[Atomics] Make Atomics.compareExchange a builtin using TF

src/runtime/runtime-atomics.cc

 // 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/base/macros.h"
 #include "src/base/platform/mutex.h"
 #include "src/conversions-inl.h"
 #include "src/factory.h"
 
 // Implement Atomic accesses to SharedArrayBuffers as defined in the
 // SharedArrayBuffer draft spec, found here
 // https://github.com/tc39/ecmascript_sharedmem
 
 namespace v8 {
 namespace internal {
 
 namespace {
 
 #if V8_CC_GNU
 
 template <typename T>
 inline T ExchangeSeqCst(T* p, T value) {
   return __atomic_exchange_n(p, value, __ATOMIC_SEQ_CST);
 }
 
+template <typename T>
+inline T CompareExchangeSeqCst(T* p, T oldval, T newval) {
+  (void)__atomic_compare_exchange_n(p, &oldval, newval, 0, __ATOMIC_SEQ_CST,
+                                    __ATOMIC_SEQ_CST);
+  return oldval;
+}
+
 #elif V8_CC_MSVC
 
 #define InterlockedExchange32 _InterlockedExchange
+#define InterlockedCompareExchange32 _InterlockedCompareExchange
+#define InterlockedCompareExchange8 _InterlockedCompareExchange8
 
 #define ATOMIC_OPS(type, suffix, vctype)                                    \
   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), \
+                                              bit_cast<vctype>(newval),     \
+                                              bit_cast<vctype>(oldval));    \
+  }
 
 ATOMIC_OPS(int8_t, 8, char)
 ATOMIC_OPS(uint8_t, 8, char)
 ATOMIC_OPS(int16_t, 16, short)  /* NOLINT(runtime/int) */
 ATOMIC_OPS(uint16_t, 16, short) /* NOLINT(runtime/int) */
 ATOMIC_OPS(int32_t, 32, long)   /* NOLINT(runtime/int) */
 ATOMIC_OPS(uint32_t, 32, long)  /* NOLINT(runtime/int) */
 
 #undef ATOMIC_OPS_INTEGER
 #undef ATOMIC_OPS
 
 #undef InterlockedExchange32
+#undef InterlockedCompareExchange32
+#undef InterlockedCompareExchange8
 
 #else
 
 #error Unsupported platform!
 
 #endif
 
 template <typename T>
 T FromObject(Handle<Object> number);
 
@@ skipping 47 matching lines @@
 }
 
 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);
 }
 
+template <typename T>
+inline Object* DoCompareExchange(Isolate* isolate, void* buffer, size_t index,
+                                 Handle<Object> oldobj, Handle<Object> newobj) {
+  T oldval = FromObject<T>(oldobj);
+  T newval = FromObject<T>(newobj);
+  T result =
+      CompareExchangeSeqCst(static_cast<T*>(buffer) + index, oldval, newval);
+  return ToObject(isolate, result);
+}
+
 }  // anonymous namespace
 
 // Duplicated from objects.h
 // V has parameters (Type, type, TYPE, C type, element_size)
 #define INTEGER_TYPED_ARRAYS(V)          \
   V(Uint8, uint8, UINT8, uint8_t, 1)     \
   V(Int8, int8, INT8, int8_t, 1)         \
   V(Uint16, uint16, UINT16, uint16_t, 2) \
   V(Int16, int16, INT16, int16_t, 2)     \
   V(Uint32, uint32, UINT32, uint32_t, 4) \
@@ skipping 44 matching lines @@
 #undef TYPED_ARRAY_CASE
 
     default:
       break;
   }
 
   UNREACHABLE();
   return isolate->heap()->undefined_value();
 }
 
+RUNTIME_FUNCTION(Runtime_AtomicsCompareExchange) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(4, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, sta, 0);
+  CONVERT_SIZE_ARG_CHECKED(index, 1);
+  CONVERT_NUMBER_ARG_HANDLE_CHECKED(oldobj, 2);
+  CONVERT_NUMBER_ARG_HANDLE_CHECKED(newobj, 3);
+  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 DoCompareExchange<ctype>(isolate, source, index, oldobj, newobj);
+
+    INTEGER_TYPED_ARRAYS(TYPED_ARRAY_CASE)
+#undef TYPED_ARRAY_CASE
+
+    default:
+      break;
+  }
+
+  UNREACHABLE();
+  return isolate->heap()->undefined_value();
+}
 
 }  // namespace internal
 }  // namespace v8