Fix format and tidy for code moved from rayon

1 files changed, 607 insertions, 0 deletions

diff --git a/compiler/rustc_thread_pool/src/scope/tests.rs b/compiler/rustc_thread_pool/src/scope/tests.rs
new file mode 100644
index 00000000000..2df3bc67e29
--- /dev/null
+++ b/compiler/rustc_thread_pool/src/scope/tests.rs
@@ -0,0 +1,607 @@
+use std::iter::once;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::{Barrier, Mutex};
+use std::vec;
+
+use rand::{Rng, SeedableRng};
+use rand_xorshift::XorShiftRng;
+
+use crate::{Scope, ScopeFifo, ThreadPoolBuilder, scope, scope_fifo, unwind};
+
+#[test]
+fn scope_empty() {
+    scope(|_| {});
+}
+
+#[test]
+fn scope_result() {
+    let x = scope(|_| 22);
+    assert_eq!(x, 22);
+}
+
+#[test]
+fn scope_two() {
+    let counter = &AtomicUsize::new(0);
+    scope(|s| {
+        s.spawn(move |_| {
+            counter.fetch_add(1, Ordering::SeqCst);
+        });
+        s.spawn(move |_| {
+            counter.fetch_add(10, Ordering::SeqCst);
+        });
+    });
+
+    let v = counter.load(Ordering::SeqCst);
+    assert_eq!(v, 11);
+}
+
+#[test]
+fn scope_divide_and_conquer() {
+    let counter_p = &AtomicUsize::new(0);
+    scope(|s| s.spawn(move |s| divide_and_conquer(s, counter_p, 1024)));
+
+    let counter_s = &AtomicUsize::new(0);
+    divide_and_conquer_seq(counter_s, 1024);
+
+    let p = counter_p.load(Ordering::SeqCst);
+    let s = counter_s.load(Ordering::SeqCst);
+    assert_eq!(p, s);
+}
+
+fn divide_and_conquer<'scope>(scope: &Scope<'scope>, counter: &'scope AtomicUsize, size: usize) {
+    if size > 1 {
+        scope.spawn(move |scope| divide_and_conquer(scope, counter, size / 2));
+        scope.spawn(move |scope| divide_and_conquer(scope, counter, size / 2));
+    } else {
+        // count the leaves
+        counter.fetch_add(1, Ordering::SeqCst);
+    }
+}
+
+fn divide_and_conquer_seq(counter: &AtomicUsize, size: usize) {
+    if size > 1 {
+        divide_and_conquer_seq(counter, size / 2);
+        divide_and_conquer_seq(counter, size / 2);
+    } else {
+        // count the leaves
+        counter.fetch_add(1, Ordering::SeqCst);
+    }
+}
+
+struct Tree<T: Send> {
+    value: T,
+    children: Vec<Tree<T>>,
+}
+
+impl<T: Send> Tree<T> {
+    fn iter(&self) -> vec::IntoIter<&T> {
+        once(&self.value)
+            .chain(self.children.iter().flat_map(Tree::iter))
+            .collect::<Vec<_>>() // seems like it shouldn't be needed... but prevents overflow
+            .into_iter()
+    }
+
+    fn update<OP>(&mut self, op: OP)
+    where
+        OP: Fn(&mut T) + Sync,
+        T: Send,
+    {
+        scope(|s| self.update_in_scope(&op, s));
+    }
+
+    fn update_in_scope<'scope, OP>(&'scope mut self, op: &'scope OP, scope: &Scope<'scope>)
+    where
+        OP: Fn(&mut T) + Sync,
+    {
+        let Tree { ref mut value, ref mut children } = *self;
+        scope.spawn(move |scope| {
+            for child in children {
+                scope.spawn(move |scope| child.update_in_scope(op, scope));
+            }
+        });
+
+        op(value);
+    }
+}
+
+fn random_tree(depth: usize) -> Tree<u32> {
+    assert!(depth > 0);
+    let mut seed = <XorShiftRng as SeedableRng>::Seed::default();
+    (0..).zip(seed.as_mut()).for_each(|(i, x)| *x = i);
+    let mut rng = XorShiftRng::from_seed(seed);
+    random_tree1(depth, &mut rng)
+}
+
+fn random_tree1(depth: usize, rng: &mut XorShiftRng) -> Tree<u32> {
+    let children = if depth == 0 {
+        vec![]
+    } else {
+        (0..rng.random_range(0..4)) // somewhere between 0 and 3 children at each level
+            .map(|_| random_tree1(depth - 1, rng))
+            .collect()
+    };
+
+    Tree { value: rng.random_range(0..1_000_000), children }
+}
+
+#[test]
+fn update_tree() {
+    let mut tree: Tree<u32> = random_tree(10);
+    let values: Vec<u32> = tree.iter().cloned().collect();
+    tree.update(|v| *v += 1);
+    let new_values: Vec<u32> = tree.iter().cloned().collect();
+    assert_eq!(values.len(), new_values.len());
+    for (&i, &j) in values.iter().zip(&new_values) {
+        assert_eq!(i + 1, j);
+    }
+}
+
+/// Check that if you have a chain of scoped tasks where T0 spawns T1
+/// spawns T2 and so forth down to Tn, the stack space should not grow
+/// linearly with N. We test this by some unsafe hackery and
+/// permitting an approx 10% change with a 10x input change.
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn linear_stack_growth() {
+    let builder = ThreadPoolBuilder::new().num_threads(1);
+    let pool = builder.build().unwrap();
+    pool.install(|| {
+        let mut max_diff = Mutex::new(0);
+        let bottom_of_stack = 0;
+        scope(|s| the_final_countdown(s, &bottom_of_stack, &max_diff, 5));
+        let diff_when_5 = *max_diff.get_mut().unwrap() as f64;
+
+        scope(|s| the_final_countdown(s, &bottom_of_stack, &max_diff, 500));
+        let diff_when_500 = *max_diff.get_mut().unwrap() as f64;
+
+        let ratio = diff_when_5 / diff_when_500;
+        assert!(ratio > 0.9 && ratio < 1.1, "stack usage ratio out of bounds: {}", ratio);
+    });
+}
+
+fn the_final_countdown<'scope>(
+    s: &Scope<'scope>,
+    bottom_of_stack: &'scope i32,
+    max: &'scope Mutex<usize>,
+    n: usize,
+) {
+    let top_of_stack = 0;
+    let p = bottom_of_stack as *const i32 as usize;
+    let q = &top_of_stack as *const i32 as usize;
+    let diff = if p > q { p - q } else { q - p };
+
+    let mut data = max.lock().unwrap();
+    *data = Ord::max(diff, *data);
+
+    if n > 0 {
+        s.spawn(move |s| the_final_countdown(s, bottom_of_stack, max, n - 1));
+    }
+}
+
+#[test]
+#[should_panic(expected = "Hello, world!")]
+fn panic_propagate_scope() {
+    scope(|_| panic!("Hello, world!"));
+}
+
+#[test]
+#[should_panic(expected = "Hello, world!")]
+fn panic_propagate_spawn() {
+    scope(|s| s.spawn(|_| panic!("Hello, world!")));
+}
+
+#[test]
+#[should_panic(expected = "Hello, world!")]
+fn panic_propagate_nested_spawn() {
+    scope(|s| s.spawn(|s| s.spawn(|s| s.spawn(|_| panic!("Hello, world!")))));
+}
+
+#[test]
+#[should_panic(expected = "Hello, world!")]
+fn panic_propagate_nested_scope_spawn() {
+    scope(|s| s.spawn(|_| scope(|s| s.spawn(|_| panic!("Hello, world!")))));
+}
+
+#[test]
+#[cfg_attr(not(panic = "unwind"), ignore)]
+fn panic_propagate_still_execute_1() {
+    let mut x = false;
+    let result = unwind::halt_unwinding(|| {
+        scope(|s| {
+            s.spawn(|_| panic!("Hello, world!")); // job A
+            s.spawn(|_| x = true); // job B, should still execute even though A panics
+        });
+    });
+    match result {
+        Ok(_) => panic!("failed to propagate panic"),
+        Err(_) => assert!(x, "job b failed to execute"),
+    }
+}
+
+#[test]
+#[cfg_attr(not(panic = "unwind"), ignore)]
+fn panic_propagate_still_execute_2() {
+    let mut x = false;
+    let result = unwind::halt_unwinding(|| {
+        scope(|s| {
+            s.spawn(|_| x = true); // job B, should still execute even though A panics
+            s.spawn(|_| panic!("Hello, world!")); // job A
+        });
+    });
+    match result {
+        Ok(_) => panic!("failed to propagate panic"),
+        Err(_) => assert!(x, "job b failed to execute"),
+    }
+}
+
+#[test]
+#[cfg_attr(not(panic = "unwind"), ignore)]
+fn panic_propagate_still_execute_3() {
+    let mut x = false;
+    let result = unwind::halt_unwinding(|| {
+        scope(|s| {
+            s.spawn(|_| x = true); // spawned job should still execute despite later panic
+            panic!("Hello, world!");
+        });
+    });
+    match result {
+        Ok(_) => panic!("failed to propagate panic"),
+        Err(_) => assert!(x, "panic after spawn, spawn failed to execute"),
+    }
+}
+
+#[test]
+#[cfg_attr(not(panic = "unwind"), ignore)]
+fn panic_propagate_still_execute_4() {
+    let mut x = false;
+    let result = unwind::halt_unwinding(|| {
+        scope(|s| {
+            s.spawn(|_| panic!("Hello, world!"));
+            x = true;
+        });
+    });
+    match result {
+        Ok(_) => panic!("failed to propagate panic"),
+        Err(_) => assert!(x, "panic in spawn tainted scope"),
+    }
+}
+
+macro_rules! test_order {
+    ($scope:ident => $spawn:ident) => {{
+        let builder = ThreadPoolBuilder::new().num_threads(1);
+        let pool = builder.build().unwrap();
+        pool.install(|| {
+            let vec = Mutex::new(vec![]);
+            $scope(|scope| {
+                let vec = &vec;
+                for i in 0..10 {
+                    scope.$spawn(move |scope| {
+                        for j in 0..10 {
+                            scope.$spawn(move |_| {
+                                vec.lock().unwrap().push(i * 10 + j);
+                            });
+                        }
+                    });
+                }
+            });
+            vec.into_inner().unwrap()
+        })
+    }};
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn lifo_order() {
+    // In the absence of stealing, `scope()` runs its `spawn()` jobs in LIFO order.
+    let vec = test_order!(scope => spawn);
+    let expected: Vec<i32> = (0..100).rev().collect(); // LIFO -> reversed
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn fifo_order() {
+    // In the absence of stealing, `scope_fifo()` runs its `spawn_fifo()` jobs in FIFO order.
+    let vec = test_order!(scope_fifo => spawn_fifo);
+    let expected: Vec<i32> = (0..100).collect(); // FIFO -> natural order
+    assert_eq!(vec, expected);
+}
+
+macro_rules! test_nested_order {
+    ($outer_scope:ident => $outer_spawn:ident,
+     $inner_scope:ident => $inner_spawn:ident) => {{
+        let builder = ThreadPoolBuilder::new().num_threads(1);
+        let pool = builder.build().unwrap();
+        pool.install(|| {
+            let vec = Mutex::new(vec![]);
+            $outer_scope(|scope| {
+                let vec = &vec;
+                for i in 0..10 {
+                    scope.$outer_spawn(move |_| {
+                        $inner_scope(|scope| {
+                            for j in 0..10 {
+                                scope.$inner_spawn(move |_| {
+                                    vec.lock().unwrap().push(i * 10 + j);
+                                });
+                            }
+                        });
+                    });
+                }
+            });
+            vec.into_inner().unwrap()
+        })
+    }};
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn nested_lifo_order() {
+    // In the absence of stealing, `scope()` runs its `spawn()` jobs in LIFO order.
+    let vec = test_nested_order!(scope => spawn, scope => spawn);
+    let expected: Vec<i32> = (0..100).rev().collect(); // LIFO -> reversed
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn nested_fifo_order() {
+    // In the absence of stealing, `scope_fifo()` runs its `spawn_fifo()` jobs in FIFO order.
+    let vec = test_nested_order!(scope_fifo => spawn_fifo, scope_fifo => spawn_fifo);
+    let expected: Vec<i32> = (0..100).collect(); // FIFO -> natural order
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn nested_lifo_fifo_order() {
+    // LIFO on the outside, FIFO on the inside
+    let vec = test_nested_order!(scope => spawn, scope_fifo => spawn_fifo);
+    let expected: Vec<i32> = (0..10).rev().flat_map(|i| (0..10).map(move |j| i * 10 + j)).collect();
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn nested_fifo_lifo_order() {
+    // FIFO on the outside, LIFO on the inside
+    let vec = test_nested_order!(scope_fifo => spawn_fifo, scope => spawn);
+    let expected: Vec<i32> = (0..10).flat_map(|i| (0..10).rev().map(move |j| i * 10 + j)).collect();
+    assert_eq!(vec, expected);
+}
+
+macro_rules! spawn_push {
+    ($scope:ident . $spawn:ident, $vec:ident, $i:expr) => {{
+        $scope.$spawn(move |_| $vec.lock().unwrap().push($i));
+    }};
+}
+
+/// Test spawns pushing a series of numbers, interleaved
+/// such that negative values are using an inner scope.
+macro_rules! test_mixed_order {
+    ($outer_scope:ident => $outer_spawn:ident,
+     $inner_scope:ident => $inner_spawn:ident) => {{
+        let builder = ThreadPoolBuilder::new().num_threads(1);
+        let pool = builder.build().unwrap();
+        pool.install(|| {
+            let vec = Mutex::new(vec![]);
+            $outer_scope(|outer_scope| {
+                let vec = &vec;
+                spawn_push!(outer_scope.$outer_spawn, vec, 0);
+                $inner_scope(|inner_scope| {
+                    spawn_push!(inner_scope.$inner_spawn, vec, -1);
+                    spawn_push!(outer_scope.$outer_spawn, vec, 1);
+                    spawn_push!(inner_scope.$inner_spawn, vec, -2);
+                    spawn_push!(outer_scope.$outer_spawn, vec, 2);
+                    spawn_push!(inner_scope.$inner_spawn, vec, -3);
+                });
+                spawn_push!(outer_scope.$outer_spawn, vec, 3);
+            });
+            vec.into_inner().unwrap()
+        })
+    }};
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn mixed_lifo_order() {
+    // NB: the end of the inner scope makes us execute some of the outer scope
+    // before they've all been spawned, so they're not perfectly LIFO.
+    let vec = test_mixed_order!(scope => spawn, scope => spawn);
+    let expected = vec![-3, 2, -2, 1, -1, 3, 0];
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn mixed_fifo_order() {
+    let vec = test_mixed_order!(scope_fifo => spawn_fifo, scope_fifo => spawn_fifo);
+    let expected = vec![-1, 0, -2, 1, -3, 2, 3];
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn mixed_lifo_fifo_order() {
+    // NB: the end of the inner scope makes us execute some of the outer scope
+    // before they've all been spawned, so they're not perfectly LIFO.
+    let vec = test_mixed_order!(scope => spawn, scope_fifo => spawn_fifo);
+    let expected = vec![-1, 2, -2, 1, -3, 3, 0];
+    assert_eq!(vec, expected);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn mixed_fifo_lifo_order() {
+    let vec = test_mixed_order!(scope_fifo => spawn_fifo, scope => spawn);
+    let expected = vec![-3, 0, -2, 1, -1, 2, 3];
+    assert_eq!(vec, expected);
+}
+
+#[test]
+fn static_scope() {
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    let mut range = 0..100;
+    let sum = range.clone().sum();
+    let iter = &mut range;
+
+    COUNTER.store(0, Ordering::Relaxed);
+    scope(|s: &Scope<'static>| {
+        // While we're allowed the locally borrowed iterator,
+        // the spawns must be static.
+        for i in iter {
+            s.spawn(move |_| {
+                COUNTER.fetch_add(i, Ordering::Relaxed);
+            });
+        }
+    });
+
+    assert_eq!(COUNTER.load(Ordering::Relaxed), sum);
+}
+
+#[test]
+fn static_scope_fifo() {
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    let mut range = 0..100;
+    let sum = range.clone().sum();
+    let iter = &mut range;
+
+    COUNTER.store(0, Ordering::Relaxed);
+    scope_fifo(|s: &ScopeFifo<'static>| {
+        // While we're allowed the locally borrowed iterator,
+        // the spawns must be static.
+        for i in iter {
+            s.spawn_fifo(move |_| {
+                COUNTER.fetch_add(i, Ordering::Relaxed);
+            });
+        }
+    });
+
+    assert_eq!(COUNTER.load(Ordering::Relaxed), sum);
+}
+
+#[test]
+fn mixed_lifetime_scope() {
+    fn increment<'slice, 'counter>(counters: &'slice [&'counter AtomicUsize]) {
+        scope(move |s: &Scope<'counter>| {
+            // We can borrow 'slice here, but the spawns can only borrow 'counter.
+            for &c in counters {
+                s.spawn(move |_| {
+                    c.fetch_add(1, Ordering::Relaxed);
+                });
+            }
+        });
+    }
+
+    let counter = AtomicUsize::new(0);
+    increment(&[&counter; 100]);
+    assert_eq!(counter.into_inner(), 100);
+}
+
+#[test]
+fn mixed_lifetime_scope_fifo() {
+    fn increment<'slice, 'counter>(counters: &'slice [&'counter AtomicUsize]) {
+        scope_fifo(move |s: &ScopeFifo<'counter>| {
+            // We can borrow 'slice here, but the spawns can only borrow 'counter.
+            for &c in counters {
+                s.spawn_fifo(move |_| {
+                    c.fetch_add(1, Ordering::Relaxed);
+                });
+            }
+        });
+    }
+
+    let counter = AtomicUsize::new(0);
+    increment(&[&counter; 100]);
+    assert_eq!(counter.into_inner(), 100);
+}
+
+#[test]
+fn scope_spawn_broadcast() {
+    let sum = AtomicUsize::new(0);
+    let n = scope(|s| {
+        s.spawn_broadcast(|_, ctx| {
+            sum.fetch_add(ctx.index(), Ordering::Relaxed);
+        });
+        crate::current_num_threads()
+    });
+    assert_eq!(sum.into_inner(), n * (n - 1) / 2);
+}
+
+#[test]
+fn scope_fifo_spawn_broadcast() {
+    let sum = AtomicUsize::new(0);
+    let n = scope_fifo(|s| {
+        s.spawn_broadcast(|_, ctx| {
+            sum.fetch_add(ctx.index(), Ordering::Relaxed);
+        });
+        crate::current_num_threads()
+    });
+    assert_eq!(sum.into_inner(), n * (n - 1) / 2);
+}
+
+#[test]
+fn scope_spawn_broadcast_nested() {
+    let sum = AtomicUsize::new(0);
+    let n = scope(|s| {
+        s.spawn_broadcast(|s, _| {
+            s.spawn_broadcast(|_, ctx| {
+                sum.fetch_add(ctx.index(), Ordering::Relaxed);
+            });
+        });
+        crate::current_num_threads()
+    });
+    assert_eq!(sum.into_inner(), n * n * (n - 1) / 2);
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn scope_spawn_broadcast_barrier() {
+    let barrier = Barrier::new(8);
+    let pool = ThreadPoolBuilder::new().num_threads(7).build().unwrap();
+    pool.in_place_scope(|s| {
+        s.spawn_broadcast(|_, _| {
+            barrier.wait();
+        });
+        barrier.wait();
+    });
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn scope_spawn_broadcast_panic_one() {
+    let count = AtomicUsize::new(0);
+    let pool = ThreadPoolBuilder::new().num_threads(7).build().unwrap();
+    let result = crate::unwind::halt_unwinding(|| {
+        pool.scope(|s| {
+            s.spawn_broadcast(|_, ctx| {
+                count.fetch_add(1, Ordering::Relaxed);
+                if ctx.index() == 3 {
+                    panic!("Hello, world!");
+                }
+            });
+        });
+    });
+    assert_eq!(count.into_inner(), 7);
+    assert!(result.is_err(), "broadcast panic should propagate!");
+}
+
+#[test]
+#[cfg_attr(any(target_os = "emscripten", target_family = "wasm"), ignore)]
+fn scope_spawn_broadcast_panic_many() {
+    let count = AtomicUsize::new(0);
+    let pool = ThreadPoolBuilder::new().num_threads(7).build().unwrap();
+    let result = crate::unwind::halt_unwinding(|| {
+        pool.scope(|s| {
+            s.spawn_broadcast(|_, ctx| {
+                count.fetch_add(1, Ordering::Relaxed);
+                if ctx.index() % 2 == 0 {
+                    panic!("Hello, world!");
+                }
+            });
+        });
+    });
+    assert_eq!(count.into_inner(), 7);
+    assert!(result.is_err(), "broadcast panic should propagate!");
+}