//! Implement thread-local storage.
use std::collections::BTreeMap;
-use std::collections::btree_map::Entry;
+use std::collections::btree_map::Entry as BTreeEntry;
+use std::collections::hash_map::Entry as HashMapEntry;
use log::trace;
use rustc_data_structures::fx::FxHashMap;
use rustc_middle::ty;
use rustc_target::abi::{Size, HasDataLayout};
+use rustc_target::spec::abi::Abi;
-use crate::{
- HelpersEvalContextExt, InterpResult, MPlaceTy, Scalar, StackPopCleanup, Tag, ThreadId,
- ThreadsEvalContextExt,
-};
+use crate::*;
pub type TlsKey = u128;
#[derive(Clone, Debug)]
struct RunningDtorsState {
- /// The last TlsKey used to retrieve a TLS destructor.
+ /// The last TlsKey used to retrieve a TLS destructor. `None` means that we
+ /// have not tried to retrieve a TLS destructor yet or that we already tried
+ /// all keys.
last_dtor_key: Option<TlsKey>,
}
/// A single per thread destructor of the thread local storage (that's how
/// things work on macOS) with a data argument.
- thread_dtors: BTreeMap<ThreadId, (ty::Instance<'tcx>, Scalar<Tag>)>,
+ macos_thread_dtors: BTreeMap<ThreadId, (ty::Instance<'tcx>, Scalar<Tag>)>,
/// State for currently running TLS dtors. If this map contains a key for a
/// specific thread, it means that we are in the "destruct" phase, during
TlsData {
next_key: 1, // start with 1 as we must not use 0 on Windows
keys: Default::default(),
- thread_dtors: Default::default(),
+ macos_thread_dtors: Default::default(),
dtors_running: Default::default(),
}
}
pub fn create_tls_key(&mut self, dtor: Option<ty::Instance<'tcx>>, max_size: Size) -> InterpResult<'tcx, TlsKey> {
let new_key = self.next_key;
self.next_key += 1;
- self.keys.insert(new_key, TlsEntry { data: Default::default(), dtor }).unwrap_none();
+ self.keys.try_insert(new_key, TlsEntry { data: Default::default(), dtor }).unwrap();
trace!("New TLS key allocated: {} with dtor {:?}", new_key, dtor);
if max_size.bits() < 128 && new_key >= (1u128 << max_size.bits() as u128) {
/// implementation](https://github.com/opensource-apple/dyld/blob/195030646877261f0c8c7ad8b001f52d6a26f514/src/threadLocalVariables.c#L389):
///
/// // NOTE: this does not need locks because it only operates on current thread data
- pub fn set_thread_dtor(
+ pub fn set_macos_thread_dtor(
&mut self,
thread: ThreadId,
dtor: ty::Instance<'tcx>,
// UB, according to libstd docs.
throw_ub_format!("setting thread's local storage destructor while destructors are already running");
}
- if self.thread_dtors.insert(thread, (dtor, data)).is_some() {
+ if self.macos_thread_dtors.insert(thread, (dtor, data)).is_some() {
throw_unsup_format!("setting more than one thread local storage destructor for the same thread is not supported");
}
Ok(())
key: Option<TlsKey>,
thread_id: ThreadId,
) -> Option<(ty::Instance<'tcx>, Scalar<Tag>, TlsKey)> {
- use std::collections::Bound::*;
+ use std::ops::Bound::*;
let thread_local = &mut self.keys;
let start = match key {
thread_local.range_mut((start, Unbounded))
{
match data.entry(thread_id) {
- Entry::Occupied(entry) => {
+ BTreeEntry::Occupied(entry) => {
if let Some(dtor) = dtor {
+ // Set TLS data to NULL, and call dtor with old value.
let data_scalar = entry.remove();
let ret = Some((*dtor, data_scalar, key));
return ret;
}
}
- Entry::Vacant(_) => {}
+ BTreeEntry::Vacant(_) => {}
}
}
None
/// the existing values stored in `dtors_running` for this thread. Returns
/// `true` if dtors for `thread` are already running.
fn set_dtors_running_for_thread(&mut self, thread: ThreadId) -> bool {
- if self.dtors_running.contains_key(&thread) {
- true
- } else {
- self.dtors_running.insert(
- thread,
- RunningDtorsState { last_dtor_key: None }
- );
- false
+ match self.dtors_running.entry(thread) {
+ HashMapEntry::Occupied(_) => true,
+ HashMapEntry::Vacant(entry) => {
+ // We cannot just do `self.dtors_running.insert` because that
+ // would overwrite `last_dtor_key` with `None`.
+ entry.insert(RunningDtorsState { last_dtor_key: None });
+ false
+ }
+ }
+ }
+
+ /// Delete all TLS entries for the given thread. This function should be
+ /// called after all TLS destructors have already finished.
+ fn delete_all_thread_tls(&mut self, thread_id: ThreadId) {
+ for TlsEntry { data, .. } in self.keys.values_mut() {
+ data.remove(&thread_id);
}
}
}
/// yet.
fn schedule_windows_tls_dtors(&mut self) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
- let active_thread = this.get_active_thread()?;
- assert_eq!(this.get_total_thread_count()?, 1, "concurrency on Windows not supported");
+ let active_thread = this.get_active_thread();
+ assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported");
// Windows has a special magic linker section that is run on certain events.
// Instead of searching for that section and supporting arbitrary hooks in there
// (that would be basically https://github.com/rust-lang/miri/issues/450),
// we specifically look up the static in libstd that we know is placed
// in that section.
- let thread_callback = this.eval_path_scalar(&["std", "sys", "windows", "thread_local", "p_thread_callback"])?;
- let thread_callback = this.memory.get_fn(thread_callback.not_undef()?)?.as_instance()?;
+ let thread_callback = this.eval_path_scalar(&["std", "sys", "windows", "thread_local_key", "p_thread_callback"])?;
+ let thread_callback = this.memory.get_fn(thread_callback.check_init()?)?.as_instance()?;
// The signature of this function is `unsafe extern "system" fn(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID)`.
let reason = this.eval_path_scalar(&["std", "sys", "windows", "c", "DLL_THREAD_DETACH"])?;
let ret_place = MPlaceTy::dangling(this.machine.layouts.unit, this).into();
this.call_function(
thread_callback,
+ Abi::System { unwind: false },
&[Scalar::null_ptr(this).into(), reason.into(), Scalar::null_ptr(this).into()],
- Some(ret_place),
+ Some(&ret_place),
StackPopCleanup::None { cleanup: true },
)?;
- this.enable_thread(active_thread)?;
+ this.enable_thread(active_thread);
Ok(())
}
/// Schedule the MacOS thread destructor of the thread local storage to be
- /// executed.
+ /// executed. Returns `true` if scheduled.
///
/// Note: It is safe to call this function also on other Unixes.
- fn schedule_macos_tls_dtor(&mut self) -> InterpResult<'tcx> {
+ fn schedule_macos_tls_dtor(&mut self) -> InterpResult<'tcx, bool> {
let this = self.eval_context_mut();
- let thread_id = this.get_active_thread()?;
- if let Some((instance, data)) = this.machine.tls.thread_dtors.remove(&thread_id) {
+ let thread_id = this.get_active_thread();
+ if let Some((instance, data)) = this.machine.tls.macos_thread_dtors.remove(&thread_id) {
trace!("Running macos dtor {:?} on {:?} at {:?}", instance, data, thread_id);
let ret_place = MPlaceTy::dangling(this.machine.layouts.unit, this).into();
this.call_function(
instance,
+ Abi::C { unwind: false },
&[data.into()],
- Some(ret_place),
+ Some(&ret_place),
StackPopCleanup::None { cleanup: true },
)?;
// we just scheduled. Since we deleted the destructor, it is
// guaranteed that we will schedule it again. The `dtors_running`
// flag will prevent the code from adding the destructor again.
- this.enable_thread(thread_id)?;
+ this.enable_thread(thread_id);
+ Ok(true)
+ } else {
+ Ok(false)
}
- Ok(())
}
- /// Schedule a pthread TLS destructor.
- fn schedule_pthread_tls_dtors(&mut self) -> InterpResult<'tcx> {
+ /// Schedule a pthread TLS destructor. Returns `true` if found
+ /// a destructor to schedule, and `false` otherwise.
+ fn schedule_next_pthread_tls_dtor(&mut self) -> InterpResult<'tcx, bool> {
let this = self.eval_context_mut();
- let active_thread = this.get_active_thread()?;
+ let active_thread = this.get_active_thread();
- assert!(this.has_terminated(active_thread)?, "running TLS dtors for non-terminated thread");
+ assert!(this.has_terminated(active_thread), "running TLS dtors for non-terminated thread");
// Fetch next dtor after `key`.
let last_key = this.machine.tls.dtors_running[&active_thread].last_dtor_key.clone();
let dtor = match this.machine.tls.fetch_tls_dtor(last_key, active_thread) {
let ret_place = MPlaceTy::dangling(this.machine.layouts.unit, this).into();
this.call_function(
instance,
+ Abi::C { unwind: false },
&[ptr.into()],
- Some(ret_place),
+ Some(&ret_place),
StackPopCleanup::None { cleanup: true },
)?;
- this.enable_thread(active_thread)?;
- return Ok(());
+ this.enable_thread(active_thread);
+ return Ok(true);
}
this.machine.tls.dtors_running.get_mut(&active_thread).unwrap().last_dtor_key = None;
- Ok(())
+ Ok(false)
}
}
/// schedules them one by one each time it is called and reenables the
/// thread so that it can be executed normally by the main execution loop.
///
- /// FIXME: we do not support yet deallocation of thread local statics.
- /// Issue: https://github.com/rust-lang/miri/issues/1369
+ /// Note: we consistently run TLS destructors for all threads, including the
+ /// main thread. However, it is not clear that we should run the TLS
+ /// destructors for the main thread. See issue:
+ /// https://github.com/rust-lang/rust/issues/28129.
fn schedule_next_tls_dtor_for_active_thread(&mut self) -> InterpResult<'tcx> {
let this = self.eval_context_mut();
- let active_thread = this.get_active_thread()?;
-
- if this.tcx.sess.target.target.target_os == "windows" {
- if !this.machine.tls.set_dtors_running_for_thread(active_thread) {
+ let active_thread = this.get_active_thread();
+
+ if !this.machine.tls.set_dtors_running_for_thread(active_thread) {
+ // This is the first time we got asked to schedule a destructor. The
+ // Windows schedule destructor function must be called exactly once,
+ // this is why it is in this block.
+ if this.tcx.sess.target.os == "windows" {
+ // On Windows, we signal that the thread quit by starting the
+ // relevant function, reenabling the thread, and going back to
+ // the scheduler.
this.schedule_windows_tls_dtors()?;
+ return Ok(())
}
- } else {
- this.machine.tls.set_dtors_running_for_thread(active_thread);
- // The macOS thread wide destructor runs "before any TLS slots get
- // freed", so do that first.
- this.schedule_macos_tls_dtor()?;
- this.schedule_pthread_tls_dtors()?;
}
+ // The remaining dtors make some progress each time around the scheduler loop,
+ // until they return `false` to indicate that they are done.
+
+ // The macOS thread wide destructor runs "before any TLS slots get
+ // freed", so do that first.
+ if this.schedule_macos_tls_dtor()? {
+ // We have scheduled a MacOS dtor to run on the thread. Execute it
+ // to completion and come back here. Scheduling a destructor
+ // destroys it, so we will not enter this branch again.
+ return Ok(())
+ }
+ if this.schedule_next_pthread_tls_dtor()? {
+ // We have scheduled a pthread destructor and removed it from the
+ // destructors list. Run it to completion and come back here.
+ return Ok(())
+ }
+
+ // All dtors done!
+ this.machine.tls.delete_all_thread_tls(active_thread);
+ this.thread_terminated()?;
Ok(())
}
projects / rust.git / blobdiff