use enum for condvar locks

Author: beepster4096

src/concurrency/sync.rs

@@ -116,15 +116,19 @@ struct RwLock {
 
 declare_id!(CondvarId);
 
+#[derive(Debug)]
+pub enum CondvarLock {
+    Mutex(MutexId),
+    RwLock { id: RwLockId, shared: bool },
+}
+
 /// A thread waiting on a conditional variable.
 #[derive(Debug)]
 struct CondvarWaiter {
     /// The thread that is waiting on this variable.
     thread: ThreadId,
     /// The mutex or rwlock on which the thread is waiting.
-    lock: u32,
-    /// If the lock is shared or exclusive
-    shared: bool,
+    lock: CondvarLock,
 }
 
 /// The conditional variable state.
@@ -571,16 +575,16 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     }
 
     /// Mark that the thread is waiting on the conditional variable.
-    fn condvar_wait(&mut self, id: CondvarId, thread: ThreadId, lock: u32, shared: bool) {
+    fn condvar_wait(&mut self, id: CondvarId, thread: ThreadId, lock: CondvarLock) {
         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, lock, shared });
+        waiters.push_back(CondvarWaiter { thread, lock });
     }
 
     /// Wake up some thread (if there is any) sleeping on the conditional
     /// variable.
-    fn condvar_signal(&mut self, id: CondvarId) -> Option<(ThreadId, u32, bool)> {
+    fn condvar_signal(&mut self, id: CondvarId) -> Option<(ThreadId, CondvarLock)> {
         let this = self.eval_context_mut();
         let current_thread = this.get_active_thread();
         let condvar = &mut this.machine.threads.sync.condvars[id];
@@ -594,7 +598,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             if let Some(data_race) = data_race {
                 data_race.validate_lock_acquire(&condvar.data_race, waiter.thread);
             }
-            (waiter.thread, waiter.lock, waiter.shared)
+            (waiter.thread, waiter.lock)
         })
     }
 

src/shims/unix/sync.rs

@@ -3,6 +3,7 @@ use std::time::SystemTime;
 use rustc_hir::LangItem;
 use rustc_middle::ty::{layout::TyAndLayout, query::TyCtxtAt, Ty};
 
+use crate::concurrency::sync::CondvarLock;
 use crate::concurrency::thread::{MachineCallback, Time};
 use crate::*;
 
@@ -696,9 +697,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     fn pthread_cond_signal(&mut self, cond_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
         let id = this.condvar_get_or_create_id(cond_op, CONDVAR_ID_OFFSET)?;
-        if let Some((thread, mutex, shared)) = this.condvar_signal(id) {
-            assert!(!shared);
-            post_cond_signal(this, thread, MutexId::from_u32(mutex))?;
+        if let Some((thread, lock)) = this.condvar_signal(id) {
+            if let CondvarLock::Mutex(mutex) = lock {
+                post_cond_signal(this, thread, mutex)?;
+            } else {
+                panic!("condvar should not have an rwlock on unix");
+            }
         }
 
         Ok(0)
@@ -711,9 +715,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let this = self.eval_context_mut();
         let id = this.condvar_get_or_create_id(cond_op, CONDVAR_ID_OFFSET)?;
 
-        while let Some((thread, mutex, shared)) = this.condvar_signal(id) {
-            assert!(!shared);
-            post_cond_signal(this, thread, MutexId::from_u32(mutex))?;
+        while let Some((thread, lock)) = this.condvar_signal(id) {
+            if let CondvarLock::Mutex(mutex) = lock {
+                post_cond_signal(this, thread, mutex)?;
+            } else {
+                panic!("condvar should not have an rwlock on unix");
+            }
         }
 
         Ok(0)
@@ -731,7 +738,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let active_thread = this.get_active_thread();
 
         release_cond_mutex_and_block(this, active_thread, mutex_id)?;
-        this.condvar_wait(id, active_thread, mutex_id.to_u32(), false);
+        this.condvar_wait(id, active_thread, CondvarLock::Mutex(mutex_id));
 
         Ok(0)
     }
@@ -770,7 +777,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         };
 
         release_cond_mutex_and_block(this, active_thread, mutex_id)?;
-        this.condvar_wait(id, active_thread, mutex_id.to_u32(), false);
+        this.condvar_wait(id, active_thread, CondvarLock::Mutex(mutex_id));
 
         // We return success for now and override it in the timeout callback.
         this.write_scalar(Scalar::from_i32(0), dest)?;

src/shims/windows/sync.rs

@@ -3,6 +3,7 @@ use std::time::Duration;
 use rustc_target::abi::Size;
 
 use crate::concurrency::init_once::InitOnceStatus;
+use crate::concurrency::sync::CondvarLock;
 use crate::concurrency::thread::MachineCallback;
 use crate::*;
 
@@ -403,7 +404,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
 
         this.block_thread(active_thread);
-        this.condvar_wait(condvar_id, active_thread, lock_id.to_u32(), shared);
+        this.condvar_wait(condvar_id, active_thread, CondvarLock::RwLock { id: lock_id, shared });
 
         if let Some(timeout_time) = timeout_time {
             struct Callback<'tcx> {
@@ -454,9 +455,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let this = self.eval_context_mut();
         let condvar_id = this.condvar_get_or_create_id(condvar_op, CONDVAR_ID_OFFSET)?;
 
-        if let Some((thread, lock, shared)) = this.condvar_signal(condvar_id) {
-            this.reacquire_cond_lock(thread, RwLockId::from_u32(lock), shared)?;
-            this.unregister_timeout_callback_if_exists(thread);
+        if let Some((thread, lock)) = this.condvar_signal(condvar_id) {
+            if let CondvarLock::RwLock { id, shared } = lock {
+                this.reacquire_cond_lock(thread, id, shared)?;
+                this.unregister_timeout_callback_if_exists(thread);
+            } else {
+                panic!("mutexes should not exist on windows");
+            }
         }
 
         Ok(())
@@ -469,9 +474,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let this = self.eval_context_mut();
         let condvar_id = this.condvar_get_or_create_id(condvar_op, CONDVAR_ID_OFFSET)?;
 
-        while let Some((thread, lock, shared)) = this.condvar_signal(condvar_id) {
-            this.reacquire_cond_lock(thread, RwLockId::from_u32(lock), shared)?;
-            this.unregister_timeout_callback_if_exists(thread);
+        while let Some((thread, lock)) = this.condvar_signal(condvar_id) {
+            if let CondvarLock::RwLock { id, shared } = lock {
+                this.reacquire_cond_lock(thread, id, shared)?;
+                this.unregister_timeout_callback_if_exists(thread);
+            } else {
+                panic!("mutexes should not exist on windows");
+            }
         }
 
         Ok(())