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 get_fields<'a>( 23 input: &'a DeriveInput, 24 msg: &str, 25 ) -> Result<&'a Punctuated<Field, Comma>, CompileError> { 26 if let Data::Struct(s) = &input.data { 27 if let Fields::Named(fs) = &s.fields { 28 Ok(&fs.named) 29 } else { 30 Err(CompileError( 31 format!("Named fields required for {}", msg), 32 input.ident.span(), 33 )) 34 } 35 } else { 36 Err(CompileError( 37 format!("Struct required for {}", msg), 38 input.ident.span(), 39 )) 40 } 41 } 42 43 fn is_c_repr(input: &DeriveInput, msg: &str) -> Result<(), CompileError> { 44 let expected = parse_quote! { #[repr(C)] }; 45 46 if input.attrs.iter().any(|attr| attr == &expected) { 47 Ok(()) 48 } else { 49 Err(CompileError( 50 format!("#[repr(C)] required for {}", msg), 51 input.ident.span(), 52 )) 53 } 54 } 55 56 fn derive_object_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, CompileError> { 57 is_c_repr(&input, "#[derive(Object)]")?; 58 59 let name = &input.ident; 60 let parent = &get_fields(&input, "#[derive(Object)]")?[0].ident; 61 62 Ok(quote! { 63 ::qemu_api::assert_field_type!(#name, #parent, 64 ::qemu_api::qom::ParentField<<#name as ::qemu_api::qom::ObjectImpl>::ParentType>); 65 66 ::qemu_api::module_init! { 67 MODULE_INIT_QOM => unsafe { 68 ::qemu_api::bindings::type_register_static(&<#name as ::qemu_api::qom::ObjectImpl>::TYPE_INFO); 69 } 70 } 71 }) 72 } 73 74 #[proc_macro_derive(Object)] 75 pub fn derive_object(input: TokenStream) -> TokenStream { 76 let input = parse_macro_input!(input as DeriveInput); 77 let expanded = derive_object_or_error(input).unwrap_or_else(Into::into); 78 79 TokenStream::from(expanded) 80 } 81 82 #[rustfmt::skip::macros(quote)] 83 fn derive_offsets_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, CompileError> { 84 is_c_repr(&input, "#[derive(offsets)]")?; 85 86 let name = &input.ident; 87 let fields = get_fields(&input, "#[derive(offsets)]")?; 88 let field_names: Vec<&Ident> = fields.iter().map(|f| f.ident.as_ref().unwrap()).collect(); 89 let field_types: Vec<&Type> = fields.iter().map(|f| &f.ty).collect(); 90 let field_vis: Vec<&Visibility> = fields.iter().map(|f| &f.vis).collect(); 91 92 Ok(quote! { 93 ::qemu_api::with_offsets! { 94 struct #name { 95 #(#field_vis #field_names: #field_types,)* 96 } 97 } 98 }) 99 } 100 101 #[proc_macro_derive(offsets)] 102 pub fn derive_offsets(input: TokenStream) -> TokenStream { 103 let input = parse_macro_input!(input as DeriveInput); 104 let expanded = derive_offsets_or_error(input).unwrap_or_else(Into::into); 105 106 TokenStream::from(expanded) 107 } 108