300 lines
10 KiB
Rust
300 lines
10 KiB
Rust
use std::collections::{hash_map::Entry, HashMap, VecDeque};
|
|
use std::convert::TryFrom;
|
|
use std::num::NonZeroU32;
|
|
use std::time::Instant;
|
|
|
|
use rustc_index::vec::{Idx, IndexVec};
|
|
|
|
use crate::*;
|
|
|
|
macro_rules! declare_id {
|
|
($name: ident) => {
|
|
#[derive(Clone, Copy, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
|
|
pub struct $name(NonZeroU32);
|
|
|
|
impl Idx for $name {
|
|
fn new(idx: usize) -> Self {
|
|
$name(NonZeroU32::new(u32::try_from(idx).unwrap() + 1).unwrap())
|
|
}
|
|
fn index(self) -> usize {
|
|
usize::try_from(self.0.get() - 1).unwrap()
|
|
}
|
|
}
|
|
|
|
impl From<u32> for $name {
|
|
fn from(id: u32) -> Self {
|
|
Self(NonZeroU32::new(id).unwrap())
|
|
}
|
|
}
|
|
|
|
impl $name {
|
|
pub fn to_u32_scalar<'tcx>(&self) -> Scalar<Tag> {
|
|
Scalar::from_u32(self.0.get())
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
declare_id!(MutexId);
|
|
|
|
/// The mutex state.
|
|
#[derive(Default, Debug)]
|
|
struct Mutex {
|
|
/// The thread that currently owns the lock.
|
|
owner: Option<ThreadId>,
|
|
/// How many times the mutex was locked by the owner.
|
|
lock_count: usize,
|
|
/// The queue of threads waiting for this mutex.
|
|
queue: VecDeque<ThreadId>,
|
|
}
|
|
|
|
declare_id!(RwLockId);
|
|
|
|
/// The read-write lock state.
|
|
#[derive(Default, Debug)]
|
|
struct RwLock {
|
|
/// The writer thread that currently owns the lock.
|
|
writer: Option<ThreadId>,
|
|
/// The readers that currently own the lock and how many times they acquired
|
|
/// the lock.
|
|
readers: HashMap<ThreadId, usize>,
|
|
/// The queue of writer threads waiting for this lock.
|
|
writer_queue: VecDeque<ThreadId>,
|
|
/// The queue of reader threads waiting for this lock.
|
|
reader_queue: VecDeque<ThreadId>,
|
|
}
|
|
|
|
declare_id!(CondvarId);
|
|
|
|
/// A thread waiting on a conditional variable.
|
|
#[derive(Debug)]
|
|
struct CondvarWaiter {
|
|
/// The thread that is waiting on this variable.
|
|
thread: ThreadId,
|
|
/// The mutex on which the thread is waiting.
|
|
mutex: MutexId,
|
|
/// The moment in time when the waiter should time out.
|
|
timeout: Option<Instant>,
|
|
}
|
|
|
|
/// The conditional variable state.
|
|
#[derive(Default, Debug)]
|
|
struct Condvar {
|
|
waiters: VecDeque<CondvarWaiter>,
|
|
}
|
|
|
|
/// The state of all synchronization variables.
|
|
#[derive(Default, Debug)]
|
|
pub(super) struct SynchronizationState {
|
|
mutexes: IndexVec<MutexId, Mutex>,
|
|
rwlocks: IndexVec<RwLockId, RwLock>,
|
|
condvars: IndexVec<CondvarId, Condvar>,
|
|
}
|
|
|
|
// Public interface to synchronization primitives. Please note that in most
|
|
// cases, the function calls are infallible and it is the client's (shim
|
|
// implementation's) responsibility to detect and deal with erroneous
|
|
// situations.
|
|
impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
|
|
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
|
|
#[inline]
|
|
/// Create state for a new mutex.
|
|
fn mutex_create(&mut self) -> MutexId {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.mutexes.push(Default::default())
|
|
}
|
|
|
|
#[inline]
|
|
/// Get the id of the thread that currently owns this lock.
|
|
fn mutex_get_owner(&mut self, id: MutexId) -> ThreadId {
|
|
let this = self.eval_context_ref();
|
|
this.machine.threads.sync.mutexes[id].owner.unwrap()
|
|
}
|
|
|
|
#[inline]
|
|
/// Check if locked.
|
|
fn mutex_is_locked(&mut self, id: MutexId) -> bool {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.mutexes[id].owner.is_some()
|
|
}
|
|
|
|
/// Lock by setting the mutex owner and increasing the lock count.
|
|
fn mutex_lock(&mut self, id: MutexId, thread: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
let mutex = &mut this.machine.threads.sync.mutexes[id];
|
|
if let Some(current_owner) = mutex.owner {
|
|
assert_eq!(thread, current_owner, "mutex already locked by another thread");
|
|
assert!(
|
|
mutex.lock_count > 0,
|
|
"invariant violation: lock_count == 0 iff the thread is unlocked"
|
|
);
|
|
} else {
|
|
mutex.owner = Some(thread);
|
|
}
|
|
mutex.lock_count = mutex.lock_count.checked_add(1).unwrap();
|
|
}
|
|
|
|
/// Unlock by decreasing the lock count. If the lock count reaches 0, unset
|
|
/// the owner.
|
|
fn mutex_unlock(&mut self, id: MutexId) -> Option<(ThreadId, usize)> {
|
|
let this = self.eval_context_mut();
|
|
let mutex = &mut this.machine.threads.sync.mutexes[id];
|
|
if let Some(current_owner) = mutex.owner {
|
|
mutex.lock_count = mutex
|
|
.lock_count
|
|
.checked_sub(1)
|
|
.expect("invariant violation: lock_count == 0 iff the thread is unlocked");
|
|
if mutex.lock_count == 0 {
|
|
mutex.owner = None;
|
|
}
|
|
Some((current_owner, mutex.lock_count))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
/// Take a thread out the queue waiting for the lock.
|
|
fn mutex_enqueue(&mut self, id: MutexId, thread: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.mutexes[id].queue.push_back(thread);
|
|
}
|
|
|
|
#[inline]
|
|
/// Take a thread out the queue waiting for the lock.
|
|
fn mutex_dequeue(&mut self, id: MutexId) -> Option<ThreadId> {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.mutexes[id].queue.pop_front()
|
|
}
|
|
|
|
#[inline]
|
|
/// Create state for a new read write lock.
|
|
fn rwlock_create(&mut self) -> RwLockId {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks.push(Default::default())
|
|
}
|
|
|
|
#[inline]
|
|
/// Check if locked.
|
|
fn rwlock_is_locked(&mut self, id: RwLockId) -> bool {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks[id].writer.is_some()
|
|
|| !this.machine.threads.sync.rwlocks[id].readers.is_empty()
|
|
}
|
|
|
|
#[inline]
|
|
/// Check if write locked.
|
|
fn rwlock_is_write_locked(&mut self, id: RwLockId) -> bool {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks[id].writer.is_some()
|
|
}
|
|
|
|
/// Add a reader that collectively with other readers owns the lock.
|
|
fn rwlock_reader_add(&mut self, id: RwLockId, reader: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
assert!(!this.rwlock_is_write_locked(id), "the lock is write locked");
|
|
let count = this.machine.threads.sync.rwlocks[id].readers.entry(reader).or_insert(0);
|
|
*count += 1;
|
|
}
|
|
|
|
/// Try removing the reader. Returns `true` if succeeded.
|
|
fn rwlock_reader_remove(&mut self, id: RwLockId, reader: ThreadId) -> bool {
|
|
let this = self.eval_context_mut();
|
|
match this.machine.threads.sync.rwlocks[id].readers.entry(reader) {
|
|
Entry::Occupied(mut entry) => {
|
|
let count = entry.get_mut();
|
|
*count -= 1;
|
|
if *count == 0 {
|
|
entry.remove();
|
|
}
|
|
true
|
|
}
|
|
Entry::Vacant(_) => false,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
/// Put the reader in the queue waiting for the lock.
|
|
fn rwlock_enqueue_reader(&mut self, id: RwLockId, reader: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
assert!(this.rwlock_is_write_locked(id), "queueing on not write locked lock");
|
|
this.machine.threads.sync.rwlocks[id].reader_queue.push_back(reader);
|
|
}
|
|
|
|
#[inline]
|
|
/// Take the reader out the queue waiting for the lock.
|
|
fn rwlock_dequeue_reader(&mut self, id: RwLockId) -> Option<ThreadId> {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks[id].reader_queue.pop_front()
|
|
}
|
|
|
|
#[inline]
|
|
/// Lock by setting the writer that owns the lock.
|
|
fn rwlock_writer_set(&mut self, id: RwLockId, writer: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
assert!(!this.rwlock_is_locked(id), "the lock is already locked");
|
|
this.machine.threads.sync.rwlocks[id].writer = Some(writer);
|
|
}
|
|
|
|
#[inline]
|
|
/// Try removing the writer.
|
|
fn rwlock_writer_remove(&mut self, id: RwLockId) -> Option<ThreadId> {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks[id].writer.take()
|
|
}
|
|
|
|
#[inline]
|
|
/// Put the writer in the queue waiting for the lock.
|
|
fn rwlock_enqueue_writer(&mut self, id: RwLockId, writer: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
assert!(this.rwlock_is_locked(id), "queueing on unlocked lock");
|
|
this.machine.threads.sync.rwlocks[id].writer_queue.push_back(writer);
|
|
}
|
|
|
|
#[inline]
|
|
/// Take the writer out the queue waiting for the lock.
|
|
fn rwlock_dequeue_writer(&mut self, id: RwLockId) -> Option<ThreadId> {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.rwlocks[id].writer_queue.pop_front()
|
|
}
|
|
|
|
#[inline]
|
|
/// Create state for a new conditional variable.
|
|
fn condvar_create(&mut self) -> CondvarId {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.condvars.push(Default::default())
|
|
}
|
|
|
|
#[inline]
|
|
/// Is the conditional variable awaited?
|
|
fn condvar_is_awaited(&mut self, id: CondvarId) -> bool {
|
|
let this = self.eval_context_mut();
|
|
!this.machine.threads.sync.condvars[id].waiters.is_empty()
|
|
}
|
|
|
|
/// Mark that the thread is waiting on the conditional variable.
|
|
fn condvar_wait(&mut self, id: CondvarId, thread: ThreadId, mutex: MutexId) {
|
|
let this = self.eval_context_mut();
|
|
let waiters = &mut this.machine.threads.sync.condvars[id].waiters;
|
|
assert!(waiters.iter().all(|waiter| waiter.thread != thread), "thread is already waiting");
|
|
waiters.push_back(CondvarWaiter { thread, mutex, timeout: None });
|
|
}
|
|
|
|
/// Wake up some thread (if there is any) sleeping on the conditional
|
|
/// variable.
|
|
fn condvar_signal(&mut self, id: CondvarId) -> Option<(ThreadId, MutexId)> {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.condvars[id]
|
|
.waiters
|
|
.pop_front()
|
|
.map(|waiter| (waiter.thread, waiter.mutex))
|
|
}
|
|
|
|
#[inline]
|
|
/// Remove the thread from the queue of threads waiting on this conditional variable.
|
|
fn condvar_remove_waiter(&mut self, id: CondvarId, thread: ThreadId) {
|
|
let this = self.eval_context_mut();
|
|
this.machine.threads.sync.condvars[id].waiters.retain(|waiter| waiter.thread != thread);
|
|
}
|
|
}
|