Rollup merge of rust-lang#84083 - ltratt:threadid_doc_tweak, r=dtolnay

Clarify the guarantees that ThreadId does and doesn't make.

The existing documentation does not spell out whether `ThreadId`s are unique during the lifetime of a thread or of a process. I had to examine the source code to realise (pleasingly!) that they're unique for the lifetime of a process. That seems worth documenting clearly, as it's a strong guarantee.

Examining the way `ThreadId`s are created also made me realise that the `as_u64` method on `ThreadId` could be a trap for the unwary on those platforms where the platform's notion of a thread identifier is also a 64 bit integer (particularly if they happen to use a similar identifier scheme to `ThreadId`). I therefore think it's worth being even clearer that there's no relationship between the two.

Author: matthiaskrgr

Cargo.lock

@@ -0,0 +1,47 @@
+[workspace]
+resolver = "1"
+members = [
+  "std",
+  "sysroot",
+]
+
+exclude = [
+  # stdarch has its own Cargo workspace
+  "stdarch",
+  "windows_targets"
+]
+
+[profile.release.package.compiler_builtins]
+# For compiler-builtins we always use a high number of codegen units.
+# The goal here is to place every single intrinsic into its own object
+# file to avoid symbol clashes with the system libgcc if possible. Note
+# that this number doesn't actually produce this many object files, we
+# just don't create more than this number of object files.
+#
+# It's a bit of a bummer that we have to pass this here, unfortunately.
+# Ideally this would be specified through an env var to Cargo so Cargo
+# knows how many CGUs are for this specific crate, but for now
+# per-crate configuration isn't specifiable in the environment.
+codegen-units = 10000
+
+# These dependencies of the standard library implement symbolication for
+# backtraces on most platforms. Their debuginfo causes both linking to be slower
+# (more data to chew through) and binaries to be larger without really all that
+# much benefit. This section turns them all to down to have no debuginfo which
+# helps to improve link times a little bit.
+[profile.release.package]
+addr2line.debug = 0
+addr2line.opt-level = "s"
+adler.debug = 0
+gimli.debug = 0
+gimli.opt-level = "s"
+miniz_oxide.debug = 0
+object.debug = 0
+rustc-demangle.debug = 0
+
+[patch.crates-io]
+# See comments in `library/rustc-std-workspace-core/README.md` for what's going on
+# here
+rustc-std-workspace-core = { path = 'rustc-std-workspace-core' }
+rustc-std-workspace-alloc = { path = 'rustc-std-workspace-alloc' }
+rustc-std-workspace-std = { path = 'rustc-std-workspace-std' }

Cargo.toml

@@ -1,28 +1,31 @@
 [package]
-authors = ["The Rust Project Developers"]
 name = "alloc"
 version = "0.0.0"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust core allocation and collections library"
 autotests = false
 autobenches = false
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "0.1.40", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "=0.1.138", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
-rand = "0.7"
-rand_xorshift = "0.2"
+rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
+rand_xorshift = "0.3.0"
 
 [[test]]
-name = "collectionstests"
+name = "alloctests"
 path = "tests/lib.rs"
 
+[[test]]
+name = "vec_deque_alloc_error"
+path = "tests/vec_deque_alloc_error.rs"
+
 [[bench]]
-name = "collectionsbenches"
+name = "allocbenches"
 path = "benches/lib.rs"
 test = true
 
@@ -35,4 +38,19 @@ harness = false
 compiler-builtins-mem = ['compiler_builtins/mem']
 compiler-builtins-c = ["compiler_builtins/c"]
 compiler-builtins-no-asm = ["compiler_builtins/no-asm"]
+compiler-builtins-no-f16-f128 = ["compiler_builtins/no-f16-f128"]
 compiler-builtins-mangled-names = ["compiler_builtins/mangled-names"]
+# Make panics and failed asserts immediately abort without formatting any message
+panic_immediate_abort = ["core/panic_immediate_abort"]
+# Choose algorithms that are optimized for binary size instead of runtime performance
+optimize_for_size = ["core/optimize_for_size"]
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    'cfg(bootstrap)',
+    'cfg(no_global_oom_handling)',
+    'cfg(no_rc)',
+    'cfg(no_sync)',
+    'cfg(randomized_layouts)',
+]

alloc/Cargo.toml

@@ -1,11 +1,11 @@
 use std::collections::BinaryHeap;
 
-use rand::{seq::SliceRandom, thread_rng};
-use test::{black_box, Bencher};
+use rand::seq::SliceRandom;
+use test::{Bencher, black_box};
 
 #[bench]
 fn bench_find_smallest_1000(b: &mut Bencher) {
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
     let mut vec: Vec<u32> = (0..100_000).collect();
     vec.shuffle(&mut rng);
 
@@ -36,7 +36,7 @@ fn bench_peek_mut_deref_mut(b: &mut Bencher) {
         let mut peek_mut = bheap.peek_mut().unwrap();
         // The compiler shouldn't be able to optimize away the `sift_down`
         // assignment in `PeekMut`'s `DerefMut` implementation since
-        // the loop may not run.
+        // the loop might not run.
         for &i in vec.iter() {
             *peek_mut = i;
         }
@@ -47,7 +47,7 @@ fn bench_peek_mut_deref_mut(b: &mut Bencher) {
 
 #[bench]
 fn bench_from_vec(b: &mut Bencher) {
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
     let mut vec: Vec<u32> = (0..100_000).collect();
     vec.shuffle(&mut rng);
 
@@ -64,7 +64,7 @@ fn bench_into_sorted_vec(b: &mut Bencher) {
 #[bench]
 fn bench_push(b: &mut Bencher) {
     let mut bheap = BinaryHeap::with_capacity(50_000);
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
     let mut vec: Vec<u32> = (0..50_000).collect();
     vec.shuffle(&mut rng);
 

alloc/benches/binary_heap.rs

@@ -1,10 +1,9 @@
 use std::collections::BTreeMap;
-use std::iter::Iterator;
 use std::ops::RangeBounds;
-use std::vec::Vec;
 
-use rand::{seq::SliceRandom, thread_rng, Rng};
-use test::{black_box, Bencher};
+use rand::Rng;
+use rand::seq::SliceRandom;
+use test::{Bencher, black_box};
 
 macro_rules! map_insert_rand_bench {
     ($name: ident, $n: expr, $map: ident) => {
@@ -13,7 +12,7 @@ macro_rules! map_insert_rand_bench {
             let n: usize = $n;
             let mut map = $map::new();
             // setup
-            let mut rng = thread_rng();
+            let mut rng = crate::bench_rng();
 
             for _ in 0..n {
                 let i = rng.gen::<usize>() % n;
@@ -54,6 +53,50 @@ macro_rules! map_insert_seq_bench {
     };
 }
 
+macro_rules! map_from_iter_rand_bench {
+    ($name: ident, $n: expr, $map: ident) => {
+        #[bench]
+        pub fn $name(b: &mut Bencher) {
+            let n: usize = $n;
+            // setup
+            let mut rng = crate::bench_rng();
+            let mut vec = Vec::with_capacity(n);
+
+            for _ in 0..n {
+                let i = rng.gen::<usize>() % n;
+                vec.push((i, i));
+            }
+
+            // measure
+            b.iter(|| {
+                let map: $map<_, _> = vec.iter().copied().collect();
+                black_box(map);
+            });
+        }
+    };
+}
+
+macro_rules! map_from_iter_seq_bench {
+    ($name: ident, $n: expr, $map: ident) => {
+        #[bench]
+        pub fn $name(b: &mut Bencher) {
+            let n: usize = $n;
+            // setup
+            let mut vec = Vec::with_capacity(n);
+
+            for i in 0..n {
+                vec.push((i, i));
+            }
+
+            // measure
+            b.iter(|| {
+                let map: $map<_, _> = vec.iter().copied().collect();
+                black_box(map);
+            });
+        }
+    };
+}
+
 macro_rules! map_find_rand_bench {
     ($name: ident, $n: expr, $map: ident) => {
         #[bench]
@@ -62,7 +105,7 @@ macro_rules! map_find_rand_bench {
             let n: usize = $n;
 
             // setup
-            let mut rng = thread_rng();
+            let mut rng = crate::bench_rng();
             let mut keys: Vec<_> = (0..n).map(|_| rng.gen::<usize>() % n).collect();
 
             for &k in &keys {
@@ -111,6 +154,12 @@ map_insert_rand_bench! {insert_rand_10_000, 10_000, BTreeMap}
 map_insert_seq_bench! {insert_seq_100,    100,    BTreeMap}
 map_insert_seq_bench! {insert_seq_10_000, 10_000, BTreeMap}
 
+map_from_iter_rand_bench! {from_iter_rand_100,    100,    BTreeMap}
+map_from_iter_rand_bench! {from_iter_rand_10_000, 10_000, BTreeMap}
+
+map_from_iter_seq_bench! {from_iter_seq_100,    100,    BTreeMap}
+map_from_iter_seq_bench! {from_iter_seq_10_000, 10_000, BTreeMap}
+
 map_find_rand_bench! {find_rand_100,    100,    BTreeMap}
 map_find_rand_bench! {find_rand_10_000, 10_000, BTreeMap}
 
@@ -119,7 +168,7 @@ map_find_seq_bench! {find_seq_10_000, 10_000, BTreeMap}
 
 fn bench_iteration(b: &mut Bencher, size: i32) {
     let mut map = BTreeMap::<i32, i32>::new();
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
 
     for _ in 0..size {
         map.insert(rng.gen(), rng.gen());
@@ -149,7 +198,7 @@ pub fn iteration_100000(b: &mut Bencher) {
 
 fn bench_iteration_mut(b: &mut Bencher, size: i32) {
     let mut map = BTreeMap::<i32, i32>::new();
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
 
     for _ in 0..size {
         map.insert(rng.gen(), rng.gen());
@@ -240,7 +289,7 @@ where
         let mut c = 0;
         for i in 0..BENCH_RANGE_SIZE {
             for j in i + 1..BENCH_RANGE_SIZE {
-                black_box(map.range(f(i, j)));
+                let _ = black_box(map.range(f(i, j)));
                 c += 1;
             }
         }
@@ -272,7 +321,7 @@ fn bench_iter(b: &mut Bencher, repeats: i32, size: i32) {
     let map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
     b.iter(|| {
         for _ in 0..repeats {
-            black_box(map.iter());
+            let _ = black_box(map.iter());
         }
     });
 }
@@ -336,15 +385,15 @@ pub fn clone_slim_100_and_clear(b: &mut Bencher) {
 #[bench]
 pub fn clone_slim_100_and_drain_all(b: &mut Bencher) {
     let src = slim_map(100);
-    b.iter(|| src.clone().drain_filter(|_, _| true).count())
+    b.iter(|| src.clone().extract_if(|_, _| true).count())
 }
 
 #[bench]
 pub fn clone_slim_100_and_drain_half(b: &mut Bencher) {
     let src = slim_map(100);
     b.iter(|| {
         let mut map = src.clone();
-        assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2);
+        assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2);
         assert_eq!(map.len(), 100 / 2);
     })
 }
@@ -407,15 +456,15 @@ pub fn clone_slim_10k_and_clear(b: &mut Bencher) {
 #[bench]
 pub fn clone_slim_10k_and_drain_all(b: &mut Bencher) {
     let src = slim_map(10_000);
-    b.iter(|| src.clone().drain_filter(|_, _| true).count())
+    b.iter(|| src.clone().extract_if(|_, _| true).count())
 }
 
 #[bench]
 pub fn clone_slim_10k_and_drain_half(b: &mut Bencher) {
     let src = slim_map(10_000);
     b.iter(|| {
         let mut map = src.clone();
-        assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 10_000 / 2);
+        assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 10_000 / 2);
         assert_eq!(map.len(), 10_000 / 2);
     })
 }
@@ -478,15 +527,15 @@ pub fn clone_fat_val_100_and_clear(b: &mut Bencher) {
 #[bench]
 pub fn clone_fat_val_100_and_drain_all(b: &mut Bencher) {
     let src = fat_val_map(100);
-    b.iter(|| src.clone().drain_filter(|_, _| true).count())
+    b.iter(|| src.clone().extract_if(|_, _| true).count())
 }
 
 #[bench]
 pub fn clone_fat_val_100_and_drain_half(b: &mut Bencher) {
     let src = fat_val_map(100);
     b.iter(|| {
         let mut map = src.clone();
-        assert_eq!(map.drain_filter(|i, _| i % 2 == 0).count(), 100 / 2);
+        assert_eq!(map.extract_if(|i, _| i % 2 == 0).count(), 100 / 2);
         assert_eq!(map.len(), 100 / 2);
     })
 }

alloc/benches/btree/map.rs

@@ -1,10 +1,10 @@
 use std::collections::BTreeSet;
 
-use rand::{thread_rng, Rng};
+use rand::Rng;
 use test::Bencher;
 
 fn random(n: usize) -> BTreeSet<usize> {
-    let mut rng = thread_rng();
+    let mut rng = crate::bench_rng();
     let mut set = BTreeSet::new();
     while set.len() < n {
         set.insert(rng.gen());
@@ -69,15 +69,15 @@ pub fn clone_100_and_clear(b: &mut Bencher) {
 #[bench]
 pub fn clone_100_and_drain_all(b: &mut Bencher) {
     let src = slim_set(100);
-    b.iter(|| src.clone().drain_filter(|_| true).count())
+    b.iter(|| src.clone().extract_if(|_| true).count())
 }
 
 #[bench]
 pub fn clone_100_and_drain_half(b: &mut Bencher) {
     let src = slim_set(100);
     b.iter(|| {
         let mut set = src.clone();
-        assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 100 / 2);
+        assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 100 / 2);
         assert_eq!(set.len(), 100 / 2);
     })
 }
@@ -140,15 +140,15 @@ pub fn clone_10k_and_clear(b: &mut Bencher) {
 #[bench]
 pub fn clone_10k_and_drain_all(b: &mut Bencher) {
     let src = slim_set(10_000);
-    b.iter(|| src.clone().drain_filter(|_| true).count())
+    b.iter(|| src.clone().extract_if(|_| true).count())
 }
 
 #[bench]
 pub fn clone_10k_and_drain_half(b: &mut Bencher) {
     let src = slim_set(10_000);
     b.iter(|| {
         let mut set = src.clone();
-        assert_eq!(set.drain_filter(|i| i % 2 == 0).count(), 10_000 / 2);
+        assert_eq!(set.extract_if(|i| i % 2 == 0).count(), 10_000 / 2);
         assert_eq!(set.len(), 10_000 / 2);
     })
 }