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Auto merge of #107586 - SparrowLii:parallel-query, r=cjgillot

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Introduce `DynSend` and `DynSync` auto trait for parallel compiler

part of parallel-rustc #101566

This PR introduces `DynSend / DynSync` trait and `FromDyn / IntoDyn` structure in rustc_data_structure::marker. `FromDyn` can dynamically check data structures for thread safety when switching to parallel environments (such as calling `par_for_each_in`). This happens only when `-Z threads > 1` so it doesn't affect single-threaded mode's compile efficiency.

r? `@cjgillot`
This commit is contained in:
bors 2023-05-13 13:47:53 +00:00
commit dd8ec9c88d
26 changed files with 557 additions and 110 deletions
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2
compiler/rustc_data_structures/src/lib.rs
View file

@ -26,6 +26,7 @@
#![feature(test)]
#![feature(thread_id_value)]
#![feature(vec_into_raw_parts)]
#![feature(allocator_api)]
#![feature(get_mut_unchecked)]
#![feature(lint_reasons)]
#![feature(unwrap_infallible)]
@ -77,6 +78,7 @@ pub mod sorted_map;
pub mod stable_hasher;
mod atomic_ref;
pub mod fingerprint;
pub mod marker;
pub mod profiling;
pub mod sharded;
pub mod stack;

257
compiler/rustc_data_structures/src/marker.rs Normal file
View file

@ -0,0 +1,257 @@
cfg_if!(
if #[cfg(not(parallel_compiler))] {
pub auto trait DynSend {}
pub auto trait DynSync {}
impl<T> DynSend for T {}
impl<T> DynSync for T {}
} else {
#[rustc_on_unimplemented(
message = "`{Self}` doesn't implement `DynSend`. \
Add it to `rustc_data_structures::marker` or use `IntoDynSyncSend` if it's already `Send`"
)]
// This is an auto trait for types which can be sent across threads if `sync::is_dyn_thread_safe()`
// is true. These types can be wrapped in a `FromDyn` to get a `Send` type. Wrapping a
// `Send` type in `IntoDynSyncSend` will create a `DynSend` type.
pub unsafe auto trait DynSend {}
#[rustc_on_unimplemented(
message = "`{Self}` doesn't implement `DynSync`. \
Add it to `rustc_data_structures::marker` or use `IntoDynSyncSend` if it's already `Sync`"
)]
// This is an auto trait for types which can be shared across threads if `sync::is_dyn_thread_safe()`
// is true. These types can be wrapped in a `FromDyn` to get a `Sync` type. Wrapping a
// `Sync` type in `IntoDynSyncSend` will create a `DynSync` type.
pub unsafe auto trait DynSync {}
// Same with `Sync` and `Send`.
unsafe impl<T: DynSync + ?Sized> DynSend for &T {}
macro_rules! impls_dyn_send_neg {
($([$t1: ty $(where $($generics1: tt)*)?])*) => {
$(impl$(<$($generics1)*>)? !DynSend for $t1 {})*
};
}
// Consistent with `std`
impls_dyn_send_neg!(
[std::env::Args]
[std::env::ArgsOs]
[*const T where T: ?Sized]
[*mut T where T: ?Sized]
[std::ptr::NonNull<T> where T: ?Sized]
[std::rc::Rc<T> where T: ?Sized]
[std::rc::Weak<T> where T: ?Sized]
[std::sync::MutexGuard<'_, T> where T: ?Sized]
[std::sync::RwLockReadGuard<'_, T> where T: ?Sized]
[std::sync::RwLockWriteGuard<'_, T> where T: ?Sized]
[std::io::StdoutLock<'_>]
[std::io::StderrLock<'_>]
);
cfg_if!(
// Consistent with `std`
// `os_imp::Env` is `!Send` in these platforms
if #[cfg(any(unix, target_os = "hermit", target_os = "wasi", target_os = "solid_asp3"))] {
impl !DynSend for std::env::VarsOs {}
}
);
macro_rules! already_send {
($([$ty: ty])*) => {
$(unsafe impl DynSend for $ty where $ty: Send {})*
};
}
// These structures are already `Send`.
already_send!(
[std::backtrace::Backtrace]
[std::io::Stdout]
[std::io::Stderr]
[std::io::Error]
[std::fs::File]
[rustc_arena::DroplessArena]
[crate::memmap::Mmap]
[crate::profiling::SelfProfiler]
[crate::owned_slice::OwnedSlice]
);
macro_rules! impl_dyn_send {
($($($attr: meta)* [$ty: ty where $($generics2: tt)*])*) => {
$(unsafe impl<$($generics2)*> DynSend for $ty {})*
};
}
impl_dyn_send!(
[std::sync::atomic::AtomicPtr<T> where T]
[std::sync::Mutex<T> where T: ?Sized+ DynSend]
[std::sync::mpsc::Sender<T> where T: DynSend]
[std::sync::Arc<T> where T: ?Sized + DynSync + DynSend]
[std::sync::LazyLock<T, F> where T: DynSend, F: DynSend]
[std::collections::HashSet<K, S> where K: DynSend, S: DynSend]
[std::collections::HashMap<K, V, S> where K: DynSend, V: DynSend, S: DynSend]
[std::collections::BTreeMap<K, V, A> where K: DynSend, V: DynSend, A: std::alloc::Allocator + Clone + DynSend]
[Vec<T, A> where T: DynSend, A: std::alloc::Allocator + DynSend]
[Box<T, A> where T: ?Sized + DynSend, A: std::alloc::Allocator + DynSend]
[crate::sync::Lock<T> where T: DynSend]
[crate::sync::RwLock<T> where T: DynSend]
[crate::tagged_ptr::CopyTaggedPtr<P, T, CP> where P: Send + crate::tagged_ptr::Pointer, T: Send + crate::tagged_ptr::Tag, const CP: bool]
[rustc_arena::TypedArena<T> where T: DynSend]
[indexmap::IndexSet<V, S> where V: DynSend, S: DynSend]
[indexmap::IndexMap<K, V, S> where K: DynSend, V: DynSend, S: DynSend]
[thin_vec::ThinVec<T> where T: DynSend]
[smallvec::SmallVec<A> where A: smallvec::Array + DynSend]
);
macro_rules! impls_dyn_sync_neg {
($([$t1: ty $(where $($generics1: tt)*)?])*) => {
$(impl$(<$($generics1)*>)? !DynSync for $t1 {})*
};
}
// Consistent with `std`
impls_dyn_sync_neg!(
[std::env::Args]
[std::env::ArgsOs]
[*const T where T: ?Sized]
[*mut T where T: ?Sized]
[std::cell::Cell<T> where T: ?Sized]
[std::cell::RefCell<T> where T: ?Sized]
[std::cell::UnsafeCell<T> where T: ?Sized]
[std::ptr::NonNull<T> where T: ?Sized]
[std::rc::Rc<T> where T: ?Sized]
[std::rc::Weak<T> where T: ?Sized]
[std::cell::OnceCell<T> where T]
[std::sync::mpsc::Receiver<T> where T]
[std::sync::mpsc::Sender<T> where T]
);
cfg_if!(
// Consistent with `std`
// `os_imp::Env` is `!Sync` in these platforms
if #[cfg(any(unix, target_os = "hermit", target_os = "wasi", target_os = "solid_asp3"))] {
impl !DynSync for std::env::VarsOs {}
}
);
macro_rules! already_sync {
($([$ty: ty])*) => {
$(unsafe impl DynSync for $ty where $ty: Sync {})*
};
}
// These structures are already `Sync`.
already_sync!(
[std::sync::atomic::AtomicBool]
[std::sync::atomic::AtomicUsize]
[std::sync::atomic::AtomicU8]
[std::sync::atomic::AtomicU32]
[std::sync::atomic::AtomicU64]
[std::backtrace::Backtrace]
[std::io::Error]
[std::fs::File]
[jobserver_crate::Client]
[crate::memmap::Mmap]
[crate::profiling::SelfProfiler]
[crate::owned_slice::OwnedSlice]
);
macro_rules! impl_dyn_sync {
($($($attr: meta)* [$ty: ty where $($generics2: tt)*])*) => {
$(unsafe impl<$($generics2)*> DynSync for $ty {})*
};
}
impl_dyn_sync!(
[std::sync::atomic::AtomicPtr<T> where T]
[std::sync::OnceLock<T> where T: DynSend + DynSync]
[std::sync::Mutex<T> where T: ?Sized + DynSend]
[std::sync::Arc<T> where T: ?Sized + DynSync + DynSend]
[std::sync::LazyLock<T, F> where T: DynSend + DynSync, F: DynSend]
[std::collections::HashSet<K, S> where K: DynSync, S: DynSync]
[std::collections::HashMap<K, V, S> where K: DynSync, V: DynSync, S: DynSync]
[std::collections::BTreeMap<K, V, A> where K: DynSync, V: DynSync, A: std::alloc::Allocator + Clone + DynSync]
[Vec<T, A> where T: DynSync, A: std::alloc::Allocator + DynSync]
[Box<T, A> where T: ?Sized + DynSync, A: std::alloc::Allocator + DynSync]
[crate::sync::Lock<T> where T: DynSend]
[crate::sync::RwLock<T> where T: DynSend + DynSync]
[crate::sync::OneThread<T> where T]
[crate::sync::WorkerLocal<T> where T: DynSend]
[crate::intern::Interned<'a, T> where 'a, T: DynSync]
[crate::tagged_ptr::CopyTaggedPtr<P, T, CP> where P: Sync + crate::tagged_ptr::Pointer, T: Sync + crate::tagged_ptr::Tag, const CP: bool]
[parking_lot::lock_api::Mutex<R, T> where R: DynSync, T: ?Sized + DynSend]
[parking_lot::lock_api::RwLock<R, T> where R: DynSync, T: ?Sized + DynSend + DynSync]
[indexmap::IndexSet<V, S> where V: DynSync, S: DynSync]
[indexmap::IndexMap<K, V, S> where K: DynSync, V: DynSync, S: DynSync]
[smallvec::SmallVec<A> where A: smallvec::Array + DynSync]
[thin_vec::ThinVec<T> where T: DynSync]
);
}
);
pub fn assert_dyn_sync<T: ?Sized + DynSync>() {}
pub fn assert_dyn_send<T: ?Sized + DynSend>() {}
pub fn assert_dyn_send_val<T: ?Sized + DynSend>(_t: &T) {}
pub fn assert_dyn_send_sync_val<T: ?Sized + DynSync + DynSend>(_t: &T) {}
#[derive(Copy, Clone)]
pub struct FromDyn<T>(T);
impl<T> FromDyn<T> {
#[inline(always)]
pub fn from(val: T) -> Self {
// Check that `sync::is_dyn_thread_safe()` is true on creation so we can
// implement `Send` and `Sync` for this structure when `T`
// implements `DynSend` and `DynSync` respectively.
#[cfg(parallel_compiler)]
assert!(crate::sync::is_dyn_thread_safe());
FromDyn(val)
}
#[inline(always)]
pub fn into_inner(self) -> T {
self.0
}
}
// `FromDyn` is `Send` if `T` is `DynSend`, since it ensures that sync::is_dyn_thread_safe() is true.
#[cfg(parallel_compiler)]
unsafe impl<T: DynSend> Send for FromDyn<T> {}
// `FromDyn` is `Sync` if `T` is `DynSync`, since it ensures that sync::is_dyn_thread_safe() is true.
#[cfg(parallel_compiler)]
unsafe impl<T: DynSync> Sync for FromDyn<T> {}
impl<T> std::ops::Deref for FromDyn<T> {
type Target = T;
#[inline(always)]
fn deref(&self) -> &Self::Target {
&self.0
}
}
// A wrapper to convert a struct that is already a `Send` or `Sync` into
// an instance of `DynSend` and `DynSync`, since the compiler cannot infer
// it automatically in some cases. (e.g. Box<dyn Send / Sync>)
#[derive(Copy, Clone)]
pub struct IntoDynSyncSend<T: ?Sized>(pub T);
#[cfg(parallel_compiler)]
unsafe impl<T: ?Sized + Send> DynSend for IntoDynSyncSend<T> {}
#[cfg(parallel_compiler)]
unsafe impl<T: ?Sized + Sync> DynSync for IntoDynSyncSend<T> {}
impl<T> std::ops::Deref for IntoDynSyncSend<T> {
type Target = T;
#[inline(always)]
fn deref(&self) -> &T {
&self.0
}
}
impl<T> std::ops::DerefMut for IntoDynSyncSend<T> {
#[inline(always)]
fn deref_mut(&mut self) -> &mut T {
&mut self.0
}
}

4
compiler/rustc_data_structures/src/owned_slice/tests.rs
View file

@ -69,6 +69,6 @@ fn drop_drops() {
#[test]
fn send_sync() {
crate::sync::assert_send::<OwnedSlice>();
crate::sync::assert_sync::<OwnedSlice>();
crate::sync::assert_dyn_send::<OwnedSlice>();
crate::sync::assert_dyn_sync::<OwnedSlice>();
}

240
compiler/rustc_data_structures/src/sync.rs
View file

@ -39,6 +39,7 @@
//!
//! [^2] `MTLockRef` is a typedef.
pub use crate::marker::*;
use crate::owned_slice::OwnedSlice;
use std::collections::HashMap;
use std::hash::{BuildHasher, Hash};
@ -55,6 +56,42 @@ pub use vec::{AppendOnlyIndexVec, AppendOnlyVec};
mod vec;
mod mode {
use super::Ordering;
use std::sync::atomic::AtomicU8;
const UNINITIALIZED: u8 = 0;
const DYN_NOT_THREAD_SAFE: u8 = 1;
const DYN_THREAD_SAFE: u8 = 2;
static DYN_THREAD_SAFE_MODE: AtomicU8 = AtomicU8::new(UNINITIALIZED);
// Whether thread safety is enabled (due to running under multiple threads).
#[inline]
pub fn is_dyn_thread_safe() -> bool {
match DYN_THREAD_SAFE_MODE.load(Ordering::Relaxed) {
DYN_NOT_THREAD_SAFE => false,
DYN_THREAD_SAFE => true,
_ => panic!("uninitialized dyn_thread_safe mode!"),
}
}
// Only set by the `-Z threads` compile option
pub fn set_dyn_thread_safe_mode(mode: bool) {
let set: u8 = if mode { DYN_THREAD_SAFE } else { DYN_NOT_THREAD_SAFE };
let previous = DYN_THREAD_SAFE_MODE.compare_exchange(
UNINITIALIZED,
set,
Ordering::Relaxed,
Ordering::Relaxed,
);
// Check that the mode was either uninitialized or was already set to the requested mode.
assert!(previous.is_ok() || previous == Err(set));
}
}
pub use mode::{is_dyn_thread_safe, set_dyn_thread_safe_mode};
cfg_if! {
if #[cfg(not(parallel_compiler))] {
pub unsafe auto trait Send {}
@ -149,7 +186,7 @@ cfg_if! {
#[macro_export]
macro_rules! parallel {
($($blocks:tt),*) => {
($($blocks:block),*) => {
// We catch panics here ensuring that all the blocks execute.
// This makes behavior consistent with the parallel compiler.
let mut panic = None;
@ -168,12 +205,6 @@ cfg_if! {
}
}
pub use 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.
@ -190,6 +221,29 @@ cfg_if! {
}
}
pub fn par_map<T: IntoIterator, R, C: FromIterator<R>>(
t: T,
mut map: impl FnMut(<<T as IntoIterator>::IntoIter as Iterator>::Item) -> R,
) -> C {
// We catch panics here ensuring that all the loop iterations execute.
let mut panic = None;
let r = t.into_iter().filter_map(|i| {
match catch_unwind(AssertUnwindSafe(|| map(i))) {
Ok(r) => Some(r),
Err(p) => {
if panic.is_none() {
panic = Some(p);
}
None
}
}
}).collect();
if let Some(panic) = panic {
resume_unwind(panic);
}
r
}
pub type MetadataRef = OwnedSlice;
pub use std::rc::Rc as Lrc;
@ -302,46 +356,165 @@ cfg_if! {
use parking_lot::RwLock as InnerRwLock;
use std::thread;
pub use rayon::{join, scope};
#[inline]
pub fn join<A, B, RA: DynSend, RB: DynSend>(oper_a: A, oper_b: B) -> (RA, RB)
where
A: FnOnce() -> RA + DynSend,
B: FnOnce() -> RB + DynSend,
{
if mode::is_dyn_thread_safe() {
let oper_a = FromDyn::from(oper_a);
let oper_b = FromDyn::from(oper_b);
let (a, b) = rayon::join(move || FromDyn::from(oper_a.into_inner()()), move || FromDyn::from(oper_b.into_inner()()));
(a.into_inner(), b.into_inner())
} else {
(oper_a(), oper_b())
}
}
// This function only works when `mode::is_dyn_thread_safe()`.
pub fn scope<'scope, OP, R>(op: OP) -> R
where
OP: FnOnce(&rayon::Scope<'scope>) -> R + DynSend,
R: DynSend,
{
let op = FromDyn::from(op);
rayon::scope(|s| FromDyn::from(op.into_inner()(s))).into_inner()
}
/// 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)*]) => {
(impl $fblock:block [$($c:expr,)*] [$block:expr $(, $rest:expr)*]) => {
parallel!(impl $fblock [$block, $($c,)*] [$($rest),*])
};
(impl $fblock:tt [$($blocks:tt,)*] []) => {
(impl $fblock:block [$($blocks:expr,)*] []) => {
::rustc_data_structures::sync::scope(|s| {
$(let block = rustc_data_structures::sync::FromDyn::from(|| $blocks);
s.spawn(move |_| block.into_inner()());)*
(|| $fblock)();
});
};
($fblock:block, $($blocks:block),*) => {
if rustc_data_structures::sync::is_dyn_thread_safe() {
// 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),*]);
} else {
// 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(|| $fblock)
) {
if panic.is_none() {
panic = Some(p);
}
}
$(
s.spawn(|_| $blocks);
if let Err(p) = ::std::panic::catch_unwind(
::std::panic::AssertUnwindSafe(|| $blocks)
) {
if panic.is_none() {
panic = Some(p);
}
}
)*
$fblock;
})
};
($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),*]);
if let Some(panic) = panic {
::std::panic::resume_unwind(panic);
}
}
};
}
pub use rayon::iter::ParallelIterator;
use rayon::iter::IntoParallelIterator;
use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelIterator};
pub fn par_iter<T: IntoParallelIterator>(t: T) -> T::Iter {
t.into_par_iter()
}
pub fn par_for_each_in<T: IntoParallelIterator>(
pub fn par_for_each_in<I, T: IntoIterator<Item = I> + IntoParallelIterator<Item = I>>(
t: T,
for_each: impl Fn(T::Item) + Sync + Send,
for_each: impl Fn(I) + DynSync + DynSend
) {
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)
});
if mode::is_dyn_thread_safe() {
let for_each = FromDyn::from(for_each);
let panic: Lock<Option<_>> = Lock::new(None);
t.into_par_iter().for_each(|i| if let Err(p) = catch_unwind(AssertUnwindSafe(|| for_each(i))) {
let mut l = panic.lock();
if l.is_none() {
*l = Some(p)
}
});
if let Some(panic) = panic.into_inner() {
resume_unwind(panic);
}
} else {
// 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 fn par_map<
I,
T: IntoIterator<Item = I> + IntoParallelIterator<Item = I>,
R: std::marker::Send,
C: FromIterator<R> + FromParallelIterator<R>
>(
t: T,
map: impl Fn(I) -> R + DynSync + DynSend
) -> C {
if mode::is_dyn_thread_safe() {
let panic: Lock<Option<_>> = Lock::new(None);
let map = FromDyn::from(map);
// We catch panics here ensuring that all the loop iterations execute.
let r = t.into_par_iter().filter_map(|i| {
match catch_unwind(AssertUnwindSafe(|| map(i))) {
Ok(r) => Some(r),
Err(p) => {
let mut l = panic.lock();
if l.is_none() {
*l = Some(p);
}
None
},
}
}).collect();
if let Some(panic) = panic.into_inner() {
resume_unwind(panic);
}
r
} else {
// We catch panics here ensuring that all the loop iterations execute.
let mut panic = None;
let r = t.into_iter().filter_map(|i| {
match catch_unwind(AssertUnwindSafe(|| map(i))) {
Ok(r) => Some(r),
Err(p) => {
if panic.is_none() {
panic = Some(p);
}
None
}
}
}).collect();
if let Some(panic) = panic {
resume_unwind(panic);
}
r
}
}
pub type MetadataRef = OwnedSlice;
@ -352,11 +525,6 @@ cfg_if! {
}
}
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) {}
#[derive(Default)]
#[cfg_attr(parallel_compiler, repr(align(64)))]
pub struct CacheAligned<T>(pub T);