1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
//! This module defines types which are thread safe if cfg!(parallel_compiler) is true.
//!
//! `Lrc` is an alias of `Arc` if cfg!(parallel_compiler) is true, `Rc` otherwise.
//!
//! `Lock` is a mutex.
//! It internally uses `parking_lot::Mutex` if cfg!(parallel_compiler) is true,
//! `RefCell` otherwise.
//!
//! `RwLock` is a read-write lock.
//! It internally uses `parking_lot::RwLock` if cfg!(parallel_compiler) is true,
//! `RefCell` otherwise.
//!
//! `MTLock` is a mutex which disappears if cfg!(parallel_compiler) is false.
//!
//! `MTRef` is an immutable reference if cfg!(parallel_compiler), and a mutable reference otherwise.
//!
//! `rustc_erase_owner!` erases an OwningRef owner into Erased or Erased + Send + Sync
//! depending on the value of cfg!(parallel_compiler).

use crate::owning_ref::{Erased, OwningRef};
use std::collections::HashMap;
use std::hash::{BuildHasher, Hash};
use std::ops::{Deref, DerefMut};
use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};

pub use std::sync::atomic::Ordering;
pub use std::sync::atomic::Ordering::SeqCst;

cfg_if! {
    if #[cfg(not(parallel_compiler))] {
        pub auto trait Send {}
        pub auto trait Sync {}

        impl<T: ?Sized> Send for T {}
        impl<T: ?Sized> Sync for T {}

        #[macro_export]
        macro_rules! rustc_erase_owner {
            ($v:expr) => {
                $v.erase_owner()
            }
        }

        use std::ops::Add;

        /// This is a single threaded variant of `AtomicU64`, `AtomicUsize`, etc.
        /// It has explicit ordering arguments and is only intended for use with
        /// the native atomic types.
        /// You should use this type through the `AtomicU64`, `AtomicUsize`, etc, type aliases
        /// as it's not intended to be used separately.
        #[derive(Debug)]
        pub struct Atomic<T: Copy>(Cell<T>);

        impl<T: Copy> Atomic<T> {
            #[inline]
            pub fn new(v: T) -> Self {
                Atomic(Cell::new(v))
            }
        }

        impl<T: Copy> Atomic<T> {
            #[inline]
            pub fn into_inner(self) -> T {
                self.0.into_inner()
            }

            #[inline]
            pub fn load(&self, _: Ordering) -> T {
                self.0.get()
            }

            #[inline]
            pub fn store(&self, val: T, _: Ordering) {
                self.0.set(val)
            }

            #[inline]
            pub fn swap(&self, val: T, _: Ordering) -> T {
                self.0.replace(val)
            }
        }

        impl<T: Copy + PartialEq> Atomic<T> {
            #[inline]
            pub fn compare_exchange(&self,
                                    current: T,
                                    new: T,
                                    _: Ordering,
                                    _: Ordering)
                                    -> Result<T, T> {
                let read = self.0.get();
                if read == current {
                    self.0.set(new);
                    Ok(read)
                } else {
                    Err(read)
                }
            }
        }

        impl<T: Add<Output=T> + Copy> Atomic<T> {
            #[inline]
            pub fn fetch_add(&self, val: T, _: Ordering) -> T {
                let old = self.0.get();
                self.0.set(old + val);
                old
            }
        }

        pub type AtomicUsize = Atomic<usize>;
        pub type AtomicBool = Atomic<bool>;
        pub type AtomicU32 = Atomic<u32>;
        pub type AtomicU64 = Atomic<u64>;

        pub fn join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
            where A: FnOnce() -> RA,
                  B: FnOnce() -> RB
        {
            (oper_a(), oper_b())
        }

        #[macro_export]
        macro_rules! parallel {
            ($($blocks:tt),*) => {
                // 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(|| $blocks)
                    ) {
                        if panic.is_none() {
                            panic = Some(p);
                        }
                    }
                )*
                if let Some(panic) = panic {
                    ::std::panic::resume_unwind(panic);
                }
            }
        }

        pub use std::iter::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, for_each: impl Fn(T::Item) + Sync + Send) {
            // 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 type MetadataRef = OwningRef<Box<dyn Erased>, [u8]>;

        pub use std::rc::Rc as Lrc;
        pub use std::rc::Weak as Weak;
        pub use std::cell::Ref as ReadGuard;
        pub use std::cell::Ref as MappedReadGuard;
        pub use std::cell::RefMut as WriteGuard;
        pub use std::cell::RefMut as MappedWriteGuard;
        pub use std::cell::RefMut as LockGuard;
        pub use std::cell::RefMut as MappedLockGuard;

        pub use std::cell::OnceCell;

        use std::cell::RefCell as InnerRwLock;
        use std::cell::RefCell as InnerLock;

        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 MTRef<'a, T> = &'a mut T;

        #[derive(Debug, Default)]
        pub struct MTLock<T>(T);

        impl<T> MTLock<T> {
            #[inline(always)]
            pub fn new(inner: T) -> Self {
                MTLock(inner)
            }

            #[inline(always)]
            pub fn into_inner(self) -> T {
                self.0
            }

            #[inline(always)]
            pub fn get_mut(&mut self) -> &mut T {
                &mut self.0
            }

            #[inline(always)]
            pub fn lock(&self) -> &T {
                &self.0
            }

            #[inline(always)]
            pub fn lock_mut(&mut self) -> &mut T {
                &mut self.0
            }
        }

        // FIXME: Probably a bad idea (in the threaded case)
        impl<T: Clone> Clone for MTLock<T> {
            #[inline]
            fn clone(&self) -> Self {
                MTLock(self.0.clone())
            }
        }
    } else {
        pub use std::marker::Send as Send;
        pub use std::marker::Sync as Sync;

        pub use parking_lot::RwLockReadGuard as ReadGuard;
        pub use parking_lot::MappedRwLockReadGuard as MappedReadGuard;
        pub use parking_lot::RwLockWriteGuard as WriteGuard;
        pub use parking_lot::MappedRwLockWriteGuard as MappedWriteGuard;

        pub use parking_lot::MutexGuard as LockGuard;
        pub use parking_lot::MappedMutexGuard as MappedLockGuard;

        pub use std::sync::OnceLock as OnceCell;

        pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32, AtomicU64};

        pub use std::sync::Arc as Lrc;
        pub use std::sync::Weak as Weak;

        pub type MTRef<'a, T> = &'a T;

        #[derive(Debug, Default)]
        pub struct MTLock<T>(Lock<T>);

        impl<T> MTLock<T> {
            #[inline(always)]
            pub fn new(inner: T) -> Self {
                MTLock(Lock::new(inner))
            }

            #[inline(always)]
            pub fn into_inner(self) -> T {
                self.0.into_inner()
            }

            #[inline(always)]
            pub fn get_mut(&mut self) -> &mut T {
                self.0.get_mut()
            }

            #[inline(always)]
            pub fn lock(&self) -> LockGuard<'_, T> {
                self.0.lock()
            }

            #[inline(always)]
            pub fn lock_mut(&self) -> LockGuard<'_, T> {
                self.lock()
            }
        }

        use parking_lot::Mutex as InnerLock;
        use parking_lot::RwLock as InnerRwLock;

        use std::thread;
        pub use rayon::{join, scope};

        /// 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)*]) => {
                parallel!(impl $fblock [$block, $($c,)*] [$($rest),*])
            };
            (impl $fblock:tt [$($blocks:tt,)*] []) => {
                ::rustc_data_structures::sync::scope(|s| {
                    $(
                        s.spawn(|_| $blocks);
                    )*
                    $fblock;
                })
            };
            ($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),*]);
            };
        }

        pub use rayon_core::WorkerLocal;

        pub use rayon::iter::ParallelIterator;
        use rayon::iter::IntoParallelIterator;

        pub fn par_iter<T: IntoParallelIterator>(t: T) -> T::Iter {
            t.into_par_iter()
        }

        pub fn par_for_each_in<T: IntoParallelIterator>(
            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)
            });
        }

        pub type MetadataRef = OwningRef<Box<dyn Erased + Send + Sync>, [u8]>;

        /// This makes locks panic if they are already held.
        /// It is only useful when you are running in a single thread
        const ERROR_CHECKING: bool = false;

        #[macro_export]
        macro_rules! rustc_erase_owner {
            ($v:expr) => {{
                let v = $v;
                ::rustc_data_structures::sync::assert_send_val(&v);
                v.erase_send_sync_owner()
            }}
        }
    }
}

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) {}

pub trait HashMapExt<K, V> {
    /// Same as HashMap::insert, but it may panic if there's already an
    /// entry for `key` with a value not equal to `value`
    fn insert_same(&mut self, key: K, value: V);
}

impl<K: Eq + Hash, V: Eq, S: BuildHasher> HashMapExt<K, V> for HashMap<K, V, S> {
    fn insert_same(&mut self, key: K, value: V) {
        self.entry(key).and_modify(|old| assert!(*old == value)).or_insert(value);
    }
}

#[derive(Debug)]
pub struct Lock<T>(InnerLock<T>);

impl<T> Lock<T> {
    #[inline(always)]
    pub fn new(inner: T) -> Self {
        Lock(InnerLock::new(inner))
    }

    #[inline(always)]
    pub fn into_inner(self) -> T {
        self.0.into_inner()
    }

    #[inline(always)]
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut()
    }

    #[cfg(parallel_compiler)]
    #[inline(always)]
    pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
        self.0.try_lock()
    }

    #[cfg(not(parallel_compiler))]
    #[inline(always)]
    pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
        self.0.try_borrow_mut().ok()
    }

    #[cfg(parallel_compiler)]
    #[inline(always)]
    pub fn lock(&self) -> LockGuard<'_, T> {
        if ERROR_CHECKING {
            self.0.try_lock().expect("lock was already held")
        } else {
            self.0.lock()
        }
    }

    #[cfg(not(parallel_compiler))]
    #[inline(always)]
    pub fn lock(&self) -> LockGuard<'_, T> {
        self.0.borrow_mut()
    }

    #[inline(always)]
    pub fn with_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
        f(&mut *self.lock())
    }

    #[inline(always)]
    pub fn borrow(&self) -> LockGuard<'_, T> {
        self.lock()
    }

    #[inline(always)]
    pub fn borrow_mut(&self) -> LockGuard<'_, T> {
        self.lock()
    }
}

impl<T: Default> Default for Lock<T> {
    #[inline]
    fn default() -> Self {
        Lock::new(T::default())
    }
}

// FIXME: Probably a bad idea
impl<T: Clone> Clone for Lock<T> {
    #[inline]
    fn clone(&self) -> Self {
        Lock::new(self.borrow().clone())
    }
}

#[derive(Debug, Default)]
pub struct RwLock<T>(InnerRwLock<T>);

impl<T> RwLock<T> {
    #[inline(always)]
    pub fn new(inner: T) -> Self {
        RwLock(InnerRwLock::new(inner))
    }

    #[inline(always)]
    pub fn into_inner(self) -> T {
        self.0.into_inner()
    }

    #[inline(always)]
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut()
    }

    #[cfg(not(parallel_compiler))]
    #[inline(always)]
    pub fn read(&self) -> ReadGuard<'_, T> {
        self.0.borrow()
    }

    #[cfg(parallel_compiler)]
    #[inline(always)]
    pub fn read(&self) -> ReadGuard<'_, T> {
        if ERROR_CHECKING {
            self.0.try_read().expect("lock was already held")
        } else {
            self.0.read()
        }
    }

    #[inline(always)]
    pub fn with_read_lock<F: FnOnce(&T) -> R, R>(&self, f: F) -> R {
        f(&*self.read())
    }

    #[cfg(not(parallel_compiler))]
    #[inline(always)]
    pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
        self.0.try_borrow_mut().map_err(|_| ())
    }

    #[cfg(parallel_compiler)]
    #[inline(always)]
    pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
        self.0.try_write().ok_or(())
    }

    #[cfg(not(parallel_compiler))]
    #[inline(always)]
    pub fn write(&self) -> WriteGuard<'_, T> {
        self.0.borrow_mut()
    }

    #[cfg(parallel_compiler)]
    #[inline(always)]
    pub fn write(&self) -> WriteGuard<'_, T> {
        if ERROR_CHECKING {
            self.0.try_write().expect("lock was already held")
        } else {
            self.0.write()
        }
    }

    #[inline(always)]
    pub fn with_write_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
        f(&mut *self.write())
    }

    #[inline(always)]
    pub fn borrow(&self) -> ReadGuard<'_, T> {
        self.read()
    }

    #[inline(always)]
    pub fn borrow_mut(&self) -> WriteGuard<'_, T> {
        self.write()
    }
}

// FIXME: Probably a bad idea
impl<T: Clone> Clone for RwLock<T> {
    #[inline]
    fn clone(&self) -> Self {
        RwLock::new(self.borrow().clone())
    }
}

/// A type which only allows its inner value to be used in one thread.
/// It will panic if it is used on multiple threads.
#[derive(Debug)]
pub struct OneThread<T> {
    #[cfg(parallel_compiler)]
    thread: thread::ThreadId,
    inner: T,
}

#[cfg(parallel_compiler)]
unsafe impl<T> std::marker::Sync for OneThread<T> {}
#[cfg(parallel_compiler)]
unsafe impl<T> std::marker::Send for OneThread<T> {}

impl<T> OneThread<T> {
    #[inline(always)]
    fn check(&self) {
        #[cfg(parallel_compiler)]
        assert_eq!(thread::current().id(), self.thread);
    }

    #[inline(always)]
    pub fn new(inner: T) -> Self {
        OneThread {
            #[cfg(parallel_compiler)]
            thread: thread::current().id(),
            inner,
        }
    }

    #[inline(always)]
    pub fn into_inner(value: Self) -> T {
        value.check();
        value.inner
    }
}

impl<T> Deref for OneThread<T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.check();
        &self.inner
    }
}

impl<T> DerefMut for OneThread<T> {
    fn deref_mut(&mut self) -> &mut T {
        self.check();
        &mut self.inner
    }
}