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Diffstat (limited to 'vendor/rustc-rayon/tests/sort-panic-safe.rs')
-rw-r--r-- | vendor/rustc-rayon/tests/sort-panic-safe.rs | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/vendor/rustc-rayon/tests/sort-panic-safe.rs b/vendor/rustc-rayon/tests/sort-panic-safe.rs new file mode 100644 index 000000000..00a973106 --- /dev/null +++ b/vendor/rustc-rayon/tests/sort-panic-safe.rs @@ -0,0 +1,162 @@ +use rand::distributions::Uniform; +use rand::{thread_rng, Rng}; +use rayon::prelude::*; +use std::cell::Cell; +use std::cmp::{self, Ordering}; +use std::panic; +use std::sync::atomic::AtomicUsize; +use std::sync::atomic::Ordering::Relaxed; +use std::thread; + +static VERSIONS: AtomicUsize = AtomicUsize::new(0); + +lazy_static::lazy_static! { + static ref DROP_COUNTS: Vec<AtomicUsize> = (0..20_000).map(|_| AtomicUsize::new(0)).collect(); +} + +#[derive(Clone, Eq)] +struct DropCounter { + x: u32, + id: usize, + version: Cell<usize>, +} + +impl PartialEq for DropCounter { + fn eq(&self, other: &Self) -> bool { + self.partial_cmp(other) == Some(Ordering::Equal) + } +} + +impl PartialOrd for DropCounter { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + self.version.set(self.version.get() + 1); + other.version.set(other.version.get() + 1); + VERSIONS.fetch_add(2, Relaxed); + self.x.partial_cmp(&other.x) + } +} + +impl Ord for DropCounter { + fn cmp(&self, other: &Self) -> Ordering { + self.partial_cmp(other).unwrap() + } +} + +impl Drop for DropCounter { + fn drop(&mut self) { + DROP_COUNTS[self.id].fetch_add(1, Relaxed); + VERSIONS.fetch_sub(self.version.get(), Relaxed); + } +} + +macro_rules! test { + ($input:ident, $func:ident) => { + let len = $input.len(); + + // Work out the total number of comparisons required to sort + // this array... + let count = AtomicUsize::new(0); + $input.to_owned().$func(|a, b| { + count.fetch_add(1, Relaxed); + a.cmp(b) + }); + + let mut panic_countdown = count.load(Relaxed); + let step = if len <= 100 { + 1 + } else { + cmp::max(1, panic_countdown / 10) + }; + + // ... and then panic after each `step` comparisons. + loop { + // Refresh the counters. + VERSIONS.store(0, Relaxed); + for i in 0..len { + DROP_COUNTS[i].store(0, Relaxed); + } + + let v = $input.to_owned(); + let _ = thread::spawn(move || { + let mut v = v; + let panic_countdown = AtomicUsize::new(panic_countdown); + v.$func(|a, b| { + if panic_countdown.fetch_sub(1, Relaxed) == 1 { + SILENCE_PANIC.with(|s| s.set(true)); + panic!(); + } + a.cmp(b) + }) + }) + .join(); + + // Check that the number of things dropped is exactly + // what we expect (i.e. the contents of `v`). + for (i, c) in DROP_COUNTS.iter().enumerate().take(len) { + let count = c.load(Relaxed); + assert!( + count == 1, + "found drop count == {} for i == {}, len == {}", + count, + i, + len + ); + } + + // Check that the most recent versions of values were dropped. + assert_eq!(VERSIONS.load(Relaxed), 0); + + if panic_countdown < step { + break; + } + panic_countdown -= step; + } + }; +} + +thread_local!(static SILENCE_PANIC: Cell<bool> = Cell::new(false)); + +#[test] +fn sort_panic_safe() { + let prev = panic::take_hook(); + panic::set_hook(Box::new(move |info| { + if !SILENCE_PANIC.with(Cell::get) { + prev(info); + } + })); + + for &len in &[1, 2, 3, 4, 5, 10, 20, 100, 500, 5_000, 20_000] { + let len_dist = Uniform::new(0, len); + for &modulus in &[5, 30, 1_000, 20_000] { + for &has_runs in &[false, true] { + let mut rng = thread_rng(); + let mut input = (0..len) + .map(|id| DropCounter { + x: rng.gen_range(0..modulus), + id, + version: Cell::new(0), + }) + .collect::<Vec<_>>(); + + if has_runs { + for c in &mut input { + c.x = c.id as u32; + } + + for _ in 0..5 { + let a = rng.sample(&len_dist); + let b = rng.sample(&len_dist); + if a < b { + input[a..b].reverse(); + } else { + input.swap(a, b); + } + } + } + + test!(input, par_sort_by); + test!(input, par_sort_unstable_by); + } + } + } +} |