Split SetProperty(...attributes, strictmode) into DefineProperty(...attributes) and SetProperty(...strictmode)

BUG= R=rossberg@chromium.org Review URL: https://codereview.chromium.org/351853005 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22064 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2014-06-27 13:48:37 +00:00 · 2014-06-27 13:48:37 +00:00 · 63431b23d1
commit 63431b23d1
parent 0133d96be3
47 changed files with 298 additions and 344 deletions
--- a/src/api.cc
+++ b/src/api.cc
@ -3030,6 +3030,9 @@ uint32_t Value::Uint32Value() const {
 }


+// TODO(verwaest): Remove the attribs argument, since it doesn't make sense for
+// existing properties. Use ForceSet instead to define or redefine properties
+// with specific attributes.
 bool v8::Object::Set(v8::Handle<Value> key, v8::Handle<Value> value,
                     v8::PropertyAttribute attribs) {
  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
@ -3041,12 +3044,8 @@ bool v8::Object::Set(v8::Handle<Value> key, v8::Handle<Value> value,
  i::Handle<i::Object> value_obj = Utils::OpenHandle(*value);
  EXCEPTION_PREAMBLE(isolate);
  has_pending_exception = i::Runtime::SetObjectProperty(
-      isolate,
-      self,
-      key_obj,
-      value_obj,
-      static_cast<PropertyAttributes>(attribs),
-      i::SLOPPY).is_null();
+      isolate, self, key_obj, value_obj, i::SLOPPY,
+      static_cast<PropertyAttributes>(attribs)).is_null();
  EXCEPTION_BAILOUT_CHECK(isolate, false);
  return true;
 }
@ -3078,7 +3077,7 @@ bool v8::Object::ForceSet(v8::Handle<Value> key,
  i::Handle<i::Object> key_obj = Utils::OpenHandle(*key);
  i::Handle<i::Object> value_obj = Utils::OpenHandle(*value);
  EXCEPTION_PREAMBLE(isolate);
-  has_pending_exception = i::Runtime::ForceSetObjectProperty(
+  has_pending_exception = i::Runtime::DefineObjectProperty(
      self,
      key_obj,
      value_obj,
--- a/src/apinatives.js
+++ b/src/apinatives.js
@ -30,10 +30,16 @@ function Instantiate(data, name) {
      var Constructor = %GetTemplateField(data, kApiConstructorOffset);
      // Note: Do not directly use a function template as a condition, our
      // internal ToBoolean doesn't handle that!
-      var result = typeof Constructor === 'undefined' ?
-          {} : new (Instantiate(Constructor))();
-      ConfigureTemplateInstance(result, data);
-      result = %ToFastProperties(result);
+      var result;
+      if (typeof Constructor === 'undefined') {
+        result = {};
+        ConfigureTemplateInstance(result, data);
+      } else {
+        // ConfigureTemplateInstance is implicitly called before calling the API
+        // constructor in HandleApiCall.
+        result = new (Instantiate(Constructor))();
+        result = %ToFastProperties(result);
+      }
      return result;
    default:
      throw 'Unknown API tag <' + tag + '>';
@ -93,15 +99,15 @@ function ConfigureTemplateInstance(obj, data) {
        var prop_data = properties[i + 2];
        var attributes = properties[i + 3];
        var value = Instantiate(prop_data, name);
-        %SetProperty(obj, name, value, attributes);
+        %AddProperty(obj, name, value, attributes);
      } else if (length == 4 || length == 5) {
        // TODO(verwaest): The 5th value used to be access_control. Remove once
        // the bindings are updated.
        var name = properties[i + 1];
-        var getter = properties[i + 2];
-        var setter = properties[i + 3];
+        var getter = Instantiate(properties[i + 2]);
+        var setter = Instantiate(properties[i + 3]);
        var attribute = properties[i + 4];
-        %SetAccessorProperty(obj, name, getter, setter, attribute);
+        %DefineAccessorPropertyUnchecked(obj, name, getter, setter, attribute);
      } else {
        throw "Bad properties array";
      }
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@ -1696,7 +1696,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
        if (property->emit_store()) {
          __ mov(r0, Operand(Smi::FromInt(NONE)));  // PropertyAttributes
          __ push(r0);
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          __ Drop(3);
        }
@ -1734,7 +1734,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
    EmitAccessor(it->second->setter);
    __ mov(r0, Operand(Smi::FromInt(NONE)));
    __ push(r0);
-    __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+    __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/src/arm/ic-arm.cc
+++ b/src/arm/ic-arm.cc
@ -872,11 +872,10 @@ void KeyedStoreIC::GenerateRuntimeSetProperty(MacroAssembler* masm,
  // Push receiver, key and value for runtime call.
  __ Push(r2, r1, r0);

-  __ mov(r1, Operand(Smi::FromInt(NONE)));          // PropertyAttributes
  __ mov(r0, Operand(Smi::FromInt(strict_mode)));   // Strict mode.
  __ Push(r1, r0);

-  __ TailCallRuntime(Runtime::kSetProperty, 5, 1);
+  __ TailCallRuntime(Runtime::kSetProperty, 4, 1);
 }


--- a/src/arm64/full-codegen-arm64.cc
+++ b/src/arm64/full-codegen-arm64.cc
@ -1698,7 +1698,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
          VisitForStackValue(value);
          __ Mov(x0, Smi::FromInt(NONE));  // PropertyAttributes
          __ Push(x0);
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          VisitForEffect(key);
          VisitForEffect(value);
@ -1736,7 +1736,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
      EmitAccessor(it->second->setter);
      __ Mov(x10, Smi::FromInt(NONE));
      __ Push(x10);
-      __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+      __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/src/array-iterator.js
+++ b/src/array-iterator.js
@ -110,7 +110,7 @@ function SetUpArrayIterator() {
    'next', ArrayIteratorNext
  ));
  %FunctionSetName(ArrayIteratorIterator, '[Symbol.iterator]');
-  %SetProperty(ArrayIterator.prototype, symbolIterator, ArrayIteratorIterator,
+  %AddProperty(ArrayIterator.prototype, symbolIterator, ArrayIteratorIterator,
      DONT_ENUM);
 }
 SetUpArrayIterator();
@ -125,7 +125,7 @@ function ExtendArrayPrototype() {
    'keys', ArrayKeys
  ));

-  %SetProperty($Array.prototype, symbolIterator, ArrayValues, DONT_ENUM);
+  %AddProperty($Array.prototype, symbolIterator, ArrayValues, DONT_ENUM);
 }
 ExtendArrayPrototype();

@ -146,10 +146,10 @@ macro TYPED_ARRAYS(FUNCTION)
 endmacro

 macro EXTEND_TYPED_ARRAY(NAME)
-  %SetProperty($NAME.prototype, 'entries', ArrayEntries, DONT_ENUM);
-  %SetProperty($NAME.prototype, 'values', ArrayValues, DONT_ENUM);
-  %SetProperty($NAME.prototype, 'keys', ArrayKeys, DONT_ENUM);
-  %SetProperty($NAME.prototype, symbolIterator, ArrayValues, DONT_ENUM);
+  %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);
 endmacro

  TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
--- a/src/array.js
+++ b/src/array.js
@ -445,7 +445,7 @@ function ArrayPush() {
  for (var i = 0; i < m; i++) {
    // Use SetProperty rather than a direct keyed store to ensure that the store
    // site doesn't become poisened with an elements transition KeyedStoreIC.
-    %SetProperty(array, i+n, %_Arguments(i), 0, kStrictMode);
+    %SetProperty(array, i+n, %_Arguments(i), kStrictMode);
  }

  var new_length = n + m;
@ -1462,7 +1462,7 @@ function SetUpArray() {

  // Set up non-enumerable constructor property on the Array.prototype
  // object.
-  %SetProperty($Array.prototype, "constructor", $Array, DONT_ENUM);
+  %AddProperty($Array.prototype, "constructor", $Array, DONT_ENUM);

  // Set up non-enumerable functions on the Array object.
  InstallFunctions($Array, DONT_ENUM, $Array(
--- a/src/arraybuffer.js
+++ b/src/arraybuffer.js
@ -74,7 +74,7 @@ function SetUpArrayBuffer() {
  %FunctionSetPrototype($ArrayBuffer, new $Object());

  // Set up the constructor property on the ArrayBuffer prototype object.
-  %SetProperty($ArrayBuffer.prototype, "constructor", $ArrayBuffer, DONT_ENUM);
+  %AddProperty($ArrayBuffer.prototype, "constructor", $ArrayBuffer, DONT_ENUM);

  InstallGetter($ArrayBuffer.prototype, "byteLength", ArrayBufferGetByteLen);

--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@ -855,11 +855,11 @@ void Genesis::HookUpInnerGlobal(Handle<GlobalObject> inner_global) {
  native_context()->set_security_token(*inner_global);
  static const PropertyAttributes attributes =
      static_cast<PropertyAttributes>(READ_ONLY | DONT_DELETE);
-  Runtime::ForceSetObjectProperty(builtins_global,
-                                  factory()->InternalizeOneByteString(
-                                      STATIC_ASCII_VECTOR("global")),
-                                  inner_global,
-                                  attributes).Assert();
+  Runtime::DefineObjectProperty(builtins_global,
+                                factory()->InternalizeOneByteString(
+                                    STATIC_ASCII_VECTOR("global")),
+                                inner_global,
+                                attributes).Assert();
  // Set up the reference from the global object to the builtins object.
  JSGlobalObject::cast(*inner_global)->set_builtins(*builtins_global);
  TransferNamedProperties(inner_global_from_snapshot, inner_global);
@ -2669,11 +2669,11 @@ Genesis::Genesis(Isolate* isolate,
    Utils::OpenHandle(*buffer)->set_should_be_freed(true);
    v8::Local<v8::Uint32Array> ta = v8::Uint32Array::New(buffer, 0, num_elems);
    Handle<JSBuiltinsObject> builtins(native_context()->builtins());
-    Runtime::ForceSetObjectProperty(builtins,
-                                    factory()->InternalizeOneByteString(
-                                        STATIC_ASCII_VECTOR("rngstate")),
-                                    Utils::OpenHandle(*ta),
-                                    NONE).Assert();
+    Runtime::DefineObjectProperty(builtins,
+                                  factory()->InternalizeOneByteString(
+                                      STATIC_ASCII_VECTOR("rngstate")),
+                                  Utils::OpenHandle(*ta),
+                                  NONE).Assert();

    // Initialize trigonometric lookup tables and constants.
    const int table_num_bytes = TrigonometricLookupTable::table_num_bytes();
@ -2688,25 +2688,25 @@ Genesis::Genesis(Isolate* isolate,
    v8::Local<v8::Float64Array> cos_table = v8::Float64Array::New(
        cos_buffer, 0, TrigonometricLookupTable::table_size());

-    Runtime::ForceSetObjectProperty(builtins,
-                                    factory()->InternalizeOneByteString(
-                                        STATIC_ASCII_VECTOR("kSinTable")),
-                                    Utils::OpenHandle(*sin_table),
-                                    NONE).Assert();
-    Runtime::ForceSetObjectProperty(
+    Runtime::DefineObjectProperty(builtins,
+                                  factory()->InternalizeOneByteString(
+                                      STATIC_ASCII_VECTOR("kSinTable")),
+                                  Utils::OpenHandle(*sin_table),
+                                  NONE).Assert();
+    Runtime::DefineObjectProperty(
        builtins,
        factory()->InternalizeOneByteString(
            STATIC_ASCII_VECTOR("kCosXIntervalTable")),
        Utils::OpenHandle(*cos_table),
        NONE).Assert();
-    Runtime::ForceSetObjectProperty(
+    Runtime::DefineObjectProperty(
        builtins,
        factory()->InternalizeOneByteString(
            STATIC_ASCII_VECTOR("kSamples")),
        factory()->NewHeapNumber(
            TrigonometricLookupTable::samples()),
        NONE).Assert();
-    Runtime::ForceSetObjectProperty(
+    Runtime::DefineObjectProperty(
        builtins,
        factory()->InternalizeOneByteString(
            STATIC_ASCII_VECTOR("kIndexConvert")),
--- a/src/collection-iterator.js
+++ b/src/collection-iterator.js
@ -75,7 +75,7 @@ function SetUpSetIterator() {
  ));

  %FunctionSetName(SetIteratorSymbolIterator, '[Symbol.iterator]');
-  %SetProperty(SetIterator.prototype, symbolIterator,
+  %AddProperty(SetIterator.prototype, symbolIterator,
      SetIteratorSymbolIterator, DONT_ENUM);
 }

@ -90,8 +90,7 @@ function ExtendSetPrototype() {
    'values', SetValues
  ));

-  %SetProperty($Set.prototype, symbolIterator, SetValues,
-      DONT_ENUM);
+  %AddProperty($Set.prototype, symbolIterator, SetValues, DONT_ENUM);
 }

 ExtendSetPrototype();
@ -172,7 +171,7 @@ function SetUpMapIterator() {
  ));

  %FunctionSetName(MapIteratorSymbolIterator, '[Symbol.iterator]');
-  %SetProperty(MapIterator.prototype, symbolIterator,
+  %AddProperty(MapIterator.prototype, symbolIterator,
      MapIteratorSymbolIterator, DONT_ENUM);
 }

@ -188,8 +187,7 @@ function ExtendMapPrototype() {
    'values', MapValues
  ));

-  %SetProperty($Map.prototype, symbolIterator, MapEntries,
-      DONT_ENUM);
+  %AddProperty($Map.prototype, symbolIterator, MapEntries, DONT_ENUM);
 }

 ExtendMapPrototype();
--- a/src/collection.js
+++ b/src/collection.js
@ -147,7 +147,7 @@ function SetUpSet() {

  %SetCode($Set, SetConstructor);
  %FunctionSetPrototype($Set, new $Object());
-  %SetProperty($Set.prototype, "constructor", $Set, DONT_ENUM);
+  %AddProperty($Set.prototype, "constructor", $Set, DONT_ENUM);

  %FunctionSetLength(SetForEach, 1);

@ -282,7 +282,7 @@ function SetUpMap() {

  %SetCode($Map, MapConstructor);
  %FunctionSetPrototype($Map, new $Object());
-  %SetProperty($Map.prototype, "constructor", $Map, DONT_ENUM);
+  %AddProperty($Map.prototype, "constructor", $Map, DONT_ENUM);

  %FunctionSetLength(MapForEach, 1);

--- 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.
-  %SetProperty($Date.prototype, "constructor", $Date, DONT_ENUM);
+  %AddProperty($Date.prototype, "constructor", $Date, DONT_ENUM);

  // Set up non-enumerable functions of the Date prototype object and
  // set their names.
--- a/src/generator.js
+++ b/src/generator.js
@ -63,14 +63,14 @@ function SetUpGenerators() {
                   ["next", GeneratorObjectNext,
                    "throw", GeneratorObjectThrow]);
  %FunctionSetName(GeneratorObjectIterator, '[Symbol.iterator]');
-  %SetProperty(GeneratorObjectPrototype, symbolIterator, GeneratorObjectIterator,
-      DONT_ENUM | DONT_DELETE | READ_ONLY);
-  %SetProperty(GeneratorObjectPrototype, "constructor",
-               GeneratorFunctionPrototype, DONT_ENUM | DONT_DELETE | READ_ONLY);
+  %AddProperty(GeneratorObjectPrototype, symbolIterator,
+      GeneratorObjectIterator, DONT_ENUM | DONT_DELETE | READ_ONLY);
+  %AddProperty(GeneratorObjectPrototype, "constructor",
+      GeneratorFunctionPrototype, DONT_ENUM | DONT_DELETE | READ_ONLY);
  %SetPrototype(GeneratorFunctionPrototype, $Function.prototype);
  %SetCode(GeneratorFunctionPrototype, GeneratorFunctionPrototypeConstructor);
-  %SetProperty(GeneratorFunctionPrototype, "constructor",
-               GeneratorFunction, DONT_ENUM | DONT_DELETE | READ_ONLY);
+  %AddProperty(GeneratorFunctionPrototype, "constructor",
+      GeneratorFunction, DONT_ENUM | DONT_DELETE | READ_ONLY);
  %SetPrototype(GeneratorFunction, $Function);
  %SetCode(GeneratorFunction, GeneratorFunctionConstructor);
 }
--- a/src/i18n.js
+++ b/src/i18n.js
@ -942,7 +942,7 @@ function initializeCollator(collator, locales, options) {
 *
 * @constructor
 */
-%SetProperty(Intl, 'Collator', function() {
+%AddProperty(Intl, 'Collator', function() {
    var locales = %_Arguments(0);
    var options = %_Arguments(1);

@ -960,7 +960,7 @@ function initializeCollator(collator, locales, options) {
 /**
 * Collator resolvedOptions method.
 */
-%SetProperty(Intl.Collator.prototype, 'resolvedOptions', function() {
+%AddProperty(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.
 */
-%SetProperty(Intl.Collator, 'supportedLocalesOf', function(locales) {
+%AddProperty(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
 */
-%SetProperty(Intl, 'NumberFormat', function() {
+%AddProperty(Intl, 'NumberFormat', function() {
    var locales = %_Arguments(0);
    var options = %_Arguments(1);

@ -1187,7 +1187,7 @@ function initializeNumberFormat(numberFormat, locales, options) {
 /**
 * NumberFormat resolvedOptions method.
 */
-%SetProperty(Intl.NumberFormat.prototype, 'resolvedOptions', function() {
+%AddProperty(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.
 */
-%SetProperty(Intl.NumberFormat, 'supportedLocalesOf', function(locales) {
+%AddProperty(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
 */
-%SetProperty(Intl, 'DateTimeFormat', function() {
+%AddProperty(Intl, 'DateTimeFormat', function() {
    var locales = %_Arguments(0);
    var options = %_Arguments(1);

@ -1580,7 +1580,7 @@ function initializeDateTimeFormat(dateFormat, locales, options) {
 /**
 * DateTimeFormat resolvedOptions method.
 */
-%SetProperty(Intl.DateTimeFormat.prototype, 'resolvedOptions', function() {
+%AddProperty(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.
 */
-%SetProperty(Intl.DateTimeFormat, 'supportedLocalesOf', function(locales) {
+%AddProperty(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
 */
-%SetProperty(Intl, 'v8BreakIterator', function() {
+%AddProperty(Intl, 'v8BreakIterator', function() {
    var locales = %_Arguments(0);
    var options = %_Arguments(1);

@ -1786,7 +1786,7 @@ function initializeBreakIterator(iterator, locales, options) {
 /**
 * BreakIterator resolvedOptions method.
 */
-%SetProperty(Intl.v8BreakIterator.prototype, 'resolvedOptions', function() {
+%AddProperty(Intl.v8BreakIterator.prototype, 'resolvedOptions', function() {
    if (%_IsConstructCall()) {
      throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
    }
@ -1819,7 +1819,7 @@ function initializeBreakIterator(iterator, locales, options) {
 * order in the returned list as in the input list.
 * Options are optional parameter.
 */
-%SetProperty(Intl.v8BreakIterator, 'supportedLocalesOf', function(locales) {
+%AddProperty(Intl.v8BreakIterator, 'supportedLocalesOf', function(locales) {
    if (%_IsConstructCall()) {
      throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);
    }
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@ -1647,7 +1647,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
        VisitForStackValue(value);
        if (property->emit_store()) {
          __ push(Immediate(Smi::FromInt(NONE)));  // PropertyAttributes
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          __ Drop(3);
        }
@ -1680,7 +1680,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
    EmitAccessor(it->second->getter);
    EmitAccessor(it->second->setter);
    __ push(Immediate(Smi::FromInt(NONE)));
-    __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+    __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@ -1132,12 +1132,11 @@ void StoreIC::GenerateRuntimeSetProperty(MacroAssembler* masm,
  __ push(edx);
  __ push(ecx);
  __ push(eax);
-  __ push(Immediate(Smi::FromInt(NONE)));  // PropertyAttributes
  __ push(Immediate(Smi::FromInt(strict_mode)));
  __ push(ebx);  // return address

  // Do tail-call to runtime routine.
-  __ TailCallRuntime(Runtime::kSetProperty, 5, 1);
+  __ TailCallRuntime(Runtime::kSetProperty, 4, 1);
 }


@ -1154,12 +1153,11 @@ void KeyedStoreIC::GenerateRuntimeSetProperty(MacroAssembler* masm,
  __ push(edx);
  __ push(ecx);
  __ push(eax);
-  __ push(Immediate(Smi::FromInt(NONE)));         // PropertyAttributes
  __ push(Immediate(Smi::FromInt(strict_mode)));  // Strict mode.
  __ push(ebx);   // return address

  // Do tail-call to runtime routine.
-  __ TailCallRuntime(Runtime::kSetProperty, 5, 1);
+  __ TailCallRuntime(Runtime::kSetProperty, 4, 1);
 }


--- a/src/ic.cc
+++ b/src/ic.cc
@ -1743,7 +1743,7 @@ MaybeHandle<Object> KeyedStoreIC::Store(Handle<Object> object,
        isolate(),
        result,
        Runtime::SetObjectProperty(
-            isolate(), object, key, value, NONE, strict_mode()),
+            isolate(), object, key, value, strict_mode()),
        Object);
    return result;
  }
@ -1811,7 +1811,7 @@ MaybeHandle<Object> KeyedStoreIC::Store(Handle<Object> object,
        isolate(),
        store_handle,
        Runtime::SetObjectProperty(
-            isolate(), object, key, value, NONE, strict_mode()),
+            isolate(), object, key, value, strict_mode()),
        Object);
  }

@ -2143,7 +2143,7 @@ RUNTIME_FUNCTION(StoreIC_Slow) {
  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
      isolate, result,
      Runtime::SetObjectProperty(
-          isolate, object, key, value, NONE, strict_mode));
+          isolate, object, key, value, strict_mode));
  return *result;
 }

@ -2160,7 +2160,7 @@ RUNTIME_FUNCTION(KeyedStoreIC_Slow) {
  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
      isolate, result,
      Runtime::SetObjectProperty(
-          isolate, object, key, value, NONE, strict_mode));
+          isolate, object, key, value, strict_mode));
  return *result;
 }

@ -2184,7 +2184,7 @@ RUNTIME_FUNCTION(ElementsTransitionAndStoreIC_Miss) {
  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
      isolate, result,
      Runtime::SetObjectProperty(
-          isolate, object, key, value, NONE, strict_mode));
+          isolate, object, key, value, strict_mode));
  return *result;
 }

--- a/src/math.js
+++ b/src/math.js
@ -260,7 +260,7 @@ function SetUpMath() {
  %CheckIsBootstrapping();

  %SetPrototype($Math, $Object.prototype);
-  %SetProperty(global, "Math", $Math, DONT_ENUM);
+  %AddProperty(global, "Math", $Math, DONT_ENUM);
  %FunctionSetInstanceClassName(MathConstructor, 'Math');

  // Set up math constants.
--- a/src/messages.js
+++ b/src/messages.js
@ -286,7 +286,7 @@ function MakeGenericError(constructor, type, args) {
 * Set up the Script function and constructor.
 */
 %FunctionSetInstanceClassName(Script, 'Script');
-%SetProperty(Script.prototype, 'constructor', Script,
+%AddProperty(Script.prototype, 'constructor', Script,
             DONT_ENUM | DONT_DELETE | READ_ONLY);
 %SetCode(Script, function(x) {
  // Script objects can only be created by the VM.
@ -1148,7 +1148,7 @@ function captureStackTrace(obj, cons_opt) {
  // holder of this setter, the accessor pair is turned into a data property.
  var setter = function(v) {
    // Set data property on the receiver (not necessarily holder).
-    %DefineOrRedefineDataProperty(this, 'stack', v, NONE);
+    %DefineDataPropertyUnchecked(this, 'stack', v, NONE);
    if (this === obj) {
      // Release context values if holder is the same as the receiver.
      stack = error_string = UNDEFINED;
@ -1163,14 +1163,14 @@ function captureStackTrace(obj, cons_opt) {
    // Stack is still a raw array awaiting to be formatted.
    var result = FormatStackTrace(obj, error_string, GetStackFrames(stack));
    // Replace this accessor to return result directly.
-    %DefineOrRedefineAccessorProperty(
+    %DefineAccessorPropertyUnchecked(
        obj, 'stack', function() { return result }, setter, DONT_ENUM);
    // Release context values.
    stack = error_string = UNDEFINED;
    return result;
  };

-  %DefineOrRedefineAccessorProperty(obj, 'stack', getter, setter, DONT_ENUM);
+  %DefineAccessorPropertyUnchecked(obj, 'stack', getter, setter, DONT_ENUM);
 }


@ -1185,8 +1185,9 @@ function SetUpError() {
    // effects when overwriting the error functions from
    // user code.
    var name = f.name;
-    %SetProperty(global, name, f, DONT_ENUM);
-    %SetProperty(builtins, '$' + name, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
+    %AddProperty(global, name, f, DONT_ENUM);
+    %AddProperty(builtins, '$' + 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.
@ -1201,17 +1202,16 @@ function SetUpError() {
      %FunctionSetPrototype(f, new $Error());
    }
    %FunctionSetInstanceClassName(f, 'Error');
-    %SetProperty(f.prototype, 'constructor', f, DONT_ENUM);
-    %SetProperty(f.prototype, "name", name, DONT_ENUM);
+    %AddProperty(f.prototype, 'constructor', f, DONT_ENUM);
+    %AddProperty(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.
-        %IgnoreAttributesAndSetProperty(this, 'stack', UNDEFINED, DONT_ENUM);
+        %AddProperty(this, 'stack', UNDEFINED, DONT_ENUM);
        if (!IS_UNDEFINED(m)) {
-          %IgnoreAttributesAndSetProperty(
-            this, 'message', ToString(m), DONT_ENUM);
+          %AddProperty(this, 'message', ToString(m), DONT_ENUM);
        }
        captureStackTrace(this, f);
      } else {
@ -1234,7 +1234,7 @@ SetUpError();

 $Error.captureStackTrace = captureStackTrace;

-%SetProperty($Error.prototype, 'message', '', DONT_ENUM);
+%AddProperty($Error.prototype, 'message', '', DONT_ENUM);

 // Global list of error objects visited during ErrorToString. This is
 // used to detect cycles in error toString formatting.
@ -1311,7 +1311,7 @@ function SetUpStackOverflowBoilerplate() {
  // Set the 'stack' property on the receiver.  If the receiver is the same as
  // holder of this setter, the accessor pair is turned into a data property.
  var setter = function(v) {
-    %DefineOrRedefineDataProperty(this, 'stack', v, NONE);
+    %DefineDataPropertyUnchecked(this, 'stack', v, NONE);
    // Tentatively clear the hidden property. If the receiver is the same as
    // holder, we release the raw stack trace this way.
    %GetAndClearOverflowedStackTrace(this);
@ -1333,12 +1333,12 @@ function SetUpStackOverflowBoilerplate() {

    var result = FormatStackTrace(holder, error_string, GetStackFrames(stack));
    // Replace this accessor to return result directly.
-    %DefineOrRedefineAccessorProperty(
+    %DefineAccessorPropertyUnchecked(
        holder, 'stack', function() { return result }, setter, DONT_ENUM);
    return result;
  };

-  %DefineOrRedefineAccessorProperty(
+  %DefineAccessorPropertyUnchecked(
      boilerplate, 'stack', getter, setter, DONT_ENUM);

  return boilerplate;
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@ -1707,7 +1707,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
        if (property->emit_store()) {
          __ li(a0, Operand(Smi::FromInt(NONE)));  // PropertyAttributes.
          __ push(a0);
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          __ Drop(3);
        }
@ -1744,7 +1744,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
    EmitAccessor(it->second->setter);
    __ li(a0, Operand(Smi::FromInt(NONE)));
    __ push(a0);
-    __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+    __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/src/object-observe.js
+++ b/src/object-observe.js
@ -438,8 +438,7 @@ function ObjectInfoEnqueueExternalChangeRecord(objectInfo, changeRecord, type) {

  for (var prop in changeRecord) {
    if (prop === 'object' || (hasType && prop === 'type')) continue;
-    %DefineOrRedefineDataProperty(newRecord, prop, changeRecord[prop],
-        READ_ONLY + DONT_DELETE);
+    %AddProperty(newRecord, prop, changeRecord[prop], READ_ONLY + DONT_DELETE);
  }
  ObjectFreezeJS(newRecord);

--- a/src/promise.js
+++ b/src/promise.js
@ -299,7 +299,7 @@ var promiseRaw = GLOBAL_PRIVATE("Promise#raw");
  // Install exported functions.

  %CheckIsBootstrapping();
-  %SetProperty(global, 'Promise', $Promise, DONT_ENUM);
+  %AddProperty(global, 'Promise', $Promise, DONT_ENUM);
  InstallFunctions($Promise, DONT_ENUM, [
    "defer", PromiseDeferred,
    "accept", PromiseResolved,
--- a/src/regexp.js
+++ b/src/regexp.js
@ -381,7 +381,7 @@ var lastMatchInfoOverride = null;
 function SetUpRegExp() {
  %CheckIsBootstrapping();
  %FunctionSetInstanceClassName($RegExp, 'RegExp');
-  %SetProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
+  %AddProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
  %SetCode($RegExp, RegExpConstructor);

  InstallFunctions($RegExp.prototype, DONT_ENUM, $Array(
@ -406,12 +406,12 @@ function SetUpRegExp() {
  };

  %OptimizeObjectForAddingMultipleProperties($RegExp, 22);
-  %DefineOrRedefineAccessorProperty($RegExp, 'input', RegExpGetInput,
-                                    RegExpSetInput, DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$_', RegExpGetInput,
-                                    RegExpSetInput, DONT_ENUM | DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$input', RegExpGetInput,
-                                    RegExpSetInput, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'input', RegExpGetInput,
+                                   RegExpSetInput, DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$_', RegExpGetInput,
+                                   RegExpSetInput, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$input', RegExpGetInput,
+                                   RegExpSetInput, DONT_ENUM | DONT_DELETE);

  // The properties multiline and $* are aliases for each other.  When this
  // value is set in SpiderMonkey, the value it is set to is coerced to a
@ -425,40 +425,40 @@ function SetUpRegExp() {
  var RegExpGetMultiline = function() { return multiline; };
  var RegExpSetMultiline = function(flag) { multiline = flag ? true : false; };

-  %DefineOrRedefineAccessorProperty($RegExp, 'multiline', RegExpGetMultiline,
-                                    RegExpSetMultiline, DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$*', RegExpGetMultiline,
-                                    RegExpSetMultiline,
-                                    DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'multiline', RegExpGetMultiline,
+                                   RegExpSetMultiline, DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$*', RegExpGetMultiline,
+                                   RegExpSetMultiline,
+                                   DONT_ENUM | DONT_DELETE);


  var NoOpSetter = function(ignored) {};


  // Static properties set by a successful match.
-  %DefineOrRedefineAccessorProperty($RegExp, 'lastMatch', RegExpGetLastMatch,
-                                    NoOpSetter, DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$&', RegExpGetLastMatch,
-                                    NoOpSetter, DONT_ENUM | DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, 'lastParen', RegExpGetLastParen,
-                                    NoOpSetter, DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$+', RegExpGetLastParen,
-                                    NoOpSetter, DONT_ENUM | DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, 'leftContext',
-                                    RegExpGetLeftContext, NoOpSetter,
-                                    DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, '$`', RegExpGetLeftContext,
-                                    NoOpSetter, DONT_ENUM | DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, 'rightContext',
-                                    RegExpGetRightContext, NoOpSetter,
-                                    DONT_DELETE);
-  %DefineOrRedefineAccessorProperty($RegExp, "$'", RegExpGetRightContext,
-                                    NoOpSetter, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'lastMatch', RegExpGetLastMatch,
+                                   NoOpSetter, DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$&', RegExpGetLastMatch,
+                                   NoOpSetter, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'lastParen', RegExpGetLastParen,
+                                   NoOpSetter, DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$+', RegExpGetLastParen,
+                                   NoOpSetter, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'leftContext',
+                                   RegExpGetLeftContext, NoOpSetter,
+                                   DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, '$`', RegExpGetLeftContext,
+                                   NoOpSetter, DONT_ENUM | DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, 'rightContext',
+                                   RegExpGetRightContext, NoOpSetter,
+                                   DONT_DELETE);
+  %DefineAccessorPropertyUnchecked($RegExp, "$'", RegExpGetRightContext,
+                                   NoOpSetter, DONT_ENUM | DONT_DELETE);

  for (var i = 1; i < 10; ++i) {
-    %DefineOrRedefineAccessorProperty($RegExp, '$' + i,
-                                      RegExpMakeCaptureGetter(i), NoOpSetter,
-                                      DONT_DELETE);
+    %DefineAccessorPropertyUnchecked($RegExp, '$' + i,
+                                     RegExpMakeCaptureGetter(i), NoOpSetter,
+                                     DONT_DELETE);
  }
  %ToFastProperties($RegExp);
 }
--- a/src/runtime.cc
+++ b/src/runtime.cc
@ -273,8 +273,12 @@ MUST_USE_RESULT static MaybeHandle<Object> CreateObjectLiteralBoilerplate(
    if (key->IsInternalizedString()) {
      if (Handle<String>::cast(key)->AsArrayIndex(&element_index)) {
        // Array index as string (uint32).
-        maybe_result = JSObject::SetOwnElement(
-            boilerplate, element_index, value, SLOPPY);
+        if (value->IsUninitialized()) {
+          maybe_result = value;
+        } else {
+          maybe_result = JSObject::SetOwnElement(
+              boilerplate, element_index, value, SLOPPY);
+        }
      } else {
        Handle<String> name(String::cast(*key));
        ASSERT(!name->AsArrayIndex(&element_index));
@ -284,8 +288,12 @@ MUST_USE_RESULT static MaybeHandle<Object> CreateObjectLiteralBoilerplate(
      }
    } else if (key->ToArrayIndex(&element_index)) {
      // Array index (uint32).
-      maybe_result = JSObject::SetOwnElement(
-          boilerplate, element_index, value, SLOPPY);
+      if (value->IsUninitialized()) {
+        maybe_result = value;
+      } else {
+        maybe_result = JSObject::SetOwnElement(
+            boilerplate, element_index, value, SLOPPY);
+      }
    } else {
      // Non-uint32 number.
      ASSERT(key->IsNumber());
@ -2097,37 +2105,6 @@ RUNTIME_FUNCTION(Runtime_EnableAccessChecks) {
 }


-// Transform getter or setter into something DefineAccessor can handle.
-static Handle<Object> InstantiateAccessorComponent(Isolate* isolate,
-                                                   Handle<Object> component) {
-  if (component->IsUndefined()) return isolate->factory()->null_value();
-  Handle<FunctionTemplateInfo> info =
-      Handle<FunctionTemplateInfo>::cast(component);
-  return Utils::OpenHandle(*Utils::ToLocal(info)->GetFunction());
-}
-
-
-RUNTIME_FUNCTION(Runtime_SetAccessorProperty) {
-  HandleScope scope(isolate);
-  ASSERT(args.length() == 5);
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
-  CONVERT_ARG_HANDLE_CHECKED(Object, getter, 2);
-  CONVERT_ARG_HANDLE_CHECKED(Object, setter, 3);
-  CONVERT_SMI_ARG_CHECKED(attribute, 4);
-  RUNTIME_ASSERT(getter->IsUndefined() || getter->IsFunctionTemplateInfo());
-  RUNTIME_ASSERT(setter->IsUndefined() || setter->IsFunctionTemplateInfo());
-  RUNTIME_ASSERT(PropertyDetails::AttributesField::is_valid(
-      static_cast<PropertyAttributes>(attribute)));
-  JSObject::DefineAccessor(object,
-                           name,
-                           InstantiateAccessorComponent(isolate, getter),
-                           InstantiateAccessorComponent(isolate, setter),
-                           static_cast<PropertyAttributes>(attribute));
-  return isolate->heap()->undefined_value();
-}
-
-
 static Object* ThrowRedeclarationError(Isolate* isolate, Handle<String> name) {
  HandleScope scope(isolate);
  Handle<Object> args[1] = { name };
@ -5039,7 +5016,7 @@ static bool IsValidAccessor(Handle<Object> obj) {
 // Steps 9c & 12 - replace an existing data property with an accessor property.
 // Step 12 - update an existing accessor property with an accessor or generic
 //           descriptor.
-RUNTIME_FUNCTION(Runtime_DefineOrRedefineAccessorProperty) {
+RUNTIME_FUNCTION(Runtime_DefineAccessorPropertyUnchecked) {
  HandleScope scope(isolate);
  ASSERT(args.length() == 5);
  CONVERT_ARG_HANDLE_CHECKED(JSObject, obj, 0);
@ -5068,7 +5045,7 @@ RUNTIME_FUNCTION(Runtime_DefineOrRedefineAccessorProperty) {
 // Steps 9b & 12 - replace an existing accessor property with a data property.
 // Step 12 - update an existing data property with a data or generic
 //           descriptor.
-RUNTIME_FUNCTION(Runtime_DefineOrRedefineDataProperty) {
+RUNTIME_FUNCTION(Runtime_DefineDataPropertyUnchecked) {
  HandleScope scope(isolate);
  ASSERT(args.length() == 4);
  CONVERT_ARG_HANDLE_CHECKED(JSObject, js_object, 0);
@ -5126,7 +5103,7 @@ RUNTIME_FUNCTION(Runtime_DefineOrRedefineDataProperty) {
  Handle<Object> result;
  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
      isolate, result,
-      Runtime::ForceSetObjectProperty(
+      Runtime::DefineObjectProperty(
          js_object, name, obj_value, attr,
          JSReceiver::CERTAINLY_NOT_STORE_FROM_KEYED));
  return *result;
@ -5147,10 +5124,8 @@ MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
                                               Handle<Object> object,
                                               Handle<Object> key,
                                               Handle<Object> value,
-                                               PropertyAttributes attr,
-                                               StrictMode strict_mode) {
-  SetPropertyMode set_mode = attr == NONE ? SET_PROPERTY : DEFINE_PROPERTY;
-
+                                               StrictMode strict_mode,
+                                               PropertyAttributes attrs) {
  if (object->IsUndefined() || object->IsNull()) {
    Handle<Object> args[2] = { key, object };
    Handle<Object> error =
@ -5169,8 +5144,7 @@ MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
    }
    Handle<Name> name = Handle<Name>::cast(name_object);
    return JSReceiver::SetProperty(Handle<JSProxy>::cast(object), name, value,
-                                   attr,
-                                   strict_mode);
+                                   attrs, strict_mode);
  }

  // If the object isn't a JavaScript object, we ignore the store.
@ -5202,7 +5176,7 @@ MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
    }

    MaybeHandle<Object> result = JSObject::SetElement(
-        js_object, index, value, attr, strict_mode, true, set_mode);
+        js_object, index, value, attrs, strict_mode, true, SET_PROPERTY);
    JSObject::ValidateElements(js_object);

    return result.is_null() ? result : value;
@ -5217,11 +5191,12 @@ MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
              isolate, value, Execution::ToNumber(isolate, value), Object);
        }
      }
-      return JSObject::SetElement(js_object, index, value, attr,
-                                  strict_mode, true, set_mode);
+      return JSObject::SetElement(js_object, index, value, attrs,
+                                  strict_mode, true, SET_PROPERTY);
    } else {
      if (name->IsString()) name = String::Flatten(Handle<String>::cast(name));
-      return JSReceiver::SetProperty(js_object, name, value, attr, strict_mode);
+      return JSReceiver::SetProperty(
+          js_object, name, value, attrs, strict_mode);
    }
  }

@ -5232,15 +5207,15 @@ MaybeHandle<Object> Runtime::SetObjectProperty(Isolate* isolate,
  Handle<String> name = Handle<String>::cast(converted);

  if (name->AsArrayIndex(&index)) {
-    return JSObject::SetElement(js_object, index, value, attr,
-                                strict_mode, true, set_mode);
+    return JSObject::SetElement(js_object, index, value, attrs,
+                                strict_mode, true, SET_PROPERTY);
  } else {
-    return JSReceiver::SetProperty(js_object, name, value, attr, strict_mode);
+    return JSReceiver::SetProperty(js_object, name, value, attrs, strict_mode);
  }
 }


-MaybeHandle<Object> Runtime::ForceSetObjectProperty(
+MaybeHandle<Object> Runtime::DefineObjectProperty(
    Handle<JSObject> js_object,
    Handle<Object> key,
    Handle<Object> value,
@ -5345,11 +5320,11 @@ RUNTIME_FUNCTION(Runtime_SetHiddenProperty) {
 }


-RUNTIME_FUNCTION(Runtime_SetProperty) {
+RUNTIME_FUNCTION(Runtime_AddProperty) {
  HandleScope scope(isolate);
-  RUNTIME_ASSERT(args.length() == 4 || args.length() == 5);
+  RUNTIME_ASSERT(args.length() == 4);

-  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
  CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
  CONVERT_SMI_ARG_CHECKED(unchecked_attributes, 3);
@ -5359,17 +5334,41 @@ RUNTIME_FUNCTION(Runtime_SetProperty) {
  PropertyAttributes attributes =
      static_cast<PropertyAttributes>(unchecked_attributes);

-  StrictMode strict_mode = SLOPPY;
-  if (args.length() == 5) {
-    CONVERT_STRICT_MODE_ARG_CHECKED(strict_mode_arg, 4);
-    strict_mode = strict_mode_arg;
+#ifdef DEBUG
+  if (key->IsName()) {
+    LookupIterator it(object, Handle<Name>::cast(key),
+                      LookupIterator::CHECK_OWN);
+    JSReceiver::GetPropertyAttributes(&it);
+    RUNTIME_ASSERT(!it.IsFound());
+  } else {
+    uint32_t index = 0;
+    RUNTIME_ASSERT(key->ToArrayIndex(&index));
+    RUNTIME_ASSERT(!JSReceiver::HasOwnElement(object, index));
  }
+#endif

  Handle<Object> result;
  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
      isolate, result,
-      Runtime::SetObjectProperty(
-          isolate, object, key, value, attributes, strict_mode));
+      Runtime::DefineObjectProperty(object, key, value, attributes));
+  return *result;
+}
+
+
+RUNTIME_FUNCTION(Runtime_SetProperty) {
+  HandleScope scope(isolate);
+  RUNTIME_ASSERT(args.length() == 4);
+
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
+  CONVERT_STRICT_MODE_ARG_CHECKED(strict_mode_arg, 3);
+  StrictMode strict_mode = strict_mode_arg;
+
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Runtime::SetObjectProperty(isolate, object, key, value, strict_mode));
  return *result;
 }

@ -5523,32 +5522,6 @@ RUNTIME_FUNCTION(Runtime_DebugPromiseHandleEpilogue) {
 }


-// Set an own property, even if it is READ_ONLY.  If the property does not
-// exist, it will be added with attributes NONE.
-RUNTIME_FUNCTION(Runtime_IgnoreAttributesAndSetProperty) {
-  HandleScope scope(isolate);
-  RUNTIME_ASSERT(args.length() == 3 || args.length() == 4);
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
-  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
-  // Compute attributes.
-  PropertyAttributes attributes = NONE;
-  if (args.length() == 4) {
-    CONVERT_SMI_ARG_CHECKED(unchecked_value, 3);
-    // Only attribute bits should be set.
-    RUNTIME_ASSERT(
-        (unchecked_value & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
-    attributes = static_cast<PropertyAttributes>(unchecked_value);
-  }
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result,
-      JSObject::SetOwnPropertyIgnoreAttributes(
-          object, name, value, attributes));
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_DeleteProperty) {
  HandleScope scope(isolate);
  ASSERT(args.length() == 3);
@ -11418,7 +11391,7 @@ static MaybeHandle<JSObject> MaterializeStackLocalsWithFrameInspector(

    RETURN_ON_EXCEPTION(
        isolate,
-        Runtime::SetObjectProperty(isolate, target, name, value, NONE, SLOPPY),
+        Runtime::SetObjectProperty(isolate, target, name, value, SLOPPY),
        JSObject);
  }

@ -11431,7 +11404,7 @@ static MaybeHandle<JSObject> MaterializeStackLocalsWithFrameInspector(

    RETURN_ON_EXCEPTION(
        isolate,
-        Runtime::SetObjectProperty(isolate, target, name, value, NONE, SLOPPY),
+        Runtime::SetObjectProperty(isolate, target, name, value, SLOPPY),
        JSObject);
  }

@ -11520,8 +11493,7 @@ MUST_USE_RESULT static MaybeHandle<JSObject> MaterializeLocalContext(
            isolate, value, Object::GetPropertyOrElement(ext, key), JSObject);
        RETURN_ON_EXCEPTION(
            isolate,
-            Runtime::SetObjectProperty(
-                isolate, target, key, value, NONE, SLOPPY),
+            Runtime::SetObjectProperty(isolate, target, key, value, SLOPPY),
            JSObject);
      }
    }
@ -11626,7 +11598,7 @@ static bool SetLocalVariableValue(Isolate* isolate,
          // We don't expect this to do anything except replacing
          // property value.
          Runtime::SetObjectProperty(isolate, ext, variable_name, new_value,
-                                     NONE, SLOPPY).Assert();
+                                     SLOPPY).Assert();
          return true;
        }
      }
@ -11677,8 +11649,7 @@ MUST_USE_RESULT static MaybeHandle<JSObject> MaterializeClosure(
          isolate, value, Object::GetPropertyOrElement(ext, key), JSObject);
      RETURN_ON_EXCEPTION(
          isolate,
-          Runtime::SetObjectProperty(
-              isolate, closure_scope, key, value, NONE, SLOPPY),
+          Runtime::DefineObjectProperty(closure_scope, key, value, NONE),
          JSObject);
    }
  }
@ -11709,8 +11680,8 @@ static bool SetClosureVariableValue(Isolate* isolate,
    Handle<JSObject> ext(JSObject::cast(context->extension()));
    if (JSReceiver::HasProperty(ext, variable_name)) {
      // We don't expect this to do anything except replacing property value.
-      Runtime::SetObjectProperty(isolate, ext, variable_name, new_value,
-                                 NONE, SLOPPY).Assert();
+      Runtime::DefineObjectProperty(
+          ext, variable_name, new_value, NONE).Assert();
      return true;
    }
  }
@ -11732,8 +11703,7 @@ MUST_USE_RESULT static MaybeHandle<JSObject> MaterializeCatchScope(
      isolate->factory()->NewJSObject(isolate->object_function());
  RETURN_ON_EXCEPTION(
      isolate,
-      Runtime::SetObjectProperty(isolate, catch_scope, name, thrown_object,
-                                 NONE, SLOPPY),
+      Runtime::DefineObjectProperty(catch_scope, name, thrown_object, NONE),
      JSObject);
  return catch_scope;
 }
@ -12796,8 +12766,7 @@ MUST_USE_RESULT static MaybeHandle<JSObject> MaterializeArgumentsObject(
  Handle<String> arguments_str = isolate->factory()->arguments_string();
  RETURN_ON_EXCEPTION(
      isolate,
-      Runtime::SetObjectProperty(
-          isolate, target, arguments_str, arguments, ::NONE, SLOPPY),
+      Runtime::DefineObjectProperty(target, arguments_str, arguments, NONE),
      JSObject);
  return target;
 }
--- a/src/runtime.h
+++ b/src/runtime.h
@ -206,7 +206,6 @@ namespace internal {
  F(GetTemplateField, 2, 1) \
  F(DisableAccessChecks, 1, 1) \
  F(EnableAccessChecks, 1, 1) \
-  F(SetAccessorProperty, 5, 1) \
  \
  /* Dates */ \
  F(DateCurrentTime, 0, 1) \
@ -224,10 +223,10 @@ namespace internal {
  F(GlobalReceiver, 1, 1) \
  F(IsAttachedGlobal, 1, 1) \
  \
-  F(SetProperty, -1 /* 4 or 5 */, 1) \
-  F(DefineOrRedefineDataProperty, 4, 1) \
-  F(DefineOrRedefineAccessorProperty, 5, 1) \
-  F(IgnoreAttributesAndSetProperty, -1 /* 3 or 4 */, 1) \
+  F(AddProperty, 4, 1) \
+  F(SetProperty, 4, 1) \
+  F(DefineDataPropertyUnchecked, 4, 1) \
+  F(DefineAccessorPropertyUnchecked, 5, 1) \
  F(GetDataProperty, 2, 1) \
  F(SetHiddenProperty, 3, 1) \
  \
@ -800,21 +799,23 @@ class Runtime : public AllStatic {
      Handle<Object> object,
      uint32_t index);

+  // Do not use SetObjectProperty to configure a property with specific
+  // attributes. The argument will be removed once the API is adapted.
  MUST_USE_RESULT static MaybeHandle<Object> SetObjectProperty(
      Isolate* isolate,
      Handle<Object> object,
      Handle<Object> key,
      Handle<Object> value,
-      PropertyAttributes attr,
-      StrictMode strict_mode);
+      StrictMode strict_mode,
+      PropertyAttributes attributes = NONE);

-  MUST_USE_RESULT static MaybeHandle<Object> ForceSetObjectProperty(
+  MUST_USE_RESULT static MaybeHandle<Object> DefineObjectProperty(
      Handle<JSObject> object,
      Handle<Object> key,
      Handle<Object> value,
      PropertyAttributes attr,
-      JSReceiver::StoreFromKeyed store_from_keyed
-        = JSReceiver::MAY_BE_STORE_FROM_KEYED);
+      JSReceiver::StoreFromKeyed store_from_keyed =
+          JSReceiver::MAY_BE_STORE_FROM_KEYED);

  MUST_USE_RESULT static MaybeHandle<Object> DeleteObjectProperty(
      Isolate* isolate,
--- a/src/scopeinfo.cc
+++ b/src/scopeinfo.cc
@ -368,13 +368,11 @@ bool ScopeInfo::CopyContextLocalsToScopeObject(Handle<ScopeInfo> scope_info,
    int context_index = Context::MIN_CONTEXT_SLOTS + i;
    RETURN_ON_EXCEPTION_VALUE(
        isolate,
-        Runtime::SetObjectProperty(
-            isolate,
+        Runtime::DefineObjectProperty(
            scope_object,
            Handle<String>(String::cast(scope_info->get(i + start))),
            Handle<Object>(context->get(context_index), isolate),
-            ::NONE,
-            SLOPPY),
+            ::NONE),
        false);
  }
  return true;
--- a/src/string-iterator.js
+++ b/src/string-iterator.js
@ -84,7 +84,7 @@ function SetUpStringIterator() {
    'next', StringIteratorNext
  ));
  %FunctionSetName(StringIteratorIterator, '[Symbol.iterator]');
-  %SetProperty(StringIterator.prototype, symbolIterator, StringIteratorIterator,
+  %AddProperty(StringIterator.prototype, symbolIterator, StringIteratorIterator,
      DONT_ENUM);
 }
 SetUpStringIterator();
@ -100,7 +100,7 @@ function ExtendStringPrototypeWithIterator() {
  %CheckIsBootstrapping();

  %FunctionSetName(StringPrototypeIterator, '[Symbol.iterator]');
-  %SetProperty($String.prototype, symbolIterator, StringPrototypeIterator,
+  %AddProperty($String.prototype, symbolIterator, StringPrototypeIterator,
      DONT_ENUM);
 }
 ExtendStringPrototypeWithIterator();
--- 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.
-  %SetProperty($String.prototype, "constructor", $String, DONT_ENUM);
+  %AddProperty($String.prototype, "constructor", $String, DONT_ENUM);

  // Set up the non-enumerable functions on the String object.
  InstallFunctions($String, DONT_ENUM, $Array(
--- a/src/symbol.js
+++ b/src/symbol.js
@ -113,7 +113,7 @@ function SetUpSymbol() {
    "keyFor", SymbolKeyFor
  ));

-  %SetProperty($Symbol.prototype, "constructor", $Symbol, DONT_ENUM);
+  %AddProperty($Symbol.prototype, "constructor", $Symbol, DONT_ENUM);
  InstallFunctions($Symbol.prototype, DONT_ENUM, $Array(
    "toString", SymbolToString,
    "valueOf", SymbolValueOf
--- a/src/typedarray.js
+++ b/src/typedarray.js
@ -299,11 +299,11 @@ macro SETUP_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
  %SetCode(global.NAME, NAMEConstructor);
  %FunctionSetPrototype(global.NAME, new $Object());

-  %SetProperty(global.NAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
+  %AddProperty(global.NAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
               READ_ONLY | DONT_ENUM | DONT_DELETE);
-  %SetProperty(global.NAME.prototype,
+  %AddProperty(global.NAME.prototype,
               "constructor", global.NAME, DONT_ENUM);
-  %SetProperty(global.NAME.prototype,
+  %AddProperty(global.NAME.prototype,
               "BYTES_PER_ELEMENT", ELEMENT_SIZE,
               READ_ONLY | DONT_ENUM | DONT_DELETE);
  InstallGetter(global.NAME.prototype, "buffer", NAME_GetBuffer);
@ -436,7 +436,7 @@ function SetupDataView() {
  %FunctionSetPrototype($DataView, new $Object);

  // Set up constructor property on the DataView prototype.
-  %SetProperty($DataView.prototype, "constructor", $DataView, DONT_ENUM);
+  %AddProperty($DataView.prototype, "constructor", $DataView, DONT_ENUM);

  InstallGetter($DataView.prototype, "buffer", DataViewGetBufferJS);
  InstallGetter($DataView.prototype, "byteOffset", DataViewGetByteOffset);
--- 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);
-    %SetProperty(object, key, f, attributes);
+    %AddProperty(object, key, f, attributes);
    %SetNativeFlag(f);
  }
  %ToFastProperties(object);
@ -39,7 +39,7 @@ function InstallFunctions(object, attributes, functions) {
 function InstallGetter(object, name, getter) {
  %FunctionSetName(getter, name);
  %FunctionRemovePrototype(getter);
-  %DefineOrRedefineAccessorProperty(object, name, getter, null, DONT_ENUM);
+  %DefineAccessorPropertyUnchecked(object, name, getter, null, DONT_ENUM);
  %SetNativeFlag(getter);
 }

@ -50,7 +50,7 @@ function InstallGetterSetter(object, name, getter, setter) {
  %FunctionSetName(setter, name);
  %FunctionRemovePrototype(getter);
  %FunctionRemovePrototype(setter);
-  %DefineOrRedefineAccessorProperty(object, name, getter, setter, DONT_ENUM);
+  %DefineAccessorPropertyUnchecked(object, name, getter, setter, DONT_ENUM);
  %SetNativeFlag(getter);
  %SetNativeFlag(setter);
 }
@ -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];
-    %SetProperty(object, name, k, attributes);
+    %AddProperty(object, name, k, attributes);
  }
  %ToFastProperties(object);
 }
@ -86,13 +86,13 @@ function SetUpLockedPrototype(constructor, fields, methods) {
  }
  if (fields) {
    for (var i = 0; i < fields.length; i++) {
-      %SetProperty(prototype, fields[i], UNDEFINED, DONT_ENUM | DONT_DELETE);
+      %AddProperty(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];
-    %SetProperty(prototype, key, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
+    %AddProperty(prototype, key, f, DONT_ENUM | DONT_DELETE | READ_ONLY);
    %SetNativeFlag(f);
  }
  %SetPrototype(prototype, null);
@ -190,13 +190,13 @@ function SetUpGlobal() {
  var attributes = DONT_ENUM | DONT_DELETE | READ_ONLY;

  // ECMA 262 - 15.1.1.1.
-  %SetProperty(global, "NaN", NAN, attributes);
+  %AddProperty(global, "NaN", NAN, attributes);

  // ECMA-262 - 15.1.1.2.
-  %SetProperty(global, "Infinity", INFINITY, attributes);
+  %AddProperty(global, "Infinity", INFINITY, attributes);

  // ECMA-262 - 15.1.1.3.
-  %SetProperty(global, "undefined", UNDEFINED, attributes);
+  %AddProperty(global, "undefined", UNDEFINED, attributes);

  // Set up non-enumerable function on the global object.
  InstallFunctions(global, DONT_ENUM, $Array(
@ -386,24 +386,22 @@ function FromGenericPropertyDescriptor(desc) {
  var obj = new $Object();

  if (desc.hasValue()) {
-    %IgnoreAttributesAndSetProperty(obj, "value", desc.getValue(), NONE);
+    %AddProperty(obj, "value", desc.getValue(), NONE);
  }
  if (desc.hasWritable()) {
-    %IgnoreAttributesAndSetProperty(obj, "writable", desc.isWritable(), NONE);
+    %AddProperty(obj, "writable", desc.isWritable(), NONE);
  }
  if (desc.hasGetter()) {
-    %IgnoreAttributesAndSetProperty(obj, "get", desc.getGet(), NONE);
+    %AddProperty(obj, "get", desc.getGet(), NONE);
  }
  if (desc.hasSetter()) {
-    %IgnoreAttributesAndSetProperty(obj, "set", desc.getSet(), NONE);
+    %AddProperty(obj, "set", desc.getSet(), NONE);
  }
  if (desc.hasEnumerable()) {
-    %IgnoreAttributesAndSetProperty(obj, "enumerable",
-                                    desc.isEnumerable(), NONE);
+    %AddProperty(obj, "enumerable", desc.isEnumerable(), NONE);
  }
  if (desc.hasConfigurable()) {
-    %IgnoreAttributesAndSetProperty(obj, "configurable",
-                                    desc.isConfigurable(), NONE);
+    %AddProperty(obj, "configurable", desc.isConfigurable(), NONE);
  }
  return obj;
 }
@ -833,7 +831,7 @@ function DefineObjectProperty(obj, p, desc, should_throw) {
      value = current.getValue();
    }

-    %DefineOrRedefineDataProperty(obj, p, value, flag);
+    %DefineDataPropertyUnchecked(obj, p, value, flag);
  } else {
    // There are 3 cases that lead here:
    // Step 4b - defining a new accessor property.
@ -843,7 +841,7 @@ function DefineObjectProperty(obj, p, desc, should_throw) {
    //           descriptor.
    var getter = desc.hasGetter() ? desc.getGet() : null;
    var setter = desc.hasSetter() ? desc.getSet() : null;
-    %DefineOrRedefineAccessorProperty(obj, p, getter, setter, flag);
+    %DefineAccessorPropertyUnchecked(obj, p, getter, setter, flag);
  }
  return true;
 }
@ -901,7 +899,7 @@ function DefineArrayProperty(obj, p, desc, should_throw) {
    // Make sure the below call to DefineObjectProperty() doesn't overwrite
    // any magic "length" property by removing the value.
    // TODO(mstarzinger): This hack should be removed once we have addressed the
-    // respective TODO in Runtime_DefineOrRedefineDataProperty.
+    // respective TODO in Runtime_DefineDataPropertyUnchecked.
    // For the time being, we need a hack to prevent Object.observe from
    // generating two change records.
    obj.length = new_length;
@ -1397,7 +1395,7 @@ function SetUpObject() {
  %SetNativeFlag($Object);
  %SetCode($Object, ObjectConstructor);

-  %SetProperty($Object.prototype, "constructor", $Object, DONT_ENUM);
+  %AddProperty($Object.prototype, "constructor", $Object, DONT_ENUM);

  // Set up non-enumerable functions on the Object.prototype object.
  InstallFunctions($Object.prototype, DONT_ENUM, $Array(
@ -1484,7 +1482,7 @@ function SetUpBoolean () {

  %SetCode($Boolean, BooleanConstructor);
  %FunctionSetPrototype($Boolean, new $Boolean(false));
-  %SetProperty($Boolean.prototype, "constructor", $Boolean, DONT_ENUM);
+  %AddProperty($Boolean.prototype, "constructor", $Boolean, DONT_ENUM);

  InstallFunctions($Boolean.prototype, DONT_ENUM, $Array(
    "toString", BooleanToString,
@ -1667,7 +1665,7 @@ function SetUpNumber() {

  %OptimizeObjectForAddingMultipleProperties($Number.prototype, 8);
  // Set up the constructor property on the Number prototype object.
-  %SetProperty($Number.prototype, "constructor", $Number, DONT_ENUM);
+  %AddProperty($Number.prototype, "constructor", $Number, DONT_ENUM);

  InstallConstants($Number, $Array(
      // ECMA-262 section 15.7.3.1.
@ -1850,7 +1848,7 @@ function SetUpFunction() {
  %CheckIsBootstrapping();

  %SetCode($Function, FunctionConstructor);
-  %SetProperty($Function.prototype, "constructor", $Function, DONT_ENUM);
+  %AddProperty($Function.prototype, "constructor", $Function, DONT_ENUM);

  InstallFunctions($Function.prototype, DONT_ENUM, $Array(
    "bind", FunctionBind,
--- a/src/weak_collection.js
+++ b/src/weak_collection.js
@ -89,7 +89,7 @@ function SetUpWeakMap() {

  %SetCode($WeakMap, WeakMapConstructor);
  %FunctionSetPrototype($WeakMap, new $Object());
-  %SetProperty($WeakMap.prototype, "constructor", $WeakMap, DONT_ENUM);
+  %AddProperty($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 $Object());
-  %SetProperty($WeakSet.prototype, "constructor", $WeakSet, DONT_ENUM);
+  %AddProperty($WeakSet.prototype, "constructor", $WeakSet, DONT_ENUM);

  // Set up the non-enumerable functions on the WeakSet prototype object.
  InstallFunctions($WeakSet.prototype, DONT_ENUM, $Array(
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@ -1680,7 +1680,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
        VisitForStackValue(value);
        if (property->emit_store()) {
          __ Push(Smi::FromInt(NONE));    // PropertyAttributes
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          __ Drop(3);
        }
@ -1713,7 +1713,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
    EmitAccessor(it->second->getter);
    EmitAccessor(it->second->setter);
    __ Push(Smi::FromInt(NONE));
-    __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+    __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/src/x87/full-codegen-x87.cc
+++ b/src/x87/full-codegen-x87.cc
@ -1644,7 +1644,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
        VisitForStackValue(value);
        if (property->emit_store()) {
          __ push(Immediate(Smi::FromInt(NONE)));  // PropertyAttributes
-          __ CallRuntime(Runtime::kSetProperty, 4);
+          __ CallRuntime(Runtime::kAddProperty, 4);
        } else {
          __ Drop(3);
        }
@ -1677,7 +1677,7 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
    EmitAccessor(it->second->getter);
    EmitAccessor(it->second->setter);
    __ push(Immediate(Smi::FromInt(NONE)));
-    __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);
+    __ CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, 5);
  }

  if (expr->has_function()) {
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@ -21719,8 +21719,8 @@ TEST(AccessCheckThrows) {
  CheckCorrectThrow("JSON.stringify(other)");
  CheckCorrectThrow("has_own_property(other, 'x')");
  CheckCorrectThrow("%GetProperty(other, 'x')");
-  CheckCorrectThrow("%SetProperty(other, 'x', 'foo', 1, 0)");
-  CheckCorrectThrow("%IgnoreAttributesAndSetProperty(other, 'x', 'foo')");
+  CheckCorrectThrow("%SetProperty(other, 'x', 'foo', 0)");
+  CheckCorrectThrow("%AddProperty(other, 'x', 'foo', 1)");
  CheckCorrectThrow("%DeleteProperty(other, 'x', 0)");
  CheckCorrectThrow("%DeleteProperty(other, '1', 0)");
  CheckCorrectThrow("%HasOwnProperty(other, 'x')");
@ -21730,7 +21730,7 @@ TEST(AccessCheckThrows) {
  CheckCorrectThrow("%GetPropertyNames(other)");
  // PROPERTY_ATTRIBUTES_NONE = 0
  CheckCorrectThrow("%GetOwnPropertyNames(other, 0)");
-  CheckCorrectThrow("%DefineOrRedefineAccessorProperty("
+  CheckCorrectThrow("%DefineAccessorPropertyUnchecked("
                        "other, 'x', null, null, 1)");

  // Reset the failed access check callback so it does not influence
--- a/test/cctest/test-compiler.cc
+++ b/test/cctest/test-compiler.cc
@ -49,7 +49,7 @@ static void SetGlobalProperty(const char* name, Object* value) {
  Handle<String> internalized_name =
      isolate->factory()->InternalizeUtf8String(name);
  Handle<JSObject> global(isolate->context()->global_object());
-  Runtime::SetObjectProperty(isolate, global, internalized_name, object, NONE,
+  Runtime::SetObjectProperty(isolate, global, internalized_name, object,
                             SLOPPY).Check();
 }

--- a/test/cctest/test-debug.cc
+++ b/test/cctest/test-debug.cc
@ -109,10 +109,8 @@ class DebugLocalContext {
        v8::Utils::OpenHandle(*context_->Global())));
    Handle<v8::internal::String> debug_string =
        factory->InternalizeOneByteString(STATIC_ASCII_VECTOR("debug"));
-    v8::internal::Runtime::SetObjectProperty(isolate, global, debug_string,
-        Handle<Object>(debug_context->global_proxy(), isolate),
-        DONT_ENUM,
-        ::v8::internal::SLOPPY).Check();
+    v8::internal::Runtime::DefineObjectProperty(global, debug_string,
+        handle(debug_context->global_proxy(), isolate), DONT_ENUM).Check();
  }

 private:
--- a/test/mjsunit/object-define-property.js
+++ b/test/mjsunit/object-define-property.js
@ -467,35 +467,35 @@ try {
 }


-// Test runtime calls to DefineOrRedefineDataProperty and
-// DefineOrRedefineAccessorProperty - make sure we don't
+// Test runtime calls to DefineDataPropertyUnchecked and
+// DefineAccessorPropertyUnchecked - make sure we don't
 // crash.
 try {
-  %DefineOrRedefineAccessorProperty(0, 0, 0, 0, 0);
+  %DefineAccessorPropertyUnchecked(0, 0, 0, 0, 0);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }

 try {
-  %DefineOrRedefineDataProperty(0, 0, 0, 0);
+  %DefineDataPropertyUnchecked(0, 0, 0, 0);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }

 try {
-  %DefineOrRedefineDataProperty(null, null, null, null);
+  %DefineDataPropertyUnchecked(null, null, null, null);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }

 try {
-  %DefineOrRedefineAccessorProperty(null, null, null, null, null);
+  %DefineAccessorPropertyUnchecked(null, null, null, null, null);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }

 try {
-  %DefineOrRedefineDataProperty({}, null, null, null);
+  %DefineDataPropertyUnchecked({}, null, null, null);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }
@ -503,13 +503,13 @@ try {
 // Defining properties null should fail even when we have
 // other allowed values
 try {
-  %DefineOrRedefineAccessorProperty(null, 'foo', func, null, 0);
+  %DefineAccessorPropertyUnchecked(null, 'foo', func, null, 0);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }

 try {
-  %DefineOrRedefineDataProperty(null, 'foo', 0, 0);
+  %DefineDataPropertyUnchecked(null, 'foo', 0, 0);
 } catch (e) {
  assertTrue(/illegal access/.test(e));
 }
--- 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...
-%SetProperty(this.__proto__, "a", 1234, NONE);
+%AddProperty(this.__proto__, "a", 1234, NONE);
 assertEquals(1234, a);
 eval("var a = 5678;");
 assertEquals(5678, a);

-%SetProperty(this.__proto__, "b", 1234, NONE);
+%AddProperty(this.__proto__, "b", 1234, NONE);
 assertEquals(1234, b);
 eval("const b = 5678;");
 assertEquals(5678, b);

-%SetProperty(this.__proto__, "c", 1234, READ_ONLY);
+%AddProperty(this.__proto__, "c", 1234, READ_ONLY);
 assertEquals(1234, c);
 eval("var c = 5678;");
 assertEquals(5678, c);

-%SetProperty(this.__proto__, "d", 1234, READ_ONLY);
+%AddProperty(this.__proto__, "d", 1234, READ_ONLY);
 assertEquals(1234, d);
 eval("const d = 5678;");
 assertEquals(5678, d);

 // Use DeclareContextSlot...
-%SetProperty(this.__proto__, "x", 1234, NONE);
+%AddProperty(this.__proto__, "x", 1234, NONE);
 assertEquals(1234, x);
 eval("with({}) { var x = 5678; }");
 assertEquals(5678, x);

-%SetProperty(this.__proto__, "y", 1234, NONE);
+%AddProperty(this.__proto__, "y", 1234, NONE);
 assertEquals(1234, y);
 eval("with({}) { const y = 5678; }");
 assertEquals(5678, y);

-%SetProperty(this.__proto__, "z", 1234, READ_ONLY);
+%AddProperty(this.__proto__, "z", 1234, READ_ONLY);
 assertEquals(1234, z);
 eval("with({}) { var z = 5678; }");
 assertEquals(5678, z);

-%SetProperty(this.__proto__, "w", 1234, READ_ONLY);
+%AddProperty(this.__proto__, "w", 1234, READ_ONLY);
 assertEquals(1234, w);
 eval("with({}) { const w = 5678; }");
 assertEquals(5678, w);
--- 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__:{}};
-%SetProperty(object, "foo", func1, DONT_ENUM | DONT_DELETE);
-%SetProperty(object, "bar", func1, DONT_ENUM | READ_ONLY);
-%SetProperty(object, "baz", func1, DONT_DELETE | READ_ONLY);
-%SetProperty(object.__proto__, "bif", func1, DONT_ENUM | DONT_DELETE);
+%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);
 object.bif = func2;

 function enumerable(obj) {
--- 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 = {};
-%SetProperty(o, "a", 0, DontEnum);
+%AddProperty(o, "a", 0, DontEnum);

 var o2 = {};
-%SetProperty(o2, "a", 0, DontEnum);
+%AddProperty(o2, "a", 0, DontEnum);

 assertTrue(%HaveSameMap(o, o2));

--- a/test/mjsunit/runtime-gen/ignoreattributesandsetproperty.js
+++ b/test/mjsunit/runtime-gen/ignoreattributesandsetproperty.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 _name = "name";
+var arg1 = 10;
 var _value = new Object();
-var _unchecked_value = 1;
-%IgnoreAttributesAndSetProperty(_object, _name, _value, _unchecked_value);
+var _unchecked_attributes = 1;
+%AddProperty(_object, arg1, _value, _unchecked_attributes);
--- a/test/mjsunit/runtime-gen/defineorredefineaccessorproperty.js
+++ b/test/mjsunit/runtime-gen/defineorredefineaccessorproperty.js
@ -6,4 +6,4 @@ var _name = "name";
 var arg2 = function() {};
 var arg3 = function() {};
 var arg4 = 2;
-%DefineOrRedefineAccessorProperty(_obj, _name, arg2, arg3, arg4);
+%DefineAccessorPropertyUnchecked(_obj, _name, arg2, arg3, arg4);
--- a/test/mjsunit/runtime-gen/defineorredefinedataproperty.js
+++ b/test/mjsunit/runtime-gen/defineorredefinedataproperty.js
@ -5,4 +5,4 @@ var _js_object = new Object();
 var _name = "name";
 var _obj_value = new Object();
 var _unchecked = 1;
-%DefineOrRedefineDataProperty(_js_object, _name, _obj_value, _unchecked);
+%DefineDataPropertyUnchecked(_js_object, _name, _obj_value, _unchecked);
--- a/test/mjsunit/runtime-gen/setaccessorproperty.js
+++ b/test/mjsunit/runtime-gen/setaccessorproperty.js
@ -1,9 +0,0 @@
-// Copyright 2014 the V8 project authors. All rights reserved.
-// AUTO-GENERATED BY tools/generate-runtime-tests.py, DO NOT MODIFY
-// Flags: --allow-natives-syntax --harmony
-var _object = new Object();
-var _name = "name";
-var arg2 = undefined;
-var arg3 = undefined;
-var _attribute = 1;
-%SetAccessorProperty(_object, _name, arg2, arg3, _attribute);
--- a/test/mjsunit/runtime-gen/setproperty.js
+++ b/test/mjsunit/runtime-gen/setproperty.js
@ -4,6 +4,5 @@
 var _object = new Object();
 var _key = new Object();
 var _value = new Object();
-var _unchecked_attributes = 1;
 var _strict_mode_arg = 1;
-%SetProperty(_object, _key, _value, _unchecked_attributes, _strict_mode_arg);
+%SetProperty(_object, _key, _value, _strict_mode_arg);
--- a/tools/generate-runtime-tests.py
+++ b/tools/generate-runtime-tests.py
@ -47,8 +47,8 @@ EXPAND_MACROS = [
 # that the parser doesn't bit-rot. Change the values as needed when you add,
 # remove or change runtime functions, but make sure we don't lose our ability
 # to parse them!
-EXPECTED_FUNCTION_COUNT = 415
-EXPECTED_FUZZABLE_COUNT = 330
+EXPECTED_FUNCTION_COUNT = 414
+EXPECTED_FUZZABLE_COUNT = 329
 EXPECTED_CCTEST_COUNT = 6
 EXPECTED_UNKNOWN_COUNT = 4
 EXPECTED_BUILTINS_COUNT = 806
@ -211,6 +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],
  "Apply": ["function() {}", None, None, None, None, None],
  "ArrayBufferSliceImpl": [None, None, 0, None],
  "ArrayConcat": ["[1, 'a']", None],
@ -225,8 +226,8 @@ CUSTOM_KNOWN_GOOD_INPUT = {
  "CreatePrivateSymbol": ["\"foo\"", None],
  "CreateSymbol": ["\"foo\"", None],
  "DateParseString": [None, "new Array(8)", None],
-  "DefineOrRedefineAccessorProperty": [None, None, "function() {}",
-                                       "function() {}", 2, None],
+  "DefineAccessorPropertyUnchecked": [None, None, "function() {}",
+                                      "function() {}", 2, None],
  "FunctionBindArguments": [None, None, "undefined", None, None],
  "GetBreakLocations": [None, 0, None],
  "GetDefaultReceiver": ["function() {}", None],
@ -242,7 +243,7 @@ CUSTOM_KNOWN_GOOD_INPUT = {
  "NumberToRadixString": [None, "2", None],
  "ParseJson": ["\"{}\"", 1],
  "RegExpExecMultiple": [None, None, "['a']", "['a']", None],
-  "SetAccessorProperty": [None, None, "undefined", "undefined", None, None],
+  "DefineAccessorProperty": [None, None, "undefined", "undefined", None, None],
  "SetIteratorInitialize": [None, None, "2", None],
  "SetDebugEventListener": ["undefined", None, None],
  "SetFunctionBreakPoint": [None, 200, None, None],