Align __lookupGetter__/__lookupSetter__ behavior with the spec

src/builtins/builtins-object.cc

 // Copyright 2016 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-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/property-descriptor.h"
 
@@ skipping 627 matching lines @@
       case LookupIterator::NOT_FOUND:
       case LookupIterator::TRANSITION:
         UNREACHABLE();
 
       case LookupIterator::ACCESS_CHECK:
         if (it.HasAccess()) continue;
         isolate->ReportFailedAccessCheck(it.GetHolder<JSObject>());
         RETURN_FAILURE_IF_SCHEDULED_EXCEPTION(isolate);
         return isolate->heap()->undefined_value();
 
-      case LookupIterator::JSPROXY:
+      case LookupIterator::JSPROXY: {
+        PropertyDescriptor desc;
+        Maybe<bool> found = JSProxy::GetOwnPropertyDescriptor(
+            isolate, it.GetHolder<JSProxy>(), it.GetName(), &desc);
+        MAYBE_RETURN(found, isolate->heap()->exception());
+        if (found.FromJust()) {
+          if (component == ACCESSOR_GETTER && desc.has_get()) {
+            return *desc.get();
+          }
+          if (component == ACCESSOR_SETTER && desc.has_set()) {
+            return *desc.set();
+          }
+          return isolate->heap()->undefined_value();
+        }
+        Handle<Object> prototype;
+        ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+            isolate, prototype, JSProxy::GetPrototype(it.GetHolder<JSProxy>()));
+        if (prototype->IsNull(isolate)) {
+          return isolate->heap()->undefined_value();
+        }
+        return ObjectLookupAccessor(isolate, prototype, key, component);
+      }
+
+      case LookupIterator::INTEGER_INDEXED_EXOTIC:
+      case LookupIterator::DATA:
         return isolate->heap()->undefined_value();
 
-      case LookupIterator::INTEGER_INDEXED_EXOTIC:
-        return isolate->heap()->undefined_value();
-      case LookupIterator::DATA:
-        continue;
       case LookupIterator::ACCESSOR: {
         Handle<Object> maybe_pair = it.GetAccessors();
         if (maybe_pair->IsAccessorPair()) {
           return *AccessorPair::GetComponent(
               Handle<AccessorPair>::cast(maybe_pair), component);
         }
       }
     }
   }
 
@@ skipping 420 matching lines @@
   CodeStubAssembler assembler(state);
 
   Node* object = assembler.Parameter(Descriptor::kObject);
   Node* context = assembler.Parameter(Descriptor::kContext);
 
   assembler.Return(assembler.GetSuperConstructor(object, context));
 }
 
 }  // namespace internal
 }  // namespace v8