[heap] Reland move slot filtering logic into sweeper.

src/base/atomic-utils.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ATOMIC_UTILS_H_
 #define V8_ATOMIC_UTILS_H_
 
 #include <limits.h>
 
 #include "src/base/atomicops.h"
@@ skipping 47 matching lines @@
  public:
   NoBarrierAtomicValue() : value_(0) {}
 
   explicit NoBarrierAtomicValue(T initial)
       : value_(cast_helper<T>::to_storage_type(initial)) {}
 
   static NoBarrierAtomicValue* FromAddress(void* address) {
     return reinterpret_cast<base::NoBarrierAtomicValue<T>*>(address);
   }
 
+  V8_INLINE bool TrySetValue(T old_value, T new_value) {
+    return base::NoBarrier_CompareAndSwap(
+               &value_, cast_helper<T>::to_storage_type(old_value),
+               cast_helper<T>::to_storage_type(new_value)) ==
+           cast_helper<T>::to_storage_type(old_value);
+  }
+
   V8_INLINE T Value() const {
     return cast_helper<T>::to_return_type(base::NoBarrier_Load(&value_));
   }
 
   V8_INLINE void SetValue(T new_value) {
     base::NoBarrier_Store(&value_, cast_helper<T>::to_storage_type(new_value));
   }
 
  private:
   STATIC_ASSERT(sizeof(T) <= sizeof(base::AtomicWord));
@@ skipping 160 matching lines @@
     return static_cast<base::AtomicWord>(1) << element;
   }
 
   base::AtomicWord bits_;
 };
 
 }  // namespace base
 }  // namespace v8
 
 #endif  // #define V8_ATOMIC_UTILS_H_