use std::collections::hash_map::Entry;
use std::convert::TryFrom;
use std::num::TryFromIntError;
+use std::rc::Rc;
use std::time::{Duration, Instant, SystemTime};
use log::trace;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::def_id::DefId;
use rustc_index::vec::{Idx, IndexVec};
-use rustc_middle::ty::{self, Instance};
use crate::sync::SynchronizationState;
use crate::*;
/// A thread.
pub struct Thread<'mir, 'tcx> {
state: ThreadState,
+
/// Name of the thread.
thread_name: Option<Vec<u8>>,
+
/// The virtual call stack.
stack: Vec<Frame<'mir, 'tcx, Tag, FrameData<'tcx>>>,
+
/// The join status.
join_status: ThreadJoinStatus,
+
+ /// The temporary used for storing the argument of
+ /// the call to `miri_start_panic` (the panic payload) when unwinding.
+ /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
+ pub(crate) panic_payload: Option<Scalar<Tag>>,
+
+ /// Last OS error location in memory. It is a 32-bit integer.
+ pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
}
impl<'mir, 'tcx> Thread<'mir, 'tcx> {
/// Get the name of the current thread, or `<unnamed>` if it was not set.
fn thread_name(&self) -> &[u8] {
- if let Some(ref thread_name) = self.thread_name {
- thread_name
- } else {
- b"<unnamed>"
- }
+ if let Some(ref thread_name) = self.thread_name { thread_name } else { b"<unnamed>" }
}
}
impl<'mir, 'tcx> std::fmt::Debug for Thread<'mir, 'tcx> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
- write!(f, "{}({:?}, {:?})", String::from_utf8_lossy(self.thread_name()), self.state, self.join_status)
+ write!(
+ f,
+ "{}({:?}, {:?})",
+ String::from_utf8_lossy(self.thread_name()),
+ self.state,
+ self.join_status
+ )
}
}
thread_name: None,
stack: Vec::new(),
join_status: ThreadJoinStatus::Joinable,
+ panic_payload: None,
+ last_error: None,
}
}
}
fn set_thread_local_alloc_id(&self, def_id: DefId, new_alloc_id: AllocId) {
self.thread_local_alloc_ids
.borrow_mut()
- .insert((def_id, self.active_thread), new_alloc_id)
- .unwrap_none();
+ .try_insert((def_id, self.active_thread), new_alloc_id)
+ .unwrap();
}
/// Borrow the stack of the active thread.
}
/// Mark that the active thread tries to join the thread with `joined_thread_id`.
- fn join_thread(&mut self, joined_thread_id: ThreadId) -> InterpResult<'tcx> {
+ fn join_thread(
+ &mut self,
+ joined_thread_id: ThreadId,
+ data_race: &Option<Rc<data_race::GlobalState>>,
+ ) -> InterpResult<'tcx> {
if self.threads[joined_thread_id].join_status != ThreadJoinStatus::Joinable {
throw_ub_format!("trying to join a detached or already joined thread");
}
self.active_thread,
joined_thread_id
);
+ } else {
+ // The thread has already terminated - mark join happens-before
+ if let Some(data_race) = data_race {
+ data_race.thread_joined(self.active_thread, joined_thread_id);
+ }
}
Ok(())
}
callback: TimeoutCallback<'mir, 'tcx>,
) {
self.timeout_callbacks
- .insert(thread, TimeoutCallbackInfo { call_time, callback })
- .unwrap_none();
+ .try_insert(thread, TimeoutCallbackInfo { call_time, callback })
+ .unwrap();
}
/// Unregister the callback for the `thread`.
None
}
+ /// Wakes up threads joining on the active one and deallocates thread-local statics.
+ /// The `AllocId` that can now be freed is returned.
+ fn thread_terminated(
+ &mut self,
+ data_race: &Option<Rc<data_race::GlobalState>>,
+ ) -> Vec<AllocId> {
+ let mut free_tls_statics = Vec::new();
+ {
+ let mut thread_local_statics = self.thread_local_alloc_ids.borrow_mut();
+ thread_local_statics.retain(|&(_def_id, thread), &mut alloc_id| {
+ if thread != self.active_thread {
+ // Keep this static around.
+ return true;
+ }
+ // Delete this static from the map and from memory.
+ // We cannot free directly here as we cannot use `?` in this context.
+ free_tls_statics.push(alloc_id);
+ return false;
+ });
+ }
+ // Set the thread into a terminated state in the data-race detector
+ if let Some(data_race) = data_race {
+ data_race.thread_terminated();
+ }
+ // Check if we need to unblock any threads.
+ for (i, thread) in self.threads.iter_enumerated_mut() {
+ if thread.state == ThreadState::BlockedOnJoin(self.active_thread) {
+ // The thread has terminated, mark happens-before edge to joining thread
+ if let Some(data_race) = data_race {
+ data_race.thread_joined(i, self.active_thread);
+ }
+ trace!("unblocking {:?} because {:?} terminated", i, self.active_thread);
+ thread.state = ThreadState::Enabled;
+ }
+ }
+ return free_tls_statics;
+ }
+
/// Decide which action to take next and on which thread.
///
/// The currently implemented scheduling policy is the one that is commonly
/// used in stateless model checkers such as Loom: run the active thread as
/// long as we can and switch only when we have to (the active thread was
/// blocked, terminated, or has explicitly asked to be preempted).
- fn schedule(&mut self) -> InterpResult<'tcx, SchedulingAction> {
+ fn schedule(
+ &mut self,
+ data_race: &Option<Rc<data_race::GlobalState>>,
+ ) -> InterpResult<'tcx, SchedulingAction> {
// Check whether the thread has **just** terminated (`check_terminated`
// checks whether the thread has popped all its stack and if yes, sets
// the thread state to terminated).
if self.threads[self.active_thread].check_terminated() {
- // Check if we need to unblock any threads.
- for (i, thread) in self.threads.iter_enumerated_mut() {
- if thread.state == ThreadState::BlockedOnJoin(self.active_thread) {
- trace!("unblocking {:?} because {:?} terminated", i, self.active_thread);
- thread.state = ThreadState::Enabled;
- }
- }
return Ok(SchedulingAction::ExecuteDtors);
}
+ // If we get here again and the thread is *still* terminated, there are no more dtors to run.
if self.threads[MAIN_THREAD].state == ThreadState::Terminated {
// The main thread terminated; stop the program.
if self.threads.iter().any(|thread| thread.state != ThreadState::Terminated) {
}
return Ok(SchedulingAction::Stop);
}
- // At least for `pthread_cond_timedwait` we need to report timeout when
- // the function is called already after the specified time even if a
- // signal is received before the thread gets scheduled. Therefore, we
- // need to schedule all timeout callbacks before we continue regular
- // execution.
- //
- // Documentation:
- // https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_timedwait.html#
- let potential_sleep_time =
- self.timeout_callbacks.values().map(|info| info.call_time.get_wait_time()).min();
- if potential_sleep_time == Some(Duration::new(0, 0)) {
- return Ok(SchedulingAction::ExecuteTimeoutCallback);
- }
- // No callbacks scheduled, pick a regular thread to execute.
+ // This thread and the program can keep going.
if self.threads[self.active_thread].state == ThreadState::Enabled
&& !self.yield_active_thread
{
// The currently active thread is still enabled, just continue with it.
return Ok(SchedulingAction::ExecuteStep);
}
+ // The active thread yielded. Let's see if there are any timeouts to take care of. We do
+ // this *before* running any other thread, to ensure that timeouts "in the past" fire before
+ // any other thread can take an action. This ensures that for `pthread_cond_timedwait`, "an
+ // error is returned if [...] the absolute time specified by abstime has already been passed
+ // at the time of the call".
+ // <https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_timedwait.html>
+ let potential_sleep_time =
+ self.timeout_callbacks.values().map(|info| info.call_time.get_wait_time()).min();
+ if potential_sleep_time == Some(Duration::new(0, 0)) {
+ return Ok(SchedulingAction::ExecuteTimeoutCallback);
+ }
+ // No callbacks scheduled, pick a regular thread to execute.
// We need to pick a new thread for execution.
for (id, thread) in self.threads.iter_enumerated() {
if thread.state == ThreadState::Enabled {
if !self.yield_active_thread || id != self.active_thread {
self.active_thread = id;
+ if let Some(data_race) = data_race {
+ data_race.thread_set_active(self.active_thread);
+ }
break;
}
}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
/// Get a thread-specific allocation id for the given thread-local static.
/// If needed, allocate a new one.
- ///
- /// FIXME: This method should be replaced as soon as
- /// https://github.com/rust-lang/rust/issues/70685 gets fixed.
- fn get_or_create_thread_local_alloc_id(&self, def_id: DefId) -> InterpResult<'tcx, AllocId> {
- let this = self.eval_context_ref();
+ fn get_or_create_thread_local_alloc_id(
+ &mut self,
+ def_id: DefId,
+ ) -> InterpResult<'tcx, AllocId> {
+ let this = self.eval_context_mut();
let tcx = this.tcx;
if let Some(new_alloc_id) = this.machine.threads.get_thread_local_alloc_id(def_id) {
// We already have a thread-specific allocation id for this
} else {
// We need to allocate a thread-specific allocation id for this
// thread-local static.
- //
- // At first, we invoke the `const_eval_raw` query and extract the
- // allocation from it. Unfortunately, we have to duplicate the code
- // from `Memory::get_global_alloc` that does this.
- //
- // Then we store the retrieved allocation back into the `alloc_map`
- // to get a fresh allocation id, which we can use as a
- // thread-specific allocation id for the thread-local static.
+ // First, we compute the initial value for this static.
if tcx.is_foreign_item(def_id) {
throw_unsup_format!("foreign thread-local statics are not supported");
}
- // Invoke the `const_eval_raw` query.
- let instance = Instance::mono(tcx.tcx, def_id);
- let gid = GlobalId { instance, promoted: None };
- let raw_const =
- tcx.const_eval_raw(ty::ParamEnv::reveal_all().and(gid)).map_err(|err| {
- // no need to report anything, the const_eval call takes care of that
- // for statics
- assert!(tcx.is_static(def_id));
- err
- })?;
- let id = raw_const.alloc_id;
- // Extract the allocation from the query result.
- let allocation = tcx.global_alloc(id).unwrap_memory();
- // Create a new allocation id for the same allocation in this hacky
- // way. Internally, `alloc_map` deduplicates allocations, but this
- // is fine because Miri will make a copy before a first mutable
- // access.
- let new_alloc_id = tcx.create_memory_alloc(allocation);
+ let allocation = tcx.eval_static_initializer(def_id)?;
+ // Create a fresh allocation with this content.
+ let new_alloc_id =
+ this.memory.allocate_with(allocation.clone(), MiriMemoryKind::Tls.into()).alloc_id;
this.machine.threads.set_thread_local_alloc_id(def_id, new_alloc_id);
Ok(new_alloc_id)
}
#[inline]
fn create_thread(&mut self) -> ThreadId {
let this = self.eval_context_mut();
- this.machine.threads.create_thread()
+ let id = this.machine.threads.create_thread();
+ if let Some(data_race) = &this.memory.extra.data_race {
+ data_race.thread_created(id);
+ }
+ id
}
#[inline]
#[inline]
fn join_thread(&mut self, joined_thread_id: ThreadId) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
- this.machine.threads.join_thread(joined_thread_id)
+ let data_race = &this.memory.extra.data_race;
+ this.machine.threads.join_thread(joined_thread_id, data_race)?;
+ Ok(())
}
#[inline]
fn set_active_thread(&mut self, thread_id: ThreadId) -> ThreadId {
let this = self.eval_context_mut();
+ if let Some(data_race) = &this.memory.extra.data_race {
+ data_race.thread_set_active(thread_id);
+ }
this.machine.threads.set_active_thread_id(thread_id)
}
this.machine.threads.get_active_thread_id()
}
+ #[inline]
+ fn active_thread_mut(&mut self) -> &mut Thread<'mir, 'tcx> {
+ let this = self.eval_context_mut();
+ this.machine.threads.active_thread_mut()
+ }
+
+ #[inline]
+ fn active_thread_ref(&self) -> &Thread<'mir, 'tcx> {
+ let this = self.eval_context_ref();
+ this.machine.threads.active_thread_ref()
+ }
+
#[inline]
fn get_total_thread_count(&self) -> usize {
let this = self.eval_context_ref();
#[inline]
fn set_active_thread_name(&mut self, new_thread_name: Vec<u8>) {
let this = self.eval_context_mut();
+ if let Some(data_race) = &this.memory.extra.data_race {
+ if let Ok(string) = String::from_utf8(new_thread_name.clone()) {
+ data_race.thread_set_name(this.machine.threads.active_thread, string);
+ }
+ }
this.machine.threads.set_thread_name(new_thread_name);
}
fn run_timeout_callback(&mut self) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
let (thread, callback) =
- this.machine.threads.get_ready_callback().expect("no callback found");
+ if let Some((thread, callback)) = this.machine.threads.get_ready_callback() {
+ (thread, callback)
+ } else {
+ // get_ready_callback can return None if the computer's clock
+ // was shifted after calling the scheduler and before the call
+ // to get_ready_callback (see issue
+ // https://github.com/rust-lang/miri/issues/1763). In this case,
+ // just do nothing, which effectively just returns to the
+ // scheduler.
+ return Ok(());
+ };
// This back-and-forth with `set_active_thread` is here because of two
// design decisions:
// 1. Make the caller and not the callback responsible for changing
#[inline]
fn schedule(&mut self) -> InterpResult<'tcx, SchedulingAction> {
let this = self.eval_context_mut();
- this.machine.threads.schedule()
+ let data_race = &this.memory.extra.data_race;
+ this.machine.threads.schedule(data_race)
+ }
+
+ /// Handles thread termination of the active thread: wakes up threads joining on this one,
+ /// and deallocated thread-local statics.
+ ///
+ /// This is called from `tls.rs` after handling the TLS dtors.
+ #[inline]
+ fn thread_terminated(&mut self) -> InterpResult<'tcx> {
+ let this = self.eval_context_mut();
+ let data_race = &this.memory.extra.data_race;
+ for alloc_id in this.machine.threads.thread_terminated(data_race) {
+ let ptr = this.memory.global_base_pointer(alloc_id.into())?;
+ this.memory.deallocate(ptr, None, MiriMemoryKind::Tls.into())?;
+ }
+ Ok(())
}
}
projects / rust.git / blobdiff