Reland "[builtins] Port Proxy set trap to CSA"

This is a reland of a9f517e2
Original change's description:
> [builtins] Port Proxy set trap to CSA
> 
> Bug: v8:6560, v8:6557
> Change-Id: I329794607e8de324fc696652555aaaeafcf519ec
> Reviewed-on: https://chromium-review.googlesource.com/625940
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Commit-Queue: Maya Lekova <mslekova@google.com>
> Cr-Commit-Position: refs/heads/master@{#47760}

Bug: v8:6560, v8:6557
Change-Id: I1b32992eac6cc5583a44703eed901e4ad15f1947
Reviewed-on: https://chromium-review.googlesource.com/647447
Commit-Queue: Maya Lekova <mslekova@google.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47772}

BUILD.gn

@@ -1003,8 +1003,6 @@ v8_source_set("v8_builtins_generators") {
     "src/builtins/builtins-promise-gen.h",
     "src/builtins/builtins-proxy-gen.cc",
     "src/builtins/builtins-proxy-gen.h",
-    "src/builtins/builtins-proxy-helpers-gen.cc",
-    "src/builtins/builtins-proxy-helpers-gen.h",
     "src/builtins/builtins-regexp-gen.cc",
     "src/builtins/builtins-regexp-gen.h",
     "src/builtins/builtins-sharedarraybuffer-gen.cc",

src/builtins/builtins-definitions.h

@@ -778,6 +778,7 @@ namespace internal {
       SharedFunctionInfo::kDontAdaptArgumentsSentinel)                         \
   TFS(ProxyGetProperty, kProxy, kName, kReceiverValue)                         \
   TFS(ProxyHasProperty, kProxy, kName)                                         \
+  TFS(ProxySetProperty, kProxy, kName, kValue, kReceiverValue, kLanguageMode)  \
                                                                                \
   /* Reflect */                                                                \
   ASM(ReflectApply)                                                            \

src/builtins/builtins-proxy-gen.cc

@@ -322,6 +322,257 @@ TF_BUILTIN(ProxyHasProperty, ProxiesCodeStubAssembler) {
                  StringConstant("has"), proxy);
 }
 
+TF_BUILTIN(ProxyGetProperty, ProxiesCodeStubAssembler) {
+  Node* context = Parameter(Descriptor::kContext);
+  Node* proxy = Parameter(Descriptor::kProxy);
+  Node* name = Parameter(Descriptor::kName);
+  Node* receiver = Parameter(Descriptor::kReceiverValue);
+
+  CSA_ASSERT(this, IsJSProxy(proxy));
+
+  // 1. Assert: IsPropertyKey(P) is true.
+  CSA_ASSERT(this, TaggedIsNotSmi(name));
+  CSA_ASSERT(this, IsName(name));
+  CSA_ASSERT(this, Word32Equal(IsPrivateSymbol(name), Int32Constant(0)));
+
+  Label throw_proxy_handler_revoked(this, Label::kDeferred),
+      trap_undefined(this);
+
+  // 2. Let handler be O.[[ProxyHandler]].
+  Node* handler = LoadObjectField(proxy, JSProxy::kHandlerOffset);
+
+  // 3. If handler is null, throw a TypeError exception.
+  GotoIf(IsNull(handler), &throw_proxy_handler_revoked);
+
+  // 4. Assert: Type(handler) is Object.
+  CSA_ASSERT(this, IsJSReceiver(handler));
+
+  // 5. Let target be O.[[ProxyTarget]].
+  Node* target = LoadObjectField(proxy, JSProxy::kTargetOffset);
+
+  // 6. Let trap be ? GetMethod(handler, "get").
+  // 7. If trap is undefined, then (see 7.a below).
+  Handle<Name> trap_name = factory()->get_string();
+  Node* trap = GetMethod(context, handler, trap_name, &trap_undefined);
+
+  // 8. Let trapResult be ? Call(trap, handler, « target, P, Receiver »).
+  Node* trap_result = CallJS(
+      CodeFactory::Call(isolate(), ConvertReceiverMode::kNotNullOrUndefined),
+      context, trap, handler, target, name, receiver);
+
+  // 9. Let targetDesc be ? target.[[GetOwnProperty]](P).
+  Label return_result(this);
+  CheckGetSetTrapResult(context, target, proxy, name, trap_result,
+                        &return_result, JSProxy::kGet);
+
+  BIND(&return_result);
+  {
+    // 11. Return trapResult.
+    Return(trap_result);
+  }
+
+  BIND(&trap_undefined);
+  {
+    // 7.a. Return ? target.[[Get]](P, Receiver).
+    // TODO(mslekova): Introduce GetPropertyWithReceiver stub
+    Return(CallRuntime(Runtime::kGetPropertyWithReceiver, context, target, name,
+                       receiver));
+  }
+
+  BIND(&throw_proxy_handler_revoked);
+  ThrowTypeError(context, MessageTemplate::kProxyRevoked, "get");
+}
+
+TF_BUILTIN(ProxySetProperty, ProxiesCodeStubAssembler) {
+  Node* context = Parameter(Descriptor::kContext);
+  Node* proxy = Parameter(Descriptor::kProxy);
+  Node* name = Parameter(Descriptor::kName);
+  Node* value = Parameter(Descriptor::kValue);
+  Node* receiver = Parameter(Descriptor::kReceiverValue);
+  Node* language_mode = Parameter(Descriptor::kLanguageMode);
+
+  CSA_ASSERT(this, IsJSProxy(proxy));
+
+  // 1. Assert: IsPropertyKey(P) is true.
+  CSA_ASSERT(this, TaggedIsNotSmi(name));
+  CSA_ASSERT(this, IsName(name));
+
+  Label throw_proxy_handler_revoked(this, Label::kDeferred),
+      trap_undefined(this), failure(this, Label::kDeferred),
+      continue_checks(this), success(this),
+      private_symbol(this, Label::kDeferred);
+
+  GotoIf(IsPrivateSymbol(name), &private_symbol);
+
+  // 2. Let handler be O.[[ProxyHandler]].
+  Node* handler = LoadObjectField(proxy, JSProxy::kHandlerOffset);
+
+  // 3. If handler is null, throw a TypeError exception.
+  GotoIfNot(IsJSReceiver(handler), &throw_proxy_handler_revoked);
+
+  // 4. Assert: Type(handler) is Object.
+  CSA_ASSERT(this, IsJSReceiver(handler));
+
+  // 5. Let target be O.[[ProxyTarget]].
+  Node* target = LoadObjectField(proxy, JSProxy::kTargetOffset);
+
+  // 6. Let trap be ? GetMethod(handler, "set").
+  // 7. If trap is undefined, then (see 7.a below).
+  Handle<Name> set_string = factory()->set_string();
+  Node* trap = GetMethod(context, handler, set_string, &trap_undefined);
+
+  // 8. Let booleanTrapResult be ToBoolean(? Call(trap, handler,
+  // « target, P, V, Receiver »)).
+  // 9. If booleanTrapResult is false, return false.
+  BranchIfToBooleanIsTrue(
+      CallJS(CodeFactory::Call(isolate(),
+                               ConvertReceiverMode::kNotNullOrUndefined),
+             context, trap, handler, target, name, value, receiver),
+      &continue_checks, &failure);
+
+  BIND(&continue_checks);
+  {
+    // 9. Let targetDesc be ? target.[[GetOwnProperty]](P).
+    Label return_result(this);
+    CheckGetSetTrapResult(context, target, proxy, name, value, &success,
+                          JSProxy::kSet);
+  }
+
+  BIND(&failure);
+  {
+    Label if_throw(this, Label::kDeferred);
+    Branch(SmiEqual(language_mode, SmiConstant(STRICT)), &if_throw, &success);
+
+    BIND(&if_throw);
+    ThrowTypeError(context, MessageTemplate::kProxyTrapReturnedFalsishFor,
+                   HeapConstant(set_string), name);
+  }
+
+  // 12. Return true.
+  BIND(&success);
+  Return(value);
+
+  BIND(&private_symbol);
+  {
+    Label failure(this), throw_error(this, Label::kDeferred);
+
+    Branch(SmiEqual(language_mode, SmiConstant(STRICT)), &throw_error,
+           &failure);
+
+    BIND(&failure);
+    Return(UndefinedConstant());
+
+    BIND(&throw_error);
+    ThrowTypeError(context, MessageTemplate::kProxyPrivate);
+  }
+
+  BIND(&trap_undefined);
+  {
+    // 7.a. Return ? target.[[Set]](P, V, Receiver).
+    CallRuntime(Runtime::kSetPropertyWithReceiver, context, target, name, value,
+                receiver, language_mode);
+    Return(value);
+  }
+
+  BIND(&throw_proxy_handler_revoked);
+  ThrowTypeError(context, MessageTemplate::kProxyRevoked, "set");
+}
+
+void ProxiesCodeStubAssembler::CheckGetSetTrapResult(
+    Node* context, Node* target, Node* proxy, Node* name, Node* trap_result,
+    Label* check_passed, JSProxy::AccessKind access_kind) {
+  Node* map = LoadMap(target);
+  VARIABLE(var_value, MachineRepresentation::kTagged);
+  VARIABLE(var_details, MachineRepresentation::kWord32);
+  VARIABLE(var_raw_value, MachineRepresentation::kTagged);
+
+  Label if_found_value(this), check_in_runtime(this, Label::kDeferred);
+
+  Node* instance_type = LoadInstanceType(target);
+  TryGetOwnProperty(context, target, target, map, instance_type, name,
+                    &if_found_value, &var_value, &var_details, &var_raw_value,
+                    check_passed, &check_in_runtime);
+
+  BIND(&if_found_value);
+  {
+    Label throw_non_configurable_data(this, Label::kDeferred),
+        throw_non_configurable_accessor(this, Label::kDeferred),
+        check_accessor(this), check_data(this);
+
+    // If targetDesc is not undefined and targetDesc.[[Configurable]] is
+    // false, then:
+    GotoIfNot(IsSetWord32(var_details.value(),
+                          PropertyDetails::kAttributesDontDeleteMask),
+              check_passed);
+
+    // If IsDataDescriptor(targetDesc) is true and
+    // targetDesc.[[Writable]] is false, then:
+    BranchIfAccessorPair(var_raw_value.value(), &check_accessor, &check_data);
+
+    BIND(&check_data);
+    {
+      Node* read_only = IsSetWord32(var_details.value(),
+                                    PropertyDetails::kAttributesReadOnlyMask);
+      GotoIfNot(read_only, check_passed);
+
+      // If SameValue(trapResult, targetDesc.[[Value]]) is false,
+      // throw a TypeError exception.
+      GotoIfNot(SameValue(trap_result, var_value.value()),
+                &throw_non_configurable_data);
+      Goto(check_passed);
+    }
+
+    BIND(&check_accessor);
+    {
+      Node* accessor_pair = var_raw_value.value();
+
+      if (access_kind == JSProxy::kGet) {
+        Label continue_check(this, Label::kDeferred);
+        // 10.b. If IsAccessorDescriptor(targetDesc) is true and
+        // targetDesc.[[Get]] is undefined, then:
+        Node* getter =
+            LoadObjectField(accessor_pair, AccessorPair::kGetterOffset);
+        // Here we check for null as well because if the getter was never
+        // defined it's set as null.
+        GotoIf(IsUndefined(getter), &continue_check);
+        GotoIf(IsNull(getter), &continue_check);
+        Goto(check_passed);
+
+        // 10.b.i. If trapResult is not undefined, throw a TypeError exception.
+        BIND(&continue_check);
+        GotoIfNot(IsUndefined(trap_result), &throw_non_configurable_accessor);
+      } else {
+        // 11.b.i. If targetDesc.[[Set]] is undefined, throw a TypeError
+        // exception.
+        Node* setter =
+            LoadObjectField(accessor_pair, AccessorPair::kSetterOffset);
+        GotoIf(IsUndefined(setter), &throw_non_configurable_accessor);
+        GotoIf(IsNull(setter), &throw_non_configurable_accessor);
+      }
+      Goto(check_passed);
+    }
+
+    BIND(&check_in_runtime);
+    {
+      CallRuntime(Runtime::kCheckProxyGetSetTrapResult, context, name, target,
+                  trap_result, SmiConstant(access_kind));
+      Return(trap_result);
+    }
+
+    BIND(&throw_non_configurable_data);
+    {
+      ThrowTypeError(context, MessageTemplate::kProxyGetNonConfigurableData,
+                     name, var_value.value(), trap_result);
+    }
+
+    BIND(&throw_non_configurable_accessor);
+    {
+      ThrowTypeError(context, MessageTemplate::kProxyGetNonConfigurableAccessor,
+                     name, trap_result);
+    }
+  }
+}
+
 void ProxiesCodeStubAssembler::CheckHasTrapResult(Node* context, Node* target,
                                                   Node* proxy, Node* name,
                                                   Label* check_passed,

src/builtins/builtins-proxy-gen.h

@@ -16,6 +16,22 @@ class ProxiesCodeStubAssembler : public CodeStubAssembler {
   explicit ProxiesCodeStubAssembler(compiler::CodeAssemblerState* state)
       : CodeStubAssembler(state) {}
 
+  void BranchIfAccessorPair(Node* value, Label* if_accessor_pair,
+                            Label* if_not_accessor_pair) {
+    GotoIf(TaggedIsSmi(value), if_not_accessor_pair);
+    Branch(IsAccessorPair(value), if_accessor_pair, if_not_accessor_pair);
+  }
+
+  // ES6 section 9.5.8 [[Get]] ( P, Receiver )
+  // name should not be an index.
+  Node* ProxyGetProperty(Node* context, Node* proxy, Node* name,
+                         Node* receiver);
+
+  // ES6 section 9.5.9 [[Set]] ( P, V, Receiver )
+  // name should not be an index.
+  Node* ProxySetProperty(Node* context, Node* proxy, Node* name, Node* value,
+                         Node* receiver);
+
  protected:
   void GotoIfRevokedProxy(Node* object, Label* if_proxy_revoked);
   Node* AllocateProxy(Node* target, Node* handler, Node* context);
@@ -24,6 +40,10 @@ class ProxiesCodeStubAssembler : public CodeStubAssembler {
                                             ParameterMode mode);
   void CheckHasTrapResult(Node* context, Node* target, Node* proxy, Node* name,
                           Label* check_passed, Label* if_bailout);
+
+  void CheckGetSetTrapResult(Node* context, Node* target, Node* proxy,
+                             Node* name, Node* trap_result, Label* if_not_found,
+                             JSProxy::AccessKind access_kind);
 };
 
 }  // namespace internal

src/builtins/builtins-proxy-helpers-gen.cc

-// Copyright 2017 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "src/builtins/builtins-proxy-helpers-gen.h"
-#include "src/builtins/builtins-utils-gen.h"
-
-namespace v8 {
-namespace internal {
-TF_BUILTIN(ProxyGetProperty, ProxyAssembler) {
-  Node* context = Parameter(Descriptor::kContext);
-  Node* proxy = Parameter(Descriptor::kProxy);
-  Node* name = Parameter(Descriptor::kName);
-  Node* receiver = Parameter(Descriptor::kReceiverValue);
-
-  CSA_ASSERT(this, IsJSProxy(proxy));
-
-  // 1. Assert: IsPropertyKey(P) is true.
-  CSA_ASSERT(this, IsName(name));
-
-  Label throw_proxy_handler_revoked(this, Label::kDeferred),
-      trap_undefined(this), no_target_desc(this, Label::kDeferred),
-      trap_not_callable(this, Label::kDeferred);
-
-  // 2. Let handler be O.[[ProxyHandler]].
-  Node* handler = LoadObjectField(proxy, JSProxy::kHandlerOffset);
-
-  // 3. If handler is null, throw a TypeError exception.
-  GotoIf(IsNull(handler), &throw_proxy_handler_revoked);
-
-  // 4. Assert: Type(handler) is Object.
-  CSA_ASSERT(this, IsJSReceiver(handler));
-
-  // 5. Let target be O.[[ProxyTarget]].
-  Node* target = LoadObjectField(proxy, JSProxy::kTargetOffset);
-
-  // 6. Let trap be ? GetMethod(handler, "get").
-  // 7. If trap is undefined, then (see 7.a below).
-  Handle<Name> trap_name = factory()->get_string();
-  Node* trap = GetMethod(context, handler, trap_name, &trap_undefined);
-
-  GotoIf(TaggedIsSmi(trap), &trap_not_callable);
-  GotoIfNot(IsCallable(trap), &trap_not_callable);
-
-  // 8. Let trapResult be ? Call(trap, handler, « target, P, Receiver »).
-  Node* trap_result = CallJS(CodeFactory::Call(isolate()), context, trap,
-                             handler, target, name, receiver);
-  // 9. Let targetDesc be ? target.[[GetOwnProperty]](P).
-  Label return_result(this);
-  CheckGetTrapResult(context, target, proxy, name, trap_result, &return_result,
-                     &no_target_desc);
-
-  BIND(&return_result);
-  {
-    // 11. Return trapResult.
-    Return(trap_result);
-  }
-
-  BIND(&no_target_desc);
-  {
-    CSA_ASSERT(this, IsJSReceiver(target));
-    CallRuntime(Runtime::kCheckProxyGetTrapResult, context, name, target,
-                trap_result);
-    Return(trap_result);
-  }
-
-  BIND(&trap_undefined);
-  {
-    // 7.a. Return ? target.[[Get]](P, Receiver).
-    Return(CallRuntime(Runtime::kGetPropertyWithReceiver, context, target, name,
-                       receiver));
-  }
-
-  BIND(&throw_proxy_handler_revoked);
-  { ThrowTypeError(context, MessageTemplate::kProxyRevoked, "get"); }
-
-  BIND(&trap_not_callable);
-  {
-    ThrowTypeError(context, MessageTemplate::kPropertyNotFunction, trap,
-                   StringConstant("get"), receiver);
-  }
-}
-
-void ProxyAssembler::CheckGetTrapResult(Node* context, Node* target,
-                                        Node* proxy, Node* name,
-                                        Node* trap_result, Label* check_passed,
-                                        Label* if_bailout) {
-  Node* map = LoadMap(target);
-  VARIABLE(var_value, MachineRepresentation::kTagged);
-  VARIABLE(var_details, MachineRepresentation::kWord32);
-  VARIABLE(var_raw_value, MachineRepresentation::kTagged);
-
-  Label if_found_value(this, Label::kDeferred);
-
-  Node* instance_type = LoadInstanceType(target);
-  TryGetOwnProperty(context, proxy, target, map, instance_type, name,
-                    &if_found_value, &var_value, &var_details, &var_raw_value,
-                    check_passed, if_bailout);
-
-  BIND(&if_found_value);
-  {
-    Label throw_non_configurable_data(this, Label::kDeferred),
-        throw_non_configurable_accessor(this, Label::kDeferred),
-        check_accessor(this), check_data(this);
-
-    // 10. If targetDesc is not undefined and targetDesc.[[Configurable]] is
-    // false, then:
-    GotoIfNot(IsSetWord32(var_details.value(),
-                          PropertyDetails::kAttributesDontDeleteMask),
-              check_passed);
-
-    // 10.a. If IsDataDescriptor(targetDesc) is true and
-    // targetDesc.[[Writable]] is false, then:
-    BranchIfAccessorPair(var_raw_value.value(), &check_accessor, &check_data);
-
-    BIND(&check_data);
-    {
-      Node* read_only = IsSetWord32(var_details.value(),
-                                    PropertyDetails::kAttributesReadOnlyMask);
-      GotoIfNot(read_only, check_passed);
-
-      // 10.a.i. If SameValue(trapResult, targetDesc.[[Value]]) is false,
-      // throw a TypeError exception.
-      GotoIfNot(SameValue(trap_result, var_value.value()),
-                &throw_non_configurable_data);
-      Goto(check_passed);
-    }
-
-    BIND(&check_accessor);
-    {
-      // 10.b. If IsAccessorDescriptor(targetDesc) is true and
-      // targetDesc.[[Get]] is undefined, then:
-      Node* accessor_pair = var_raw_value.value();
-      Node* getter =
-          LoadObjectField(accessor_pair, AccessorPair::kGetterOffset);
-
-      // Here we check for null as well because if the getter was never
-      // defined it's set as null.
-      GotoIfNot(Word32Or(IsUndefined(getter), IsNull(getter)), check_passed);
-
-      // 10.b.i. If trapResult is not undefined, throw a TypeError exception.
-      GotoIfNot(IsUndefined(trap_result), &throw_non_configurable_accessor);
-      Goto(check_passed);
-    }
-
-    BIND(&throw_non_configurable_data);
-    {
-      ThrowTypeError(context, MessageTemplate::kProxyGetNonConfigurableData,
-                     name, var_value.value(), trap_result);
-    }
-
-    BIND(&throw_non_configurable_accessor);
-    {
-      ThrowTypeError(context, MessageTemplate::kProxyGetNonConfigurableAccessor,
-                     name, trap_result);
-    }
-  }
-}
-}  // namespace internal
-}  // namespace v8

src/builtins/builtins-proxy-helpers-gen.h

-// Copyright 2017 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef V8_BUILTINS_BUILTINS_PROXY_HELPERS_GEN_H_
-#define V8_BUILTINS_BUILTINS_PROXY_HELPERS_GEN_H_
-
-#include "src/code-stub-assembler.h"
-
-namespace v8 {
-namespace internal {
-using compiler::Node;
-
-class ProxyAssembler : public CodeStubAssembler {
- public:
-  explicit ProxyAssembler(compiler::CodeAssemblerState* state)
-      : CodeStubAssembler(state) {}
-
-  void BranchIfAccessorPair(Node* value, Label* if_accessor_pair,
-                            Label* if_not_accessor_pair) {
-    GotoIf(TaggedIsSmi(value), if_not_accessor_pair);
-    Branch(IsAccessorPair(value), if_accessor_pair, if_not_accessor_pair);
-  }
-
-  // ES6 section 9.5.8 [[Get]] ( P, Receiver )
-  Node* ProxyGetProperty(Node* context, Node* proxy, Node* name,
-                         Node* receiver);
-
- protected:
-  void CheckGetTrapResult(Node* context, Node* target, Node* proxy, Node* name,
-                          Node* trap_result, Label* if_not_found,
-                          Label* if_bailout);
-};
-
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_BUILTINS_BUILTINS_PROXY_HELPERS_GEN_H_

src/code-stub-assembler.cc

@@ -6922,6 +6922,7 @@ void CodeStubAssembler::EmitElementStore(Node* object, Node* key, Node* value,
                                          ElementsKind elements_kind,
                                          KeyedAccessStoreMode store_mode,
                                          Label* bailout) {
+  CSA_ASSERT(this, Word32BinaryNot(IsJSProxy(object)));
   Node* elements = LoadElements(object);
   if (IsSmiOrObjectElementsKind(elements_kind) &&
       store_mode != STORE_NO_TRANSITION_HANDLE_COW) {

src/feedback-vector.cc

@@ -839,6 +839,10 @@ KeyedAccessStoreMode KeyedStoreICNexus::GetKeyedAccessStoreMode() const {
       // Element store with prototype chain check.
       Handle<Tuple2> data_handler = Handle<Tuple2>::cast(maybe_code_handler);
       handler = handle(Code::cast(data_handler->value2()));
+    } else if (maybe_code_handler->IsSmi()) {
+      // Skip proxy handlers.
+      DCHECK_EQ(*maybe_code_handler, *StoreHandler::StoreProxy(GetIsolate()));
+      continue;
     } else {
       // Element store without prototype chain check.
       handler = Handle<Code>::cast(maybe_code_handler);

src/ic/accessor-assembler.cc

@@ -261,8 +261,8 @@ void AccessorAssembler::HandleLoadICSmiHandlerCase(
 
   Label constant(this), field(this), normal(this, Label::kDeferred),
       interceptor(this, Label::kDeferred), nonexistent(this),
-      accessor(this, Label::kDeferred), proxy(this, Label::kDeferred),
-      global(this, Label::kDeferred), module_export(this, Label::kDeferred);
+      accessor(this, Label::kDeferred), global(this, Label::kDeferred),
+      module_export(this, Label::kDeferred), proxy(this, Label::kDeferred);
   GotoIf(WordEqual(handler_kind, IntPtrConstant(LoadHandler::kField)), &field);
 
   GotoIf(WordEqual(handler_kind, IntPtrConstant(LoadHandler::kConstant)),
@@ -370,9 +370,35 @@ void AccessorAssembler::HandleLoadICSmiHandlerCase(
 
   BIND(&proxy);
   {
-    exit_point->ReturnCallStub(
-        Builtins::CallableFor(isolate(), Builtins::kProxyGetProperty),
-        p->context, holder, p->name, p->receiver);
+    VARIABLE(var_index, MachineType::PointerRepresentation());
+    VARIABLE(var_unique, MachineRepresentation::kTagged);
+
+    Label if_index(this), if_unique_name(this),
+        to_name_failed(this, Label::kDeferred);
+
+    if (support_elements == kSupportElements) {
+      TryToName(p->name, &if_index, &var_index, &if_unique_name, &var_unique,
+                &to_name_failed);
+
+      BIND(&if_unique_name);
+      exit_point->ReturnCallStub(
+          Builtins::CallableFor(isolate(), Builtins::kProxyGetProperty),
+          p->context, holder, var_unique.value(), p->receiver);
+
+      BIND(&if_index);
+      // TODO(mslekova): introduce TryToName that doesn't try to compute
+      // the intptr index value
+      Goto(&to_name_failed);
+
+      BIND(&to_name_failed);
+      exit_point->ReturnCallRuntime(Runtime::kGetPropertyWithReceiver,
+                                    p->context, holder, p->name, p->receiver);
+
+    } else {
+      exit_point->ReturnCallStub(
+          Builtins::CallableFor(isolate(), Builtins::kProxyGetProperty),
+          p->context, holder, p->name, p->receiver);
+    }
   }
 
   BIND(&global);
@@ -612,7 +638,7 @@ void AccessorAssembler::JumpIfDataProperty(Node* details, Label* writable,
 
 void AccessorAssembler::HandleStoreICHandlerCase(
     const StoreICParameters* p, Node* handler, Label* miss,
-    ElementSupport support_elements) {
+    LanguageMode language_mode, ElementSupport support_elements) {
   Label if_smi_handler(this), if_nonsmi_handler(this);
   Label if_proto_handler(this), if_element_handler(this), call_handler(this),
       store_global(this);
@@ -626,10 +652,17 @@ void AccessorAssembler::HandleStoreICHandlerCase(
     Node* holder = p->receiver;
     Node* handler_word = SmiUntag(handler);
 
-    Label if_fast_smi(this), slow(this);
-    GotoIfNot(
-        WordEqual(handler_word, IntPtrConstant(StoreHandler::kStoreNormal)),
-        &if_fast_smi);
+    Label if_fast_smi(this), if_proxy(this);
+
+    STATIC_ASSERT(StoreHandler::kStoreNormal + 1 == StoreHandler::kProxy);
+    STATIC_ASSERT(StoreHandler::kProxy + 1 == StoreHandler::kKindsNumber);
+
+    Node* handler_kind = DecodeWord<StoreHandler::KindBits>(handler_word);
+    GotoIf(IntPtrLessThan(handler_kind,
+                          IntPtrConstant(StoreHandler::kStoreNormal)),
+           &if_fast_smi);
+    GotoIf(WordEqual(handler_kind, IntPtrConstant(StoreHandler::kProxy)),
+           &if_proxy);
 
     Node* properties = LoadSlowProperties(holder);
 
@@ -655,6 +688,9 @@ void AccessorAssembler::HandleStoreICHandlerCase(
     BIND(&if_fast_smi);
     // Handle non-transitioning field stores.
     HandleStoreICSmiHandlerCase(handler_word, holder, p->value, nullptr, miss);
+
+    BIND(&if_proxy);
+    HandleStoreToProxy(p, holder, miss, support_elements, language_mode);
   }
 
   BIND(&if_nonsmi_handler);
@@ -673,7 +709,10 @@ void AccessorAssembler::HandleStoreICHandlerCase(
   }
 
   BIND(&if_proto_handler);
-  { HandleStoreICProtoHandler(p, handler, miss, support_elements); }
+  {
+    HandleStoreICProtoHandler(p, handler, miss, support_elements,
+                              language_mode);
+  }
 
   // |handler| is a heap object. Must be code, call it.
   BIND(&call_handler);
@@ -762,7 +801,7 @@ void AccessorAssembler::HandleStoreICElementHandlerCase(
 
 void AccessorAssembler::HandleStoreICProtoHandler(
     const StoreICParameters* p, Node* handler, Label* miss,
-    ElementSupport support_elements) {
+    ElementSupport support_elements, LanguageMode language_mode) {
   // IC dispatchers rely on these assumptions to be held.
   STATIC_ASSERT(FixedArray::kLengthOffset ==
                 StoreHandler::kTransitionCellOffset);
@@ -792,12 +831,12 @@ void AccessorAssembler::HandleStoreICProtoHandler(
 
   VARIABLE(var_transition, MachineRepresentation::kTagged);
   Label if_transition(this), if_transition_to_constant(this),
-      if_store_normal(this);
+      if_store_normal(this), if_proxy(this), do_store(this);
   BIND(&tuple_handler);
   {
     Node* transition = LoadWeakCellValue(maybe_transition_cell, miss);
     var_transition.Bind(transition);
-    Goto(&if_transition);
+    Goto(&do_store);
   }
 
   BIND(&array_handler);
@@ -815,7 +854,19 @@ void AccessorAssembler::HandleStoreICProtoHandler(
         LoadFixedArrayElement(handler, StoreHandler::kTransitionCellIndex);
     Node* transition = LoadWeakCellValue(maybe_transition_cell, miss);
     var_transition.Bind(transition);
-    Goto(&if_transition);
+    Goto(&do_store);
+  }
+
+  BIND(&do_store);
+  {
+    Branch(SmiEqual(smi_or_code, SmiConstant(StoreHandler::kProxy)), &if_proxy,
+           &if_transition);
+  }
+
+  BIND(&if_proxy);
+  {
+    Node* proxy = var_transition.value();
+    HandleStoreToProxy(p, proxy, miss, support_elements, language_mode);
   }
 
   BIND(&if_transition);
@@ -866,9 +917,8 @@ void AccessorAssembler::HandleStoreICProtoHandler(
                                    DescriptorArray::kEntryValueIndex));
       Node* descriptors = LoadMapDescriptors(transition);
       CSA_ASSERT(
-          this,
-          UintPtrLessThan(descriptor,
-                          LoadAndUntagFixedArrayBaseLength(descriptors)));
+          this, UintPtrLessThan(descriptor,
+                                LoadAndUntagFixedArrayBaseLength(descriptors)));
 
       Node* constant = LoadFixedArrayElement(descriptors, value_index);
       GotoIf(WordNotEqual(p->value, constant), miss);
@@ -915,6 +965,42 @@ void AccessorAssembler::HandleStoreICProtoHandler(
   }
 }
 
+void AccessorAssembler::HandleStoreToProxy(const StoreICParameters* p,
+                                           Node* proxy, Label* miss,
+                                           ElementSupport support_elements,
+                                           LanguageMode language_mode) {
+  VARIABLE(var_index, MachineType::PointerRepresentation());
+  VARIABLE(var_unique, MachineRepresentation::kTagged);
+
+  Label if_index(this), if_unique_name(this),
+      to_name_failed(this, Label::kDeferred);
+
+  if (support_elements == kSupportElements) {
+    TryToName(p->name, &if_index, &var_index, &if_unique_name, &var_unique,
+              &to_name_failed);
+
+    BIND(&if_unique_name);
+    CallBuiltin(Builtins::kProxySetProperty, p->context, proxy,
+                var_unique.value(), p->value, p->receiver,
+                SmiConstant(language_mode));
+    Return(p->value);
+
+    // The index case is handled earlier by the runtime.
+    BIND(&if_index);
+    // TODO(mslekova): introduce TryToName that doesn't try to compute
+    // the intptr index value
+    Goto(&to_name_failed);
+
+    BIND(&to_name_failed);
+    TailCallRuntime(Runtime::kSetPropertyWithReceiver, p->context, proxy,
+                    p->name, p->value, p->receiver, SmiConstant(language_mode));
+  } else {
+    Node* name = ToName(p->context, p->name);
+    TailCallBuiltin(Builtins::kProxySetProperty, p->context, proxy, name,
+                    p->value, p->receiver, SmiConstant(language_mode));
+  }
+}
+
 void AccessorAssembler::HandleStoreICSmiHandlerCase(Node* handler_word,
                                                     Node* holder, Node* value,
                                                     Node* transition,
@@ -2237,7 +2323,7 @@ void AccessorAssembler::StoreIC(const StoreICParameters* p,
   BIND(&if_handler);
   {
     Comment("StoreIC_if_handler");
-    HandleStoreICHandlerCase(p, var_handler.value(), &miss);
+    HandleStoreICHandlerCase(p, var_handler.value(), &miss, language_mode);
   }
 
   BIND(&try_polymorphic);
@@ -2298,7 +2384,8 @@ void AccessorAssembler::KeyedStoreIC(const StoreICParameters* p,
     BIND(&if_handler);
     {
       Comment("KeyedStoreIC_if_handler");
-      HandleStoreICHandlerCase(p, var_handler.value(), &miss, kSupportElements);
+      HandleStoreICHandlerCase(p, var_handler.value(), &miss, language_mode,
+                               kSupportElements);
     }
 
     BIND(&try_polymorphic);

src/ic/accessor-assembler.h

@@ -93,6 +93,7 @@ class AccessorAssembler : public CodeStubAssembler {
   enum ElementSupport { kOnlyProperties, kSupportElements };
   void HandleStoreICHandlerCase(
       const StoreICParameters* p, Node* handler, Label* miss,
+      LanguageMode language_mode,
       ElementSupport support_elements = kOnlyProperties);
   void JumpIfDataProperty(Node* details, Label* writable, Label* readonly);
 
@@ -164,7 +165,8 @@ class AccessorAssembler : public CodeStubAssembler {
                                        Node* handler, Label* miss);
 
   void HandleStoreICProtoHandler(const StoreICParameters* p, Node* handler,
-                                 Label* miss, ElementSupport support_elements);
+                                 Label* miss, ElementSupport support_elements,
+                                 LanguageMode language_mode);
   // If |transition| is nullptr then the normal field store is generated or
   // transitioning store otherwise.
   void HandleStoreICSmiHandlerCase(Node* handler_word, Node* holder,
@@ -175,6 +177,10 @@ class AccessorAssembler : public CodeStubAssembler {
                                  Representation representation, Node* value,
                                  Node* transition, Label* miss);
 
+  void HandleStoreToProxy(const StoreICParameters* p, Node* proxy, Label* miss,
+                          ElementSupport support_elements,
+                          LanguageMode language_mode);
+
   // KeyedLoadIC_Generic implementation.
 
   void GenericElementLoad(Node* receiver, Node* receiver_map,

src/ic/handler-configuration-inl.h

@@ -113,6 +113,11 @@ Handle<Smi> StoreHandler::StoreNormal(Isolate* isolate) {
   return handle(Smi::FromInt(config), isolate);
 }
 
+Handle<Smi> StoreHandler::StoreProxy(Isolate* isolate) {
+  int config = KindBits::encode(kProxy);
+  return handle(Smi::FromInt(config), isolate);
+}
+
 Handle<Smi> StoreHandler::StoreField(Isolate* isolate, Kind kind,
                                      int descriptor, FieldIndex field_index,
                                      Representation representation,

src/ic/handler-configuration.h

@@ -160,8 +160,10 @@ class StoreHandler {
     kStoreElement,
     kStoreField,
     kStoreConstField,
-    kStoreNormal,
     kTransitionToField,
+    kStoreNormal,
+    kProxy,
+    kKindsNumber,  // Keep last
     // TODO(ishell): remove once constant field tracking is done.
     kTransitionToConstant = kStoreConstField
   };
@@ -227,6 +229,9 @@ class StoreHandler {
   // Creates a Smi-handler for storing a property to a slow object.
   static inline Handle<Smi> StoreNormal(Isolate* isolate);
 
+  // Creates a Smi-handler for storing a property on a proxy.
+  static inline Handle<Smi> StoreProxy(Isolate* isolate);
+
   // Creates a Smi-handler for transitioning store to a field.
   static inline Handle<Smi> TransitionToField(Isolate* isolate, int descriptor,
                                               FieldIndex field_index,

src/ic/ic.h

@@ -359,6 +359,9 @@ class StoreIC : public IC {
                                  Handle<JSObject> holder,
                                  Handle<Map> transition, Handle<Name> name);
 
+  Handle<Object> StoreProxy(Handle<Map> receiver_map, Handle<JSProxy> proxy,
+                            Handle<JSReceiver> receiver, Handle<Name> name);
+
   friend class IC;
 
   bool created_new_transition_ = false;

src/ic/keyed-store-generic.cc

@@ -841,7 +841,8 @@ void KeyedStoreGenericAssembler::EmitGenericPropertyStore(
       BIND(&found_handler);
       {
         Comment("KeyedStoreGeneric found transition handler");
-        HandleStoreICHandlerCase(p, var_handler.value(), notfound);
+        HandleStoreICHandlerCase(p, var_handler.value(), notfound,
+                                 language_mode);
       }
     }
   }
@@ -949,7 +950,8 @@ void KeyedStoreGenericAssembler::EmitGenericPropertyStore(
     BIND(&found_handler);
     {
       Comment("KeyedStoreGeneric found handler");
-      HandleStoreICHandlerCase(p, var_handler.value(), &stub_cache_miss);
+      HandleStoreICHandlerCase(p, var_handler.value(), &stub_cache_miss,
+                               language_mode);
     }
     BIND(&stub_cache_miss);
     {
@@ -1020,13 +1022,14 @@ void KeyedStoreGenericAssembler::StoreIC_Uninitialized(
   Node* vector = Parameter(Descriptor::kVector);
   Node* context = Parameter(Descriptor::kContext);
 
-  Label miss(this);
+  Label miss(this), if_proxy(this, Label::kDeferred);
 
   GotoIf(TaggedIsSmi(receiver), &miss);
   Node* receiver_map = LoadMap(receiver);
   Node* instance_type = LoadMapInstanceType(receiver_map);
+  GotoIf(Word32Equal(instance_type, Int32Constant(JS_PROXY_TYPE)), &if_proxy);
   // Receivers requiring non-standard element accesses (interceptors, access
-  // checks, strings and string wrappers, proxies) are handled in the runtime.
+  // checks, strings and string wrappers) are handled in the runtime.
   GotoIf(Int32LessThanOrEqual(instance_type,
                               Int32Constant(LAST_SPECIAL_RECEIVER_TYPE)),
          &miss);
@@ -1040,6 +1043,12 @@ void KeyedStoreGenericAssembler::StoreIC_Uninitialized(
   EmitGenericPropertyStore(receiver, receiver_map, &p, &miss, language_mode,
                            kDontUseStubCache);
 
+  BIND(&if_proxy);
+  {
+    CallBuiltin(Builtins::kProxySetProperty, context, receiver, name, value,
+                receiver, SmiConstant(language_mode));
+    Return(value);
+  }
   BIND(&miss);
   {
     // Undo the optimistic state transition.

src/lookup.cc

@@ -13,12 +13,42 @@
 namespace v8 {
 namespace internal {
 
+// static
+LookupIterator LookupIterator::PropertyOrElement(
+    Isolate* isolate, Handle<Object> receiver, Handle<Object> key,
+    bool* success, Handle<JSReceiver> holder, Configuration configuration) {
+  uint32_t index = 0;
+  if (key->ToArrayIndex(&index)) {
+    *success = true;
+    return LookupIterator(isolate, receiver, index, holder, configuration);
+  }
+
+  Handle<Name> name;
+  *success = Object::ToName(isolate, key).ToHandle(&name);
+  if (!*success) {
+    DCHECK(isolate->has_pending_exception());
+    // Return an unusable dummy.
+    return LookupIterator(receiver, isolate->factory()->empty_string());
+  }
+
+  if (name->AsArrayIndex(&index)) {
+    LookupIterator it(isolate, receiver, index, holder, configuration);
+    // Here we try to avoid having to rebuild the string later
+    // by storing it on the indexed LookupIterator.
+    it.name_ = name;
+    return it;
+  }
+
+  return LookupIterator(receiver, name, holder, configuration);
+}
+
 // static
 LookupIterator LookupIterator::PropertyOrElement(Isolate* isolate,
                                                  Handle<Object> receiver,
                                                  Handle<Object> key,
                                                  bool* success,
                                                  Configuration configuration) {
+  // TODO(mslekova): come up with better way to avoid duplication
   uint32_t index = 0;
   if (key->ToArrayIndex(&index)) {
     *success = true;

src/lookup.h

@@ -126,6 +126,11 @@ class V8_EXPORT_PRIVATE LookupIterator final BASE_EMBEDDED {
     return LookupIterator(receiver, name, holder, configuration);
   }
 
+  static LookupIterator PropertyOrElement(
+      Isolate* isolate, Handle<Object> receiver, Handle<Object> key,
+      bool* success, Handle<JSReceiver> holder,
+      Configuration configuration = DEFAULT);
+
   static LookupIterator PropertyOrElement(
       Isolate* isolate, Handle<Object> receiver, Handle<Object> key,
       bool* success, Configuration configuration = DEFAULT);

src/objects.cc

@@ -1106,7 +1106,7 @@ MaybeHandle<Object> JSProxy::GetProperty(Isolate* isolate,
       Execution::Call(isolate, trap, handler, arraysize(args), args), Object);
 
   MaybeHandle<Object> result =
-      JSProxy::CheckGetTrapResult(isolate, name, target, trap_result);
+      JSProxy::CheckGetSetTrapResult(isolate, name, target, trap_result, kGet);
   if (result.is_null()) {
     return result;
   }
@@ -1116,10 +1116,11 @@ MaybeHandle<Object> JSProxy::GetProperty(Isolate* isolate,
 }
 
 // static
-MaybeHandle<Object> JSProxy::CheckGetTrapResult(Isolate* isolate,
-                                                Handle<Name> name,
-                                                Handle<JSReceiver> target,
-                                                Handle<Object> trap_result) {
+MaybeHandle<Object> JSProxy::CheckGetSetTrapResult(Isolate* isolate,
+                                                   Handle<Name> name,
+                                                   Handle<JSReceiver> target,
+                                                   Handle<Object> trap_result,
+                                                   AccessKind access_kind) {
   // 9. Let targetDesc be ? target.[[GetOwnProperty]](P).
   PropertyDescriptor target_desc;
   Maybe<bool> target_found =
@@ -1136,24 +1137,43 @@ MaybeHandle<Object> JSProxy::CheckGetTrapResult(Isolate* isolate,
                         !target_desc.writable() &&
                         !trap_result->SameValue(*target_desc.value());
     if (inconsistent) {
-      THROW_NEW_ERROR(
-          isolate, NewTypeError(MessageTemplate::kProxyGetNonConfigurableData,
-                                name, target_desc.value(), trap_result),
-          Object);
+      if (access_kind == kGet) {
+        THROW_NEW_ERROR(
+            isolate,
+            NewTypeError(MessageTemplate::kProxyGetNonConfigurableData, name,
+                         target_desc.value(), trap_result),
+            Object);
+      } else {
+        isolate->Throw(*isolate->factory()->NewTypeError(
+            MessageTemplate::kProxySetFrozenData, name));
+        return MaybeHandle<Object>();
+      }
     }
     // 10.b. If IsAccessorDescriptor(targetDesc) and targetDesc.[[Configurable]]
     //       is false and targetDesc.[[Get]] is undefined, then
     // 10.b.i. If trapResult is not undefined, throw a TypeError exception.
-    inconsistent = PropertyDescriptor::IsAccessorDescriptor(&target_desc) &&
-                   !target_desc.configurable() &&
-                   target_desc.get()->IsUndefined(isolate) &&
-                   !trap_result->IsUndefined(isolate);
+    if (access_kind == kGet) {
+      inconsistent = PropertyDescriptor::IsAccessorDescriptor(&target_desc) &&
+                     !target_desc.configurable() &&
+                     target_desc.get()->IsUndefined(isolate) &&
+                     !trap_result->IsUndefined(isolate);
+    } else {
+      inconsistent = PropertyDescriptor::IsAccessorDescriptor(&target_desc) &&
+                     !target_desc.configurable() &&
+                     target_desc.set()->IsUndefined(isolate);
+    }
     if (inconsistent) {
-      THROW_NEW_ERROR(
-          isolate,
-          NewTypeError(MessageTemplate::kProxyGetNonConfigurableAccessor, name,
-                       trap_result),
-          Object);
+      if (access_kind == kGet) {
+        THROW_NEW_ERROR(
+            isolate,
+            NewTypeError(MessageTemplate::kProxyGetNonConfigurableAccessor,
+                         name, trap_result),
+            Object);
+      } else {
+        isolate->Throw(*isolate->factory()->NewTypeError(
+            MessageTemplate::kProxySetFrozenAccessor, name));
+        return MaybeHandle<Object>();
+      }
     }
   }
   return isolate->factory()->undefined_value();
@@ -5527,29 +5547,11 @@ Maybe<bool> JSProxy::SetProperty(Handle<JSProxy> proxy, Handle<Name> name,
                                 trap_name, name));
   }
 
-  // Enforce the invariant.
-  PropertyDescriptor target_desc;
-  Maybe<bool> owned =
-      JSReceiver::GetOwnPropertyDescriptor(isolate, target, name, &target_desc);
-  MAYBE_RETURN(owned, Nothing<bool>());
-  if (owned.FromJust()) {
-    bool inconsistent = PropertyDescriptor::IsDataDescriptor(&target_desc) &&
-                        !target_desc.configurable() &&
-                        !target_desc.writable() &&
-                        !value->SameValue(*target_desc.value());
-    if (inconsistent) {
-      isolate->Throw(*isolate->factory()->NewTypeError(
-          MessageTemplate::kProxySetFrozenData, name));
-      return Nothing<bool>();
-    }
-    inconsistent = PropertyDescriptor::IsAccessorDescriptor(&target_desc) &&
-                   !target_desc.configurable() &&
-                   target_desc.set()->IsUndefined(isolate);
-    if (inconsistent) {
-      isolate->Throw(*isolate->factory()->NewTypeError(
-          MessageTemplate::kProxySetFrozenAccessor, name));
-      return Nothing<bool>();
-    }
+  MaybeHandle<Object> result =
+      JSProxy::CheckGetSetTrapResult(isolate, name, target, value, kSet);
+
+  if (result.is_null()) {
+    return Nothing<bool>();
   }
   return Just(true);
 }

src/objects.h

@@ -6046,10 +6046,13 @@ class JSProxy: public JSReceiver {
       Isolate* isolate, Handle<JSProxy> proxy, Handle<Name> name,
       Handle<Object> receiver, bool* was_found);
 
-  static MaybeHandle<Object> CheckGetTrapResult(Isolate* isolate,
-                                                Handle<Name> name,
-                                                Handle<JSReceiver> target,
-                                                Handle<Object> trap_result);
+  enum AccessKind { kGet, kSet };
+
+  static MaybeHandle<Object> CheckGetSetTrapResult(Isolate* isolate,
+                                                   Handle<Name> name,
+                                                   Handle<JSReceiver> target,
+                                                   Handle<Object> trap_result,
+                                                   AccessKind access_kind);
 
   // ES6 9.5.9
   MUST_USE_RESULT static Maybe<bool> SetProperty(Handle<JSProxy> proxy,

src/runtime/runtime-proxy.cc

@@ -51,24 +51,47 @@ RUNTIME_FUNCTION(Runtime_GetPropertyWithReceiver) {
 
   DCHECK_EQ(3, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, holder, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, name, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 2);
 
-  LookupIterator it =
-      LookupIterator::PropertyOrElement(isolate, receiver, name, holder);
+  bool success;
+  LookupIterator it = LookupIterator::PropertyOrElement(isolate, receiver, name,
+                                                        &success, holder);
   RETURN_RESULT_OR_FAILURE(isolate, Object::GetProperty(&it));
 }
 
-RUNTIME_FUNCTION(Runtime_CheckProxyGetTrapResult) {
+RUNTIME_FUNCTION(Runtime_SetPropertyWithReceiver) {
   HandleScope scope(isolate);
 
-  DCHECK_EQ(3, args.length());
+  DCHECK_EQ(5, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, holder, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, name, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
+  CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 3);
+  CONVERT_LANGUAGE_MODE_ARG_CHECKED(language_mode, 4);
+
+  bool success;
+  LookupIterator it = LookupIterator::PropertyOrElement(isolate, receiver, name,
+                                                        &success, holder);
+
+  Maybe<bool> result = Object::SetSuperProperty(
+      &it, value, language_mode, Object::MAY_BE_STORE_FROM_KEYED);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return *isolate->factory()->ToBoolean(result.FromJust());
+}
+
+RUNTIME_FUNCTION(Runtime_CheckProxyGetSetTrapResult) {
+  HandleScope scope(isolate);
+
+  DCHECK_EQ(4, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Name, name, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, target, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, trap_result, 2);
+  CONVERT_NUMBER_CHECKED(int64_t, access_kind, Int64, args[3]);
 
-  RETURN_RESULT_OR_FAILURE(
-      isolate, JSProxy::CheckGetTrapResult(isolate, name, target, trap_result));
+  RETURN_RESULT_OR_FAILURE(isolate, JSProxy::CheckGetSetTrapResult(
+                                        isolate, name, target, trap_result,
+                                        JSProxy::AccessKind(access_kind)));
 }
 
 RUNTIME_FUNCTION(Runtime_CheckProxyHasTrap) {

src/runtime/runtime.h

@@ -468,8 +468,9 @@ namespace internal {
   F(JSProxyGetHandler, 1, 1)        \
   F(JSProxyRevoke, 1, 1)            \
   F(GetPropertyWithReceiver, 2, 1)  \
-  F(CheckProxyGetTrapResult, 2, 1)  \
-  F(CheckProxyHasTrap, 2, 1)
+  F(CheckProxyHasTrap, 2, 1)        \
+  F(SetPropertyWithReceiver, 5, 1)  \
+  F(CheckProxyGetSetTrapResult, 2, 1)
 
 #define FOR_EACH_INTRINSIC_REGEXP(F)                \
   F(IsRegExp, 1, 1)                                 \

src/v8.gyp

@@ -206,8 +206,6 @@
         'builtins/builtins-promise-gen.h',
         'builtins/builtins-proxy-gen.cc',
         'builtins/builtins-proxy-gen.h',
-        'builtins/builtins-proxy-helpers-gen.cc',
-        'builtins/builtins-proxy-helpers-gen.h',
         'builtins/builtins-regexp-gen.cc',
         'builtins/builtins-regexp-gen.h',
         'builtins/builtins-sharedarraybuffer-gen.cc',

test/mjsunit/es6/proxies-get.js

@@ -193,7 +193,6 @@
     'Error from proxy getOwnPropertyDescriptor trap');
 })();
 
-
 (function testGetPropertyDetailsBailout2() {
   var obj = {};
   Object.defineProperty(obj, 'prop', {
@@ -211,3 +210,13 @@
     " property on the proxy target but the proxy did not return its actual" +
     " value (expected '53' but got '42')");
 })();
+
+(function test32BitIndex() {
+  var index = (1 << 31) + 1;
+  var obj = {};
+  obj[index] = 42;
+  var p = new Proxy(obj, {});
+  for (var i = 0; i < 3; ++i) {
+    assertEquals(42, p[index]);
+  }
+})();

test/mjsunit/es6/proxies-set.js

@@ -308,3 +308,101 @@ TestTrapReceiverArgument(strictReflectSet);
     }
   }
 })();
+
+
+function TestTargetProxy(mySet) {
+  var q = new Proxy({}, {});
+  var proxy = new Proxy(q, {
+    set: function(t, k, v) {
+      return Reflect.set(t, k, v);
+    }
+  });
+
+  for (var p of properties) {
+    assertTrueIf(mySet.returnsBool, mySet(proxy, p, 42));
+    assertSame(42, q[p]);
+  }
+};
+
+TestTargetProxy(sloppyDefaultSet);
+TestTargetProxy(sloppyReflectSet);
+TestTargetProxy(strictDefaultSet);
+TestTargetProxy(strictReflectSet);
+
+
+(function TestAccessorNoSet() {
+  var target = {
+  };
+  Object.defineProperty(target, 'prop', {
+    get: function() {
+      return 42;
+    },
+    configurable: false
+  })
+  var handler = {
+    set: function() { return true; }
+  }
+  var proxy = new Proxy(target, handler);
+  assertThrows(function() { proxy.prop = 0; }, TypeError);
+})();
+
+(function TestProxyInPrototype() {
+  var handler = {
+    set: function(t, k, v) {
+      Reflect.set(t, k, v);
+    }
+  };
+  var obj = {};
+  var proxy = new Proxy(obj, handler);
+  var o = Object.create(proxy);
+
+  for (var i = 0; i < 3; ++i) {
+    o.prop = 42 + i;
+    assertEquals(42 + i, obj.prop);
+  }
+})();
+
+(function TestProxyInPrototypeNoTrap() {
+  var handler = {
+  };
+  var obj = {};
+  var proxy = new Proxy(obj, handler);
+  var o = Object.create(proxy);
+
+  for (var i = 0; i < 3; ++i) {
+    o.prop = 42 + i;
+    assertEquals(42 + i, o.prop);
+    assertEquals(undefined, obj.prop);
+  }
+})();
+
+// Note: this case is currently handled by runtime.
+(function TestDifferentHolder() {
+  var obj = {
+    '1337': 100
+  };
+  var handler = {
+    set(target, name, value, receiver) {
+      if (name != '1337') return Reflect.set(target, name, value, receiver);
+
+      assertSame(target, obj);
+      assertSame(receiver, p);
+      return target[name] = value;
+    }
+  };
+  var p = new Proxy(obj, handler);
+  for (var i = 0; i < 3; ++i) {
+    assertEquals(42, p[1337] = 42);
+  }
+})();
+
+(function test32BitIndex() {
+  var index = (1 << 31) + 1;
+  var obj = {};
+  obj[index] = 42;
+  var p = new Proxy(obj, {});
+  for (var i = 0; i < 3; ++i) {
+    p[index] = 100;
+    assertEquals(100, obj[index]);
+  }
+})();