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-rw-r--r--compiler/rustc_data_structures/src/sync.rs630
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diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
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+//! This module defines types which are thread safe if cfg!(parallel_compiler) is true.
+//!
+//! `Lrc` is an alias of `Arc` if cfg!(parallel_compiler) is true, `Rc` otherwise.
+//!
+//! `Lock` is a mutex.
+//! It internally uses `parking_lot::Mutex` if cfg!(parallel_compiler) is true,
+//! `RefCell` otherwise.
+//!
+//! `RwLock` is a read-write lock.
+//! It internally uses `parking_lot::RwLock` if cfg!(parallel_compiler) is true,
+//! `RefCell` otherwise.
+//!
+//! `MTLock` is a mutex which disappears if cfg!(parallel_compiler) is false.
+//!
+//! `MTRef` is an immutable reference if cfg!(parallel_compiler), and a mutable reference otherwise.
+//!
+//! `rustc_erase_owner!` erases an OwningRef owner into Erased or Erased + Send + Sync
+//! depending on the value of cfg!(parallel_compiler).
+
+use crate::owning_ref::{Erased, OwningRef};
+use std::collections::HashMap;
+use std::hash::{BuildHasher, Hash};
+use std::ops::{Deref, DerefMut};
+use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
+
+pub use std::sync::atomic::Ordering;
+pub use std::sync::atomic::Ordering::SeqCst;
+
+cfg_if! {
+ if #[cfg(not(parallel_compiler))] {
+ pub auto trait Send {}
+ pub auto trait Sync {}
+
+ impl<T: ?Sized> Send for T {}
+ impl<T: ?Sized> Sync for T {}
+
+ #[macro_export]
+ macro_rules! rustc_erase_owner {
+ ($v:expr) => {
+ $v.erase_owner()
+ }
+ }
+
+ use std::ops::Add;
+
+ /// This is a single threaded variant of `AtomicU64`, `AtomicUsize`, etc.
+ /// It has explicit ordering arguments and is only intended for use with
+ /// the native atomic types.
+ /// You should use this type through the `AtomicU64`, `AtomicUsize`, etc, type aliases
+ /// as it's not intended to be used separately.
+ #[derive(Debug)]
+ pub struct Atomic<T: Copy>(Cell<T>);
+
+ impl<T: Copy> Atomic<T> {
+ #[inline]
+ pub fn new(v: T) -> Self {
+ Atomic(Cell::new(v))
+ }
+ }
+
+ impl<T: Copy> Atomic<T> {
+ #[inline]
+ pub fn into_inner(self) -> T {
+ self.0.into_inner()
+ }
+
+ #[inline]
+ pub fn load(&self, _: Ordering) -> T {
+ self.0.get()
+ }
+
+ #[inline]
+ pub fn store(&self, val: T, _: Ordering) {
+ self.0.set(val)
+ }
+
+ #[inline]
+ pub fn swap(&self, val: T, _: Ordering) -> T {
+ self.0.replace(val)
+ }
+ }
+
+ impl<T: Copy + PartialEq> Atomic<T> {
+ #[inline]
+ pub fn compare_exchange(&self,
+ current: T,
+ new: T,
+ _: Ordering,
+ _: Ordering)
+ -> Result<T, T> {
+ let read = self.0.get();
+ if read == current {
+ self.0.set(new);
+ Ok(read)
+ } else {
+ Err(read)
+ }
+ }
+ }
+
+ impl<T: Add<Output=T> + Copy> Atomic<T> {
+ #[inline]
+ pub fn fetch_add(&self, val: T, _: Ordering) -> T {
+ let old = self.0.get();
+ self.0.set(old + val);
+ old
+ }
+ }
+
+ pub type AtomicUsize = Atomic<usize>;
+ pub type AtomicBool = Atomic<bool>;
+ pub type AtomicU32 = Atomic<u32>;
+ pub type AtomicU64 = Atomic<u64>;
+
+ pub fn join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
+ where A: FnOnce() -> RA,
+ B: FnOnce() -> RB
+ {
+ (oper_a(), oper_b())
+ }
+
+ #[macro_export]
+ macro_rules! parallel {
+ ($($blocks:tt),*) => {
+ // We catch panics here ensuring that all the blocks execute.
+ // This makes behavior consistent with the parallel compiler.
+ let mut panic = None;
+ $(
+ if let Err(p) = ::std::panic::catch_unwind(
+ ::std::panic::AssertUnwindSafe(|| $blocks)
+ ) {
+ if panic.is_none() {
+ panic = Some(p);
+ }
+ }
+ )*
+ if let Some(panic) = panic {
+ ::std::panic::resume_unwind(panic);
+ }
+ }
+ }
+
+ pub use std::iter::Iterator as ParallelIterator;
+
+ pub fn par_iter<T: IntoIterator>(t: T) -> T::IntoIter {
+ t.into_iter()
+ }
+
+ pub fn par_for_each_in<T: IntoIterator>(t: T, mut for_each: impl FnMut(T::Item) + Sync + Send) {
+ // We catch panics here ensuring that all the loop iterations execute.
+ // This makes behavior consistent with the parallel compiler.
+ let mut panic = None;
+ t.into_iter().for_each(|i| {
+ if let Err(p) = catch_unwind(AssertUnwindSafe(|| for_each(i))) {
+ if panic.is_none() {
+ panic = Some(p);
+ }
+ }
+ });
+ if let Some(panic) = panic {
+ resume_unwind(panic);
+ }
+ }
+
+ pub type MetadataRef = OwningRef<Box<dyn Erased>, [u8]>;
+
+ pub use std::rc::Rc as Lrc;
+ pub use std::rc::Weak as Weak;
+ pub use std::cell::Ref as ReadGuard;
+ pub use std::cell::Ref as MappedReadGuard;
+ pub use std::cell::RefMut as WriteGuard;
+ pub use std::cell::RefMut as MappedWriteGuard;
+ pub use std::cell::RefMut as LockGuard;
+ pub use std::cell::RefMut as MappedLockGuard;
+
+ pub use std::cell::OnceCell;
+
+ use std::cell::RefCell as InnerRwLock;
+ use std::cell::RefCell as InnerLock;
+
+ use std::cell::Cell;
+
+ #[derive(Debug)]
+ pub struct WorkerLocal<T>(OneThread<T>);
+
+ impl<T> WorkerLocal<T> {
+ /// Creates a new worker local where the `initial` closure computes the
+ /// value this worker local should take for each thread in the thread pool.
+ #[inline]
+ pub fn new<F: FnMut(usize) -> T>(mut f: F) -> WorkerLocal<T> {
+ WorkerLocal(OneThread::new(f(0)))
+ }
+
+ /// Returns the worker-local value for each thread
+ #[inline]
+ pub fn into_inner(self) -> Vec<T> {
+ vec![OneThread::into_inner(self.0)]
+ }
+ }
+
+ impl<T> Deref for WorkerLocal<T> {
+ type Target = T;
+
+ #[inline(always)]
+ fn deref(&self) -> &T {
+ &*self.0
+ }
+ }
+
+ pub type MTRef<'a, T> = &'a mut T;
+
+ #[derive(Debug, Default)]
+ pub struct MTLock<T>(T);
+
+ impl<T> MTLock<T> {
+ #[inline(always)]
+ pub fn new(inner: T) -> Self {
+ MTLock(inner)
+ }
+
+ #[inline(always)]
+ pub fn into_inner(self) -> T {
+ self.0
+ }
+
+ #[inline(always)]
+ pub fn get_mut(&mut self) -> &mut T {
+ &mut self.0
+ }
+
+ #[inline(always)]
+ pub fn lock(&self) -> &T {
+ &self.0
+ }
+
+ #[inline(always)]
+ pub fn lock_mut(&mut self) -> &mut T {
+ &mut self.0
+ }
+ }
+
+ // FIXME: Probably a bad idea (in the threaded case)
+ impl<T: Clone> Clone for MTLock<T> {
+ #[inline]
+ fn clone(&self) -> Self {
+ MTLock(self.0.clone())
+ }
+ }
+ } else {
+ pub use std::marker::Send as Send;
+ pub use std::marker::Sync as Sync;
+
+ pub use parking_lot::RwLockReadGuard as ReadGuard;
+ pub use parking_lot::MappedRwLockReadGuard as MappedReadGuard;
+ pub use parking_lot::RwLockWriteGuard as WriteGuard;
+ pub use parking_lot::MappedRwLockWriteGuard as MappedWriteGuard;
+
+ pub use parking_lot::MutexGuard as LockGuard;
+ pub use parking_lot::MappedMutexGuard as MappedLockGuard;
+
+ pub use std::sync::OnceLock as OnceCell;
+
+ pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32, AtomicU64};
+
+ pub use std::sync::Arc as Lrc;
+ pub use std::sync::Weak as Weak;
+
+ pub type MTRef<'a, T> = &'a T;
+
+ #[derive(Debug, Default)]
+ pub struct MTLock<T>(Lock<T>);
+
+ impl<T> MTLock<T> {
+ #[inline(always)]
+ pub fn new(inner: T) -> Self {
+ MTLock(Lock::new(inner))
+ }
+
+ #[inline(always)]
+ pub fn into_inner(self) -> T {
+ self.0.into_inner()
+ }
+
+ #[inline(always)]
+ pub fn get_mut(&mut self) -> &mut T {
+ self.0.get_mut()
+ }
+
+ #[inline(always)]
+ pub fn lock(&self) -> LockGuard<'_, T> {
+ self.0.lock()
+ }
+
+ #[inline(always)]
+ pub fn lock_mut(&self) -> LockGuard<'_, T> {
+ self.lock()
+ }
+ }
+
+ use parking_lot::Mutex as InnerLock;
+ use parking_lot::RwLock as InnerRwLock;
+
+ use std::thread;
+ pub use rayon::{join, scope};
+
+ /// Runs a list of blocks in parallel. The first block is executed immediately on
+ /// the current thread. Use that for the longest running block.
+ #[macro_export]
+ macro_rules! parallel {
+ (impl $fblock:tt [$($c:tt,)*] [$block:tt $(, $rest:tt)*]) => {
+ parallel!(impl $fblock [$block, $($c,)*] [$($rest),*])
+ };
+ (impl $fblock:tt [$($blocks:tt,)*] []) => {
+ ::rustc_data_structures::sync::scope(|s| {
+ $(
+ s.spawn(|_| $blocks);
+ )*
+ $fblock;
+ })
+ };
+ ($fblock:tt, $($blocks:tt),*) => {
+ // Reverse the order of the later blocks since Rayon executes them in reverse order
+ // when using a single thread. This ensures the execution order matches that
+ // of a single threaded rustc
+ parallel!(impl $fblock [] [$($blocks),*]);
+ };
+ }
+
+ pub use rayon_core::WorkerLocal;
+
+ pub use rayon::iter::ParallelIterator;
+ use rayon::iter::IntoParallelIterator;
+
+ pub fn par_iter<T: IntoParallelIterator>(t: T) -> T::Iter {
+ t.into_par_iter()
+ }
+
+ pub fn par_for_each_in<T: IntoParallelIterator>(
+ t: T,
+ for_each: impl Fn(T::Item) + Sync + Send,
+ ) {
+ let ps: Vec<_> = t.into_par_iter().map(|i| catch_unwind(AssertUnwindSafe(|| for_each(i)))).collect();
+ ps.into_iter().for_each(|p| if let Err(panic) = p {
+ resume_unwind(panic)
+ });
+ }
+
+ pub type MetadataRef = OwningRef<Box<dyn Erased + Send + Sync>, [u8]>;
+
+ /// This makes locks panic if they are already held.
+ /// It is only useful when you are running in a single thread
+ const ERROR_CHECKING: bool = false;
+
+ #[macro_export]
+ macro_rules! rustc_erase_owner {
+ ($v:expr) => {{
+ let v = $v;
+ ::rustc_data_structures::sync::assert_send_val(&v);
+ v.erase_send_sync_owner()
+ }}
+ }
+ }
+}
+
+pub fn assert_sync<T: ?Sized + Sync>() {}
+pub fn assert_send<T: ?Sized + Send>() {}
+pub fn assert_send_val<T: ?Sized + Send>(_t: &T) {}
+pub fn assert_send_sync_val<T: ?Sized + Sync + Send>(_t: &T) {}
+
+pub trait HashMapExt<K, V> {
+ /// Same as HashMap::insert, but it may panic if there's already an
+ /// entry for `key` with a value not equal to `value`
+ fn insert_same(&mut self, key: K, value: V);
+}
+
+impl<K: Eq + Hash, V: Eq, S: BuildHasher> HashMapExt<K, V> for HashMap<K, V, S> {
+ fn insert_same(&mut self, key: K, value: V) {
+ self.entry(key).and_modify(|old| assert!(*old == value)).or_insert(value);
+ }
+}
+
+#[derive(Debug)]
+pub struct Lock<T>(InnerLock<T>);
+
+impl<T> Lock<T> {
+ #[inline(always)]
+ pub fn new(inner: T) -> Self {
+ Lock(InnerLock::new(inner))
+ }
+
+ #[inline(always)]
+ pub fn into_inner(self) -> T {
+ self.0.into_inner()
+ }
+
+ #[inline(always)]
+ pub fn get_mut(&mut self) -> &mut T {
+ self.0.get_mut()
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
+ self.0.try_lock()
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
+ self.0.try_borrow_mut().ok()
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn lock(&self) -> LockGuard<'_, T> {
+ if ERROR_CHECKING {
+ self.0.try_lock().expect("lock was already held")
+ } else {
+ self.0.lock()
+ }
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn lock(&self) -> LockGuard<'_, T> {
+ self.0.borrow_mut()
+ }
+
+ #[inline(always)]
+ pub fn with_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
+ f(&mut *self.lock())
+ }
+
+ #[inline(always)]
+ pub fn borrow(&self) -> LockGuard<'_, T> {
+ self.lock()
+ }
+
+ #[inline(always)]
+ pub fn borrow_mut(&self) -> LockGuard<'_, T> {
+ self.lock()
+ }
+}
+
+impl<T: Default> Default for Lock<T> {
+ #[inline]
+ fn default() -> Self {
+ Lock::new(T::default())
+ }
+}
+
+// FIXME: Probably a bad idea
+impl<T: Clone> Clone for Lock<T> {
+ #[inline]
+ fn clone(&self) -> Self {
+ Lock::new(self.borrow().clone())
+ }
+}
+
+#[derive(Debug, Default)]
+pub struct RwLock<T>(InnerRwLock<T>);
+
+impl<T> RwLock<T> {
+ #[inline(always)]
+ pub fn new(inner: T) -> Self {
+ RwLock(InnerRwLock::new(inner))
+ }
+
+ #[inline(always)]
+ pub fn into_inner(self) -> T {
+ self.0.into_inner()
+ }
+
+ #[inline(always)]
+ pub fn get_mut(&mut self) -> &mut T {
+ self.0.get_mut()
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn read(&self) -> ReadGuard<'_, T> {
+ self.0.borrow()
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn read(&self) -> ReadGuard<'_, T> {
+ if ERROR_CHECKING {
+ self.0.try_read().expect("lock was already held")
+ } else {
+ self.0.read()
+ }
+ }
+
+ #[inline(always)]
+ pub fn with_read_lock<F: FnOnce(&T) -> R, R>(&self, f: F) -> R {
+ f(&*self.read())
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
+ self.0.try_borrow_mut().map_err(|_| ())
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
+ self.0.try_write().ok_or(())
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn write(&self) -> WriteGuard<'_, T> {
+ self.0.borrow_mut()
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn write(&self) -> WriteGuard<'_, T> {
+ if ERROR_CHECKING {
+ self.0.try_write().expect("lock was already held")
+ } else {
+ self.0.write()
+ }
+ }
+
+ #[inline(always)]
+ pub fn with_write_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
+ f(&mut *self.write())
+ }
+
+ #[inline(always)]
+ pub fn borrow(&self) -> ReadGuard<'_, T> {
+ self.read()
+ }
+
+ #[inline(always)]
+ pub fn borrow_mut(&self) -> WriteGuard<'_, T> {
+ self.write()
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn clone_guard<'a>(rg: &ReadGuard<'a, T>) -> ReadGuard<'a, T> {
+ ReadGuard::clone(rg)
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn clone_guard<'a>(rg: &ReadGuard<'a, T>) -> ReadGuard<'a, T> {
+ ReadGuard::rwlock(&rg).read()
+ }
+
+ #[cfg(not(parallel_compiler))]
+ #[inline(always)]
+ pub fn leak(&self) -> &T {
+ ReadGuard::leak(self.read())
+ }
+
+ #[cfg(parallel_compiler)]
+ #[inline(always)]
+ pub fn leak(&self) -> &T {
+ let guard = self.read();
+ let ret = unsafe { &*(&*guard as *const T) };
+ std::mem::forget(guard);
+ ret
+ }
+}
+
+// FIXME: Probably a bad idea
+impl<T: Clone> Clone for RwLock<T> {
+ #[inline]
+ fn clone(&self) -> Self {
+ RwLock::new(self.borrow().clone())
+ }
+}
+
+/// A type which only allows its inner value to be used in one thread.
+/// It will panic if it is used on multiple threads.
+#[derive(Debug)]
+pub struct OneThread<T> {
+ #[cfg(parallel_compiler)]
+ thread: thread::ThreadId,
+ inner: T,
+}
+
+#[cfg(parallel_compiler)]
+unsafe impl<T> std::marker::Sync for OneThread<T> {}
+#[cfg(parallel_compiler)]
+unsafe impl<T> std::marker::Send for OneThread<T> {}
+
+impl<T> OneThread<T> {
+ #[inline(always)]
+ fn check(&self) {
+ #[cfg(parallel_compiler)]
+ assert_eq!(thread::current().id(), self.thread);
+ }
+
+ #[inline(always)]
+ pub fn new(inner: T) -> Self {
+ OneThread {
+ #[cfg(parallel_compiler)]
+ thread: thread::current().id(),
+ inner,
+ }
+ }
+
+ #[inline(always)]
+ pub fn into_inner(value: Self) -> T {
+ value.check();
+ value.inner
+ }
+}
+
+impl<T> Deref for OneThread<T> {
+ type Target = T;
+
+ fn deref(&self) -> &T {
+ self.check();
+ &self.inner
+ }
+}
+
+impl<T> DerefMut for OneThread<T> {
+ fn deref_mut(&mut self) -> &mut T {
+ self.check();
+ &mut self.inner
+ }
+}
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