 10 Fields, Ident, Type, Visibility, 11 }; 12 13 struct CompileError(String, Span); 14 15 impl From<CompileError> for proc_macro2::TokenStream { 16 fn from(err: CompileError) -> Self { 17 let CompileError(msg, span) = err; 18 quote_spanned! { span => compile_error!(#msg); } 19 } 20 } 21 22 fn is_c_repr(input: &DeriveInput, msg: &str) -> Result<(), CompileError> { 23 let expected = parse_quote! { #[repr(C)] }; 24 25 if input.attrs.iter().any(|attr| attr == &expected) { 26 Ok(()) 27 } else { 28 Err(CompileError( 29 format!("#[repr(C)] required for {}", msg), 30 input.ident.span(), 31 )) 32 } 33 } 34 35 #[proc_macro_derive(Object)] 36 pub fn derive_object(input: TokenStream) -> TokenStream { 37 let input = parse_macro_input!(input as DeriveInput); 38 let name = input.ident; 39 40 let expanded = quote! { 41 ::qemu_api::module_init! { 42 MODULE_INIT_QOM => unsafe { 43 ::qemu_api::bindings::type_register_static(&<#name as ::qemu_api::definitions::ObjectImpl>::TYPE_INFO); 44 } 45 } 46 }; 47 48 TokenStream::from(expanded) 49 } 50 51 fn get_fields(input: &DeriveInput) -> Result<&Punctuated<Field, Comma>, CompileError> { 52 if let Data::Struct(s) = &input.data { 53 if let Fields::Named(fs) = &s.fields { 54 Ok(&fs.named) 55 } else { 56 Err(CompileError( 57 "Cannot generate offsets for unnamed fields.".to_string(), 58 input.ident.span(), 59 )) 60 } 61 } else { 62 Err(CompileError( 63 "Cannot generate offsets for union or enum.".to_string(), 64 input.ident.span(), 65 )) 66 } 67 } 68 69 #[rustfmt::skip::macros(quote)] 70 fn derive_offsets_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, CompileError> { 71 is_c_repr(&input, "#[derive(offsets)]")?; 72 73 let name = &input.ident; 74 let fields = get_fields(&input)?; 75 let field_names: Vec<&Ident> = fields.iter().map(|f| f.ident.as_ref().unwrap()).collect(); 76 let field_types: Vec<&Type> = fields.iter().map(|f| &f.ty).collect(); 77 let field_vis: Vec<&Visibility> = fields.iter().map(|f| &f.vis).collect(); 78 79 Ok(quote! { 80 ::qemu_api::with_offsets! { 81 struct #name { 82 #(#field_vis #field_names: #field_types,)* 83 } 84 } 85 }) 86 } 87 88 #[proc_macro_derive(offsets)] 89 pub fn derive_offsets(input: TokenStream) -> TokenStream { 90 let input = parse_macro_input!(input as DeriveInput); 91 let expanded = derive_offsets_or_error(input).unwrap_or_else(Into::into); 92 93 TokenStream::from(expanded) 94 } 95