diff options
Diffstat (limited to 'compiler/rustc_data_structures/src')
38 files changed, 2077 insertions, 532 deletions
diff --git a/compiler/rustc_data_structures/src/aligned.rs b/compiler/rustc_data_structures/src/aligned.rs new file mode 100644 index 000000000..0e5ecfd9b --- /dev/null +++ b/compiler/rustc_data_structures/src/aligned.rs @@ -0,0 +1,33 @@ +use std::ptr::Alignment; + +/// Returns the ABI-required minimum alignment of a type in bytes. +/// +/// This is equivalent to [`mem::align_of`], but also works for some unsized +/// types (e.g. slices or rustc's `List`s). +/// +/// [`mem::align_of`]: std::mem::align_of +pub const fn align_of<T: ?Sized + Aligned>() -> Alignment { + T::ALIGN +} + +/// A type with a statically known alignment. +/// +/// # Safety +/// +/// `Self::ALIGN` must be equal to the alignment of `Self`. For sized types it +/// is [`mem::align_of<Self>()`], for unsized types it depends on the type, for +/// example `[T]` has alignment of `T`. +/// +/// [`mem::align_of<Self>()`]: std::mem::align_of +pub unsafe trait Aligned { + /// Alignment of `Self`. + const ALIGN: Alignment; +} + +unsafe impl<T> Aligned for T { + const ALIGN: Alignment = Alignment::of::<Self>(); +} + +unsafe impl<T> Aligned for [T] { + const ALIGN: Alignment = Alignment::of::<T>(); +} diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs index b6e866f15..9995c0834 100644 --- a/compiler/rustc_data_structures/src/fingerprint.rs +++ b/compiler/rustc_data_structures/src/fingerprint.rs @@ -1,4 +1,4 @@ -use crate::stable_hasher; +use crate::stable_hasher::{Hash64, StableHasher, StableHasherResult}; use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; use std::hash::{Hash, Hasher}; @@ -9,32 +9,49 @@ mod tests; #[repr(C)] pub struct Fingerprint(u64, u64); -impl Fingerprint { - pub const ZERO: Fingerprint = Fingerprint(0, 0); +pub trait FingerprintComponent { + fn as_u64(&self) -> u64; +} +impl FingerprintComponent for Hash64 { #[inline] - pub fn new(_0: u64, _1: u64) -> Fingerprint { - Fingerprint(_0, _1) + fn as_u64(&self) -> u64 { + Hash64::as_u64(*self) } +} +impl FingerprintComponent for u64 { #[inline] - pub fn from_smaller_hash(hash: u64) -> Fingerprint { - Fingerprint(hash, hash) + fn as_u64(&self) -> u64 { + *self + } +} + +impl Fingerprint { + pub const ZERO: Fingerprint = Fingerprint(0, 0); + + #[inline] + pub fn new<A, B>(_0: A, _1: B) -> Fingerprint + where + A: FingerprintComponent, + B: FingerprintComponent, + { + Fingerprint(_0.as_u64(), _1.as_u64()) } #[inline] - pub fn to_smaller_hash(&self) -> u64 { + pub fn to_smaller_hash(&self) -> Hash64 { // Even though both halves of the fingerprint are expected to be good // quality hash values, let's still combine the two values because the // Fingerprints in DefPathHash have the StableCrateId portion which is // the same for all DefPathHashes from the same crate. Combining the // two halves makes sure we get a good quality hash in such cases too. - self.0.wrapping_mul(3).wrapping_add(self.1) + Hash64::new(self.0.wrapping_mul(3).wrapping_add(self.1)) } #[inline] - pub fn as_value(&self) -> (u64, u64) { - (self.0, self.1) + pub fn split(&self) -> (Hash64, Hash64) { + (Hash64::new(self.0), Hash64::new(self.1)) } #[inline] @@ -47,6 +64,11 @@ impl Fingerprint { ) } + #[inline] + pub(crate) fn as_u128(self) -> u128 { + u128::from(self.1) << 64 | u128::from(self.0) + } + // Combines two hashes in an order independent way. Make sure this is what // you want. #[inline] @@ -131,9 +153,9 @@ impl FingerprintHasher for crate::unhash::Unhasher { } } -impl stable_hasher::StableHasherResult for Fingerprint { +impl StableHasherResult for Fingerprint { #[inline] - fn finish(hasher: stable_hasher::StableHasher) -> Self { + fn finish(hasher: StableHasher) -> Self { let (_0, _1) = hasher.finalize(); Fingerprint(_0, _1) } diff --git a/compiler/rustc_data_structures/src/fingerprint/tests.rs b/compiler/rustc_data_structures/src/fingerprint/tests.rs index 9b0783e33..09ec2622a 100644 --- a/compiler/rustc_data_structures/src/fingerprint/tests.rs +++ b/compiler/rustc_data_structures/src/fingerprint/tests.rs @@ -1,11 +1,12 @@ use super::*; +use crate::stable_hasher::Hash64; // Check that `combine_commutative` is order independent. #[test] fn combine_commutative_is_order_independent() { - let a = Fingerprint::new(0xf6622fb349898b06, 0x70be9377b2f9c610); - let b = Fingerprint::new(0xa9562bf5a2a5303c, 0x67d9b6c82034f13d); - let c = Fingerprint::new(0x0d013a27811dbbc3, 0x9a3f7b3d9142ec43); + let a = Fingerprint::new(Hash64::new(0xf6622fb349898b06), Hash64::new(0x70be9377b2f9c610)); + let b = Fingerprint::new(Hash64::new(0xa9562bf5a2a5303c), Hash64::new(0x67d9b6c82034f13d)); + let c = Fingerprint::new(Hash64::new(0x0d013a27811dbbc3), Hash64::new(0x9a3f7b3d9142ec43)); let permutations = [(a, b, c), (a, c, b), (b, a, c), (b, c, a), (c, a, b), (c, b, a)]; let f = a.combine_commutative(b).combine_commutative(c); for p in &permutations { diff --git a/compiler/rustc_data_structures/src/functor.rs b/compiler/rustc_data_structures/src/functor.rs index 28fcf80b3..e3fcaccb1 100644 --- a/compiler/rustc_data_structures/src/functor.rs +++ b/compiler/rustc_data_structures/src/functor.rs @@ -1,4 +1,4 @@ -use rustc_index::vec::{Idx, IndexVec}; +use rustc_index::{Idx, IndexVec}; use std::{mem, rc::Rc, sync::Arc}; pub trait IdFunctor: Sized { diff --git a/compiler/rustc_data_structures/src/graph/dominators/mod.rs b/compiler/rustc_data_structures/src/graph/dominators/mod.rs index 0df9dc112..a5db14d91 100644 --- a/compiler/rustc_data_structures/src/graph/dominators/mod.rs +++ b/compiler/rustc_data_structures/src/graph/dominators/mod.rs @@ -10,7 +10,8 @@ //! <https://www.cs.princeton.edu/courses/archive/spr03/cs423/download/dominators.pdf> use super::ControlFlowGraph; -use rustc_index::vec::{Idx, IndexSlice, IndexVec}; +use rustc_index::{Idx, IndexSlice, IndexVec}; + use std::cmp::Ordering; #[cfg(test)] @@ -25,7 +26,7 @@ rustc_index::newtype_index! { struct PreorderIndex {} } -pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> { +pub fn dominators<G: ControlFlowGraph>(graph: &G) -> Dominators<G::Node> { // compute the post order index (rank) for each node let mut post_order_rank = IndexVec::from_elem_n(0, graph.num_nodes()); @@ -108,28 +109,27 @@ pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> { // they have been placed in the bucket. // // We compute a partial set of immediate dominators here. - let z = parent[w]; - for &v in bucket[z].iter() { + for &v in bucket[w].iter() { // This uses the result of Lemma 5 from section 2 from the original // 1979 paper, to compute either the immediate or relative dominator // for a given vertex v. // // eval returns a vertex y, for which semi[y] is minimum among - // vertices semi[v] +> y *> v. Note that semi[v] = z as we're in the - // z bucket. + // vertices semi[v] +> y *> v. Note that semi[v] = w as we're in the + // w bucket. // // Given such a vertex y, semi[y] <= semi[v] and idom[y] = idom[v]. // If semi[y] = semi[v], though, idom[v] = semi[v]. // // Using this, we can either set idom[v] to be: - // * semi[v] (i.e. z), if semi[y] is z + // * semi[v] (i.e. w), if semi[y] is w // * idom[y], otherwise // // We don't directly set to idom[y] though as it's not necessarily // known yet. The second preorder traversal will cleanup by updating // the idom for any that were missed in this pass. let y = eval(&mut parent, lastlinked, &semi, &mut label, v); - idom[v] = if semi[y] < z { y } else { z }; + idom[v] = if semi[y] < w { y } else { w }; } // This loop computes the semi[w] for w. @@ -212,10 +212,11 @@ pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> { // If we don't yet know the idom directly, then push this vertex into // our semidominator's bucket, where it will get processed at a later // stage to compute its immediate dominator. - if parent[w] != semi[w] { + let z = parent[w]; + if z != semi[w] { bucket[semi[w]].push(w); } else { - idom[w] = parent[w]; + idom[w] = z; } // Optimization: We share the parent array between processed and not @@ -241,7 +242,12 @@ pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> { immediate_dominators[*node] = Some(pre_order_to_real[idom[idx]]); } - Dominators { post_order_rank, immediate_dominators } + let start_node = graph.start_node(); + immediate_dominators[start_node] = None; + + let time = compute_access_time(start_node, &immediate_dominators); + + Dominators { start_node, post_order_rank, immediate_dominators, time } } /// Evaluate the link-eval virtual forest, providing the currently minimum semi @@ -307,34 +313,31 @@ fn compress( /// Tracks the list of dominators for each node. #[derive(Clone, Debug)] pub struct Dominators<N: Idx> { + start_node: N, post_order_rank: IndexVec<N, usize>, // Even though we track only the immediate dominator of each node, it's // possible to get its full list of dominators by looking up the dominator // of each dominator. (See the `impl Iterator for Iter` definition). immediate_dominators: IndexVec<N, Option<N>>, + time: IndexVec<N, Time>, } impl<Node: Idx> Dominators<Node> { - /// Whether the given Node has an immediate dominator. + /// Returns true if node is reachable from the start node. pub fn is_reachable(&self, node: Node) -> bool { - self.immediate_dominators[node].is_some() + node == self.start_node || self.immediate_dominators[node].is_some() } - pub fn immediate_dominator(&self, node: Node) -> Node { - assert!(self.is_reachable(node), "node {node:?} is not reachable"); - self.immediate_dominators[node].unwrap() + /// Returns the immediate dominator of node, if any. + pub fn immediate_dominator(&self, node: Node) -> Option<Node> { + self.immediate_dominators[node] } /// Provides an iterator over each dominator up the CFG, for the given Node. /// See the `impl Iterator for Iter` definition to understand how this works. pub fn dominators(&self, node: Node) -> Iter<'_, Node> { assert!(self.is_reachable(node), "node {node:?} is not reachable"); - Iter { dominators: self, node: Some(node) } - } - - pub fn dominates(&self, dom: Node, node: Node) -> bool { - // FIXME -- could be optimized by using post-order-rank - self.dominators(node).any(|n| n == dom) + Iter { dom_tree: self, node: Some(node) } } /// Provide deterministic ordering of nodes such that, if any two nodes have a dominator @@ -344,10 +347,22 @@ impl<Node: Idx> Dominators<Node> { pub fn rank_partial_cmp(&self, lhs: Node, rhs: Node) -> Option<Ordering> { self.post_order_rank[rhs].partial_cmp(&self.post_order_rank[lhs]) } + + /// Returns true if `a` dominates `b`. + /// + /// # Panics + /// + /// Panics if `b` is unreachable. + pub fn dominates(&self, a: Node, b: Node) -> bool { + let a = self.time[a]; + let b = self.time[b]; + assert!(b.start != 0, "node {b:?} is not reachable"); + a.start <= b.start && b.finish <= a.finish + } } pub struct Iter<'dom, Node: Idx> { - dominators: &'dom Dominators<Node>, + dom_tree: &'dom Dominators<Node>, node: Option<Node>, } @@ -356,15 +371,74 @@ impl<'dom, Node: Idx> Iterator for Iter<'dom, Node> { fn next(&mut self) -> Option<Self::Item> { if let Some(node) = self.node { - let dom = self.dominators.immediate_dominator(node); - if dom == node { - self.node = None; // reached the root - } else { - self.node = Some(dom); - } + self.node = self.dom_tree.immediate_dominator(node); Some(node) } else { None } } } + +/// Describes the number of vertices discovered at the time when processing of a particular vertex +/// started and when it finished. Both values are zero for unreachable vertices. +#[derive(Copy, Clone, Default, Debug)] +struct Time { + start: u32, + finish: u32, +} + +fn compute_access_time<N: Idx>( + start_node: N, + immediate_dominators: &IndexSlice<N, Option<N>>, +) -> IndexVec<N, Time> { + // Transpose the dominator tree edges, so that child nodes of vertex v are stored in + // node[edges[v].start..edges[v].end]. + let mut edges: IndexVec<N, std::ops::Range<u32>> = + IndexVec::from_elem(0..0, immediate_dominators); + for &idom in immediate_dominators.iter() { + if let Some(idom) = idom { + edges[idom].end += 1; + } + } + let mut m = 0; + for e in edges.iter_mut() { + m += e.end; + e.start = m; + e.end = m; + } + let mut node = IndexVec::from_elem_n(Idx::new(0), m.try_into().unwrap()); + for (i, &idom) in immediate_dominators.iter_enumerated() { + if let Some(idom) = idom { + edges[idom].start -= 1; + node[edges[idom].start] = i; + } + } + + // Perform a depth-first search of the dominator tree. Record the number of vertices discovered + // when vertex v is discovered first as time[v].start, and when its processing is finished as + // time[v].finish. + let mut time: IndexVec<N, Time> = IndexVec::from_elem(Time::default(), immediate_dominators); + let mut stack = Vec::new(); + + let mut discovered = 1; + stack.push(start_node); + time[start_node].start = discovered; + + while let Some(&i) = stack.last() { + let e = &mut edges[i]; + if e.start == e.end { + // Finish processing vertex i. + time[i].finish = discovered; + stack.pop(); + } else { + let j = node[e.start]; + e.start += 1; + // Start processing vertex j. + discovered += 1; + time[j].start = discovered; + stack.push(j); + } + } + + time +} diff --git a/compiler/rustc_data_structures/src/graph/dominators/tests.rs b/compiler/rustc_data_structures/src/graph/dominators/tests.rs index ff31d8f7f..5472bb808 100644 --- a/compiler/rustc_data_structures/src/graph/dominators/tests.rs +++ b/compiler/rustc_data_structures/src/graph/dominators/tests.rs @@ -8,7 +8,7 @@ fn diamond() { let dominators = dominators(&graph); let immediate_dominators = &dominators.immediate_dominators; - assert_eq!(immediate_dominators[0], Some(0)); + assert_eq!(immediate_dominators[0], None); assert_eq!(immediate_dominators[1], Some(0)); assert_eq!(immediate_dominators[2], Some(0)); assert_eq!(immediate_dominators[3], Some(0)); @@ -30,7 +30,7 @@ fn paper() { assert_eq!(immediate_dominators[3], Some(6)); assert_eq!(immediate_dominators[4], Some(6)); assert_eq!(immediate_dominators[5], Some(6)); - assert_eq!(immediate_dominators[6], Some(6)); + assert_eq!(immediate_dominators[6], None); } #[test] @@ -43,3 +43,40 @@ fn paper_slt() { dominators(&graph); } + +#[test] +fn immediate_dominator() { + let graph = TestGraph::new(1, &[(1, 2), (2, 3)]); + let dominators = dominators(&graph); + assert_eq!(dominators.immediate_dominator(0), None); + assert_eq!(dominators.immediate_dominator(1), None); + assert_eq!(dominators.immediate_dominator(2), Some(1)); + assert_eq!(dominators.immediate_dominator(3), Some(2)); +} + +#[test] +fn transitive_dominator() { + let graph = TestGraph::new( + 0, + &[ + // First tree branch. + (0, 1), + (1, 2), + (2, 3), + (3, 4), + // Second tree branch. + (1, 5), + (5, 6), + // Third tree branch. + (0, 7), + // These links make 0 the dominator for 2 and 3. + (7, 2), + (5, 3), + ], + ); + + let dom_tree = dominators(&graph); + let immediate_dominators = &dom_tree.immediate_dominators; + assert_eq!(immediate_dominators[2], Some(0)); + assert_eq!(immediate_dominators[3], Some(0)); // This used to return Some(1). +} diff --git a/compiler/rustc_data_structures/src/graph/iterate/mod.rs b/compiler/rustc_data_structures/src/graph/iterate/mod.rs index 01a83b40a..9eb4b5278 100644 --- a/compiler/rustc_data_structures/src/graph/iterate/mod.rs +++ b/compiler/rustc_data_structures/src/graph/iterate/mod.rs @@ -1,6 +1,6 @@ use super::{DirectedGraph, WithNumNodes, WithStartNode, WithSuccessors}; use rustc_index::bit_set::BitSet; -use rustc_index::vec::{IndexSlice, IndexVec}; +use rustc_index::{IndexSlice, IndexVec}; use std::ops::ControlFlow; #[cfg(test)] diff --git a/compiler/rustc_data_structures/src/graph/mod.rs b/compiler/rustc_data_structures/src/graph/mod.rs index 3560df6e5..e06ab2fe3 100644 --- a/compiler/rustc_data_structures/src/graph/mod.rs +++ b/compiler/rustc_data_structures/src/graph/mod.rs @@ -1,4 +1,4 @@ -use rustc_index::vec::Idx; +use rustc_index::Idx; pub mod dominators; pub mod implementation; diff --git a/compiler/rustc_data_structures/src/graph/scc/mod.rs b/compiler/rustc_data_structures/src/graph/scc/mod.rs index 28c357e54..cf9312ea8 100644 --- a/compiler/rustc_data_structures/src/graph/scc/mod.rs +++ b/compiler/rustc_data_structures/src/graph/scc/mod.rs @@ -8,7 +8,7 @@ use crate::fx::FxHashSet; use crate::graph::vec_graph::VecGraph; use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors}; -use rustc_index::vec::{Idx, IndexSlice, IndexVec}; +use rustc_index::{Idx, IndexSlice, IndexVec}; use std::ops::Range; #[cfg(test)] diff --git a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs index 94232bb76..00f6266ce 100644 --- a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs +++ b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs @@ -1,5 +1,5 @@ use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors}; -use rustc_index::vec::{Idx, IndexVec}; +use rustc_index::{Idx, IndexVec}; #[cfg(test)] mod tests; diff --git a/compiler/rustc_data_structures/src/hashes.rs b/compiler/rustc_data_structures/src/hashes.rs new file mode 100644 index 000000000..ad068cdbc --- /dev/null +++ b/compiler/rustc_data_structures/src/hashes.rs @@ -0,0 +1,132 @@ +//! rustc encodes a lot of hashes. If hashes are stored as `u64` or `u128`, a `derive(Encodable)` +//! will apply varint encoding to the hashes, which is less efficient than directly encoding the 8 +//! or 16 bytes of the hash. +//! +//! The types in this module represent 64-bit or 128-bit hashes produced by a `StableHasher`. +//! `Hash64` and `Hash128` expose some utilty functions to encourage users to not extract the inner +//! hash value as an integer type and accidentally apply varint encoding to it. +//! +//! In contrast with `Fingerprint`, users of these types cannot and should not attempt to construct +//! and decompose these types into constitutent pieces. The point of these types is only to +//! connect the fact that they can only be produced by a `StableHasher` to their +//! `Encode`/`Decode` impls. + +use crate::stable_hasher::{StableHasher, StableHasherResult}; +use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; +use std::fmt; +use std::ops::BitXorAssign; + +#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Default)] +pub struct Hash64 { + inner: u64, +} + +impl Hash64 { + pub const ZERO: Hash64 = Hash64 { inner: 0 }; + + #[inline] + pub(crate) fn new(n: u64) -> Self { + Self { inner: n } + } + + #[inline] + pub fn as_u64(self) -> u64 { + self.inner + } +} + +impl BitXorAssign<u64> for Hash64 { + #[inline] + fn bitxor_assign(&mut self, rhs: u64) { + self.inner ^= rhs; + } +} + +impl<S: Encoder> Encodable<S> for Hash64 { + #[inline] + fn encode(&self, s: &mut S) { + s.emit_raw_bytes(&self.inner.to_le_bytes()); + } +} + +impl<D: Decoder> Decodable<D> for Hash64 { + #[inline] + fn decode(d: &mut D) -> Self { + Self { inner: u64::from_le_bytes(d.read_raw_bytes(8).try_into().unwrap()) } + } +} + +impl StableHasherResult for Hash64 { + #[inline] + fn finish(hasher: StableHasher) -> Self { + Self { inner: hasher.finalize().0 } + } +} + +impl fmt::Debug for Hash64 { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.inner.fmt(f) + } +} + +impl fmt::LowerHex for Hash64 { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::LowerHex::fmt(&self.inner, f) + } +} + +#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Default)] +pub struct Hash128 { + inner: u128, +} + +impl Hash128 { + #[inline] + pub fn truncate(self) -> Hash64 { + Hash64 { inner: self.inner as u64 } + } + + #[inline] + pub fn wrapping_add(self, other: Self) -> Self { + Self { inner: self.inner.wrapping_add(other.inner) } + } + + #[inline] + pub fn as_u128(self) -> u128 { + self.inner + } +} + +impl<S: Encoder> Encodable<S> for Hash128 { + #[inline] + fn encode(&self, s: &mut S) { + s.emit_raw_bytes(&self.inner.to_le_bytes()); + } +} + +impl<D: Decoder> Decodable<D> for Hash128 { + #[inline] + fn decode(d: &mut D) -> Self { + Self { inner: u128::from_le_bytes(d.read_raw_bytes(16).try_into().unwrap()) } + } +} + +impl StableHasherResult for Hash128 { + #[inline] + fn finish(hasher: StableHasher) -> Self { + let (_0, _1) = hasher.finalize(); + Self { inner: u128::from(_0) | (u128::from(_1) << 64) } + } +} + +impl fmt::Debug for Hash128 { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.inner.fmt(f) + } +} + +impl fmt::LowerHex for Hash128 { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::LowerHex::fmt(&self.inner, f) + } +} diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs index e373bd184..859e384d8 100644 --- a/compiler/rustc_data_structures/src/lib.rs +++ b/compiler/rustc_data_structures/src/lib.rs @@ -26,13 +26,18 @@ #![feature(test)] #![feature(thread_id_value)] #![feature(vec_into_raw_parts)] +#![feature(allocator_api)] #![feature(get_mut_unchecked)] #![feature(lint_reasons)] #![feature(unwrap_infallible)] +#![feature(strict_provenance)] +#![feature(ptr_alignment_type)] +#![feature(macro_metavar_expr)] #![allow(rustc::default_hash_types)] #![allow(rustc::potential_query_instability)] #![deny(rustc::untranslatable_diagnostic)] #![deny(rustc::diagnostic_outside_of_impl)] +#![deny(unsafe_op_in_unsafe_fn)] #[macro_use] extern crate tracing; @@ -73,6 +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; @@ -82,7 +88,9 @@ pub mod transitive_relation; pub mod vec_linked_list; pub mod work_queue; pub use atomic_ref::AtomicRef; +pub mod aligned; pub mod frozen; +mod hashes; pub mod owned_slice; pub mod sso; pub mod steal; @@ -94,21 +102,27 @@ pub mod unord; pub use ena::undo_log; pub use ena::unify; -pub struct OnDrop<F: Fn()>(pub F); +/// Returns a structure that calls `f` when dropped. +pub fn defer<F: FnOnce()>(f: F) -> OnDrop<F> { + OnDrop(Some(f)) +} + +pub struct OnDrop<F: FnOnce()>(Option<F>); -impl<F: Fn()> OnDrop<F> { - /// Forgets the function which prevents it from running. - /// Ensure that the function owns no memory, otherwise it will be leaked. +impl<F: FnOnce()> OnDrop<F> { + /// Disables on-drop call. #[inline] - pub fn disable(self) { - std::mem::forget(self); + pub fn disable(mut self) { + self.0.take(); } } -impl<F: Fn()> Drop for OnDrop<F> { +impl<F: FnOnce()> Drop for OnDrop<F> { #[inline] fn drop(&mut self) { - (self.0)(); + if let Some(f) = self.0.take() { + f(); + } } } diff --git a/compiler/rustc_data_structures/src/marker.rs b/compiler/rustc_data_structures/src/marker.rs new file mode 100644 index 000000000..f8c06f9a8 --- /dev/null +++ b/compiler/rustc_data_structures/src/marker.rs @@ -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 + } +} diff --git a/compiler/rustc_data_structures/src/memmap.rs b/compiler/rustc_data_structures/src/memmap.rs index ef37a606f..ca908671a 100644 --- a/compiler/rustc_data_structures/src/memmap.rs +++ b/compiler/rustc_data_structures/src/memmap.rs @@ -13,7 +13,8 @@ pub struct Mmap(Vec<u8>); impl Mmap { #[inline] pub unsafe fn map(file: File) -> io::Result<Self> { - memmap2::Mmap::map(&file).map(Mmap) + // Safety: this is in fact not safe. + unsafe { memmap2::Mmap::map(&file).map(Mmap) } } } diff --git a/compiler/rustc_data_structures/src/obligation_forest/mod.rs b/compiler/rustc_data_structures/src/obligation_forest/mod.rs index 27a869eb7..a47908648 100644 --- a/compiler/rustc_data_structures/src/obligation_forest/mod.rs +++ b/compiler/rustc_data_structures/src/obligation_forest/mod.rs @@ -366,7 +366,7 @@ impl<O: ForestObligation> ObligationForest<O> { && self .error_cache .get(&obligation_tree_id) - .map_or(false, |errors| errors.contains(v.key())); + .is_some_and(|errors| errors.contains(v.key())); if already_failed { Err(()) diff --git a/compiler/rustc_data_structures/src/owned_slice.rs b/compiler/rustc_data_structures/src/owned_slice.rs index 048401f66..cbb3047d8 100644 --- a/compiler/rustc_data_structures/src/owned_slice.rs +++ b/compiler/rustc_data_structures/src/owned_slice.rs @@ -1,5 +1,6 @@ use std::{borrow::Borrow, ops::Deref}; +use crate::sync::Lrc; // Use our fake Send/Sync traits when on not parallel compiler, // so that `OwnedSlice` only implements/requires Send/Sync // for parallel compiler builds. @@ -7,7 +8,7 @@ use crate::sync::{Send, Sync}; /// An owned slice. /// -/// This is similar to `Box<[u8]>` but allows slicing and using anything as the +/// This is similar to `Lrc<[u8]>` but allows slicing and using anything as the /// backing buffer. /// /// See [`slice_owned`] for `OwnedSlice` construction and examples. @@ -16,6 +17,7 @@ use crate::sync::{Send, Sync}; /// /// This is essentially a replacement for `owning_ref` which is a lot simpler /// and even sound! 🌸 +#[derive(Clone)] pub struct OwnedSlice { /// This is conceptually a `&'self.owner [u8]`. bytes: *const [u8], @@ -31,7 +33,7 @@ pub struct OwnedSlice { // \/ // ⊂(´･◡･⊂ )∘˚˳° (I am the phantom remnant of #97770) #[expect(dead_code)] - owner: Box<dyn Send + Sync>, + owner: Lrc<dyn Send + Sync>, } /// Makes an [`OwnedSlice`] out of an `owner` and a `slicer` function. @@ -72,10 +74,10 @@ where O: Send + Sync + 'static, F: FnOnce(&O) -> Result<&[u8], E>, { - // We box the owner of the bytes, so it doesn't move. + // We wrap the owner of the bytes in, so it doesn't move. // // Since the owner does not move and we don't access it in any way - // before drop, there is nothing that can invalidate the bytes pointer. + // before dropping, there is nothing that can invalidate the bytes pointer. // // Thus, "extending" the lifetime of the reference returned from `F` is fine. // We pretend that we pass it a reference that lives as long as the returned slice. @@ -83,12 +85,39 @@ where // N.B. the HRTB on the `slicer` is important — without it the caller could provide // a short lived slice, unrelated to the owner. - let owner = Box::new(owner); + let owner = Lrc::new(owner); let bytes = slicer(&*owner)?; Ok(OwnedSlice { bytes, owner }) } +impl OwnedSlice { + /// Slice this slice by `slicer`. + /// + /// # Examples + /// + /// ```rust + /// # use rustc_data_structures::owned_slice::{OwnedSlice, slice_owned}; + /// let vec = vec![1, 2, 3, 4]; + /// + /// // Identical to slicing via `&v[1..3]` but produces an owned slice + /// let slice: OwnedSlice = slice_owned(vec, |v| &v[..]); + /// assert_eq!(&*slice, [1, 2, 3, 4]); + /// + /// let slice = slice.slice(|slice| &slice[1..][..2]); + /// assert_eq!(&*slice, [2, 3]); + /// ``` + /// + pub fn slice(self, slicer: impl FnOnce(&[u8]) -> &[u8]) -> OwnedSlice { + // This is basically identical to `try_slice_owned`, + // `slicer` can only return slices of its argument or some static data, + // both of which are valid while `owner` is alive. + + let bytes = slicer(&self); + OwnedSlice { bytes, ..self } + } +} + impl Deref for OwnedSlice { type Target = [u8]; @@ -108,10 +137,12 @@ impl Borrow<[u8]> for OwnedSlice { } } -// Safety: `OwnedSlice` is conceptually `(&'self.1 [u8], Box<dyn Send + Sync>)`, which is `Send` +// Safety: `OwnedSlice` is conceptually `(&'self.1 [u8], Arc<dyn Send + Sync>)`, which is `Send` +#[cfg(parallel_compiler)] unsafe impl Send for OwnedSlice {} -// Safety: `OwnedSlice` is conceptually `(&'self.1 [u8], Box<dyn Send + Sync>)`, which is `Sync` +// Safety: `OwnedSlice` is conceptually `(&'self.1 [u8], Arc<dyn Send + Sync>)`, which is `Sync` +#[cfg(parallel_compiler)] unsafe impl Sync for OwnedSlice {} #[cfg(test)] diff --git a/compiler/rustc_data_structures/src/owned_slice/tests.rs b/compiler/rustc_data_structures/src/owned_slice/tests.rs index e715fb553..520871a12 100644 --- a/compiler/rustc_data_structures/src/owned_slice/tests.rs +++ b/compiler/rustc_data_structures/src/owned_slice/tests.rs @@ -7,8 +7,8 @@ use std::{ }; use crate::{ + defer, owned_slice::{slice_owned, try_slice_owned, OwnedSlice}, - OnDrop, }; #[test] @@ -26,7 +26,7 @@ fn static_storage() { } #[test] -fn slice_the_slice() { +fn slice_owned_the_slice() { let slice = slice_owned(vec![1, 2, 3, 4, 5, 6], Vec::as_slice); let slice = slice_owned(slice, |s| &s[1..][..4]); let slice = slice_owned(slice, |s| s); @@ -36,6 +36,16 @@ fn slice_the_slice() { } #[test] +fn slice_the_slice() { + let slice = slice_owned(vec![1, 2, 3, 4, 5, 6], Vec::as_slice) + .slice(|s| &s[1..][..4]) + .slice(|s| s) + .slice(|s| &s[1..]); + + assert_eq!(&*slice, &[1, 2, 3, 4, 5, 6][1..][..4][1..]); +} + +#[test] fn try_and_fail() { let res = try_slice_owned(vec![0], |v| v.get(12..).ok_or(())); @@ -56,7 +66,7 @@ fn boxed() { fn drop_drops() { let flag = Arc::new(AtomicBool::new(false)); let flag_prime = Arc::clone(&flag); - let d = OnDrop(move || flag_prime.store(true, atomic::Ordering::Relaxed)); + let d = defer(move || flag_prime.store(true, atomic::Ordering::Relaxed)); let slice = slice_owned(d, |_| &[]); @@ -69,6 +79,6 @@ 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>(); } diff --git a/compiler/rustc_data_structures/src/profiling.rs b/compiler/rustc_data_structures/src/profiling.rs index 1ed584eaf..3c76c2b79 100644 --- a/compiler/rustc_data_structures/src/profiling.rs +++ b/compiler/rustc_data_structures/src/profiling.rs @@ -87,6 +87,7 @@ use crate::fx::FxHashMap; use std::borrow::Borrow; use std::collections::hash_map::Entry; use std::error::Error; +use std::fmt::Display; use std::fs; use std::intrinsics::unlikely; use std::path::Path; @@ -97,11 +98,10 @@ use std::time::{Duration, Instant}; pub use measureme::EventId; use measureme::{EventIdBuilder, Profiler, SerializableString, StringId}; use parking_lot::RwLock; -use serde_json::json; use smallvec::SmallVec; bitflags::bitflags! { - struct EventFilter: u32 { + struct EventFilter: u16 { const GENERIC_ACTIVITIES = 1 << 0; const QUERY_PROVIDERS = 1 << 1; const QUERY_CACHE_HITS = 1 << 2; @@ -557,7 +557,7 @@ impl SelfProfiler { let crate_name = crate_name.unwrap_or("unknown-crate"); // HACK(eddyb) we need to pad the PID, strange as it may seem, as its // length can behave as a source of entropy for heap addresses, when - // ASLR is disabled and the heap is otherwise determinic. + // ASLR is disabled and the heap is otherwise deterministic. let pid: u32 = process::id(); let filename = format!("{crate_name}-{pid:07}.rustc_profile"); let path = output_directory.join(&filename); @@ -763,6 +763,31 @@ impl Drop for VerboseTimingGuard<'_> { } } +struct JsonTimePassesEntry<'a> { + pass: &'a str, + time: f64, + start_rss: Option<usize>, + end_rss: Option<usize>, +} + +impl Display for JsonTimePassesEntry<'_> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + let Self { pass: what, time, start_rss, end_rss } = self; + write!(f, r#"{{"pass":"{what}","time":{time},"rss_start":"#).unwrap(); + match start_rss { + Some(rss) => write!(f, "{rss}")?, + None => write!(f, "null")?, + } + write!(f, r#","rss_end":"#)?; + match end_rss { + Some(rss) => write!(f, "{rss}")?, + None => write!(f, "null")?, + } + write!(f, "}}")?; + Ok(()) + } +} + pub fn print_time_passes_entry( what: &str, dur: Duration, @@ -772,13 +797,10 @@ pub fn print_time_passes_entry( ) { match format { TimePassesFormat::Json => { - let json = json!({ - "pass": what, - "time": dur.as_secs_f64(), - "rss_start": start_rss, - "rss_end": end_rss, - }); - eprintln!("time: {json}"); + let entry = + JsonTimePassesEntry { pass: what, time: dur.as_secs_f64(), start_rss, end_rss }; + + eprintln!(r#"time: {entry}"#); return; } TimePassesFormat::Text => (), @@ -843,14 +865,16 @@ cfg_if! { use std::mem; use windows::{ - Win32::System::ProcessStatus::{K32GetProcessMemoryInfo, PROCESS_MEMORY_COUNTERS}, + // FIXME: change back to K32GetProcessMemoryInfo when windows crate + // updated to 0.49.0+ to drop dependency on psapi.dll + Win32::System::ProcessStatus::{GetProcessMemoryInfo, PROCESS_MEMORY_COUNTERS}, Win32::System::Threading::GetCurrentProcess, }; let mut pmc = PROCESS_MEMORY_COUNTERS::default(); let pmc_size = mem::size_of_val(&pmc); unsafe { - K32GetProcessMemoryInfo( + GetProcessMemoryInfo( GetCurrentProcess(), &mut pmc, pmc_size as u32, @@ -894,3 +918,6 @@ cfg_if! { } } } + +#[cfg(test)] +mod tests; diff --git a/compiler/rustc_data_structures/src/profiling/tests.rs b/compiler/rustc_data_structures/src/profiling/tests.rs new file mode 100644 index 000000000..2b09de085 --- /dev/null +++ b/compiler/rustc_data_structures/src/profiling/tests.rs @@ -0,0 +1,19 @@ +use super::JsonTimePassesEntry; + +#[test] +fn with_rss() { + let entry = + JsonTimePassesEntry { pass: "typeck", time: 56.1, start_rss: Some(10), end_rss: Some(20) }; + + assert_eq!(entry.to_string(), r#"{"pass":"typeck","time":56.1,"rss_start":10,"rss_end":20}"#) +} + +#[test] +fn no_rss() { + let entry = JsonTimePassesEntry { pass: "typeck", time: 56.1, start_rss: None, end_rss: None }; + + assert_eq!( + entry.to_string(), + r#"{"pass":"typeck","time":56.1,"rss_start":null,"rss_end":null}"# + ) +} diff --git a/compiler/rustc_data_structures/src/sharded.rs b/compiler/rustc_data_structures/src/sharded.rs index bd7a86f67..7ed70ba1e 100644 --- a/compiler/rustc_data_structures/src/sharded.rs +++ b/compiler/rustc_data_structures/src/sharded.rs @@ -1,14 +1,10 @@ use crate::fx::{FxHashMap, FxHasher}; -use crate::sync::{Lock, LockGuard}; +use crate::sync::{CacheAligned, Lock, LockGuard}; use std::borrow::Borrow; use std::collections::hash_map::RawEntryMut; use std::hash::{Hash, Hasher}; use std::mem; -#[derive(Default)] -#[cfg_attr(parallel_compiler, repr(align(64)))] -struct CacheAligned<T>(T); - #[cfg(parallel_compiler)] // 32 shards is sufficient to reduce contention on an 8-core Ryzen 7 1700, // but this should be tested on higher core count CPUs. How the `Sharded` type gets used diff --git a/compiler/rustc_data_structures/src/sip128.rs b/compiler/rustc_data_structures/src/sip128.rs index d849fe037..4a0ed87f7 100644 --- a/compiler/rustc_data_structures/src/sip128.rs +++ b/compiler/rustc_data_structures/src/sip128.rs @@ -96,28 +96,30 @@ macro_rules! compress { unsafe fn copy_nonoverlapping_small(src: *const u8, dst: *mut u8, count: usize) { debug_assert!(count <= 8); - if count == 8 { - ptr::copy_nonoverlapping(src, dst, 8); - return; - } + unsafe { + if count == 8 { + ptr::copy_nonoverlapping(src, dst, 8); + return; + } - let mut i = 0; - if i + 3 < count { - ptr::copy_nonoverlapping(src.add(i), dst.add(i), 4); - i += 4; - } + let mut i = 0; + if i + 3 < count { + ptr::copy_nonoverlapping(src.add(i), dst.add(i), 4); + i += 4; + } - if i + 1 < count { - ptr::copy_nonoverlapping(src.add(i), dst.add(i), 2); - i += 2 - } + if i + 1 < count { + ptr::copy_nonoverlapping(src.add(i), dst.add(i), 2); + i += 2 + } - if i < count { - *dst.add(i) = *src.add(i); - i += 1; - } + if i < count { + *dst.add(i) = *src.add(i); + i += 1; + } - debug_assert_eq!(i, count); + debug_assert_eq!(i, count); + } } // # Implementation @@ -232,38 +234,40 @@ impl SipHasher128 { // overflow) if it wasn't already. #[inline(never)] unsafe fn short_write_process_buffer<const LEN: usize>(&mut self, bytes: [u8; LEN]) { - let nbuf = self.nbuf; - debug_assert!(LEN <= 8); - debug_assert!(nbuf < BUFFER_SIZE); - debug_assert!(nbuf + LEN >= BUFFER_SIZE); - debug_assert!(nbuf + LEN < BUFFER_WITH_SPILL_SIZE); + unsafe { + let nbuf = self.nbuf; + debug_assert!(LEN <= 8); + debug_assert!(nbuf < BUFFER_SIZE); + debug_assert!(nbuf + LEN >= BUFFER_SIZE); + debug_assert!(nbuf + LEN < BUFFER_WITH_SPILL_SIZE); + + // Copy first part of input into end of buffer, possibly into spill + // element. The memcpy call is optimized away because the size is known. + let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf); + ptr::copy_nonoverlapping(bytes.as_ptr(), dst, LEN); + + // Process buffer. + for i in 0..BUFFER_CAPACITY { + let elem = self.buf.get_unchecked(i).assume_init().to_le(); + self.state.v3 ^= elem; + Sip13Rounds::c_rounds(&mut self.state); + self.state.v0 ^= elem; + } - // Copy first part of input into end of buffer, possibly into spill - // element. The memcpy call is optimized away because the size is known. - let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf); - ptr::copy_nonoverlapping(bytes.as_ptr(), dst, LEN); - - // Process buffer. - for i in 0..BUFFER_CAPACITY { - let elem = self.buf.get_unchecked(i).assume_init().to_le(); - self.state.v3 ^= elem; - Sip13Rounds::c_rounds(&mut self.state); - self.state.v0 ^= elem; + // Copy remaining input into start of buffer by copying LEN - 1 + // elements from spill (at most LEN - 1 bytes could have overflowed + // into the spill). The memcpy call is optimized away because the size + // is known. And the whole copy is optimized away for LEN == 1. + let dst = self.buf.as_mut_ptr() as *mut u8; + let src = self.buf.get_unchecked(BUFFER_SPILL_INDEX) as *const _ as *const u8; + ptr::copy_nonoverlapping(src, dst, LEN - 1); + + // This function should only be called when the write fills the buffer. + // Therefore, when LEN == 1, the new `self.nbuf` must be zero. + // LEN is statically known, so the branch is optimized away. + self.nbuf = if LEN == 1 { 0 } else { nbuf + LEN - BUFFER_SIZE }; + self.processed += BUFFER_SIZE; } - - // Copy remaining input into start of buffer by copying LEN - 1 - // elements from spill (at most LEN - 1 bytes could have overflowed - // into the spill). The memcpy call is optimized away because the size - // is known. And the whole copy is optimized away for LEN == 1. - let dst = self.buf.as_mut_ptr() as *mut u8; - let src = self.buf.get_unchecked(BUFFER_SPILL_INDEX) as *const _ as *const u8; - ptr::copy_nonoverlapping(src, dst, LEN - 1); - - // This function should only be called when the write fills the buffer. - // Therefore, when LEN == 1, the new `self.nbuf` must be zero. - // LEN is statically known, so the branch is optimized away. - self.nbuf = if LEN == 1 { 0 } else { nbuf + LEN - BUFFER_SIZE }; - self.processed += BUFFER_SIZE; } // A write function for byte slices. @@ -301,57 +305,59 @@ impl SipHasher128 { // containing the byte offset `self.nbuf`. #[inline(never)] unsafe fn slice_write_process_buffer(&mut self, msg: &[u8]) { - let length = msg.len(); - let nbuf = self.nbuf; - debug_assert!(nbuf < BUFFER_SIZE); - debug_assert!(nbuf + length >= BUFFER_SIZE); - - // Always copy first part of input into current element of buffer. - // This function should only be called when the write fills the buffer, - // so we know that there is enough input to fill the current element. - let valid_in_elem = nbuf % ELEM_SIZE; - let needed_in_elem = ELEM_SIZE - valid_in_elem; - - let src = msg.as_ptr(); - let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf); - copy_nonoverlapping_small(src, dst, needed_in_elem); - - // Process buffer. + unsafe { + let length = msg.len(); + let nbuf = self.nbuf; + debug_assert!(nbuf < BUFFER_SIZE); + debug_assert!(nbuf + length >= BUFFER_SIZE); + + // Always copy first part of input into current element of buffer. + // This function should only be called when the write fills the buffer, + // so we know that there is enough input to fill the current element. + let valid_in_elem = nbuf % ELEM_SIZE; + let needed_in_elem = ELEM_SIZE - valid_in_elem; + + let src = msg.as_ptr(); + let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf); + copy_nonoverlapping_small(src, dst, needed_in_elem); + + // Process buffer. + + // Using `nbuf / ELEM_SIZE + 1` rather than `(nbuf + needed_in_elem) / + // ELEM_SIZE` to show the compiler that this loop's upper bound is > 0. + // We know that is true, because last step ensured we have a full + // element in the buffer. + let last = nbuf / ELEM_SIZE + 1; + + for i in 0..last { + let elem = self.buf.get_unchecked(i).assume_init().to_le(); + self.state.v3 ^= elem; + Sip13Rounds::c_rounds(&mut self.state); + self.state.v0 ^= elem; + } - // Using `nbuf / ELEM_SIZE + 1` rather than `(nbuf + needed_in_elem) / - // ELEM_SIZE` to show the compiler that this loop's upper bound is > 0. - // We know that is true, because last step ensured we have a full - // element in the buffer. - let last = nbuf / ELEM_SIZE + 1; + // Process the remaining element-sized chunks of input. + let mut processed = needed_in_elem; + let input_left = length - processed; + let elems_left = input_left / ELEM_SIZE; + let extra_bytes_left = input_left % ELEM_SIZE; + + for _ in 0..elems_left { + let elem = (msg.as_ptr().add(processed) as *const u64).read_unaligned().to_le(); + self.state.v3 ^= elem; + Sip13Rounds::c_rounds(&mut self.state); + self.state.v0 ^= elem; + processed += ELEM_SIZE; + } - for i in 0..last { - let elem = self.buf.get_unchecked(i).assume_init().to_le(); - self.state.v3 ^= elem; - Sip13Rounds::c_rounds(&mut self.state); - self.state.v0 ^= elem; - } + // Copy remaining input into start of buffer. + let src = msg.as_ptr().add(processed); + let dst = self.buf.as_mut_ptr() as *mut u8; + copy_nonoverlapping_small(src, dst, extra_bytes_left); - // Process the remaining element-sized chunks of input. - let mut processed = needed_in_elem; - let input_left = length - processed; - let elems_left = input_left / ELEM_SIZE; - let extra_bytes_left = input_left % ELEM_SIZE; - - for _ in 0..elems_left { - let elem = (msg.as_ptr().add(processed) as *const u64).read_unaligned().to_le(); - self.state.v3 ^= elem; - Sip13Rounds::c_rounds(&mut self.state); - self.state.v0 ^= elem; - processed += ELEM_SIZE; + self.nbuf = extra_bytes_left; + self.processed += nbuf + processed; } - - // Copy remaining input into start of buffer. - let src = msg.as_ptr().add(processed); - let dst = self.buf.as_mut_ptr() as *mut u8; - copy_nonoverlapping_small(src, dst, extra_bytes_left); - - self.nbuf = extra_bytes_left; - self.processed += nbuf + processed; } #[inline] diff --git a/compiler/rustc_data_structures/src/sorted_map/index_map.rs b/compiler/rustc_data_structures/src/sorted_map/index_map.rs index 7d23ff519..c172ee1c9 100644 --- a/compiler/rustc_data_structures/src/sorted_map/index_map.rs +++ b/compiler/rustc_data_structures/src/sorted_map/index_map.rs @@ -3,7 +3,7 @@ use std::hash::{Hash, Hasher}; use crate::stable_hasher::{HashStable, StableHasher}; -use rustc_index::vec::{Idx, IndexVec}; +use rustc_index::{Idx, IndexVec}; /// An indexed multi-map that preserves insertion order while permitting both *O*(log *n*) lookup of /// an item by key and *O*(1) lookup by index. diff --git a/compiler/rustc_data_structures/src/sso/map.rs b/compiler/rustc_data_structures/src/sso/map.rs index 89b8c8526..99581ed23 100644 --- a/compiler/rustc_data_structures/src/sso/map.rs +++ b/compiler/rustc_data_structures/src/sso/map.rs @@ -256,12 +256,9 @@ impl<K: Eq + Hash, V> SsoHashMap<K, V> { pub fn remove(&mut self, key: &K) -> Option<V> { match self { SsoHashMap::Array(array) => { - if let Some(index) = array.iter().position(|(k, _v)| k == key) { - Some(array.swap_remove(index).1) - } else { - None - } + array.iter().position(|(k, _v)| k == key).map(|index| array.swap_remove(index).1) } + SsoHashMap::Map(map) => map.remove(key), } } diff --git a/compiler/rustc_data_structures/src/stable_hasher.rs b/compiler/rustc_data_structures/src/stable_hasher.rs index 3ed1de1bc..6d57d81c5 100644 --- a/compiler/rustc_data_structures/src/stable_hasher.rs +++ b/compiler/rustc_data_structures/src/stable_hasher.rs @@ -1,7 +1,8 @@ use crate::sip128::SipHasher128; -use rustc_index::bit_set; -use rustc_index::vec; +use rustc_index::bit_set::{self, BitSet}; +use rustc_index::{Idx, IndexVec}; use smallvec::SmallVec; +use std::fmt; use std::hash::{BuildHasher, Hash, Hasher}; use std::marker::PhantomData; use std::mem; @@ -9,6 +10,8 @@ use std::mem; #[cfg(test)] mod tests; +pub use crate::hashes::{Hash128, Hash64}; + /// When hashing something that ends up affecting properties like symbol names, /// we want these symbol names to be calculated independently of other factors /// like what architecture you're compiling *from*. @@ -20,8 +23,8 @@ pub struct StableHasher { state: SipHasher128, } -impl ::std::fmt::Debug for StableHasher { - fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { +impl fmt::Debug for StableHasher { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{:?}", self.state) } } @@ -42,21 +45,6 @@ impl StableHasher { } } -impl StableHasherResult for u128 { - #[inline] - fn finish(hasher: StableHasher) -> Self { - let (_0, _1) = hasher.finalize(); - u128::from(_0) | (u128::from(_1) << 64) - } -} - -impl StableHasherResult for u64 { - #[inline] - fn finish(hasher: StableHasher) -> Self { - hasher.finalize().0 - } -} - impl StableHasher { #[inline] pub fn finalize(self) -> (u64, u64) { @@ -107,7 +95,8 @@ impl Hasher for StableHasher { #[inline] fn write_u128(&mut self, i: u128) { - self.state.write(&i.to_le_bytes()); + self.write_u64(i as u64); + self.write_u64((i >> 64) as u64); } #[inline] @@ -286,6 +275,9 @@ impl_stable_traits_for_trivial_type!(i128); impl_stable_traits_for_trivial_type!(char); impl_stable_traits_for_trivial_type!(()); +impl_stable_traits_for_trivial_type!(Hash64); +impl_stable_traits_for_trivial_type!(Hash128); + impl<CTX> HashStable<CTX> for ! { fn hash_stable(&self, _ctx: &mut CTX, _hasher: &mut StableHasher) { unreachable!() @@ -565,7 +557,7 @@ where } } -impl<I: vec::Idx, T, CTX> HashStable<CTX> for vec::IndexVec<I, T> +impl<I: Idx, T, CTX> HashStable<CTX> for IndexVec<I, T> where T: HashStable<CTX>, { @@ -577,13 +569,13 @@ where } } -impl<I: vec::Idx, CTX> HashStable<CTX> for bit_set::BitSet<I> { +impl<I: Idx, CTX> HashStable<CTX> for BitSet<I> { fn hash_stable(&self, _ctx: &mut CTX, hasher: &mut StableHasher) { ::std::hash::Hash::hash(self, hasher); } } -impl<R: vec::Idx, C: vec::Idx, CTX> HashStable<CTX> for bit_set::BitMatrix<R, C> { +impl<R: Idx, C: Idx, CTX> HashStable<CTX> for bit_set::BitMatrix<R, C> { fn hash_stable(&self, _ctx: &mut CTX, hasher: &mut StableHasher) { ::std::hash::Hash::hash(self, hasher); } @@ -668,7 +660,7 @@ fn stable_hash_reduce<HCX, I, C, F>( .map(|value| { let mut hasher = StableHasher::new(); hash_function(&mut hasher, hcx, value); - hasher.finish::<u128>() + hasher.finish::<Hash128>() }) .reduce(|accum, value| accum.wrapping_add(value)); hash.hash_stable(hcx, hasher); diff --git a/compiler/rustc_data_structures/src/stable_hasher/tests.rs b/compiler/rustc_data_structures/src/stable_hasher/tests.rs index a98b1bc36..c8921f6a7 100644 --- a/compiler/rustc_data_structures/src/stable_hasher/tests.rs +++ b/compiler/rustc_data_structures/src/stable_hasher/tests.rs @@ -72,7 +72,7 @@ fn test_hash_isize() { assert_eq!(h.finalize(), expected); } -fn hash<T: HashStable<()>>(t: &T) -> u128 { +fn hash<T: HashStable<()>>(t: &T) -> Hash128 { let mut h = StableHasher::new(); let ctx = &mut (); t.hash_stable(ctx, &mut h); diff --git a/compiler/rustc_data_structures/src/svh.rs b/compiler/rustc_data_structures/src/svh.rs index 61654b9e8..71679086f 100644 --- a/compiler/rustc_data_structures/src/svh.rs +++ b/compiler/rustc_data_structures/src/svh.rs @@ -5,58 +5,36 @@ //! mismatches where we have two versions of the same crate that were //! compiled from distinct sources. -use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; +use crate::fingerprint::Fingerprint; use std::fmt; -use std::hash::{Hash, Hasher}; use crate::stable_hasher; -#[derive(Copy, Clone, PartialEq, Eq, Debug)] +#[derive(Copy, Clone, PartialEq, Eq, Debug, Encodable, Decodable, Hash)] pub struct Svh { - hash: u64, + hash: Fingerprint, } impl Svh { /// Creates a new `Svh` given the hash. If you actually want to /// compute the SVH from some HIR, you want the `calculate_svh` /// function found in `rustc_incremental`. - pub fn new(hash: u64) -> Svh { + pub fn new(hash: Fingerprint) -> Svh { Svh { hash } } - pub fn as_u64(&self) -> u64 { - self.hash + pub fn as_u128(self) -> u128 { + self.hash.as_u128() } - pub fn to_string(&self) -> String { - format!("{:016x}", self.hash) - } -} - -impl Hash for Svh { - fn hash<H>(&self, state: &mut H) - where - H: Hasher, - { - self.hash.to_le().hash(state); + pub fn to_hex(self) -> String { + format!("{:032x}", self.hash.as_u128()) } } impl fmt::Display for Svh { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad(&self.to_string()) - } -} - -impl<S: Encoder> Encodable<S> for Svh { - fn encode(&self, s: &mut S) { - s.emit_u64(self.as_u64().to_le()); - } -} - -impl<D: Decoder> Decodable<D> for Svh { - fn decode(d: &mut D) -> Svh { - Svh::new(u64::from_le(d.read_u64())) + f.pad(&self.to_hex()) } } diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs index ef1da8519..6c3197d8e 100644 --- a/compiler/rustc_data_structures/src/sync.rs +++ b/compiler/rustc_data_structures/src/sync.rs @@ -39,12 +39,15 @@ //! //! [^2] `MTLockRef` is a typedef. -use crate::owned_slice::OwnedSlice; +pub use crate::marker::*; use std::collections::HashMap; use std::hash::{BuildHasher, Hash}; use std::ops::{Deref, DerefMut}; use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe}; +mod worker_local; +pub use worker_local::{Registry, WorkerLocal}; + pub use std::sync::atomic::Ordering; pub use std::sync::atomic::Ordering::SeqCst; @@ -52,6 +55,43 @@ 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 {} @@ -146,7 +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; @@ -165,12 +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. @@ -187,7 +221,28 @@ cfg_if! { } } - pub type MetadataRef = OwnedSlice; + 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 use std::rc::Rc as Lrc; pub use std::rc::Weak as Weak; @@ -205,33 +260,6 @@ cfg_if! { 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 MTLockRef<'a, T> = &'a mut MTLock<T>; #[derive(Debug, Default)] @@ -326,51 +354,166 @@ 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_core::WorkerLocal; + use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelIterator}; - pub use rayon::iter::ParallelIterator; - use rayon::iter::IntoParallelIterator; + pub fn par_for_each_in<I, T: IntoIterator<Item = I> + IntoParallelIterator<Item = I>>( + t: T, + for_each: impl Fn(I) + DynSync + DynSend + ) { + 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) + } + }); - pub fn par_iter<T: IntoParallelIterator>(t: T) -> T::Iter { - t.into_par_iter() + 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_for_each_in<T: IntoParallelIterator>( + pub fn par_map< + I, + T: IntoIterator<Item = I> + IntoParallelIterator<Item = I>, + R: std::marker::Send, + C: FromIterator<R> + FromParallelIterator<R> + >( 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) - }); - } + 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(); - pub type MetadataRef = OwnedSlice; + 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 + } + } /// This makes locks panic if they are already held. /// It is only useful when you are running in a single thread @@ -378,10 +521,9 @@ 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); pub trait HashMapExt<K, V> { /// Same as HashMap::insert, but it may panic if there's already an diff --git a/compiler/rustc_data_structures/src/sync/vec.rs b/compiler/rustc_data_structures/src/sync/vec.rs index 1783b4b35..e36dded9e 100644 --- a/compiler/rustc_data_structures/src/sync/vec.rs +++ b/compiler/rustc_data_structures/src/sync/vec.rs @@ -1,6 +1,6 @@ use std::marker::PhantomData; -use rustc_index::vec::Idx; +use rustc_index::Idx; #[derive(Default)] pub struct AppendOnlyIndexVec<I: Idx, T: Copy> { diff --git a/compiler/rustc_data_structures/src/sync/worker_local.rs b/compiler/rustc_data_structures/src/sync/worker_local.rs new file mode 100644 index 000000000..d61bb55be --- /dev/null +++ b/compiler/rustc_data_structures/src/sync/worker_local.rs @@ -0,0 +1,173 @@ +use crate::sync::Lock; +use std::cell::Cell; +use std::cell::OnceCell; +use std::ops::Deref; +use std::ptr; +use std::sync::Arc; + +#[cfg(parallel_compiler)] +use {crate::cold_path, crate::sync::CacheAligned}; + +/// A pointer to the `RegistryData` which uniquely identifies a registry. +/// This identifier can be reused if the registry gets freed. +#[derive(Clone, Copy, PartialEq)] +struct RegistryId(*const RegistryData); + +impl RegistryId { + #[inline(always)] + /// Verifies that the current thread is associated with the registry and returns its unique + /// index within the registry. This panics if the current thread is not associated with this + /// registry. + /// + /// Note that there's a race possible where the identifer in `THREAD_DATA` could be reused + /// so this can succeed from a different registry. + #[cfg(parallel_compiler)] + fn verify(self) -> usize { + let (id, index) = THREAD_DATA.with(|data| (data.registry_id.get(), data.index.get())); + + if id == self { + index + } else { + cold_path(|| panic!("Unable to verify registry association")) + } + } +} + +struct RegistryData { + thread_limit: usize, + threads: Lock<usize>, +} + +/// Represents a list of threads which can access worker locals. +#[derive(Clone)] +pub struct Registry(Arc<RegistryData>); + +thread_local! { + /// The registry associated with the thread. + /// This allows the `WorkerLocal` type to clone the registry in its constructor. + static REGISTRY: OnceCell<Registry> = OnceCell::new(); +} + +struct ThreadData { + registry_id: Cell<RegistryId>, + index: Cell<usize>, +} + +thread_local! { + /// A thread local which contains the identifer of `REGISTRY` but allows for faster access. + /// It also holds the index of the current thread. + static THREAD_DATA: ThreadData = const { ThreadData { + registry_id: Cell::new(RegistryId(ptr::null())), + index: Cell::new(0), + }}; +} + +impl Registry { + /// Creates a registry which can hold up to `thread_limit` threads. + pub fn new(thread_limit: usize) -> Self { + Registry(Arc::new(RegistryData { thread_limit, threads: Lock::new(0) })) + } + + /// Gets the registry associated with the current thread. Panics if there's no such registry. + pub fn current() -> Self { + REGISTRY.with(|registry| registry.get().cloned().expect("No assocated registry")) + } + + /// Registers the current thread with the registry so worker locals can be used on it. + /// Panics if the thread limit is hit or if the thread already has an associated registry. + pub fn register(&self) { + let mut threads = self.0.threads.lock(); + if *threads < self.0.thread_limit { + REGISTRY.with(|registry| { + if registry.get().is_some() { + drop(threads); + panic!("Thread already has a registry"); + } + registry.set(self.clone()).ok(); + THREAD_DATA.with(|data| { + data.registry_id.set(self.id()); + data.index.set(*threads); + }); + *threads += 1; + }); + } else { + drop(threads); + panic!("Thread limit reached"); + } + } + + /// Gets the identifer of this registry. + fn id(&self) -> RegistryId { + RegistryId(&*self.0) + } +} + +/// Holds worker local values for each possible thread in a registry. You can only access the +/// worker local value through the `Deref` impl on the registry associated with the thread it was +/// created on. It will panic otherwise. +pub struct WorkerLocal<T> { + #[cfg(not(parallel_compiler))] + local: T, + #[cfg(parallel_compiler)] + locals: Box<[CacheAligned<T>]>, + #[cfg(parallel_compiler)] + registry: Registry, +} + +// This is safe because the `deref` call will return a reference to a `T` unique to each thread +// or it will panic for threads without an associated local. So there isn't a need for `T` to do +// it's own synchronization. The `verify` method on `RegistryId` has an issue where the the id +// can be reused, but `WorkerLocal` has a reference to `Registry` which will prevent any reuse. +#[cfg(parallel_compiler)] +unsafe impl<T: Send> Sync for WorkerLocal<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 registry. + #[inline] + pub fn new<F: FnMut(usize) -> T>(mut initial: F) -> WorkerLocal<T> { + #[cfg(parallel_compiler)] + { + let registry = Registry::current(); + WorkerLocal { + locals: (0..registry.0.thread_limit).map(|i| CacheAligned(initial(i))).collect(), + registry, + } + } + #[cfg(not(parallel_compiler))] + { + WorkerLocal { local: initial(0) } + } + } + + /// Returns the worker-local values for each thread + #[inline] + pub fn into_inner(self) -> impl Iterator<Item = T> { + #[cfg(parallel_compiler)] + { + self.locals.into_vec().into_iter().map(|local| local.0) + } + #[cfg(not(parallel_compiler))] + { + std::iter::once(self.local) + } + } +} + +impl<T> Deref for WorkerLocal<T> { + type Target = T; + + #[inline(always)] + #[cfg(not(parallel_compiler))] + fn deref(&self) -> &T { + &self.local + } + + #[inline(always)] + #[cfg(parallel_compiler)] + fn deref(&self) -> &T { + // This is safe because `verify` will only return values less than + // `self.registry.thread_limit` which is the size of the `self.locals` array. + unsafe { &self.locals.get_unchecked(self.registry.id().verify()).0 } + } +} diff --git a/compiler/rustc_data_structures/src/tagged_ptr.rs b/compiler/rustc_data_structures/src/tagged_ptr.rs index 651bc556c..2914eece6 100644 --- a/compiler/rustc_data_structures/src/tagged_ptr.rs +++ b/compiler/rustc_data_structures/src/tagged_ptr.rs @@ -3,166 +3,281 @@ //! In order to utilize the pointer packing, you must have two types: a pointer, //! and a tag. //! -//! The pointer must implement the `Pointer` trait, with the primary requirement -//! being conversion to and from a usize. Note that the pointer must be -//! dereferenceable, so raw pointers generally cannot implement the `Pointer` -//! trait. This implies that the pointer must also be nonzero. +//! The pointer must implement the [`Pointer`] trait, with the primary +//! requirement being convertible to and from a raw pointer. Note that the +//! pointer must be dereferenceable, so raw pointers generally cannot implement +//! the [`Pointer`] trait. This implies that the pointer must also be non-null. //! -//! Many common pointer types already implement the `Pointer` trait. +//! Many common pointer types already implement the [`Pointer`] trait. //! -//! The tag must implement the `Tag` trait. We assert that the tag and `Pointer` -//! are compatible at compile time. +//! The tag must implement the [`Tag`] trait. +//! +//! We assert that the tag and the [`Pointer`] types are compatible at compile +//! time. -use std::mem::ManuallyDrop; use std::ops::Deref; +use std::ptr::NonNull; use std::rc::Rc; use std::sync::Arc; +use crate::aligned::Aligned; + mod copy; mod drop; +mod impl_tag; pub use copy::CopyTaggedPtr; pub use drop::TaggedPtr; -/// This describes the pointer type encapsulated by TaggedPtr. +/// This describes the pointer type encapsulated by [`TaggedPtr`] and +/// [`CopyTaggedPtr`]. /// /// # Safety /// -/// The usize returned from `into_usize` must be a valid, dereferenceable, -/// pointer to `<Self as Deref>::Target`. Note that pointers to `Pointee` must -/// be thin, even though `Pointee` may not be sized. +/// The pointer returned from [`into_ptr`] must be a [valid], pointer to +/// [`<Self as Deref>::Target`]. /// -/// Note that the returned pointer from `into_usize` should be castable to `&mut -/// <Self as Deref>::Target` if `Pointer: DerefMut`. +/// Note that if `Self` implements [`DerefMut`] the pointer returned from +/// [`into_ptr`] must be valid for writes (and thus calling [`NonNull::as_mut`] +/// on it must be safe). /// -/// The BITS constant must be correct. At least `BITS` bits, least-significant, -/// must be zero on all returned pointers from `into_usize`. +/// The [`BITS`] constant must be correct. [`BITS`] least-significant bits, +/// must be zero on all pointers returned from [`into_ptr`]. /// -/// For example, if the alignment of `Pointee` is 2, then `BITS` should be 1. +/// For example, if the alignment of [`Self::Target`] is 2, then `BITS` should be 1. +/// +/// [`BITS`]: Pointer::BITS +/// [`into_ptr`]: Pointer::into_ptr +/// [valid]: std::ptr#safety +/// [`<Self as Deref>::Target`]: Deref::Target +/// [`Self::Target`]: Deref::Target +/// [`DerefMut`]: std::ops::DerefMut pub unsafe trait Pointer: Deref { + /// Number of unused (always zero) **least-significant bits** in this + /// pointer, usually related to the pointees alignment. + /// + /// For example if [`BITS`] = `2`, then given `ptr = Self::into_ptr(..)`, + /// `ptr.addr() & 0b11 == 0` must be true. + /// /// Most likely the value you want to use here is the following, unless - /// your Pointee type is unsized (e.g., `ty::List<T>` in rustc) in which - /// case you'll need to manually figure out what the right type to pass to - /// align_of is. + /// your [`Self::Target`] type is unsized (e.g., `ty::List<T>` in rustc) + /// or your pointer is over/under aligned, in which case you'll need to + /// manually figure out what the right type to pass to [`bits_for`] is, or + /// what the value to set here. /// - /// ```ignore UNSOLVED (what to do about the Self) + /// ```rust /// # use std::ops::Deref; - /// std::mem::align_of::<<Self as Deref>::Target>().trailing_zeros() as usize; + /// # use rustc_data_structures::tagged_ptr::bits_for; + /// # struct T; + /// # impl Deref for T { type Target = u8; fn deref(&self) -> &u8 { &0 } } + /// # impl T { + /// const BITS: u32 = bits_for::<<Self as Deref>::Target>(); + /// # } /// ``` - const BITS: usize; - fn into_usize(self) -> usize; + /// + /// [`BITS`]: Pointer::BITS + /// [`Self::Target`]: Deref::Target + const BITS: u32; - /// # Safety + /// Turns this pointer into a raw, non-null pointer. + /// + /// The inverse of this function is [`from_ptr`]. /// - /// The passed `ptr` must be returned from `into_usize`. + /// This function guarantees that the least-significant [`Self::BITS`] bits + /// are zero. /// - /// This acts as `ptr::read` semantically, it should not be called more than - /// once on non-`Copy` `Pointer`s. - unsafe fn from_usize(ptr: usize) -> Self; + /// [`from_ptr`]: Pointer::from_ptr + /// [`Self::BITS`]: Pointer::BITS + fn into_ptr(self) -> NonNull<Self::Target>; - /// This provides a reference to the `Pointer` itself, rather than the - /// `Deref::Target`. It is used for cases where we want to call methods that - /// may be implement differently for the Pointer than the Pointee (e.g., - /// `Rc::clone` vs cloning the inner value). + /// Re-creates the original pointer, from a raw pointer returned by [`into_ptr`]. /// /// # Safety /// - /// The passed `ptr` must be returned from `into_usize`. - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R; + /// The passed `ptr` must be returned from [`into_ptr`]. + /// + /// This acts as [`ptr::read::<Self>()`] semantically, it should not be called more than + /// once on non-[`Copy`] `Pointer`s. + /// + /// [`into_ptr`]: Pointer::into_ptr + /// [`ptr::read::<Self>()`]: std::ptr::read + unsafe fn from_ptr(ptr: NonNull<Self::Target>) -> Self; } -/// This describes tags that the `TaggedPtr` struct can hold. +/// This describes tags that the [`TaggedPtr`] struct can hold. /// /// # Safety /// -/// The BITS constant must be correct. +/// The [`BITS`] constant must be correct. /// -/// No more than `BITS` least significant bits may be set in the returned usize. +/// No more than [`BITS`] least-significant bits may be set in the returned usize. +/// +/// [`BITS`]: Tag::BITS pub unsafe trait Tag: Copy { - const BITS: usize; + /// Number of least-significant bits in the return value of [`into_usize`] + /// which may be non-zero. In other words this is the bit width of the + /// value. + /// + /// [`into_usize`]: Tag::into_usize + const BITS: u32; + /// Turns this tag into an integer. + /// + /// The inverse of this function is [`from_usize`]. + /// + /// This function guarantees that only the least-significant [`Self::BITS`] + /// bits can be non-zero. + /// + /// [`from_usize`]: Tag::from_usize + /// [`Self::BITS`]: Tag::BITS fn into_usize(self) -> usize; + /// Re-creates the tag from the integer returned by [`into_usize`]. + /// /// # Safety /// - /// The passed `tag` must be returned from `into_usize`. + /// The passed `tag` must be returned from [`into_usize`]. + /// + /// [`into_usize`]: Tag::into_usize unsafe fn from_usize(tag: usize) -> Self; } -unsafe impl<T> Pointer for Box<T> { - const BITS: usize = std::mem::align_of::<T>().trailing_zeros() as usize; - #[inline] - fn into_usize(self) -> usize { - Box::into_raw(self) as usize +/// Returns the number of bits available for use for tags in a pointer to `T` +/// (this is based on `T`'s alignment). +pub const fn bits_for<T: ?Sized + Aligned>() -> u32 { + crate::aligned::align_of::<T>().as_nonzero().trailing_zeros() +} + +/// Returns the correct [`Tag::BITS`] constant for a set of tag values. +pub const fn bits_for_tags(mut tags: &[usize]) -> u32 { + let mut bits = 0; + + while let &[tag, ref rest @ ..] = tags { + tags = rest; + + // bits required to represent `tag`, + // position of the most significant 1 + let b = usize::BITS - tag.leading_zeros(); + if b > bits { + bits = b; + } } + + bits +} + +unsafe impl<T: ?Sized + Aligned> Pointer for Box<T> { + const BITS: u32 = bits_for::<Self::Target>(); + #[inline] - unsafe fn from_usize(ptr: usize) -> Self { - Box::from_raw(ptr as *mut T) + fn into_ptr(self) -> NonNull<T> { + // Safety: pointers from `Box::into_raw` are valid & non-null + unsafe { NonNull::new_unchecked(Box::into_raw(self)) } } - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R { - let raw = ManuallyDrop::new(Self::from_usize(ptr)); - f(&raw) + + #[inline] + unsafe fn from_ptr(ptr: NonNull<T>) -> Self { + // Safety: `ptr` comes from `into_ptr` which calls `Box::into_raw` + unsafe { Box::from_raw(ptr.as_ptr()) } } } -unsafe impl<T> Pointer for Rc<T> { - const BITS: usize = std::mem::align_of::<T>().trailing_zeros() as usize; +unsafe impl<T: ?Sized + Aligned> Pointer for Rc<T> { + const BITS: u32 = bits_for::<Self::Target>(); + #[inline] - fn into_usize(self) -> usize { - Rc::into_raw(self) as usize + fn into_ptr(self) -> NonNull<T> { + // Safety: pointers from `Rc::into_raw` are valid & non-null + unsafe { NonNull::new_unchecked(Rc::into_raw(self).cast_mut()) } } + #[inline] - unsafe fn from_usize(ptr: usize) -> Self { - Rc::from_raw(ptr as *const T) - } - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R { - let raw = ManuallyDrop::new(Self::from_usize(ptr)); - f(&raw) + unsafe fn from_ptr(ptr: NonNull<T>) -> Self { + // Safety: `ptr` comes from `into_ptr` which calls `Rc::into_raw` + unsafe { Rc::from_raw(ptr.as_ptr()) } } } -unsafe impl<T> Pointer for Arc<T> { - const BITS: usize = std::mem::align_of::<T>().trailing_zeros() as usize; +unsafe impl<T: ?Sized + Aligned> Pointer for Arc<T> { + const BITS: u32 = bits_for::<Self::Target>(); + #[inline] - fn into_usize(self) -> usize { - Arc::into_raw(self) as usize + fn into_ptr(self) -> NonNull<T> { + // Safety: pointers from `Arc::into_raw` are valid & non-null + unsafe { NonNull::new_unchecked(Arc::into_raw(self).cast_mut()) } } + #[inline] - unsafe fn from_usize(ptr: usize) -> Self { - Arc::from_raw(ptr as *const T) - } - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R { - let raw = ManuallyDrop::new(Self::from_usize(ptr)); - f(&raw) + unsafe fn from_ptr(ptr: NonNull<T>) -> Self { + // Safety: `ptr` comes from `into_ptr` which calls `Arc::into_raw` + unsafe { Arc::from_raw(ptr.as_ptr()) } } } -unsafe impl<'a, T: 'a> Pointer for &'a T { - const BITS: usize = std::mem::align_of::<T>().trailing_zeros() as usize; +unsafe impl<'a, T: 'a + ?Sized + Aligned> Pointer for &'a T { + const BITS: u32 = bits_for::<Self::Target>(); + #[inline] - fn into_usize(self) -> usize { - self as *const T as usize + fn into_ptr(self) -> NonNull<T> { + NonNull::from(self) } + #[inline] - unsafe fn from_usize(ptr: usize) -> Self { - &*(ptr as *const T) - } - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R { - f(&*(&ptr as *const usize as *const Self)) + unsafe fn from_ptr(ptr: NonNull<T>) -> Self { + // Safety: + // `ptr` comes from `into_ptr` which gets the pointer from a reference + unsafe { ptr.as_ref() } } } -unsafe impl<'a, T: 'a> Pointer for &'a mut T { - const BITS: usize = std::mem::align_of::<T>().trailing_zeros() as usize; +unsafe impl<'a, T: 'a + ?Sized + Aligned> Pointer for &'a mut T { + const BITS: u32 = bits_for::<Self::Target>(); + #[inline] - fn into_usize(self) -> usize { - self as *mut T as usize + fn into_ptr(self) -> NonNull<T> { + NonNull::from(self) } + #[inline] - unsafe fn from_usize(ptr: usize) -> Self { - &mut *(ptr as *mut T) + unsafe fn from_ptr(mut ptr: NonNull<T>) -> Self { + // Safety: + // `ptr` comes from `into_ptr` which gets the pointer from a reference + unsafe { ptr.as_mut() } + } +} + +/// A tag type used in [`CopyTaggedPtr`] and [`TaggedPtr`] tests. +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +#[cfg(test)] +enum Tag2 { + B00 = 0b00, + B01 = 0b01, + B10 = 0b10, + B11 = 0b11, +} + +#[cfg(test)] +unsafe impl Tag for Tag2 { + const BITS: u32 = 2; + + fn into_usize(self) -> usize { + self as _ } - unsafe fn with_ref<R, F: FnOnce(&Self) -> R>(ptr: usize, f: F) -> R { - f(&*(&ptr as *const usize as *const Self)) + + unsafe fn from_usize(tag: usize) -> Self { + match tag { + 0b00 => Tag2::B00, + 0b01 => Tag2::B01, + 0b10 => Tag2::B10, + 0b11 => Tag2::B11, + _ => unreachable!(), + } + } +} + +#[cfg(test)] +impl<HCX> crate::stable_hasher::HashStable<HCX> for Tag2 { + fn hash_stable(&self, hcx: &mut HCX, hasher: &mut crate::stable_hasher::StableHasher) { + (*self as u8).hash_stable(hcx, hasher); } } diff --git a/compiler/rustc_data_structures/src/tagged_ptr/copy.rs b/compiler/rustc_data_structures/src/tagged_ptr/copy.rs index e1d3e0bd3..e893a2c78 100644 --- a/compiler/rustc_data_structures/src/tagged_ptr/copy.rs +++ b/compiler/rustc_data_structures/src/tagged_ptr/copy.rs @@ -1,78 +1,94 @@ use super::{Pointer, Tag}; use crate::stable_hasher::{HashStable, StableHasher}; use std::fmt; +use std::hash::{Hash, Hasher}; use std::marker::PhantomData; +use std::mem::ManuallyDrop; use std::num::NonZeroUsize; +use std::ops::{Deref, DerefMut}; +use std::ptr::NonNull; -/// A `Copy` TaggedPtr. +/// A [`Copy`] tagged pointer. /// -/// You should use this instead of the `TaggedPtr` type in all cases where -/// `P: Copy`. +/// This is essentially `{ pointer: P, tag: T }` packed in a single pointer. +/// +/// You should use this instead of the [`TaggedPtr`] type in all cases where +/// `P` implements [`Copy`]. /// /// If `COMPARE_PACKED` is true, then the pointers will be compared and hashed without -/// unpacking. Otherwise we don't implement PartialEq/Eq/Hash; if you want that, -/// wrap the TaggedPtr. +/// unpacking. Otherwise we don't implement [`PartialEq`], [`Eq`] and [`Hash`]; +/// if you want that, wrap the [`CopyTaggedPtr`]. +/// +/// [`TaggedPtr`]: crate::tagged_ptr::TaggedPtr pub struct CopyTaggedPtr<P, T, const COMPARE_PACKED: bool> where P: Pointer, T: Tag, { - packed: NonZeroUsize, - data: PhantomData<(P, T)>, -} - -impl<P, T, const COMPARE_PACKED: bool> Copy for CopyTaggedPtr<P, T, COMPARE_PACKED> -where - P: Pointer, - T: Tag, - P: Copy, -{ -} - -impl<P, T, const COMPARE_PACKED: bool> Clone for CopyTaggedPtr<P, T, COMPARE_PACKED> -where - P: Pointer, - T: Tag, - P: Copy, -{ - fn clone(&self) -> Self { - *self - } + /// This is semantically a pair of `pointer: P` and `tag: T` fields, + /// however we pack them in a single pointer, to save space. + /// + /// We pack the tag into the **most**-significant bits of the pointer to + /// ease retrieval of the value. A left shift is a multiplication and + /// those are embeddable in instruction encoding, for example: + /// + /// ```asm + /// // (<https://godbolt.org/z/jqcYPWEr3>) + /// example::shift_read3: + /// mov eax, dword ptr [8*rdi] + /// ret + /// + /// example::mask_read3: + /// and rdi, -8 + /// mov eax, dword ptr [rdi] + /// ret + /// ``` + /// + /// This is ASM outputted by rustc for reads of values behind tagged + /// pointers for different approaches of tagging: + /// - `shift_read3` uses `<< 3` (the tag is in the most-significant bits) + /// - `mask_read3` uses `& !0b111` (the tag is in the least-significant bits) + /// + /// The shift approach thus produces less instructions and is likely faster + /// (see <https://godbolt.org/z/Y913sMdWb>). + /// + /// Encoding diagram: + /// ```text + /// [ packed.addr ] + /// [ tag ] [ pointer.addr >> T::BITS ] <-- usize::BITS - T::BITS bits + /// ^ + /// | + /// T::BITS bits + /// ``` + /// + /// The tag can be retrieved by `packed.addr() >> T::BITS` and the pointer + /// can be retrieved by `packed.map_addr(|addr| addr << T::BITS)`. + packed: NonNull<P::Target>, + tag_ghost: PhantomData<T>, } -// We pack the tag into the *upper* bits of the pointer to ease retrieval of the -// value; a left shift is a multiplication and those are embeddable in -// instruction encoding. -impl<P, T, const COMPARE_PACKED: bool> CopyTaggedPtr<P, T, COMPARE_PACKED> +// Note that even though `CopyTaggedPtr` is only really expected to work with +// `P: Copy`, can't add `P: Copy` bound, because `CopyTaggedPtr` is used in the +// `TaggedPtr`'s implementation. +impl<P, T, const CP: bool> CopyTaggedPtr<P, T, CP> where P: Pointer, T: Tag, { - const TAG_BIT_SHIFT: usize = usize::BITS as usize - T::BITS; - const ASSERTION: () = { - assert!(T::BITS <= P::BITS); - // Used for the transmute_copy's below - assert!(std::mem::size_of::<&P::Target>() == std::mem::size_of::<usize>()); - }; - + /// Tags `pointer` with `tag`. + /// + /// Note that this leaks `pointer`: it won't be dropped when + /// `CopyTaggedPtr` is dropped. If you have a pointer with a significant + /// drop, use [`TaggedPtr`] instead. + /// + /// [`TaggedPtr`]: crate::tagged_ptr::TaggedPtr + #[inline] pub fn new(pointer: P, tag: T) -> Self { - // Trigger assert! - let () = Self::ASSERTION; - let packed_tag = tag.into_usize() << Self::TAG_BIT_SHIFT; - - Self { - // SAFETY: We know that the pointer is non-null, as it must be - // dereferenceable per `Pointer` safety contract. - packed: unsafe { - NonZeroUsize::new_unchecked((P::into_usize(pointer) >> T::BITS) | packed_tag) - }, - data: PhantomData, - } + Self { packed: Self::pack(P::into_ptr(pointer), tag), tag_ghost: PhantomData } } - pub(super) fn pointer_raw(&self) -> usize { - self.packed.get() << T::BITS - } + /// Retrieves the pointer. + #[inline] pub fn pointer(self) -> P where P: Copy, @@ -81,66 +97,143 @@ where // // Note that this isn't going to double-drop or anything because we have // P: Copy - unsafe { P::from_usize(self.pointer_raw()) } - } - pub fn pointer_ref(&self) -> &P::Target { - // SAFETY: pointer_raw returns the original pointer - unsafe { std::mem::transmute_copy(&self.pointer_raw()) } - } - pub fn pointer_mut(&mut self) -> &mut P::Target - where - P: std::ops::DerefMut, - { - // SAFETY: pointer_raw returns the original pointer - unsafe { std::mem::transmute_copy(&self.pointer_raw()) } + unsafe { P::from_ptr(self.pointer_raw()) } } + + /// Retrieves the tag. #[inline] pub fn tag(&self) -> T { - unsafe { T::from_usize(self.packed.get() >> Self::TAG_BIT_SHIFT) } + // Unpack the tag, according to the `self.packed` encoding scheme + let tag = self.packed.addr().get() >> Self::TAG_BIT_SHIFT; + + // Safety: + // The shift retrieves the original value from `T::into_usize`, + // satisfying `T::from_usize`'s preconditions. + unsafe { T::from_usize(tag) } } + + /// Sets the tag to a new value. #[inline] pub fn set_tag(&mut self, tag: T) { - let mut packed = self.packed.get(); - let new_tag = T::into_usize(tag) << Self::TAG_BIT_SHIFT; - let tag_mask = (1 << T::BITS) - 1; - packed &= !(tag_mask << Self::TAG_BIT_SHIFT); - packed |= new_tag; - self.packed = unsafe { NonZeroUsize::new_unchecked(packed) }; + self.packed = Self::pack(self.pointer_raw(), tag); + } + + const TAG_BIT_SHIFT: u32 = usize::BITS - T::BITS; + const ASSERTION: () = { assert!(T::BITS <= P::BITS) }; + + /// Pack pointer `ptr` that comes from [`P::into_ptr`] with a `tag`, + /// according to `self.packed` encoding scheme. + /// + /// [`P::into_ptr`]: Pointer::into_ptr + #[inline] + fn pack(ptr: NonNull<P::Target>, tag: T) -> NonNull<P::Target> { + // Trigger assert! + let () = Self::ASSERTION; + + let packed_tag = tag.into_usize() << Self::TAG_BIT_SHIFT; + + ptr.map_addr(|addr| { + // Safety: + // - The pointer is `NonNull` => it's address is `NonZeroUsize` + // - `P::BITS` least significant bits are always zero (`Pointer` contract) + // - `T::BITS <= P::BITS` (from `Self::ASSERTION`) + // + // Thus `addr >> T::BITS` is guaranteed to be non-zero. + // + // `{non_zero} | packed_tag` can't make the value zero. + + let packed = (addr.get() >> T::BITS) | packed_tag; + unsafe { NonZeroUsize::new_unchecked(packed) } + }) } + + /// Retrieves the original raw pointer from `self.packed`. + #[inline] + pub(super) fn pointer_raw(&self) -> NonNull<P::Target> { + self.packed.map_addr(|addr| unsafe { NonZeroUsize::new_unchecked(addr.get() << T::BITS) }) + } + + /// This provides a reference to the `P` pointer itself, rather than the + /// `Deref::Target`. It is used for cases where we want to call methods + /// that may be implement differently for the Pointer than the Pointee + /// (e.g., `Rc::clone` vs cloning the inner value). + pub(super) fn with_pointer_ref<R>(&self, f: impl FnOnce(&P) -> R) -> R { + // Safety: + // - `self.raw.pointer_raw()` is originally returned from `P::into_ptr` + // and as such is valid for `P::from_ptr`. + // - This also allows us to not care whatever `f` panics or not. + // - Even though we create a copy of the pointer, we store it inside + // `ManuallyDrop` and only access it by-ref, so we don't double-drop. + // + // Semantically this is just `f(&self.pointer)` (where `self.pointer` + // is non-packed original pointer). + // + // Note that even though `CopyTaggedPtr` is only really expected to + // work with `P: Copy`, we have to assume `P: ?Copy`, because + // `CopyTaggedPtr` is used in the `TaggedPtr`'s implementation. + let ptr = unsafe { ManuallyDrop::new(P::from_ptr(self.pointer_raw())) }; + f(&ptr) + } +} + +impl<P, T, const CP: bool> Copy for CopyTaggedPtr<P, T, CP> +where + P: Pointer + Copy, + T: Tag, +{ } -impl<P, T, const COMPARE_PACKED: bool> std::ops::Deref for CopyTaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> Clone for CopyTaggedPtr<P, T, CP> +where + P: Pointer + Copy, + T: Tag, +{ + #[inline] + fn clone(&self) -> Self { + *self + } +} + +impl<P, T, const CP: bool> Deref for CopyTaggedPtr<P, T, CP> where P: Pointer, T: Tag, { type Target = P::Target; + + #[inline] fn deref(&self) -> &Self::Target { - self.pointer_ref() + // Safety: + // `pointer_raw` returns the original pointer from `P::into_ptr` which, + // by the `Pointer`'s contract, must be valid. + unsafe { self.pointer_raw().as_ref() } } } -impl<P, T, const COMPARE_PACKED: bool> std::ops::DerefMut for CopyTaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> DerefMut for CopyTaggedPtr<P, T, CP> where - P: Pointer + std::ops::DerefMut, + P: Pointer + DerefMut, T: Tag, { + #[inline] fn deref_mut(&mut self) -> &mut Self::Target { - self.pointer_mut() + // Safety: + // `pointer_raw` returns the original pointer from `P::into_ptr` which, + // by the `Pointer`'s contract, must be valid for writes if + // `P: DerefMut`. + unsafe { self.pointer_raw().as_mut() } } } -impl<P, T, const COMPARE_PACKED: bool> fmt::Debug for CopyTaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> fmt::Debug for CopyTaggedPtr<P, T, CP> where - P: Pointer, - P::Target: fmt::Debug, + P: Pointer + fmt::Debug, T: Tag + fmt::Debug, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_struct("CopyTaggedPtr") - .field("pointer", &self.pointer_ref()) - .field("tag", &self.tag()) - .finish() + self.with_pointer_ref(|ptr| { + f.debug_struct("CopyTaggedPtr").field("pointer", ptr).field("tag", &self.tag()).finish() + }) } } @@ -149,6 +242,7 @@ where P: Pointer, T: Tag, { + #[inline] fn eq(&self, other: &Self) -> bool { self.packed == other.packed } @@ -161,25 +255,74 @@ where { } -impl<P, T> std::hash::Hash for CopyTaggedPtr<P, T, true> +impl<P, T> Hash for CopyTaggedPtr<P, T, true> where P: Pointer, T: Tag, { - fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + #[inline] + fn hash<H: Hasher>(&self, state: &mut H) { self.packed.hash(state); } } -impl<P, T, HCX, const COMPARE_PACKED: bool> HashStable<HCX> for CopyTaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, HCX, const CP: bool> HashStable<HCX> for CopyTaggedPtr<P, T, CP> where P: Pointer + HashStable<HCX>, T: Tag + HashStable<HCX>, { fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) { - unsafe { - Pointer::with_ref(self.pointer_raw(), |p: &P| p.hash_stable(hcx, hasher)); - } + self.with_pointer_ref(|ptr| ptr.hash_stable(hcx, hasher)); self.tag().hash_stable(hcx, hasher); } } + +// Safety: +// `CopyTaggedPtr<P, T, ..>` is semantically just `{ ptr: P, tag: T }`, as such +// it's ok to implement `Sync` as long as `P: Sync, T: Sync` +unsafe impl<P, T, const CP: bool> Sync for CopyTaggedPtr<P, T, CP> +where + P: Sync + Pointer, + T: Sync + Tag, +{ +} + +// Safety: +// `CopyTaggedPtr<P, T, ..>` is semantically just `{ ptr: P, tag: T }`, as such +// it's ok to implement `Send` as long as `P: Send, T: Send` +unsafe impl<P, T, const CP: bool> Send for CopyTaggedPtr<P, T, CP> +where + P: Send + Pointer, + T: Send + Tag, +{ +} + +/// Test that `new` does not compile if there is not enough alignment for the +/// tag in the pointer. +/// +/// ```compile_fail,E0080 +/// use rustc_data_structures::tagged_ptr::{CopyTaggedPtr, Tag}; +/// +/// #[derive(Copy, Clone, Debug, PartialEq, Eq)] +/// enum Tag2 { B00 = 0b00, B01 = 0b01, B10 = 0b10, B11 = 0b11 }; +/// +/// unsafe impl Tag for Tag2 { +/// const BITS: u32 = 2; +/// +/// fn into_usize(self) -> usize { todo!() } +/// unsafe fn from_usize(tag: usize) -> Self { todo!() } +/// } +/// +/// let value = 12u16; +/// let reference = &value; +/// let tag = Tag2::B01; +/// +/// let _ptr = CopyTaggedPtr::<_, _, true>::new(reference, tag); +/// ``` +// For some reason miri does not get the compile error +// probably it `check`s instead of `build`ing? +#[cfg(not(miri))] +const _: () = (); + +#[cfg(test)] +mod tests; diff --git a/compiler/rustc_data_structures/src/tagged_ptr/copy/tests.rs b/compiler/rustc_data_structures/src/tagged_ptr/copy/tests.rs new file mode 100644 index 000000000..bfcc2e603 --- /dev/null +++ b/compiler/rustc_data_structures/src/tagged_ptr/copy/tests.rs @@ -0,0 +1,50 @@ +use std::ptr; + +use crate::stable_hasher::{HashStable, StableHasher}; +use crate::tagged_ptr::{CopyTaggedPtr, Pointer, Tag, Tag2}; + +#[test] +fn smoke() { + let value = 12u32; + let reference = &value; + let tag = Tag2::B01; + + let ptr = tag_ptr(reference, tag); + + assert_eq!(ptr.tag(), tag); + assert_eq!(*ptr, 12); + assert!(ptr::eq(ptr.pointer(), reference)); + + let copy = ptr; + + let mut ptr = ptr; + ptr.set_tag(Tag2::B00); + assert_eq!(ptr.tag(), Tag2::B00); + + assert_eq!(copy.tag(), tag); + assert_eq!(*copy, 12); + assert!(ptr::eq(copy.pointer(), reference)); +} + +#[test] +fn stable_hash_hashes_as_tuple() { + let hash_packed = { + let mut hasher = StableHasher::new(); + tag_ptr(&12, Tag2::B11).hash_stable(&mut (), &mut hasher); + + hasher.finalize() + }; + + let hash_tupled = { + let mut hasher = StableHasher::new(); + (&12, Tag2::B11).hash_stable(&mut (), &mut hasher); + hasher.finalize() + }; + + assert_eq!(hash_packed, hash_tupled); +} + +/// Helper to create tagged pointers without specifying `COMPARE_PACKED` if it does not matter. +fn tag_ptr<P: Pointer, T: Tag>(ptr: P, tag: T) -> CopyTaggedPtr<P, T, true> { + CopyTaggedPtr::new(ptr, tag) +} diff --git a/compiler/rustc_data_structures/src/tagged_ptr/drop.rs b/compiler/rustc_data_structures/src/tagged_ptr/drop.rs index b0315c93d..4e42b5b4a 100644 --- a/compiler/rustc_data_structures/src/tagged_ptr/drop.rs +++ b/compiler/rustc_data_structures/src/tagged_ptr/drop.rs @@ -1,14 +1,21 @@ -use super::{Pointer, Tag}; -use crate::stable_hasher::{HashStable, StableHasher}; use std::fmt; +use std::hash::{Hash, Hasher}; +use std::ops::{Deref, DerefMut}; use super::CopyTaggedPtr; +use super::{Pointer, Tag}; +use crate::stable_hasher::{HashStable, StableHasher}; -/// A TaggedPtr implementing `Drop`. +/// A tagged pointer that supports pointers that implement [`Drop`]. +/// +/// This is essentially `{ pointer: P, tag: T }` packed in a single pointer. +/// +/// You should use [`CopyTaggedPtr`] instead of the this type in all cases +/// where `P` implements [`Copy`]. /// /// If `COMPARE_PACKED` is true, then the pointers will be compared and hashed without -/// unpacking. Otherwise we don't implement PartialEq/Eq/Hash; if you want that, -/// wrap the TaggedPtr. +/// unpacking. Otherwise we don't implement [`PartialEq`], [`Eq`] and [`Hash`]; +/// if you want that, wrap the [`TaggedPtr`]. pub struct TaggedPtr<P, T, const COMPARE_PACKED: bool> where P: Pointer, @@ -17,58 +24,67 @@ where raw: CopyTaggedPtr<P, T, COMPARE_PACKED>, } -impl<P, T, const COMPARE_PACKED: bool> Clone for TaggedPtr<P, T, COMPARE_PACKED> -where - P: Pointer + Clone, - T: Tag, -{ - fn clone(&self) -> Self { - unsafe { Self::new(P::with_ref(self.raw.pointer_raw(), |p| p.clone()), self.raw.tag()) } - } -} - -// We pack the tag into the *upper* bits of the pointer to ease retrieval of the -// value; a right shift is a multiplication and those are embeddable in -// instruction encoding. -impl<P, T, const COMPARE_PACKED: bool> TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> TaggedPtr<P, T, CP> where P: Pointer, T: Tag, { + /// Tags `pointer` with `tag`. + #[inline] pub fn new(pointer: P, tag: T) -> Self { TaggedPtr { raw: CopyTaggedPtr::new(pointer, tag) } } - pub fn pointer_ref(&self) -> &P::Target { - self.raw.pointer_ref() - } + /// Retrieves the tag. + #[inline] pub fn tag(&self) -> T { self.raw.tag() } + + /// Sets the tag to a new value. + #[inline] + pub fn set_tag(&mut self, tag: T) { + self.raw.set_tag(tag) + } +} + +impl<P, T, const CP: bool> Clone for TaggedPtr<P, T, CP> +where + P: Pointer + Clone, + T: Tag, +{ + fn clone(&self) -> Self { + let ptr = self.raw.with_pointer_ref(P::clone); + + Self::new(ptr, self.tag()) + } } -impl<P, T, const COMPARE_PACKED: bool> std::ops::Deref for TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> Deref for TaggedPtr<P, T, CP> where P: Pointer, T: Tag, { type Target = P::Target; + + #[inline] fn deref(&self) -> &Self::Target { - self.raw.pointer_ref() + self.raw.deref() } } -impl<P, T, const COMPARE_PACKED: bool> std::ops::DerefMut for TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> DerefMut for TaggedPtr<P, T, CP> where - P: Pointer + std::ops::DerefMut, + P: Pointer + DerefMut, T: Tag, { + #[inline] fn deref_mut(&mut self) -> &mut Self::Target { - self.raw.pointer_mut() + self.raw.deref_mut() } } -impl<P, T, const COMPARE_PACKED: bool> Drop for TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> Drop for TaggedPtr<P, T, CP> where P: Pointer, T: Tag, @@ -76,22 +92,20 @@ where fn drop(&mut self) { // No need to drop the tag, as it's Copy unsafe { - drop(P::from_usize(self.raw.pointer_raw())); + drop(P::from_ptr(self.raw.pointer_raw())); } } } -impl<P, T, const COMPARE_PACKED: bool> fmt::Debug for TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, const CP: bool> fmt::Debug for TaggedPtr<P, T, CP> where - P: Pointer, - P::Target: fmt::Debug, + P: Pointer + fmt::Debug, T: Tag + fmt::Debug, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_struct("TaggedPtr") - .field("pointer", &self.pointer_ref()) - .field("tag", &self.tag()) - .finish() + self.raw.with_pointer_ref(|ptr| { + f.debug_struct("TaggedPtr").field("pointer", ptr).field("tag", &self.tag()).finish() + }) } } @@ -100,6 +114,7 @@ where P: Pointer, T: Tag, { + #[inline] fn eq(&self, other: &Self) -> bool { self.raw.eq(&other.raw) } @@ -112,17 +127,18 @@ where { } -impl<P, T> std::hash::Hash for TaggedPtr<P, T, true> +impl<P, T> Hash for TaggedPtr<P, T, true> where P: Pointer, T: Tag, { - fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + #[inline] + fn hash<H: Hasher>(&self, state: &mut H) { self.raw.hash(state); } } -impl<P, T, HCX, const COMPARE_PACKED: bool> HashStable<HCX> for TaggedPtr<P, T, COMPARE_PACKED> +impl<P, T, HCX, const CP: bool> HashStable<HCX> for TaggedPtr<P, T, CP> where P: Pointer + HashStable<HCX>, T: Tag + HashStable<HCX>, @@ -131,3 +147,33 @@ where self.raw.hash_stable(hcx, hasher); } } + +/// Test that `new` does not compile if there is not enough alignment for the +/// tag in the pointer. +/// +/// ```compile_fail,E0080 +/// use rustc_data_structures::tagged_ptr::{TaggedPtr, Tag}; +/// +/// #[derive(Copy, Clone, Debug, PartialEq, Eq)] +/// enum Tag2 { B00 = 0b00, B01 = 0b01, B10 = 0b10, B11 = 0b11 }; +/// +/// unsafe impl Tag for Tag2 { +/// const BITS: u32 = 2; +/// +/// fn into_usize(self) -> usize { todo!() } +/// unsafe fn from_usize(tag: usize) -> Self { todo!() } +/// } +/// +/// let value = 12u16; +/// let reference = &value; +/// let tag = Tag2::B01; +/// +/// let _ptr = TaggedPtr::<_, _, true>::new(reference, tag); +/// ``` +// For some reason miri does not get the compile error +// probably it `check`s instead of `build`ing? +#[cfg(not(miri))] +const _: () = (); + +#[cfg(test)] +mod tests; diff --git a/compiler/rustc_data_structures/src/tagged_ptr/drop/tests.rs b/compiler/rustc_data_structures/src/tagged_ptr/drop/tests.rs new file mode 100644 index 000000000..2c17d678d --- /dev/null +++ b/compiler/rustc_data_structures/src/tagged_ptr/drop/tests.rs @@ -0,0 +1,71 @@ +use std::{ptr, sync::Arc}; + +use crate::tagged_ptr::{Pointer, Tag, Tag2, TaggedPtr}; + +#[test] +fn smoke() { + let value = 12u32; + let reference = &value; + let tag = Tag2::B01; + + let ptr = tag_ptr(reference, tag); + + assert_eq!(ptr.tag(), tag); + assert_eq!(*ptr, 12); + + let clone = ptr.clone(); + assert_eq!(clone.tag(), tag); + assert_eq!(*clone, 12); + + let mut ptr = ptr; + ptr.set_tag(Tag2::B00); + assert_eq!(ptr.tag(), Tag2::B00); + + assert_eq!(clone.tag(), tag); + assert_eq!(*clone, 12); + assert!(ptr::eq(&*ptr, &*clone)) +} + +#[test] +fn boxed() { + let value = 12u32; + let boxed = Box::new(value); + let tag = Tag2::B01; + + let ptr = tag_ptr(boxed, tag); + + assert_eq!(ptr.tag(), tag); + assert_eq!(*ptr, 12); + + let clone = ptr.clone(); + assert_eq!(clone.tag(), tag); + assert_eq!(*clone, 12); + + let mut ptr = ptr; + ptr.set_tag(Tag2::B00); + assert_eq!(ptr.tag(), Tag2::B00); + + assert_eq!(clone.tag(), tag); + assert_eq!(*clone, 12); + assert!(!ptr::eq(&*ptr, &*clone)) +} + +#[test] +fn arclones() { + let value = 12u32; + let arc = Arc::new(value); + let tag = Tag2::B01; + + let ptr = tag_ptr(arc, tag); + + assert_eq!(ptr.tag(), tag); + assert_eq!(*ptr, 12); + + let clone = ptr.clone(); + assert!(ptr::eq(&*ptr, &*clone)) +} + +/// Helper to create tagged pointers without specifying `COMPARE_PACKED` if it does not matter. +fn tag_ptr<P: Pointer, T: Tag>(ptr: P, tag: T) -> TaggedPtr<P, T, true> { + TaggedPtr::new(ptr, tag) +} diff --git a/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs new file mode 100644 index 000000000..cb7f7d318 --- /dev/null +++ b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag.rs @@ -0,0 +1,144 @@ +/// Implements [`Tag`] for a given type. +/// +/// You can use `impl_tag` on structs and enums. +/// You need to specify the type and all its possible values, +/// which can only be paths with optional fields. +/// +/// [`Tag`]: crate::tagged_ptr::Tag +/// +/// # Examples +/// +/// Basic usage: +/// +/// ``` +/// #![feature(macro_metavar_expr)] +/// use rustc_data_structures::{impl_tag, tagged_ptr::Tag}; +/// +/// #[derive(Copy, Clone, PartialEq, Debug)] +/// enum SomeTag { +/// A, +/// B, +/// X { v: bool }, +/// Y(bool, bool), +/// } +/// +/// impl_tag! { +/// // The type for which the `Tag` will be implemented +/// impl Tag for SomeTag; +/// // You need to specify all possible tag values: +/// SomeTag::A, // 0 +/// SomeTag::B, // 1 +/// // For variants with fields, you need to specify the fields: +/// SomeTag::X { v: true }, // 2 +/// SomeTag::X { v: false }, // 3 +/// // For tuple variants use named syntax: +/// SomeTag::Y { 0: true, 1: true }, // 4 +/// SomeTag::Y { 0: false, 1: true }, // 5 +/// SomeTag::Y { 0: true, 1: false }, // 6 +/// SomeTag::Y { 0: false, 1: false }, // 7 +/// } +/// +/// // Tag values are assigned in order: +/// assert_eq!(SomeTag::A.into_usize(), 0); +/// assert_eq!(SomeTag::X { v: false }.into_usize(), 3); +/// assert_eq!(SomeTag::Y(false, true).into_usize(), 5); +/// +/// assert_eq!(unsafe { SomeTag::from_usize(1) }, SomeTag::B); +/// assert_eq!(unsafe { SomeTag::from_usize(2) }, SomeTag::X { v: true }); +/// assert_eq!(unsafe { SomeTag::from_usize(7) }, SomeTag::Y(false, false)); +/// ``` +/// +/// Structs are supported: +/// +/// ``` +/// #![feature(macro_metavar_expr)] +/// # use rustc_data_structures::impl_tag; +/// #[derive(Copy, Clone)] +/// struct Flags { a: bool, b: bool } +/// +/// impl_tag! { +/// impl Tag for Flags; +/// Flags { a: true, b: true }, +/// Flags { a: false, b: true }, +/// Flags { a: true, b: false }, +/// Flags { a: false, b: false }, +/// } +/// ``` +/// +/// Not specifying all values results in a compile error: +/// +/// ```compile_fail,E0004 +/// #![feature(macro_metavar_expr)] +/// # use rustc_data_structures::impl_tag; +/// #[derive(Copy, Clone)] +/// enum E { +/// A, +/// B, +/// } +/// +/// impl_tag! { +/// impl Tag for E; +/// E::A, +/// } +/// ``` +#[macro_export] +macro_rules! impl_tag { + ( + impl Tag for $Self:ty; + $( + $($path:ident)::* $( { $( $fields:tt )* })?, + )* + ) => { + // Safety: + // `bits_for_tags` is called on the same `${index()}`-es as + // `into_usize` returns, thus `BITS` constant is correct. + unsafe impl $crate::tagged_ptr::Tag for $Self { + const BITS: u32 = $crate::tagged_ptr::bits_for_tags(&[ + $( + ${index()}, + $( ${ignore(path)} )* + )* + ]); + + #[inline] + fn into_usize(self) -> usize { + // This forbids use of repeating patterns (`Enum::V`&`Enum::V`, etc) + // (or at least it should, see <https://github.com/rust-lang/rust/issues/110613>) + #[forbid(unreachable_patterns)] + match self { + // `match` is doing heavy lifting here, by requiring exhaustiveness + $( + $($path)::* $( { $( $fields )* } )? => ${index()}, + )* + } + } + + #[inline] + unsafe fn from_usize(tag: usize) -> Self { + match tag { + $( + ${index()} => $($path)::* $( { $( $fields )* } )?, + )* + + // Safety: + // `into_usize` only returns `${index()}` of the same + // repetition as we are filtering above, thus if this is + // reached, the safety contract of this function was + // already breached. + _ => unsafe { + debug_assert!( + false, + "invalid tag: {tag}\ + (this is a bug in the caller of `from_usize`)" + ); + std::hint::unreachable_unchecked() + }, + } + } + + } + }; +} + +#[cfg(test)] +mod tests; diff --git a/compiler/rustc_data_structures/src/tagged_ptr/impl_tag/tests.rs b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag/tests.rs new file mode 100644 index 000000000..62c926153 --- /dev/null +++ b/compiler/rustc_data_structures/src/tagged_ptr/impl_tag/tests.rs @@ -0,0 +1,34 @@ +#[test] +fn bits_constant() { + use crate::tagged_ptr::Tag; + + #[derive(Copy, Clone)] + struct Unit; + impl_tag! { impl Tag for Unit; Unit, } + assert_eq!(Unit::BITS, 0); + + #[derive(Copy, Clone)] + enum Enum3 { + A, + B, + C, + } + impl_tag! { impl Tag for Enum3; Enum3::A, Enum3::B, Enum3::C, } + assert_eq!(Enum3::BITS, 2); + + #[derive(Copy, Clone)] + struct Eight(bool, bool, bool); + impl_tag! { + impl Tag for Eight; + Eight { 0: true, 1: true, 2: true }, + Eight { 0: true, 1: true, 2: false }, + Eight { 0: true, 1: false, 2: true }, + Eight { 0: true, 1: false, 2: false }, + Eight { 0: false, 1: true, 2: true }, + Eight { 0: false, 1: true, 2: false }, + Eight { 0: false, 1: false, 2: true }, + Eight { 0: false, 1: false, 2: false }, + } + + assert_eq!(Eight::BITS, 3); +} diff --git a/compiler/rustc_data_structures/src/vec_linked_list.rs b/compiler/rustc_data_structures/src/vec_linked_list.rs index ce60d40b2..fda72c9a3 100644 --- a/compiler/rustc_data_structures/src/vec_linked_list.rs +++ b/compiler/rustc_data_structures/src/vec_linked_list.rs @@ -1,4 +1,4 @@ -use rustc_index::vec::{Idx, IndexVec}; +use rustc_index::{Idx, IndexVec}; pub fn iter<Ls>( first: Option<Ls::LinkIndex>, diff --git a/compiler/rustc_data_structures/src/work_queue.rs b/compiler/rustc_data_structures/src/work_queue.rs index 10317f1af..9db6b6f20 100644 --- a/compiler/rustc_data_structures/src/work_queue.rs +++ b/compiler/rustc_data_structures/src/work_queue.rs @@ -1,5 +1,5 @@ use rustc_index::bit_set::BitSet; -use rustc_index::vec::Idx; +use rustc_index::Idx; use std::collections::VecDeque; /// A work queue is a handy data structure for tracking work left to |