Commit 7e06561f authored by Ethan D. Twardy's avatar Ethan D. Twardy Committed by Miguel Ojeda
Browse files

rust: macros: enable paste! use from macro_rules! 

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: default avatarEthan D. Twardy <ethan.twardy@gmail.com>
Reviewed-by: default avatarAlice 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: default avatarMiguel Ojeda <ojeda@kernel.org>
parent 8d3f5079

rust/macros/lib.rs

+34 −8
Original line number Diff line number Diff line
@@ -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! {

rust/macros/paste.rs

+12 −3
Original line number Diff line number Diff line
@@ -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>) {