From b4bcaf75879d5499e42145f098b179f215ac3876 Mon Sep 17 00:00:00 2001
From: Ryan VanderMeulen <ryanvm@gmail.com>
Date: Thu, 30 Jan 2014 16:59:57 -0500
Subject: [PATCH] Backed out changeset f434624463d9 (bug 965837) for bustage.

---
 mfbt/Atomics.h             | 40 +-------------------------------------
 mfbt/tests/TestAtomics.cpp | 39 -------------------------------------
 2 files changed, 1 insertion(+), 78 deletions(-)

diff --git a/mfbt/Atomics.h b/mfbt/Atomics.h
index ab2b85f19b4d..03ae7c34f35b 100644
--- a/mfbt/Atomics.h
+++ b/mfbt/Atomics.h
@@ -934,7 +934,7 @@ class Atomic;
  * swap method is provided.
  */
 template<typename T, MemoryOrdering Order>
-class Atomic<T, Order, typename EnableIf<IsIntegral<T>::value && !IsSame<T, bool>::value>::Type>
+class Atomic<T, Order, typename EnableIf<IsIntegral<T>::value>::Type>
   : public detail::AtomicBaseIncDec<T, Order>
 {
     typedef typename detail::AtomicBaseIncDec<T, Order> Base;
@@ -1006,44 +1006,6 @@ class Atomic<T, Order, typename EnableIf<IsEnum<T>::value>::Type>
     Atomic(Atomic<T, Order>& aOther) MOZ_DELETE;
 };
 
-/**
- * Atomic<T> implementation for boolean types.
- *
- * The atomic store and load operations and the atomic swap method is provided.
- *
- * Note:
- *
- * - sizeof(Atomic<bool>) != sizeof(bool) for some implementations of
- *   bool and/or some implementations of std::atomic. This is allowed in
- *   [atomic.types.generic]p9.
- *
- * - It's not obvious whether the 8-bit atomic functions on Windows are always
- *   inlined or not. If they are not inlined, the corresponding functions in the
- *   runtime library are not available on Windows XP. This is why we implement
- *   Atomic<bool> with an underlying type of uint32_t.
- */
-template<MemoryOrdering Order>
-class Atomic<bool, Order>
-  : protected detail::AtomicBase<uint32_t, Order>
-{
-    typedef typename detail::AtomicBase<uint32_t, Order> Base;
-
-  public:
-    MOZ_CONSTEXPR Atomic() : Base() {}
-    MOZ_CONSTEXPR Atomic(bool aInit) : Base(aInit) {}
-
-    // We provide boolean wrappers for the underlying AtomicBase methods.
-    operator bool() const { return Base::operator uint32_t(); }
-    bool operator=(bool aValue) { return Base::operator=(aValue); }
-    bool exchange(bool aValue) { return Base::exchange(aValue); }
-    bool compareExchange(bool aOldValue, bool aNewValue) {
-      return Base::compareExchange(aOldValue, aNewValue);
-    }
-
-  private:
-    Atomic(Atomic<bool, Order>& aOther) MOZ_DELETE;
-};
-
 } // namespace mozilla
 
 #endif /* mozilla_Atomics_h */
diff --git a/mfbt/tests/TestAtomics.cpp b/mfbt/tests/TestAtomics.cpp
index e1289c8d668a..9ed214956556 100644
--- a/mfbt/tests/TestAtomics.cpp
+++ b/mfbt/tests/TestAtomics.cpp
@@ -165,36 +165,6 @@ TestEnumWithOrdering()
   MOZ_ASSERT(atomic == EnumType_3, "CAS should have changed atomic's value.");
 }
 
-template <MemoryOrdering Order>
-static void
-TestBoolWithOrdering()
-{
-  Atomic<bool, Order> atomic(false);
-  MOZ_ASSERT(atomic == false, "Atomic variable did not initialize");
-
-  // Test assignment
-  DebugOnly<bool> result;
-  result = (atomic = true);
-  MOZ_ASSERT(atomic == true, "Atomic assignment failed");
-  MOZ_ASSERT(result == true, "Atomic assignment returned the wrong value");
-
-  // Test exchange.
-  atomic = false;
-  result = atomic.exchange(true);
-  MOZ_ASSERT(atomic == true, "Atomic exchange did not work");
-  MOZ_ASSERT(result == false, "Atomic exchange returned the wrong value");
-
-  // Test CAS.
-  atomic = false;
-  DebugOnly<bool> boolResult = atomic.compareExchange(true, false);
-  MOZ_ASSERT(!boolResult, "CAS should have returned false.");
-  MOZ_ASSERT(atomic == false, "CAS shouldn't have done anything.");
-
-  boolResult = atomic.compareExchange(false, true);
-  MOZ_ASSERT(boolResult, "CAS should have succeeded.");
-  MOZ_ASSERT(atomic == true, "CAS should have changed atomic's value.");
-}
-
 template <typename T>
 static void
 TestType()
@@ -221,14 +191,6 @@ TestEnum()
   TestEnumWithOrdering<Relaxed>();
 }
 
-static void
-TestBool()
-{
-  TestBoolWithOrdering<SequentiallyConsistent>();
-  TestBoolWithOrdering<ReleaseAcquire>();
-  TestBoolWithOrdering<Relaxed>();
-}
-
 int main()
 {
   TestType<uint32_t>();
@@ -240,5 +202,4 @@ int main()
   TestPointer<uint16_t*>();
   TestPointer<uint32_t*>();
   TestEnum();
-  TestBool();
 }