rust: macros: replace quote! with quote::quote and use proc-macro2

We now have access to the `quote` crate providing the `quote!` macro
that does the same (and more) as our own `quote!` macro. Thus replace
our own version with the one from the crate.
Since the `quote` crate uses the `proc-macro2` library, we also use that
in our macros instead of `proc-macro`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Author: BennoLossin

rust/macros/concat_idents.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{token_stream, Ident, TokenStream, TokenTree};
+use proc_macro2::{token_stream, Ident, TokenStream, TokenTree};
 
 use crate::helpers::expect_punct;
 

rust/macros/helpers.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{token_stream, Group, TokenStream, TokenTree};
+use proc_macro2::{token_stream, Group, TokenStream, TokenTree};
 
 pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
     if let Some(TokenTree::Ident(ident)) = it.next() {
@@ -166,7 +166,7 @@ pub(crate) fn parse_generics(input: TokenStream) -> (Generics, Vec<TokenTree>) {
                     1 => {
                         // Here depending on the token, it might be a generic variable name.
                         match tt.clone() {
-                            TokenTree::Ident(i) if at_start && i.to_string() == "const" => {
+                            TokenTree::Ident(i) if at_start && i == "const" => {
                                 let Some(name) = toks.next() else {
                                     // Parsing error.
                                     break;

rust/macros/lib.rs

@@ -2,8 +2,6 @@
 
 //! Crate for all kernel procedural macros.
 
-#[macro_use]
-mod quote;
 mod concat_idents;
 mod helpers;
 mod module;
@@ -76,7 +74,7 @@ use proc_macro::TokenStream;
 ///   - `alias`: byte array of alias name of the kernel module.
 #[proc_macro]
 pub fn module(ts: TokenStream) -> TokenStream {
-    module::module(ts)
+    module::module(ts.into()).into()
 }
 
 /// Declares or implements a vtable trait.
@@ -151,7 +149,7 @@ pub fn module(ts: TokenStream) -> TokenStream {
 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
 #[proc_macro_attribute]
 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
-    vtable::vtable(attr, ts)
+    vtable::vtable(attr.into(), ts.into()).into()
 }
 
 /// Concatenate two identifiers.
@@ -194,7 +192,7 @@ pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro]
 pub fn concat_idents(ts: TokenStream) -> TokenStream {
-    concat_idents::concat_idents(ts)
+    concat_idents::concat_idents(ts.into()).into()
 }
 
 /// Used to specify the pinning information of the fields of a struct.
@@ -243,7 +241,7 @@ pub fn concat_idents(ts: TokenStream) -> TokenStream {
 //  ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
 #[proc_macro_attribute]
 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
-    pin_data::pin_data(inner, item)
+    pin_data::pin_data(inner.into(), item.into()).into()
 }
 
 /// Used to implement `PinnedDrop` safely.
@@ -270,7 +268,7 @@ pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_attribute]
 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
-    pinned_drop::pinned_drop(args, input)
+    pinned_drop::pinned_drop(args.into(), input.into()).into()
 }
 
 /// Paste identifiers together.
@@ -382,9 +380,13 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
 /// [`paste`]: https://docs.rs/paste/
 #[proc_macro]
 pub fn paste(input: TokenStream) -> TokenStream {
+    let input: proc_macro2::TokenStream = input.into();
     let mut tokens = input.into_iter().collect();
     paste::expand(&mut tokens);
-    tokens.into_iter().collect()
+    tokens
+        .into_iter()
+        .collect::<proc_macro2::TokenStream>()
+        .into()
 }
 
 /// Derives the [`Zeroable`] trait for the given struct.
@@ -403,5 +405,5 @@ pub fn paste(input: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_derive(Zeroable)]
 pub fn derive_zeroable(input: TokenStream) -> TokenStream {
-    zeroable::derive(input)
+    zeroable::derive(input.into()).into()
 }

rust/macros/module.rs

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 use crate::helpers::*;
-use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
+use proc_macro2::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
 use std::fmt::Write;
 
 fn expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String> {

rust/macros/paste.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{Delimiter, Group, Ident, Spacing, Span, TokenTree};
+use proc_macro2::{Delimiter, Group, Ident, Spacing, Span, TokenTree};
 
 fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree {
     let mut tokens = tokens.iter();

rust/macros/pin_data.rs

@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::helpers::{parse_generics, Generics};
-use proc_macro::{Group, Punct, Spacing, TokenStream, TokenTree};
+use proc_macro2::{Group, Punct, Spacing, TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
     // This proc-macro only does some pre-parsing and then delegates the actual parsing to
@@ -25,7 +26,7 @@ pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
     // The name of the struct with ty_generics.
     let struct_name = rest
         .iter()
-        .skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if i.to_string() == "struct"))
+        .skip_while(|tt| !matches!(tt, TokenTree::Ident(i) if *i == "struct"))
         .nth(1)
         .and_then(|tt| match tt {
             TokenTree::Ident(_) => {
@@ -62,7 +63,7 @@ pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
         .into_iter()
         .flat_map(|tt| {
             // We ignore top level `struct` tokens, since they would emit a compile error.
-            if matches!(&tt, TokenTree::Ident(i) if i.to_string() == "struct") {
+            if matches!(&tt, TokenTree::Ident(i) if *i == "struct") {
                 vec![tt]
             } else {
                 replace_self_and_deny_type_defs(&struct_name, tt, &mut errs)
@@ -95,11 +96,7 @@ fn replace_self_and_deny_type_defs(
 ) -> Vec<TokenTree> {
     match tt {
         TokenTree::Ident(ref i)
-            if i.to_string() == "enum"
-                || i.to_string() == "trait"
-                || i.to_string() == "struct"
-                || i.to_string() == "union"
-                || i.to_string() == "impl" =>
+            if *i == "enum" || *i == "trait" || *i == "struct" || *i == "union" || *i == "impl" =>
         {
             errs.extend(
                 format!(
@@ -116,7 +113,7 @@ fn replace_self_and_deny_type_defs(
             );
             vec![tt]
         }
-        TokenTree::Ident(i) if i.to_string() == "Self" => struct_name.clone(),
+        TokenTree::Ident(i) if i == "Self" => struct_name.clone(),
         TokenTree::Literal(_) | TokenTree::Punct(_) | TokenTree::Ident(_) => vec![tt],
         TokenTree::Group(g) => vec![TokenTree::Group(Group::new(
             g.delimiter(),

rust/macros/pinned_drop.rs

@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-use proc_macro::{TokenStream, TokenTree};
+use proc_macro2::{TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn pinned_drop(_args: TokenStream, input: TokenStream) -> TokenStream {
     let mut toks = input.into_iter().collect::<Vec<_>>();
     assert!(!toks.is_empty());
     // Ensure that we have an `impl` item.
-    assert!(matches!(&toks[0], TokenTree::Ident(i) if i.to_string() == "impl"));
+    assert!(matches!(&toks[0], TokenTree::Ident(i) if *i == "impl"));
     // Ensure that we are implementing `PinnedDrop`.
     let mut nesting: usize = 0;
     let mut pinned_drop_idx = None;
@@ -24,7 +25,7 @@ pub(crate) fn pinned_drop(_args: TokenStream, input: TokenStream) -> TokenStream
         if i >= 1 && nesting == 0 {
             // Found the end of the generics, this should be `PinnedDrop`.
             assert!(
-                matches!(tt, TokenTree::Ident(i) if i.to_string() == "PinnedDrop"),
+                matches!(tt, TokenTree::Ident(i) if *i == "PinnedDrop"),
                 "expected 'PinnedDrop', found: '{:?}'",
                 tt
             );

rust/macros/quote.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{Delimiter, Group, TokenStream, TokenTree};
+use proc_macro2::{Delimiter, Group, TokenStream, TokenTree};
 use std::collections::HashSet;
 use std::fmt::Write;
 
@@ -31,15 +31,15 @@ pub(crate) fn vtable(_attr: TokenStream, ts: TokenStream) -> TokenStream {
     let mut consts = HashSet::new();
     while let Some(token) = body_it.next() {
         match token {
-            TokenTree::Ident(ident) if ident.to_string() == "fn" => {
+            TokenTree::Ident(ident) if ident == "fn" => {
                 let fn_name = match body_it.next() {
                     Some(TokenTree::Ident(ident)) => ident.to_string(),
                     // Possibly we've encountered a fn pointer type instead.
                     _ => continue,
                 };
                 functions.push(fn_name);
             }
-            TokenTree::Ident(ident) if ident.to_string() == "const" => {
+            TokenTree::Ident(ident) if ident == "const" => {
                 let const_name = match body_it.next() {
                     Some(TokenTree::Ident(ident)) => ident.to_string(),
                     // Possibly we've encountered an inline const block instead.

rust/macros/vtable.rs

@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 
 use crate::helpers::{parse_generics, Generics};
-use proc_macro::{TokenStream, TokenTree};
+use proc_macro2::{TokenStream, TokenTree};
+use quote::quote;
 
 pub(crate) fn derive(input: TokenStream) -> TokenStream {
     let (