Introduced Atomic8 and added no-barrier Atomic8 accessors.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/228613005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20598 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/atomicops.h

@@ -63,6 +63,7 @@
 namespace v8 {
 namespace internal {
 
+typedef char Atomic8;
 typedef int32_t Atomic32;
 #ifdef V8_HOST_ARCH_64_BIT
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
@@ -120,10 +121,12 @@ Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
                                 Atomic32 new_value);
 
 void MemoryBarrier();
+void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value);
 void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value);
 void Acquire_Store(volatile Atomic32* ptr, Atomic32 value);
 void Release_Store(volatile Atomic32* ptr, Atomic32 value);
 
+Atomic8 NoBarrier_Load(volatile const Atomic8* ptr);
 Atomic32 NoBarrier_Load(volatile const Atomic32* ptr);
 Atomic32 Acquire_Load(volatile const Atomic32* ptr);
 Atomic32 Release_Load(volatile const Atomic32* ptr);

src/atomicops_internals_arm64_gcc.h

@@ -144,6 +144,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return prev;
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
@@ -162,6 +166,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   );  // NOLINT
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }

src/atomicops_internals_arm_gcc.h

@@ -311,6 +311,14 @@ inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }
 
+// Byte accessors.
+
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) { return *ptr; }
+
 } }  // namespace v8::internal
 
 #endif  // V8_ATOMICOPS_INTERNALS_ARM_GCC_H_

src/atomicops_internals_mac.h

@@ -93,6 +93,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return Acquire_CompareAndSwap(ptr, old_value, new_value);
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
@@ -107,6 +111,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }

src/atomicops_internals_mips_gcc.h

@@ -136,6 +136,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
@@ -154,6 +158,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }

src/atomicops_internals_tsan.h

@@ -276,6 +276,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return cmp;
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  __tsan_atomic8_store(ptr, value, __tsan_memory_order_relaxed);
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   __tsan_atomic32_store(ptr, value, __tsan_memory_order_relaxed);
 }
@@ -289,6 +293,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   __tsan_atomic32_store(ptr, value, __tsan_memory_order_release);
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return __tsan_atomic8_load(ptr, __tsan_memory_order_relaxed);
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return __tsan_atomic32_load(ptr, __tsan_memory_order_relaxed);
 }

src/atomicops_internals_x86_gcc.h

@@ -107,6 +107,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
@@ -152,6 +156,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   // See comments in Atomic64 version of Release_Store(), below.
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }

src/atomicops_internals_x86_msvc.h

@@ -100,6 +100,10 @@ inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
+inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
+  *ptr = value;
+}
+
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
@@ -114,6 +118,10 @@ inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
   // See comments in Atomic64 version of Release_Store() below.
 }
 
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
+  return *ptr;
+}
+
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }

test/cctest/test-atomicops.cc

@@ -214,6 +214,21 @@ static void TestStore() {
 }
 
 
+// Merge this test with TestStore as soon as we have Atomic8 acquire
+// and release stores.
+static void TestStoreAtomic8() {
+  const Atomic8 kVal1 = TestFillValue<Atomic8>();
+  const Atomic8 kVal2 = static_cast<Atomic8>(-1);
+
+  Atomic8 value;
+
+  NoBarrier_Store(&value, kVal1);
+  CHECK_EQU(kVal1, value);
+  NoBarrier_Store(&value, kVal2);
+  CHECK_EQU(kVal2, value);
+}
+
+
 // This is a simple sanity check to ensure that values are correct.
 // Not testing atomicity.
 template <class AtomicType>
@@ -240,6 +255,21 @@ static void TestLoad() {
 }
 
 
+// Merge this test with TestLoad as soon as we have Atomic8 acquire
+// and release loads.
+static void TestLoadAtomic8() {
+  const Atomic8 kVal1 = TestFillValue<Atomic8>();
+  const Atomic8 kVal2 = static_cast<Atomic8>(-1);
+
+  Atomic8 value;
+
+  value = kVal1;
+  CHECK_EQU(kVal1, NoBarrier_Load(&value));
+  value = kVal2;
+  CHECK_EQU(kVal2, NoBarrier_Load(&value));
+}
+
+
 TEST(AtomicIncrement) {
   TestAtomicIncrement<Atomic32>();
   TestAtomicIncrement<AtomicWord>();
@@ -265,12 +295,14 @@ TEST(AtomicIncrementBounds) {
 
 
 TEST(Store) {
+  TestStoreAtomic8();
   TestStore<Atomic32>();
   TestStore<AtomicWord>();
 }
 
 
 TEST(Load) {
+  TestLoadAtomic8();
   TestLoad<Atomic32>();
   TestLoad<AtomicWord>();
 }