diff --git a/compiler-rt/lib/tsan/rtl/tsan_mutexset.h b/compiler-rt/lib/tsan/rtl/tsan_mutexset.h
--- a/compiler-rt/lib/tsan/rtl/tsan_mutexset.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_mutexset.h
@@ -23,9 +23,12 @@
   // The oldest mutexes are discarded on overflow.
   static const uptr kMaxSize = 16;
   struct Desc {
+    uptr addr;
+    StackID stack_id;
     u64 id;
     u64 epoch;
-    int count;
+    u32 seq;
+    u32 count;
     bool write;
   };
 
@@ -34,21 +37,24 @@
   void Add(u64 id, bool write, u64 epoch);
   void Del(u64 id, bool write);
   void Remove(u64 id);  // Removes the mutex completely (if it's destroyed).
+  void AddAddr(uptr addr, StackID stack_id, bool write);
+  void DelAddr(uptr addr, bool destroy = false);
   uptr Size() const;
   Desc Get(uptr i) const;
 
+  MutexSet(const MutexSet& other) { *this = other; }
   void operator=(const MutexSet &other) {
     internal_memcpy(this, &other, sizeof(*this));
   }
 
  private:
 #if !SANITIZER_GO
-  uptr size_;
+  u32 seq_ = 0;
+  uptr size_ = 0;
   Desc descs_[kMaxSize];
-#endif
 
   void RemovePos(uptr i);
-  MutexSet(const MutexSet&);
+#endif
 };
 
 // Go does not have mutexes, so do not spend memory and time.
@@ -59,7 +65,8 @@
 void MutexSet::Add(u64 id, bool write, u64 epoch) {}
 void MutexSet::Del(u64 id, bool write) {}
 void MutexSet::Remove(u64 id) {}
-void MutexSet::RemovePos(uptr i) {}
+void MutexSet::AddAddr(uptr addr, StackID stack_id, bool write) {}
+void MutexSet::DelAddr(uptr addr, bool destroy) {}
 uptr MutexSet::Size() const { return 0; }
 MutexSet::Desc MutexSet::Get(uptr i) const { return Desc(); }
 #endif
diff --git a/compiler-rt/lib/tsan/rtl/tsan_mutexset.cpp b/compiler-rt/lib/tsan/rtl/tsan_mutexset.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_mutexset.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_mutexset.cpp
@@ -17,7 +17,6 @@
 const uptr MutexSet::kMaxSize;
 
 MutexSet::MutexSet() {
-  size_ = 0;
   internal_memset(&descs_, 0, sizeof(descs_));
 }
 
@@ -44,9 +43,12 @@
     CHECK_EQ(size_, kMaxSize - 1);
   }
   // Add new mutex descriptor.
+  descs_[size_].addr = 0;
+  descs_[size_].stack_id = kInvalidStackID;
   descs_[size_].id = id;
   descs_[size_].write = write;
   descs_[size_].epoch = epoch;
+  descs_[size_].seq = seq_++;
   descs_[size_].count = 1;
   size_++;
 }
@@ -70,6 +72,46 @@
   }
 }
 
+void MutexSet::AddAddr(uptr addr, StackID stack_id, bool write) {
+  // Look up existing mutex with the same id.
+  for (uptr i = 0; i < size_; i++) {
+    if (descs_[i].addr == addr) {
+      descs_[i].count++;
+      descs_[i].seq = seq_++;
+      return;
+    }
+  }
+  // On overflow, find the oldest mutex and drop it.
+  if (size_ == kMaxSize) {
+    uptr min = 0;
+    for (uptr i = 0; i < size_; i++) {
+      if (descs_[i].seq < descs_[min].seq)
+        min = i;
+    }
+    RemovePos(min);
+    CHECK_EQ(size_, kMaxSize - 1);
+  }
+  // Add new mutex descriptor.
+  descs_[size_].addr = addr;
+  descs_[size_].stack_id = stack_id;
+  descs_[size_].id = 0;
+  descs_[size_].write = write;
+  descs_[size_].epoch = 0;
+  descs_[size_].seq = seq_++;
+  descs_[size_].count = 1;
+  size_++;
+}
+
+void MutexSet::DelAddr(uptr addr, bool destroy) {
+  for (uptr i = 0; i < size_; i++) {
+    if (descs_[i].addr == addr) {
+      if (destroy || --descs_[i].count == 0)
+        RemovePos(i);
+      return;
+    }
+  }
+}
+
 void MutexSet::RemovePos(uptr i) {
   CHECK_LT(i, size_);
   descs_[i] = descs_[size_ - 1];