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 {
from(err: CompileError) -> Self16 fn from(err: CompileError) -> Self {
17 let CompileError(msg, span) = err;
18 quote_spanned! { span => compile_error!(#msg); }
19 }
20 }
21
is_c_repr(input: &DeriveInput, msg: &str) -> Result<(), CompileError>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)]
derive_object(input: TokenStream) -> TokenStream36 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
get_fields(input: &DeriveInput) -> Result<&Punctuated<Field, Comma>, CompileError>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)]
derive_offsets_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream, CompileError>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)]
derive_offsets(input: TokenStream) -> TokenStream89 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