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#![deny(warnings)]
extern crate proc_macro;
#[macro_use]
extern crate quote;
extern crate core;
extern crate proc_macro2;
#[macro_use]
extern crate syn;
use proc_macro2::Span;
use syn::{parse, spanned::Spanned, FnArg, ItemFn, PathArguments, ReturnType, Type, Visibility};
use proc_macro::TokenStream;
#[proc_macro_attribute]
pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
let f = parse_macro_input!(input as ItemFn);
if f.sig.inputs.len() > 3 {
return parse::Error::new(
f.sig.inputs.last().unwrap().span(),
"`#[entry]` function has too many arguments",
)
.to_compile_error()
.into();
}
for arg in &f.sig.inputs {
match arg {
FnArg::Receiver(_) => {
return parse::Error::new(arg.span(), "invalid argument")
.to_compile_error()
.into();
}
FnArg::Typed(t) => {
if !is_simple_type(&t.ty, "usize") {
return parse::Error::new(t.ty.span(), "argument type must be usize")
.to_compile_error()
.into();
}
}
}
}
let valid_signature = f.sig.constness.is_none()
&& f.sig.asyncness.is_none()
&& f.vis == Visibility::Inherited
&& f.sig.abi.is_none()
&& f.sig.generics.params.is_empty()
&& f.sig.generics.where_clause.is_none()
&& f.sig.variadic.is_none()
&& match f.sig.output {
ReturnType::Default => false,
ReturnType::Type(_, ref ty) => matches!(**ty, Type::Never(_)),
};
if !valid_signature {
return parse::Error::new(
f.span(),
"`#[entry]` function must have signature `[unsafe] fn([arg0: usize, ...]) -> !`",
)
.to_compile_error()
.into();
}
if !args.is_empty() {
return parse::Error::new(Span::call_site(), "This attribute accepts no arguments")
.to_compile_error()
.into();
}
let attrs = f.attrs;
let unsafety = f.sig.unsafety;
let args = f.sig.inputs;
let stmts = f.block.stmts;
quote!(
#[export_name = "main"]
#(#attrs)*
pub #unsafety fn __risc_v_rt__main(#args) -> ! {
#(#stmts)*
}
)
.into()
}
#[allow(unused)]
fn is_simple_type(ty: &Type, name: &str) -> bool {
if let Type::Path(p) = ty {
if p.qself.is_none() && p.path.leading_colon.is_none() && p.path.segments.len() == 1 {
let segment = p.path.segments.first().unwrap();
if segment.ident == name && segment.arguments == PathArguments::None {
return true;
}
}
}
false
}
#[proc_macro_attribute]
pub fn pre_init(args: TokenStream, input: TokenStream) -> TokenStream {
let f = parse_macro_input!(input as ItemFn);
let valid_signature = f.sig.constness.is_none()
&& f.sig.asyncness.is_none()
&& f.vis == Visibility::Inherited
&& f.sig.unsafety.is_some()
&& f.sig.abi.is_none()
&& f.sig.inputs.is_empty()
&& f.sig.generics.params.is_empty()
&& f.sig.generics.where_clause.is_none()
&& f.sig.variadic.is_none()
&& match f.sig.output {
ReturnType::Default => true,
ReturnType::Type(_, ref ty) => match **ty {
Type::Tuple(ref tuple) => tuple.elems.is_empty(),
_ => false,
},
};
if !valid_signature {
return parse::Error::new(
f.span(),
"`#[pre_init]` function must have signature `unsafe fn()`",
)
.to_compile_error()
.into();
}
if !args.is_empty() {
return parse::Error::new(Span::call_site(), "This attribute accepts no arguments")
.to_compile_error()
.into();
}
let attrs = f.attrs;
let ident = f.sig.ident;
let block = f.block;
quote!(
#[export_name = "__pre_init"]
#(#attrs)*
pub unsafe fn #ident() #block
)
.into()
}