diff --git a/src/array-iterator.js b/src/array-iterator.js
index fb18789f98..f04d6c974a 100644
--- a/src/array-iterator.js
+++ b/src/array-iterator.js
@@ -110,8 +110,8 @@ function SetUpArrayIterator() {
     'next', ArrayIteratorNext
   ));
   %FunctionSetName(ArrayIteratorIterator, '[Symbol.iterator]');
-  %AddProperty(ArrayIterator.prototype, symbolIterator, ArrayIteratorIterator,
-      DONT_ENUM);
+  %AddNamedProperty(ArrayIterator.prototype, symbolIterator,
+                    ArrayIteratorIterator, DONT_ENUM);
 }
 SetUpArrayIterator();
 
@@ -125,7 +125,7 @@ function ExtendArrayPrototype() {
     'keys', ArrayKeys
   ));
 
-  %AddProperty($Array.prototype, symbolIterator, ArrayValues, DONT_ENUM);
+  %AddNamedProperty($Array.prototype, symbolIterator, ArrayValues, DONT_ENUM);
 }
 ExtendArrayPrototype();
 
@@ -146,10 +146,10 @@ macro TYPED_ARRAYS(FUNCTION)
 endmacro
 
 macro EXTEND_TYPED_ARRAY(NAME)
-  %AddProperty($NAME.prototype, 'entries', ArrayEntries, DONT_ENUM);
-  %AddProperty($NAME.prototype, 'values', ArrayValues, DONT_ENUM);
-  %AddProperty($NAME.prototype, 'keys', ArrayKeys, DONT_ENUM);
-  %AddProperty($NAME.prototype, symbolIterator, ArrayValues, DONT_ENUM);
+  %AddNamedProperty($NAME.prototype, 'entries', ArrayEntries, DONT_ENUM);
+  %AddNamedProperty($NAME.prototype, 'values', ArrayValues, DONT_ENUM);
+  %AddNamedProperty($NAME.prototype, 'keys', ArrayKeys, DONT_ENUM);
+  %AddNamedProperty($NAME.prototype, symbolIterator, ArrayValues, DONT_ENUM);
 endmacro
 
   TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
diff --git a/src/array.js b/src/array.js
index ca91c69d2c..15cbbf21a6 100644
--- a/src/array.js
+++ b/src/array.js
@@ -1460,7 +1460,7 @@ function SetUpArray() {
 
   // Set up non-enumerable constructor property on the Array.prototype
   // object.
-  %AddProperty($Array.prototype, "constructor", $Array, DONT_ENUM);
+  %AddNamedProperty($Array.prototype, "constructor", $Array, DONT_ENUM);
 
   // Set up non-enumerable functions on the Array object.
   InstallFunctions($Array, DONT_ENUM, $Array(
diff --git a/src/arraybuffer.js b/src/arraybuffer.js
index a34469cefb..e1c887fdb8 100644
--- a/src/arraybuffer.js
+++ b/src/arraybuffer.js
@@ -74,7 +74,8 @@ function SetUpArrayBuffer() {
   %FunctionSetPrototype($ArrayBuffer, new $Object());
 
   // Set up the constructor property on the ArrayBuffer prototype object.
-  %AddProperty($ArrayBuffer.prototype, "constructor", $ArrayBuffer, DONT_ENUM);
+  %AddNamedProperty(
+      $ArrayBuffer.prototype, "constructor", $ArrayBuffer, DONT_ENUM);
 
   InstallGetter($ArrayBuffer.prototype, "byteLength", ArrayBufferGetByteLen);
 
diff --git a/src/collection-iterator.js b/src/collection-iterator.js
index 096e30dcab..2bccc8d7a2 100644
--- a/src/collection-iterator.js
+++ b/src/collection-iterator.js
@@ -75,7 +75,7 @@ function SetUpSetIterator() {
   ));
 
   %FunctionSetName(SetIteratorSymbolIterator, '[Symbol.iterator]');
-  %AddProperty(SetIterator.prototype, symbolIterator,
+  %AddNamedProperty(SetIterator.prototype, symbolIterator,
       SetIteratorSymbolIterator, DONT_ENUM);
 }
 
@@ -91,7 +91,7 @@ function ExtendSetPrototype() {
     'values', SetValues
   ));
 
-  %AddProperty($Set.prototype, symbolIterator, SetValues, DONT_ENUM);
+  %AddNamedProperty($Set.prototype, symbolIterator, SetValues, DONT_ENUM);
 }
 
 ExtendSetPrototype();
@@ -172,7 +172,7 @@ function SetUpMapIterator() {
   ));
 
   %FunctionSetName(MapIteratorSymbolIterator, '[Symbol.iterator]');
-  %AddProperty(MapIterator.prototype, symbolIterator,
+  %AddNamedProperty(MapIterator.prototype, symbolIterator,
       MapIteratorSymbolIterator, DONT_ENUM);
 }
 
@@ -188,7 +188,7 @@ function ExtendMapPrototype() {
     'values', MapValues
   ));
 
-  %AddProperty($Map.prototype, symbolIterator, MapEntries, DONT_ENUM);
+  %AddNamedProperty($Map.prototype, symbolIterator, MapEntries, DONT_ENUM);
 }
 
 ExtendMapPrototype();
diff --git a/src/collection.js b/src/collection.js
index ac12331eed..e5fc0b33c8 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -147,7 +147,7 @@ function SetUpSet() {
 
   %SetCode($Set, SetConstructor);
   %FunctionSetPrototype($Set, new $Object());
-  %AddProperty($Set.prototype, "constructor", $Set, DONT_ENUM);
+  %AddNamedProperty($Set.prototype, "constructor", $Set, DONT_ENUM);
 
   %FunctionSetLength(SetForEach, 1);
 
@@ -282,7 +282,7 @@ function SetUpMap() {
 
   %SetCode($Map, MapConstructor);
   %FunctionSetPrototype($Map, new $Object());
-  %AddProperty($Map.prototype, "constructor", $Map, DONT_ENUM);
+  %AddNamedProperty($Map.prototype, "constructor", $Map, DONT_ENUM);
 
   %FunctionSetLength(MapForEach, 1);
 
diff --git a/src/date.js b/src/date.js
index c4c7f6e383..87c87bfda6 100644
--- a/src/date.js
+++ b/src/date.js
@@ -763,7 +763,7 @@ function SetUpDate() {
   ));
 
   // Set up non-enumerable constructor property of the Date prototype object.
-  %AddProperty($Date.prototype, "constructor", $Date, DONT_ENUM);
+  %AddNamedProperty($Date.prototype, "constructor", $Date, DONT_ENUM);
 
   // Set up non-enumerable functions of the Date prototype object and
   // set their names.
diff --git a/src/generator.js b/src/generator.js
index 316ffa0f01..54f6d8cd7e 100644
--- a/src/generator.js
+++ b/src/generator.js
@@ -63,13 +63,13 @@ function SetUpGenerators() {
                    ["next", GeneratorObjectNext,
                     "throw", GeneratorObjectThrow]);
   %FunctionSetName(GeneratorObjectIterator, '[Symbol.iterator]');
-  %AddProperty(GeneratorObjectPrototype, symbolIterator,
+  %AddNamedProperty(GeneratorObjectPrototype, symbolIterator,
       GeneratorObjectIterator, DONT_ENUM | DONT_DELETE | READ_ONLY);
-  %AddProperty(GeneratorObjectPrototype, "constructor",
+  %AddNamedProperty(GeneratorObjectPrototype, "constructor",
       GeneratorFunctionPrototype, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunctionPrototype, $Function.prototype);
   %SetCode(GeneratorFunctionPrototype, GeneratorFunctionPrototypeConstructor);
-  %AddProperty(GeneratorFunctionPrototype, "constructor",
+  %AddNamedProperty(GeneratorFunctionPrototype, "constructor",
       GeneratorFunction, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunction, $Function);
   %SetCode(GeneratorFunction, GeneratorFunctionConstructor);
diff --git a/src/i18n.js b/src/i18n.js
index 6dcb86fe9e..61e0ac98e5 100644
--- a/src/i18n.js
+++ b/src/i18n.js
@@ -942,7 +942,7 @@ function initializeCollator(collator, locales, options) {
  *
  * @constructor
  */
-%AddProperty(Intl, 'Collator', function() {
+%AddNamedProperty(Intl, 'Collator', function() {
     var locales = %_Arguments(0);
     var options = %_Arguments(1);
 
@@ -960,7 +960,7 @@ function initializeCollator(collator, locales, options) {
 /**
  * Collator resolvedOptions method.
  */
-%AddProperty(Intl.Collator.prototype, 'resolvedOptions', function() {
+%AddNamedProperty(Intl.Collator.prototype, 'resolvedOptions', function() {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -997,7 +997,7 @@ function initializeCollator(collator, locales, options) {
  * order in the returned list as in the input list.
  * Options are optional parameter.
  */
-%AddProperty(Intl.Collator, 'supportedLocalesOf', function(locales) {
+%AddNamedProperty(Intl.Collator, 'supportedLocalesOf', function(locales) {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1169,7 +1169,7 @@ function initializeNumberFormat(numberFormat, locales, options) {
  *
  * @constructor
  */
-%AddProperty(Intl, 'NumberFormat', function() {
+%AddNamedProperty(Intl, 'NumberFormat', function() {
     var locales = %_Arguments(0);
     var options = %_Arguments(1);
 
@@ -1187,7 +1187,7 @@ function initializeNumberFormat(numberFormat, locales, options) {
 /**
  * NumberFormat resolvedOptions method.
  */
-%AddProperty(Intl.NumberFormat.prototype, 'resolvedOptions', function() {
+%AddNamedProperty(Intl.NumberFormat.prototype, 'resolvedOptions', function() {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1243,7 +1243,7 @@ function initializeNumberFormat(numberFormat, locales, options) {
  * order in the returned list as in the input list.
  * Options are optional parameter.
  */
-%AddProperty(Intl.NumberFormat, 'supportedLocalesOf', function(locales) {
+%AddNamedProperty(Intl.NumberFormat, 'supportedLocalesOf', function(locales) {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1562,7 +1562,7 @@ function initializeDateTimeFormat(dateFormat, locales, options) {
  *
  * @constructor
  */
-%AddProperty(Intl, 'DateTimeFormat', function() {
+%AddNamedProperty(Intl, 'DateTimeFormat', function() {
     var locales = %_Arguments(0);
     var options = %_Arguments(1);
 
@@ -1580,7 +1580,7 @@ function initializeDateTimeFormat(dateFormat, locales, options) {
 /**
  * DateTimeFormat resolvedOptions method.
  */
-%AddProperty(Intl.DateTimeFormat.prototype, 'resolvedOptions', function() {
+%AddNamedProperty(Intl.DateTimeFormat.prototype, 'resolvedOptions', function() {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1636,7 +1636,7 @@ function initializeDateTimeFormat(dateFormat, locales, options) {
  * order in the returned list as in the input list.
  * Options are optional parameter.
  */
-%AddProperty(Intl.DateTimeFormat, 'supportedLocalesOf', function(locales) {
+%AddNamedProperty(Intl.DateTimeFormat, 'supportedLocalesOf', function(locales) {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1768,7 +1768,7 @@ function initializeBreakIterator(iterator, locales, options) {
  *
  * @constructor
  */
-%AddProperty(Intl, 'v8BreakIterator', function() {
+%AddNamedProperty(Intl, 'v8BreakIterator', function() {
     var locales = %_Arguments(0);
     var options = %_Arguments(1);
 
@@ -1786,7 +1786,8 @@ function initializeBreakIterator(iterator, locales, options) {
 /**
  * BreakIterator resolvedOptions method.
  */
-%AddProperty(Intl.v8BreakIterator.prototype, 'resolvedOptions', function() {
+%AddNamedProperty(Intl.v8BreakIterator.prototype, 'resolvedOptions',
+  function() {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
@@ -1819,7 +1820,8 @@ function initializeBreakIterator(iterator, locales, options) {
  * order in the returned list as in the input list.
  * Options are optional parameter.
  */
-%AddProperty(Intl.v8BreakIterator, 'supportedLocalesOf', function(locales) {
+%AddNamedProperty(Intl.v8BreakIterator, 'supportedLocalesOf',
+  function(locales) {
     if (%_IsConstructCall()) {
       throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
     }
diff --git a/src/math.js b/src/math.js
index 679fc5fce8..6491399292 100644
--- a/src/math.js
+++ b/src/math.js
@@ -260,7 +260,7 @@ function SetUpMath() {
   %CheckIsBootstrapping();
 
   %SetPrototype($Math, $Object.prototype);
-  %AddProperty(global, "Math", $Math, DONT_ENUM);
+  %AddNamedProperty(global, "Math", $Math, DONT_ENUM);
   %FunctionSetInstanceClassName(MathConstructor, 'Math');
 
   // Set up math constants.
diff --git a/src/messages.js b/src/messages.js
index 5aa4111b5d..28af372b7f 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -286,8 +286,8 @@ function MakeGenericError(constructor, type, args) {
  * Set up the Script function and constructor.
  */
 %FunctionSetInstanceClassName(Script, 'Script');
-%AddProperty(Script.prototype, 'constructor', Script,
-             DONT_ENUM | DONT_DELETE | READ_ONLY);
+%AddNamedProperty(Script.prototype, 'constructor', Script,
+                  DONT_ENUM | DONT_DELETE | READ_ONLY);
 %SetCode(Script, function(x) {
   // Script objects can only be created by the VM.
   throw new $Error("Not supported");
@@ -1160,9 +1160,9 @@ function SetUpError() {
     // effects when overwriting the error functions from
     // user code.
     var name = f.name;
-    %AddProperty(global, name, f, DONT_ENUM);
-    %AddProperty(builtins, '$' + name, f,
-                 DONT_ENUM | DONT_DELETE | READ_ONLY);
+    %AddNamedProperty(global, name, f, DONT_ENUM);
+    %AddNamedProperty(builtins, '$' + name, f,
+                      DONT_ENUM | DONT_DELETE | READ_ONLY);
     // Configure the error function.
     if (name == 'Error') {
       // The prototype of the Error object must itself be an error.
@@ -1177,16 +1177,16 @@ function SetUpError() {
       %FunctionSetPrototype(f, new $Error());
     }
     %FunctionSetInstanceClassName(f, 'Error');
-    %AddProperty(f.prototype, 'constructor', f, DONT_ENUM);
-    %AddProperty(f.prototype, "name", name, DONT_ENUM);
+    %AddNamedProperty(f.prototype, 'constructor', f, DONT_ENUM);
+    %AddNamedProperty(f.prototype, "name", name, DONT_ENUM);
     %SetCode(f, function(m) {
       if (%_IsConstructCall()) {
         // Define all the expected properties directly on the error
         // object. This avoids going through getters and setters defined
         // on prototype objects.
-        %AddProperty(this, 'stack', UNDEFINED, DONT_ENUM);
+        %AddNamedProperty(this, 'stack', UNDEFINED, DONT_ENUM);
         if (!IS_UNDEFINED(m)) {
-          %AddProperty(this, 'message', ToString(m), DONT_ENUM);
+          %AddNamedProperty(this, 'message', ToString(m), DONT_ENUM);
         }
         try { captureStackTrace(this, f); } catch (e) { }
       } else {
@@ -1209,7 +1209,7 @@ SetUpError();
 
 $Error.captureStackTrace = captureStackTrace;
 
-%AddProperty($Error.prototype, 'message', '', DONT_ENUM);
+%AddNamedProperty($Error.prototype, 'message', '', DONT_ENUM);
 
 // Global list of error objects visited during ErrorToString. This is
 // used to detect cycles in error toString formatting.
diff --git a/src/object-observe.js b/src/object-observe.js
index 9d80784d61..76f39159e1 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -450,7 +450,8 @@ function ObjectInfoEnqueueExternalChangeRecord(objectInfo, changeRecord, type) {
 
   for (var prop in changeRecord) {
     if (prop === 'object' || (hasType && prop === 'type')) continue;
-    %AddProperty(newRecord, prop, changeRecord[prop], READ_ONLY + DONT_DELETE);
+    %DefineDataPropertyUnchecked(
+        newRecord, prop, changeRecord[prop], READ_ONLY + DONT_DELETE);
   }
   ObjectFreezeJS(newRecord);
 
diff --git a/src/promise.js b/src/promise.js
index c94e05968d..2797d79acb 100644
--- a/src/promise.js
+++ b/src/promise.js
@@ -325,7 +325,7 @@ var lastMicrotaskId = 0;
   // Install exported functions.
 
   %CheckIsBootstrapping();
-  %AddProperty(global, 'Promise', $Promise, DONT_ENUM);
+  %AddNamedProperty(global, 'Promise', $Promise, DONT_ENUM);
   InstallFunctions($Promise, DONT_ENUM, [
     "defer", PromiseDeferred,
     "accept", PromiseResolved,
diff --git a/src/regexp.js b/src/regexp.js
index 556ca37ac6..d7883fb693 100644
--- a/src/regexp.js
+++ b/src/regexp.js
@@ -381,7 +381,7 @@ var lastMatchInfoOverride = null;
 function SetUpRegExp() {
   %CheckIsBootstrapping();
   %FunctionSetInstanceClassName($RegExp, 'RegExp');
-  %AddProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
+  %AddNamedProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
   %SetCode($RegExp, RegExpConstructor);
 
   InstallFunctions($RegExp.prototype, DONT_ENUM, $Array(
diff --git a/src/runtime.cc b/src/runtime.cc
index 432f20a916..2f0b50dfd8 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5195,12 +5195,12 @@ RUNTIME_FUNCTION(Runtime_SetHiddenProperty) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_AddProperty) {
+RUNTIME_FUNCTION(Runtime_AddNamedProperty) {
   HandleScope scope(isolate);
   RUNTIME_ASSERT(args.length() == 4);
 
   CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Name, key, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
   CONVERT_SMI_ARG_CHECKED(unchecked_attributes, 3);
   RUNTIME_ASSERT(
@@ -5210,27 +5210,17 @@ RUNTIME_FUNCTION(Runtime_AddProperty) {
       static_cast<PropertyAttributes>(unchecked_attributes);
 
 #ifdef DEBUG
-  bool duplicate;
   uint32_t index = 0;
-  if (key->IsName() || !key->ToArrayIndex(&index)) {
-    if (key->IsNumber()) {
-      ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, key,
-                                         Execution::ToString(isolate, key));
-    }
-    LookupIterator it(object, Handle<Name>::cast(key),
-                      LookupIterator::CHECK_OWN_REAL);
-    JSReceiver::GetPropertyAttributes(&it);
-    duplicate = it.IsFound();
-  } else {
-    duplicate = JSReceiver::HasOwnElement(object, index);
-  }
-  RUNTIME_ASSERT(!duplicate);
+  ASSERT(!key->ToArrayIndex(&index));
+  LookupIterator it(object, key, LookupIterator::CHECK_OWN_REAL);
+  JSReceiver::GetPropertyAttributes(&it);
+  RUNTIME_ASSERT(!it.IsFound());
 #endif
 
   Handle<Object> result;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, result,
-      Runtime::DefineObjectProperty(object, key, value, attributes));
+      JSObject::SetOwnPropertyIgnoreAttributes(object, key, value, attributes));
   return *result;
 }
 
diff --git a/src/runtime.h b/src/runtime.h
index 475721bb30..00f38ca22b 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -224,7 +224,7 @@ namespace internal {
   F(GlobalProxy, 1, 1)                                 \
   F(IsAttachedGlobal, 1, 1)                            \
                                                        \
-  F(AddProperty, 4, 1)                                 \
+  F(AddNamedProperty, 4, 1)                            \
   F(AddPropertyForTemplate, 4, 1)                      \
   F(SetProperty, 4, 1)                                 \
   F(DefineDataPropertyUnchecked, 4, 1)                 \
diff --git a/src/string-iterator.js b/src/string-iterator.js
index 7a2309de70..7222885a56 100644
--- a/src/string-iterator.js
+++ b/src/string-iterator.js
@@ -84,8 +84,8 @@ function SetUpStringIterator() {
     'next', StringIteratorNext
   ));
   %FunctionSetName(StringIteratorIterator, '[Symbol.iterator]');
-  %AddProperty(StringIterator.prototype, symbolIterator, StringIteratorIterator,
-      DONT_ENUM);
+  %AddNamedProperty(StringIterator.prototype, symbolIterator,
+                    StringIteratorIterator, DONT_ENUM);
 }
 SetUpStringIterator();
 
@@ -100,7 +100,7 @@ function ExtendStringPrototypeWithIterator() {
   %CheckIsBootstrapping();
 
   %FunctionSetName(StringPrototypeIterator, '[Symbol.iterator]');
-  %AddProperty($String.prototype, symbolIterator, StringPrototypeIterator,
-      DONT_ENUM);
+  %AddNamedProperty($String.prototype, symbolIterator,
+                    StringPrototypeIterator, DONT_ENUM);
 }
 ExtendStringPrototypeWithIterator();
diff --git a/src/string.js b/src/string.js
index d949c64433..9719df4c28 100644
--- a/src/string.js
+++ b/src/string.js
@@ -915,7 +915,7 @@ function SetUpString() {
   %FunctionSetPrototype($String, new $String());
 
   // Set up the constructor property on the String prototype object.
-  %AddProperty($String.prototype, "constructor", $String, DONT_ENUM);
+  %AddNamedProperty($String.prototype, "constructor", $String, DONT_ENUM);
 
   // Set up the non-enumerable functions on the String object.
   InstallFunctions($String, DONT_ENUM, $Array(
diff --git a/src/symbol.js b/src/symbol.js
index c3e2aec0bc..0ac3a125a0 100644
--- a/src/symbol.js
+++ b/src/symbol.js
@@ -113,7 +113,7 @@ function SetUpSymbol() {
     "keyFor", SymbolKeyFor
   ));
 
-  %AddProperty($Symbol.prototype, "constructor", $Symbol, DONT_ENUM);
+  %AddNamedProperty($Symbol.prototype, "constructor", $Symbol, DONT_ENUM);
   InstallFunctions($Symbol.prototype, DONT_ENUM, $Array(
     "toString", SymbolToString,
     "valueOf", SymbolValueOf
diff --git a/src/typedarray.js b/src/typedarray.js
index ab5fc5c9e3..c149b35b98 100644
--- a/src/typedarray.js
+++ b/src/typedarray.js
@@ -299,13 +299,13 @@ macro SETUP_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
   %SetCode(global.NAME, NAMEConstructor);
   %FunctionSetPrototype(global.NAME, new $Object());
 
-  %AddProperty(global.NAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
-               READ_ONLY | DONT_ENUM | DONT_DELETE);
-  %AddProperty(global.NAME.prototype,
-               "constructor", global.NAME, DONT_ENUM);
-  %AddProperty(global.NAME.prototype,
-               "BYTES_PER_ELEMENT", ELEMENT_SIZE,
-               READ_ONLY | DONT_ENUM | DONT_DELETE);
+  %AddNamedProperty(global.NAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
+                    READ_ONLY | DONT_ENUM | DONT_DELETE);
+  %AddNamedProperty(global.NAME.prototype,
+                    "constructor", global.NAME, DONT_ENUM);
+  %AddNamedProperty(global.NAME.prototype,
+                    "BYTES_PER_ELEMENT", ELEMENT_SIZE,
+                    READ_ONLY | DONT_ENUM | DONT_DELETE);
   InstallGetter(global.NAME.prototype, "buffer", NAME_GetBuffer);
   InstallGetter(global.NAME.prototype, "byteOffset", NAME_GetByteOffset);
   InstallGetter(global.NAME.prototype, "byteLength", NAME_GetByteLength);
@@ -436,7 +436,7 @@ function SetupDataView() {
   %FunctionSetPrototype($DataView, new $Object);
 
   // Set up constructor property on the DataView prototype.
-  %AddProperty($DataView.prototype, "constructor", $DataView, DONT_ENUM);
+  %AddNamedProperty($DataView.prototype, "constructor", $DataView, DONT_ENUM);
 
   InstallGetter($DataView.prototype, "buffer", DataViewGetBufferJS);
   InstallGetter($DataView.prototype, "byteOffset", DataViewGetByteOffset);
diff --git a/src/v8natives.js b/src/v8natives.js
index 576186a8a7..009a3fb112 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -28,7 +28,7 @@ function InstallFunctions(object, attributes, functions) {
     var f = functions[i + 1];
     %FunctionSetName(f, key);
     %FunctionRemovePrototype(f);
-    %AddProperty(object, key, f, attributes);
+    %AddNamedProperty(object, key, f, attributes);
     %SetNativeFlag(f);
   }
   %ToFastProperties(object);
@@ -65,7 +65,7 @@ function InstallConstants(object, constants) {
   for (var i = 0; i < constants.length; i += 2) {
     var name = constants[i];
     var k = constants[i + 1];
-    %AddProperty(object, name, k, attributes);
+    %AddNamedProperty(object, name, k, attributes);
   }
   %ToFastProperties(object);
 }
@@ -86,13 +86,14 @@ function SetUpLockedPrototype(constructor, fields, methods) {
   }
   if (fields) {
     for (var i = 0; i < fields.length; i++) {
-      %AddProperty(prototype, fields[i], UNDEFINED, DONT_ENUM | DONT_DELETE);
+      %AddNamedProperty(prototype, fields[i],
+                        UNDEFINED, DONT_ENUM | DONT_DELETE);
     }
   }
   for (var i = 0; i < methods.length; i += 2) {
     var key = methods[i];
     var f = methods[i + 1];
-    %AddProperty(prototype, key, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
+    %AddNamedProperty(prototype, key, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
     %SetNativeFlag(f);
   }
   %SetPrototype(prototype, null);
@@ -190,13 +191,13 @@ function SetUpGlobal() {
   var attributes = DONT_ENUM | DONT_DELETE | READ_ONLY;
 
   // ECMA 262 - 15.1.1.1.
-  %AddProperty(global, "NaN", NAN, attributes);
+  %AddNamedProperty(global, "NaN", NAN, attributes);
 
   // ECMA-262 - 15.1.1.2.
-  %AddProperty(global, "Infinity", INFINITY, attributes);
+  %AddNamedProperty(global, "Infinity", INFINITY, attributes);
 
   // ECMA-262 - 15.1.1.3.
-  %AddProperty(global, "undefined", UNDEFINED, attributes);
+  %AddNamedProperty(global, "undefined", UNDEFINED, attributes);
 
   // Set up non-enumerable function on the global object.
   InstallFunctions(global, DONT_ENUM, $Array(
@@ -386,22 +387,22 @@ function FromGenericPropertyDescriptor(desc) {
   var obj = new $Object();
 
   if (desc.hasValue()) {
-    %AddProperty(obj, "value", desc.getValue(), NONE);
+    %AddNamedProperty(obj, "value", desc.getValue(), NONE);
   }
   if (desc.hasWritable()) {
-    %AddProperty(obj, "writable", desc.isWritable(), NONE);
+    %AddNamedProperty(obj, "writable", desc.isWritable(), NONE);
   }
   if (desc.hasGetter()) {
-    %AddProperty(obj, "get", desc.getGet(), NONE);
+    %AddNamedProperty(obj, "get", desc.getGet(), NONE);
   }
   if (desc.hasSetter()) {
-    %AddProperty(obj, "set", desc.getSet(), NONE);
+    %AddNamedProperty(obj, "set", desc.getSet(), NONE);
   }
   if (desc.hasEnumerable()) {
-    %AddProperty(obj, "enumerable", desc.isEnumerable(), NONE);
+    %AddNamedProperty(obj, "enumerable", desc.isEnumerable(), NONE);
   }
   if (desc.hasConfigurable()) {
-    %AddProperty(obj, "configurable", desc.isConfigurable(), NONE);
+    %AddNamedProperty(obj, "configurable", desc.isConfigurable(), NONE);
   }
   return obj;
 }
@@ -1407,7 +1408,7 @@ function SetUpObject() {
   %SetNativeFlag($Object);
   %SetCode($Object, ObjectConstructor);
 
-  %AddProperty($Object.prototype, "constructor", $Object, DONT_ENUM);
+  %AddNamedProperty($Object.prototype, "constructor", $Object, DONT_ENUM);
 
   // Set up non-enumerable functions on the Object.prototype object.
   InstallFunctions($Object.prototype, DONT_ENUM, $Array(
@@ -1494,7 +1495,7 @@ function SetUpBoolean () {
 
   %SetCode($Boolean, BooleanConstructor);
   %FunctionSetPrototype($Boolean, new $Boolean(false));
-  %AddProperty($Boolean.prototype, "constructor", $Boolean, DONT_ENUM);
+  %AddNamedProperty($Boolean.prototype, "constructor", $Boolean, DONT_ENUM);
 
   InstallFunctions($Boolean.prototype, DONT_ENUM, $Array(
     "toString", BooleanToString,
@@ -1677,7 +1678,7 @@ function SetUpNumber() {
 
   %OptimizeObjectForAddingMultipleProperties($Number.prototype, 8);
   // Set up the constructor property on the Number prototype object.
-  %AddProperty($Number.prototype, "constructor", $Number, DONT_ENUM);
+  %AddNamedProperty($Number.prototype, "constructor", $Number, DONT_ENUM);
 
   InstallConstants($Number, $Array(
       // ECMA-262 section 15.7.3.1.
@@ -1860,7 +1861,7 @@ function SetUpFunction() {
   %CheckIsBootstrapping();
 
   %SetCode($Function, FunctionConstructor);
-  %AddProperty($Function.prototype, "constructor", $Function, DONT_ENUM);
+  %AddNamedProperty($Function.prototype, "constructor", $Function, DONT_ENUM);
 
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
diff --git a/src/weak_collection.js b/src/weak_collection.js
index d61243aa13..d9666ca128 100644
--- a/src/weak_collection.js
+++ b/src/weak_collection.js
@@ -89,7 +89,7 @@ function SetUpWeakMap() {
 
   %SetCode($WeakMap, WeakMapConstructor);
   %FunctionSetPrototype($WeakMap, new $Object());
-  %AddProperty($WeakMap.prototype, "constructor", $WeakMap, DONT_ENUM);
+  %AddNamedProperty($WeakMap.prototype, "constructor", $WeakMap, DONT_ENUM);
 
   // Set up the non-enumerable functions on the WeakMap prototype object.
   InstallFunctions($WeakMap.prototype, DONT_ENUM, $Array(
@@ -169,7 +169,7 @@ function SetUpWeakSet() {
 
   %SetCode($WeakSet, WeakSetConstructor);
   %FunctionSetPrototype($WeakSet, new $Object());
-  %AddProperty($WeakSet.prototype, "constructor", $WeakSet, DONT_ENUM);
+  %AddNamedProperty($WeakSet.prototype, "constructor", $WeakSet, DONT_ENUM);
 
   // Set up the non-enumerable functions on the WeakSet prototype object.
   InstallFunctions($WeakSet.prototype, DONT_ENUM, $Array(
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 625117205a..f4b410b591 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -21634,7 +21634,7 @@ TEST(AccessCheckThrows) {
   CheckCorrectThrow("has_own_property(other, 'x')");
   CheckCorrectThrow("%GetProperty(other, 'x')");
   CheckCorrectThrow("%SetProperty(other, 'x', 'foo', 0)");
-  CheckCorrectThrow("%AddProperty(other, 'x', 'foo', 1)");
+  CheckCorrectThrow("%AddNamedProperty(other, 'x', 'foo', 1)");
   CheckCorrectThrow("%DeleteProperty(other, 'x', 0)");
   CheckCorrectThrow("%DeleteProperty(other, '1', 0)");
   CheckCorrectThrow("%HasOwnProperty(other, 'x')");
diff --git a/test/mjsunit/regress/regress-1199637.js b/test/mjsunit/regress/regress-1199637.js
index 3db48555fe..397aeb8762 100644
--- a/test/mjsunit/regress/regress-1199637.js
+++ b/test/mjsunit/regress/regress-1199637.js
@@ -34,43 +34,43 @@ const NONE = 0;
 const READ_ONLY = 1;
 
 // Use DeclareGlobal...
-%AddProperty(this.__proto__, "a", 1234, NONE);
+%AddNamedProperty(this.__proto__, "a", 1234, NONE);
 assertEquals(1234, a);
 eval("var a = 5678;");
 assertEquals(5678, a);
 
-%AddProperty(this.__proto__, "b", 1234, NONE);
+%AddNamedProperty(this.__proto__, "b", 1234, NONE);
 assertEquals(1234, b);
 eval("const b = 5678;");
 assertEquals(5678, b);
 
-%AddProperty(this.__proto__, "c", 1234, READ_ONLY);
+%AddNamedProperty(this.__proto__, "c", 1234, READ_ONLY);
 assertEquals(1234, c);
 eval("var c = 5678;");
 assertEquals(5678, c);
 
-%AddProperty(this.__proto__, "d", 1234, READ_ONLY);
+%AddNamedProperty(this.__proto__, "d", 1234, READ_ONLY);
 assertEquals(1234, d);
 eval("const d = 5678;");
 assertEquals(5678, d);
 
 // Use DeclareContextSlot...
-%AddProperty(this.__proto__, "x", 1234, NONE);
+%AddNamedProperty(this.__proto__, "x", 1234, NONE);
 assertEquals(1234, x);
 eval("with({}) { var x = 5678; }");
 assertEquals(5678, x);
 
-%AddProperty(this.__proto__, "y", 1234, NONE);
+%AddNamedProperty(this.__proto__, "y", 1234, NONE);
 assertEquals(1234, y);
 eval("with({}) { const y = 5678; }");
 assertEquals(5678, y);
 
-%AddProperty(this.__proto__, "z", 1234, READ_ONLY);
+%AddNamedProperty(this.__proto__, "z", 1234, READ_ONLY);
 assertEquals(1234, z);
 eval("with({}) { var z = 5678; }");
 assertEquals(5678, z);
 
-%AddProperty(this.__proto__, "w", 1234, READ_ONLY);
+%AddNamedProperty(this.__proto__, "w", 1234, READ_ONLY);
 assertEquals(1234, w);
 eval("with({}) { const w = 5678; }");
 assertEquals(5678, w);
diff --git a/test/mjsunit/regress/regress-334.js b/test/mjsunit/regress/regress-334.js
index 2a001d3c2f..c52c72aa90 100644
--- a/test/mjsunit/regress/regress-334.js
+++ b/test/mjsunit/regress/regress-334.js
@@ -37,10 +37,10 @@ function func1(){}
 function func2(){}
 
 var object = {__proto__:{}};
-%AddProperty(object, "foo", func1, DONT_ENUM | DONT_DELETE);
-%AddProperty(object, "bar", func1, DONT_ENUM | READ_ONLY);
-%AddProperty(object, "baz", func1, DONT_DELETE | READ_ONLY);
-%AddProperty(object.__proto__, "bif", func1, DONT_ENUM | DONT_DELETE);
+%AddNamedProperty(object, "foo", func1, DONT_ENUM | DONT_DELETE);
+%AddNamedProperty(object, "bar", func1, DONT_ENUM | READ_ONLY);
+%AddNamedProperty(object, "baz", func1, DONT_DELETE | READ_ONLY);
+%AddNamedProperty(object.__proto__, "bif", func1, DONT_ENUM | DONT_DELETE);
 object.bif = func2;
 
 function enumerable(obj) {
diff --git a/test/mjsunit/regress/regress-cntl-descriptors-enum.js b/test/mjsunit/regress/regress-cntl-descriptors-enum.js
index 861ab27393..fd4ac6d6c0 100644
--- a/test/mjsunit/regress/regress-cntl-descriptors-enum.js
+++ b/test/mjsunit/regress/regress-cntl-descriptors-enum.js
@@ -30,10 +30,10 @@
 DontEnum = 2;
 
 var o = {};
-%AddProperty(o, "a", 0, DontEnum);
+%AddNamedProperty(o, "a", 0, DontEnum);
 
 var o2 = {};
-%AddProperty(o2, "a", 0, DontEnum);
+%AddNamedProperty(o2, "a", 0, DontEnum);
 
 assertTrue(%HaveSameMap(o, o2));
 
diff --git a/test/mjsunit/runtime-gen/addproperty.js b/test/mjsunit/runtime-gen/addnamedproperty.js
similarity index 75%
rename from test/mjsunit/runtime-gen/addproperty.js
rename to test/mjsunit/runtime-gen/addnamedproperty.js
index 48b985d094..df4aaed9db 100644
--- a/test/mjsunit/runtime-gen/addproperty.js
+++ b/test/mjsunit/runtime-gen/addnamedproperty.js
@@ -2,7 +2,7 @@
 // AUTO-GENERATED BY tools/generate-runtime-tests.py, DO NOT MODIFY
 // Flags: --allow-natives-syntax --harmony
 var _object = new Object();
-var arg1 = 10;
+var arg1 = "bla";
 var _value = new Object();
 var _unchecked_attributes = 1;
-%AddProperty(_object, arg1, _value, _unchecked_attributes);
+%AddNamedProperty(_object, arg1, _value, _unchecked_attributes);
diff --git a/tools/generate-runtime-tests.py b/tools/generate-runtime-tests.py
index c81d90007b..be12501436 100755
--- a/tools/generate-runtime-tests.py
+++ b/tools/generate-runtime-tests.py
@@ -211,7 +211,7 @@ _NUMBER_FORMAT = (
 # Format: "FunctionName": ["arg0", "arg1", ..., argslength].
 # None means "fall back to autodetected value".
 CUSTOM_KNOWN_GOOD_INPUT = {
-  "AddProperty": [None, 10, None, None, None],
+  "AddNamedProperty": [None, "\"bla\"", None, None, None],
   "AddPropertyForTemplate": [None, 10, None, None, None],
   "Apply": ["function() {}", None, None, None, None, None],
   "ArrayBufferSliceImpl": [None, None, 0, None],