diff --git a/src/concurrency/data_race.rs b/src/concurrency/data_race.rs
index 410c2b9c3d..0e176ec91f 100644
--- a/src/concurrency/data_race.rs
+++ b/src/concurrency/data_race.rs
@@ -54,7 +54,10 @@ use rustc_target::abi::{Align, Size};
 
 use crate::*;
 
-use super::weak_memory::EvalContextExt as _;
+use super::{
+    vector_clock::{VClock, VTimestamp, VectorIdx},
+    weak_memory::EvalContextExt as _,
+};
 
 pub type AllocExtra = VClockAlloc;
 
diff --git a/src/concurrency/mod.rs b/src/concurrency/mod.rs
index 5f8bba8027..07c3f0d599 100644
--- a/src/concurrency/mod.rs
+++ b/src/concurrency/mod.rs
@@ -1,3 +1,5 @@
 pub mod data_race;
 mod range_object_map;
+pub mod sync;
+mod vector_clock;
 pub mod weak_memory;
diff --git a/src/sync.rs b/src/concurrency/sync.rs
similarity index 99%
rename from src/sync.rs
rename to src/concurrency/sync.rs
index de7d528d33..81e5a83a1f 100644
--- a/src/sync.rs
+++ b/src/concurrency/sync.rs
@@ -7,6 +7,7 @@ use log::trace;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_index::vec::{Idx, IndexVec};
 
+use super::vector_clock::VClock;
 use crate::*;
 
 /// We cannot use the `newtype_index!` macro because we have to use 0 as a
@@ -150,7 +151,7 @@ struct FutexWaiter {
 
 /// The state of all synchronization variables.
 #[derive(Default, Debug)]
-pub(super) struct SynchronizationState {
+pub(crate) struct SynchronizationState {
     mutexes: IndexVec<MutexId, Mutex>,
     rwlocks: IndexVec<RwLockId, RwLock>,
     condvars: IndexVec<CondvarId, Condvar>,
diff --git a/src/vector_clock.rs b/src/concurrency/vector_clock.rs
similarity index 100%
rename from src/vector_clock.rs
rename to src/concurrency/vector_clock.rs
diff --git a/src/concurrency/weak_memory.rs b/src/concurrency/weak_memory.rs
index 317258a028..30037b6394 100644
--- a/src/concurrency/weak_memory.rs
+++ b/src/concurrency/weak_memory.rs
@@ -87,6 +87,7 @@ use crate::*;
 use super::{
     data_race::{GlobalState as DataRaceState, ThreadClockSet},
     range_object_map::{AccessType, RangeObjectMap},
+    vector_clock::{VClock, VTimestamp, VectorIdx},
 };
 
 pub type AllocExtra = StoreBufferAlloc;
diff --git a/src/lib.rs b/src/lib.rs
index 8ca3e8d15e..550d9b9d7b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -61,9 +61,7 @@ mod operator;
 mod range_map;
 mod shims;
 mod stacked_borrows;
-mod sync;
-mod thread;
-mod vector_clock;
+pub mod thread;
 
 // Establish a "crate-wide prelude": we often import `crate::*`.
 
@@ -105,12 +103,10 @@ pub use crate::range_map::RangeMap;
 pub use crate::stacked_borrows::{
     CallId, EvalContextExt as StackedBorEvalContextExt, Item, Permission, SbTag, Stack, Stacks,
 };
-pub use crate::sync::{CondvarId, EvalContextExt as SyncEvalContextExt, MutexId, RwLockId};
 pub use crate::thread::{
     EvalContextExt as ThreadsEvalContextExt, SchedulingAction, ThreadId, ThreadManager, ThreadState,
 };
-pub use crate::vector_clock::{VClock, VTimestamp, VectorIdx};
-
+pub use concurrency::sync::{CondvarId, EvalContextExt as SyncEvalContextExt, MutexId, RwLockId};
 /// Insert rustc arguments at the beginning of the argument list that Miri wants to be
 /// set per default, for maximal validation power.
 pub const MIRI_DEFAULT_ARGS: &[&str] = &[
diff --git a/src/shims/time.rs b/src/shims/time.rs
index 67303c47db..d639939ec5 100644
--- a/src/shims/time.rs
+++ b/src/shims/time.rs
@@ -1,7 +1,7 @@
 use std::time::{Duration, Instant, SystemTime};
 
+use crate::thread::Time;
 use crate::*;
-use thread::Time;
 
 /// Returns the time elapsed between the provided time and the unix epoch as a `Duration`.
 pub fn system_time_to_duration<'tcx>(time: &SystemTime) -> InterpResult<'tcx, Duration> {
diff --git a/src/shims/unix/sync.rs b/src/shims/unix/sync.rs
index 69e632915b..246cb100bc 100644
--- a/src/shims/unix/sync.rs
+++ b/src/shims/unix/sync.rs
@@ -3,8 +3,8 @@ use std::time::SystemTime;
 use rustc_hir::LangItem;
 use rustc_middle::ty::{layout::TyAndLayout, query::TyCtxtAt, subst::Subst, Ty};
 
+use crate::thread::Time;
 use crate::*;
-use thread::Time;
 
 // pthread_mutexattr_t is either 4 or 8 bytes, depending on the platform.
 
diff --git a/src/thread.rs b/src/thread.rs
index b92728be20..dc8b1c2911 100644
--- a/src/thread.rs
+++ b/src/thread.rs
@@ -15,7 +15,7 @@ use rustc_middle::ty::layout::TyAndLayout;
 use rustc_target::spec::abi::Abi;
 
 use crate::concurrency::data_race;
-use crate::sync::SynchronizationState;
+use crate::concurrency::sync::SynchronizationState;
 use crate::*;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]