Make instanceof and Object.getPrototypeOf work for proxies, plus a few other tweaks.

src/v8natives.js

Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index 469059ba21a3981a8e1c6b9d5e9db057f74f098d..0a42a5197558cb23ace828679610fc95fc6548fc 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -399,6 +399,23 @@ function ToPropertyDescriptor(obj) {
 }
 
 
+// For Harmony proxies.
+function ToCompletePropertyDescriptor(obj) {
+  var desc = ToPropertyDescriptor(obj)
+  if (IsGenericDescriptor(desc) || IsDataDescriptor(desc)) {
+    if (!("value" in desc)) desc.value = undefined

[Kevin Millikin (Chromium), 2011/06/01 15:14:31]

undefined ==> void 0

+    if (!("writable" in desc)) desc.writable = false
+  } else {
+    // Is accessor descriptor.
+    if (!("get" in desc)) desc.get = undefined
+    if (!("set" in desc)) desc.set = undefined
+  }
+  if (!("enumerable" in desc)) desc.enumerable = false
+  if (!("configurable" in desc)) desc.configurable = false
+  return desc
+}
+
+
 function PropertyDescriptor() {
   // Initialize here so they are all in-object and have the same map.
   // Default values from ES5 8.6.1.
@@ -547,9 +564,23 @@ function ConvertDescriptorArrayToDescriptor(desc_array) {
 
 // ES5 section 8.12.2.
 function GetProperty(obj, p) {
+  if (%IsJSProxy(obj)) {
+    var handler = %GetHandler(obj)
+    var getProperty = handler.getPropertyDescriptor
+    if (IS_UNDEFINED(getProperty))
+      throw MakeTypeError("handler_trap_missing",
+                          [handler, "getPropertyDescriptor"])
+    var descriptor = getProperty.call(handler, p)
+    if (IS_UNDEFINED(descriptor)) return descriptor
+    var desc = ToCompletePropertyDescriptor(descriptor)
+    if (!desc.configurable)
+      throw MakeTypeError("proxy_prop_not_configurable",
+                          [handler, "getPropertyDescriptor", p, descriptor])
+    return desc
+  }
   var prop = GetOwnProperty(obj);
   if (!IS_UNDEFINED(prop)) return prop;
-  var proto = obj.__proto__;
+  var proto = %GetPrototype(obj);
   if (IS_NULL(proto)) return void 0;
   return GetProperty(proto, p);
 }
@@ -557,6 +588,12 @@ function GetProperty(obj, p) {
 
 // ES5 section 8.12.6
 function HasProperty(obj, p) {
+  if (%IsJSProxy(obj)) {
+    var handler = %GetHandler(obj)
+    var has = handler.has
+    if (IS_UNDEFINED(has)) has = DerivedHasTrap
+    return ToBoolean(has.call(handler, obj, p))
+  }
   var desc = GetProperty(obj, p);
   return IS_UNDEFINED(desc) ? false : true;
 }
@@ -745,7 +782,7 @@ function DefineOwnProperty(obj, p, desc, should_throw) {
 function ObjectGetPrototypeOf(obj) {
   if (!IS_SPEC_OBJECT(obj))
     throw MakeTypeError("obj_ctor_property_non_object", ["getPrototypeOf"]);
-  return obj.__proto__;
+  return %GetPrototype(obj);
 }