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rust: macros: enable paste! use from macro_rules!

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According to the rustdoc for the proc_macro crate[1], tokens captured
from a "macro variable" (e.g. from within macro_rules!) may be delimited
by invisible tokens and be contained within a proc_macro::Group.

Previously, this scenario was not handled by macros::paste, which caused
a proc-macro panic when the corresponding tests are enabled. Enable the
tests, and handle this case by making macros::paste::concat recursive.

Link: https://doc.rust-lang.org/stable/proc_macro/enum.Delimiter.html [1]
Signed-off-by: Ethan D. Twardy <ethan.twardy@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1076
Link: https://lore.kernel.org/r/20240704145607.17732-4-ethan.twardy@gmail.com
[ Rebased (one fix was already applied) and reworded. Remove unneeded
  `rust` as language in examples. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Ethan D. Twardy 2024-07-04 09:55:44 -05:00 committed by Miguel Ojeda
parent 8d3f50795a
commit 7e06561fcd
2 changed files with 46 additions and 11 deletions
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42
rust/macros/lib.rs
View File

@ -304,12 +304,25 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
///
/// # Example
///
/// ```ignore
/// use kernel::macro::paste;
///
/// ```
/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
/// macro_rules! pub_no_prefix {
/// ($prefix:ident, $($newname:ident),+) => {
/// paste! {
/// kernel::macros::paste! {
/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
/// }
/// };
@ -348,9 +361,22 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
/// * `lower`: change the identifier to lower case.
/// * `upper`: change the identifier to upper case.
///
/// ```ignore
/// use kernel::macro::paste;
///
/// ```
/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
/// macro_rules! pub_no_prefix {
/// ($prefix:ident, $($newname:ident),+) => {
/// kernel::macros::paste! {
@ -385,7 +411,7 @@ pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
///
/// Literals can also be concatenated with other identifiers:
///
/// ```ignore
/// ```
/// macro_rules! create_numbered_fn {
/// ($name:literal, $val:literal) => {
/// kernel::macros::paste! {

15
rust/macros/paste.rs
View File

@ -2,7 +2,7 @@
use proc_macro::{Delimiter, Group, Ident, Spacing, Span, TokenTree};
fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree {
fn concat_helper(tokens: &[TokenTree]) -> Vec<(String, Span)> {
let mut tokens = tokens.iter();
let mut segments = Vec::new();
let mut span = None;
@ -46,12 +46,21 @@ fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree {
};
segments.push((value, sp));
}
_ => panic!("unexpected token in paste segments"),
Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::None => {
let tokens = group.stream().into_iter().collect::<Vec<TokenTree>>();
segments.append(&mut concat_helper(tokens.as_slice()));
}
token => panic!("unexpected token in paste segments: {:?}", token),
};
}
segments
}
fn concat(tokens: &[TokenTree], group_span: Span) -> TokenTree {
let segments = concat_helper(tokens);
let pasted: String = segments.into_iter().map(|x| x.0).collect();
TokenTree::Ident(Ident::new(&pasted, span.unwrap_or(group_span)))
TokenTree::Ident(Ident::new(&pasted, group_span))
}
pub(crate) fn expand(tokens: &mut Vec<TokenTree>) {