From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- rust/syn/ext.rs | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 rust/syn/ext.rs (limited to 'rust/syn/ext.rs') diff --git a/rust/syn/ext.rs b/rust/syn/ext.rs new file mode 100644 index 000000000..a9be9af42 --- /dev/null +++ b/rust/syn/ext.rs @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +//! Extension traits to provide parsing methods on foreign types. + +use crate::buffer::Cursor; +use crate::error::Result; +use crate::parse::ParseStream; +use crate::parse::Peek; +use crate::sealed::lookahead; +use crate::token::CustomToken; +use proc_macro2::Ident; + +/// Additional methods for `Ident` not provided by proc-macro2 or libproc_macro. +/// +/// This trait is sealed and cannot be implemented for types outside of Syn. It +/// is implemented only for `proc_macro2::Ident`. +pub trait IdentExt: Sized + private::Sealed { + /// Parses any identifier including keywords. + /// + /// This is useful when parsing macro input which allows Rust keywords as + /// identifiers. + /// + /// # Example + /// + /// ``` + /// use syn::{Error, Ident, Result, Token}; + /// use syn::ext::IdentExt; + /// use syn::parse::ParseStream; + /// + /// mod kw { + /// syn::custom_keyword!(name); + /// } + /// + /// // Parses input that looks like `name = NAME` where `NAME` can be + /// // any identifier. + /// // + /// // Examples: + /// // + /// // name = anything + /// // name = impl + /// fn parse_dsl(input: ParseStream) -> Result { + /// input.parse::()?; + /// input.parse::()?; + /// let name = input.call(Ident::parse_any)?; + /// Ok(name) + /// } + /// ``` + fn parse_any(input: ParseStream) -> Result; + + /// Peeks any identifier including keywords. Usage: + /// `input.peek(Ident::peek_any)` + /// + /// This is different from `input.peek(Ident)` which only returns true in + /// the case of an ident which is not a Rust keyword. + #[allow(non_upper_case_globals)] + const peek_any: private::PeekFn = private::PeekFn; + + /// Strips the raw marker `r#`, if any, from the beginning of an ident. + /// + /// - unraw(`x`) = `x` + /// - unraw(`move`) = `move` + /// - unraw(`r#move`) = `move` + /// + /// # Example + /// + /// In the case of interop with other languages like Python that have a + /// different set of keywords than Rust, we might come across macro input + /// that involves raw identifiers to refer to ordinary variables in the + /// other language with a name that happens to be a Rust keyword. + /// + /// The function below appends an identifier from the caller's input onto a + /// fixed prefix. Without using `unraw()`, this would tend to produce + /// invalid identifiers like `__pyo3_get_r#move`. + /// + /// ``` + /// use proc_macro2::Span; + /// use syn::Ident; + /// use syn::ext::IdentExt; + /// + /// fn ident_for_getter(variable: &Ident) -> Ident { + /// let getter = format!("__pyo3_get_{}", variable.unraw()); + /// Ident::new(&getter, Span::call_site()) + /// } + /// ``` + fn unraw(&self) -> Ident; +} + +impl IdentExt for Ident { + fn parse_any(input: ParseStream) -> Result { + input.step(|cursor| match cursor.ident() { + Some((ident, rest)) => Ok((ident, rest)), + None => Err(cursor.error("expected ident")), + }) + } + + fn unraw(&self) -> Ident { + let string = self.to_string(); + if let Some(string) = string.strip_prefix("r#") { + Ident::new(string, self.span()) + } else { + self.clone() + } + } +} + +impl Peek for private::PeekFn { + type Token = private::IdentAny; +} + +impl CustomToken for private::IdentAny { + fn peek(cursor: Cursor) -> bool { + cursor.ident().is_some() + } + + fn display() -> &'static str { + "identifier" + } +} + +impl lookahead::Sealed for private::PeekFn {} + +mod private { + use proc_macro2::Ident; + + pub trait Sealed {} + + impl Sealed for Ident {} + + pub struct PeekFn; + pub struct IdentAny; + + impl Copy for PeekFn {} + impl Clone for PeekFn { + fn clone(&self) -> Self { + *self + } + } +} -- cgit v1.3.1