From 1ae4a0cc3487f28b29f36afe8056535afad21e7b Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Sun, 10 Aug 2025 14:25:43 -0700 Subject: library: Migrate from `cfg_if` to `cfg_select` Migrate the standard library from using the external `cfg_if` crate to using the now-built-in `cfg_select` macro. This does not yet eliminate the dependency from `library/std/Cargo.toml`, because while the standard library itself no longer uses `cfg_if`, it also incorporates the `backtrace` crate, which does. Migration assisted by the following vim command (after selecting the full `cfg_if!` invocation): ``` '<,'>s/\(cfg_if::\)\?cfg_if/cfg_select/ | '<,'>s/^\( *\)} else {/\1}\r\1_ => {/c | '<,'>s/^\( *\)} else if #\[cfg(\(.*\))\] /\1}\r\1\2 => /e | '<,'>s/if #\[cfg(\(.*\))\] {/\1 => {/e ``` This is imperfect, but substantially accelerated the process. This prompts for confirmation on the `} else {` since that can also appear inside one of the arms. This also requires manual intervention to handle any multi-line conditions. --- library/std/src/thread/current.rs | 13 ++++++++----- library/std/src/thread/mod.rs | 14 ++++++++------ 2 files changed, 16 insertions(+), 11 deletions(-) (limited to 'library/std/src/thread') diff --git a/library/std/src/thread/current.rs b/library/std/src/thread/current.rs index 5c879903526..7da1621da45 100644 --- a/library/std/src/thread/current.rs +++ b/library/std/src/thread/current.rs @@ -18,8 +18,8 @@ local_pointer! { pub(super) mod id { use super::*; - cfg_if::cfg_if! { - if #[cfg(target_thread_local)] { + cfg_select! { + target_thread_local => { use crate::cell::Cell; #[thread_local] @@ -34,7 +34,8 @@ pub(super) mod id { pub(super) fn set(id: ThreadId) { ID.set(Some(id)) } - } else if #[cfg(target_pointer_width = "16")] { + } + target_pointer_width = "16" => { local_pointer! { static ID0; static ID16; @@ -59,7 +60,8 @@ pub(super) mod id { ID32.set(ptr::without_provenance_mut((val >> 32) as usize)); ID48.set(ptr::without_provenance_mut((val >> 48) as usize)); } - } else if #[cfg(target_pointer_width = "32")] { + } + target_pointer_width = "32" => { local_pointer! { static ID0; static ID32; @@ -78,7 +80,8 @@ pub(super) mod id { ID0.set(ptr::without_provenance_mut(val as usize)); ID32.set(ptr::without_provenance_mut((val >> 32) as usize)); } - } else { + } + _ => { local_pointer! { static ID; } diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs index 292323d0118..b6059c28cec 100644 --- a/library/std/src/thread/mod.rs +++ b/library/std/src/thread/mod.rs @@ -1212,8 +1212,8 @@ impl ThreadId { panic!("failed to generate unique thread ID: bitspace exhausted") } - cfg_if::cfg_if! { - if #[cfg(target_has_atomic = "64")] { + cfg_select! { + target_has_atomic = "64" => { use crate::sync::atomic::{Atomic, AtomicU64}; static COUNTER: Atomic = AtomicU64::new(0); @@ -1229,7 +1229,8 @@ impl ThreadId { Err(id) => last = id, } } - } else { + } + _ => { use crate::sync::{Mutex, PoisonError}; static COUNTER: Mutex = Mutex::new(0); @@ -1318,8 +1319,8 @@ use thread_name_string::ThreadNameString; /// Note however that this also means that the name reported in pre-main functions /// will be incorrect, but that's just something we have to live with. pub(crate) mod main_thread { - cfg_if::cfg_if! { - if #[cfg(target_has_atomic = "64")] { + cfg_select! { + target_has_atomic = "64" => { use super::ThreadId; use crate::sync::atomic::{Atomic, AtomicU64}; use crate::sync::atomic::Ordering::Relaxed; @@ -1335,7 +1336,8 @@ pub(crate) mod main_thread { pub(crate) unsafe fn set(id: ThreadId) { MAIN.store(id.as_u64().get(), Relaxed) } - } else { + } + _ => { use super::ThreadId; use crate::mem::MaybeUninit; use crate::sync::atomic::{Atomic, AtomicBool}; -- cgit 1.4.1-3-g733a5 From d0841c7decfa4a9cda77c0078c9140036273133f Mon Sep 17 00:00:00 2001 From: Quinn Tucker Date: Tue, 19 Aug 2025 16:47:25 -0400 Subject: Fix typos in LocalKey documentation --- library/std/src/thread/local.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'library/std/src/thread') diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs index 0ad014ccd3e..701ca88e640 100644 --- a/library/std/src/thread/local.rs +++ b/library/std/src/thread/local.rs @@ -24,10 +24,10 @@ use crate::fmt; /// [`with`]) within a thread, and values that implement [`Drop`] get /// destructed when a thread exits. Some platform-specific caveats apply, which /// are explained below. -/// Note that, should the destructor panics, the whole process will be [aborted]. +/// Note that, should the destructor panic, the whole process will be [aborted]. /// /// A `LocalKey`'s initializer cannot recursively depend on itself. Using a -/// `LocalKey` in this way may cause panics, aborts or infinite recursion on +/// `LocalKey` in this way may cause panics, aborts, or infinite recursion on /// the first call to `with`. /// /// [aborted]: crate::process::abort -- cgit 1.4.1-3-g733a5 From 14022c8a9a3c667f24602fae3cbfad9a3ead50b1 Mon Sep 17 00:00:00 2001 From: Quinn Tucker Date: Tue, 19 Aug 2025 17:14:26 -0400 Subject: Adjust wording for conciseness --- library/std/src/thread/local.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'library/std/src/thread') diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs index 701ca88e640..e255b383323 100644 --- a/library/std/src/thread/local.rs +++ b/library/std/src/thread/local.rs @@ -8,8 +8,8 @@ use crate::fmt; /// A thread local storage (TLS) key which owns its contents. /// -/// This key uses the fastest possible implementation available to it for the -/// target platform. It is instantiated with the [`thread_local!`] macro and the +/// This key uses the fastest implementation available on the target platform. +/// It is instantiated with the [`thread_local!`] macro and the /// primary method is the [`with`] method, though there are helpers to make /// working with [`Cell`] types easier. /// -- cgit 1.4.1-3-g733a5 From e84d29284c0f4d83e4033b39c6f21826d448373b Mon Sep 17 00:00:00 2001 From: Quinn Tucker Date: Tue, 19 Aug 2025 19:05:19 -0400 Subject: Tweak wording again --- library/std/src/thread/local.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'library/std/src/thread') diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs index e255b383323..797feeb2bbb 100644 --- a/library/std/src/thread/local.rs +++ b/library/std/src/thread/local.rs @@ -24,7 +24,7 @@ use crate::fmt; /// [`with`]) within a thread, and values that implement [`Drop`] get /// destructed when a thread exits. Some platform-specific caveats apply, which /// are explained below. -/// Note that, should the destructor panic, the whole process will be [aborted]. +/// Note that if the destructor panics, the whole process will be [aborted]. /// /// A `LocalKey`'s initializer cannot recursively depend on itself. Using a /// `LocalKey` in this way may cause panics, aborts, or infinite recursion on -- cgit 1.4.1-3-g733a5