[Atomics] Make Atomics.exchange a builtin using TF

src/runtime/runtime-atomics.cc

Index: src/runtime/runtime-atomics.cc
diff --git a/src/runtime/runtime-atomics.cc b/src/runtime/runtime-atomics.cc
index ff7ded9b090e365dced25ce8a3a6ce6f6ba4f0cb..4cc5b6f1f08f65016105565d23ab87c3335b11bd 100644
--- a/src/runtime/runtime-atomics.cc
+++ b/src/runtime/runtime-atomics.cc
@@ -57,15 +57,9 @@ inline T XorSeqCst(T* p, T value) {
   return __atomic_fetch_xor(p, value, __ATOMIC_SEQ_CST);
 }
 
-template <typename T>
-inline T ExchangeSeqCst(T* p, T value) {
-  return __atomic_exchange_n(p, value, __ATOMIC_SEQ_CST);
-}
-
 #elif V8_CC_MSVC
 
 #define InterlockedCompareExchange32 _InterlockedCompareExchange
-#define InterlockedExchange32 _InterlockedExchange
 #define InterlockedExchangeAdd32 _InterlockedExchangeAdd
 #define InterlockedAnd32 _InterlockedAnd
 #define InterlockedOr32 _InterlockedOr
@@ -95,10 +89,6 @@ inline T ExchangeSeqCst(T* p, T value) {
     return InterlockedXor##suffix(reinterpret_cast<vctype*>(p),             \
                                   bit_cast<vctype>(value));                 \
   }                                                                         \
-  inline type ExchangeSeqCst(type* p, type value) {                         \
-    return InterlockedExchange##suffix(reinterpret_cast<vctype*>(p),        \
-                                       bit_cast<vctype>(value));            \
-  }                                                                         \
                                                                             \
   inline type CompareExchangeSeqCst(type* p, type oldval, type newval) {    \
     return InterlockedCompareExchange##suffix(reinterpret_cast<vctype*>(p), \
@@ -117,7 +107,6 @@ ATOMIC_OPS(uint32_t, 32, long)  /* NOLINT(runtime/int) */
 #undef ATOMIC_OPS
 
 #undef InterlockedCompareExchange32
-#undef InterlockedExchange32
 #undef InterlockedExchangeAdd32
 #undef InterlockedAnd32
 #undef InterlockedOr32
@@ -243,15 +232,6 @@ inline Object* DoXor(Isolate* isolate, void* buffer, size_t index,
 }
 
 
-template <typename T>
-inline Object* DoExchange(Isolate* isolate, void* buffer, size_t index,
-                          Handle<Object> obj) {
-  T value = FromObject<T>(obj);
-  T result = ExchangeSeqCst(static_cast<T*>(buffer) + index, value);
-  return ToObject(isolate, result);
-}
-
-
 // Uint8Clamped functions
 
 uint8_t ClampToUint8(int32_t value) {
@@ -298,19 +278,6 @@ DO_UINT8_CLAMPED_OP(Xor, ^)
 #undef DO_UINT8_CLAMPED_OP
 
 
-inline Object* DoExchangeUint8Clamped(Isolate* isolate, void* buffer,
-                                      size_t index, Handle<Object> obj) {
-  typedef int32_t convert_type;
-  uint8_t* p = static_cast<uint8_t*>(buffer) + index;
-  uint8_t result = ClampToUint8(FromObject<convert_type>(obj));
-  uint8_t expected;
-  do {
-    expected = *p;
-  } while (CompareExchangeSeqCst(p, expected, result) != expected);
-  return ToObject(isolate, expected);
-}
-
-
 }  // anonymous namespace
 
 // Duplicated from objects.h
@@ -541,38 +508,6 @@ RUNTIME_FUNCTION(Runtime_AtomicsXor) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_AtomicsExchange) {
-  HandleScope scope(isolate);
-  DCHECK_EQ(3, args.length());
-  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
-  CONVERT_SIZE_ARG_CHECKED(index, 1);
-  CONVERT_NUMBER_ARG_HANDLE_CHECKED(value, 2);
-  CHECK(sta->GetBuffer()->is_shared());
-  CHECK_LT(index, NumberToSize(sta->length()));
-
-  uint8_t* source = static_cast<uint8_t*>(sta->GetBuffer()->backing_store()) +
-                    NumberToSize(sta->byte_offset());
-
-  switch (sta->type()) {
-#define TYPED_ARRAY_CASE(Type, typeName, TYPE, ctype, size) \
-  case kExternal##Type##Array:                              \
-    return DoExchange<ctype>(isolate, source, index, value);
-
-    INTEGER_TYPED_ARRAYS(TYPED_ARRAY_CASE)
-#undef TYPED_ARRAY_CASE
-
-    case kExternalUint8ClampedArray:
-      return DoExchangeUint8Clamped(isolate, source, index, value);
-
-    default:
-      break;
-  }
-
-  UNREACHABLE();
-  return isolate->heap()->undefined_value();
-}
-
-
 RUNTIME_FUNCTION(Runtime_AtomicsIsLockFree) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());