Attempt to speed up v8::Object::SetPrivate

src/api.cc

 // Copyright 2012 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/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 3582 matching lines @@
       DefineObjectProperty(self, key_obj, value_obj,
                            static_cast<i::PropertyAttributes>(attribs))
           .is_null();
   EXCEPTION_BAILOUT_CHECK_SCOPED(isolate, false);
   return true;
 }
 
 
 Maybe<bool> v8::Object::SetPrivate(Local<Context> context, Local<Private> key,
                                    Local<Value> value) {
-  return DefineOwnProperty(context, Local<Name>(reinterpret_cast<Name*>(*key)),
-                           value, DontEnum);
+  PREPARE_FOR_EXECUTION_PRIMITIVE(context, "v8::Object::SetPrivate()", bool);
+  auto self = Utils::OpenHandle(this);
+  auto key_obj = Utils::OpenHandle(reinterpret_cast<Name*>(*key));
+  auto value_obj = Utils::OpenHandle(*value);
+  if (self->IsJSProxy()) {
+    i::PropertyDescriptor desc;
+    desc.set_writable(true);
+    desc.set_enumerable(false);
+    desc.set_configurable(true);
+    desc.set_value(value_obj);
+    return i::JSProxy::SetPrivateProperty(
+        isolate, i::Handle<i::JSProxy>::cast(self),
+        i::Handle<i::Symbol>::cast(key_obj), &desc, i::Object::DONT_THROW);
+  }
+  auto js_object = i::Handle<i::JSObject>::cast(self);
+  i::LookupIterator it(js_object, key_obj);
+  has_pending_exception = i::JSObject::DefineOwnPropertyIgnoreAttributes(
+                              &it, value_obj, i::DONT_ENUM)
+                              .is_null();
+  RETURN_ON_FAILED_EXECUTION_PRIMITIVE(bool);
+  return Just(true);
 }
 
 
 MaybeLocal<Value> v8::Object::Get(Local<v8::Context> context,
                                   Local<Value> key) {
   PREPARE_FOR_EXECUTION(context, "v8::Object::Get()", Value);
   auto self = Utils::OpenHandle(this);
   auto key_obj = Utils::OpenHandle(*key);
   i::Handle<i::Object> result;
   has_pending_exception =
@@ skipping 4939 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8