Revert of Assume that ReportFailedAccessCheck always schedules an exception.

src/objects.cc

 // Copyright 2013 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 993 matching lines @@
 
   // Cross-Origin [[Get]] of Well-Known Symbols does not throw, and returns
   // undefined.
   Handle<Name> name = it->GetName();
   if (name->IsSymbol() && Symbol::cast(*name)->is_well_known_symbol()) {
     return it->factory()->undefined_value();
   }
 
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(it->isolate(), Object);
-  UNREACHABLE();
-  return MaybeHandle<Object>();
+  return it->factory()->undefined_value();
 }
 
 
 Maybe<PropertyAttributes> JSObject::GetPropertyAttributesWithFailedAccessCheck(
     LookupIterator* it) {
   Handle<JSObject> checked = it->GetHolder<JSObject>();
   while (AllCanRead(it)) {
     if (it->state() == LookupIterator::ACCESSOR) {
       return Just(it->property_details().attributes());
     }
     DCHECK_EQ(LookupIterator::INTERCEPTOR, it->state());
     auto result = GetPropertyAttributesWithInterceptor(it);
     if (it->isolate()->has_scheduled_exception()) break;
     if (result.IsJust() && result.FromJust() != ABSENT) return result;
   }
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(it->isolate(),
                                       Nothing<PropertyAttributes>());
-  UNREACHABLE();
-  return Nothing<PropertyAttributes>();
+  return Just(ABSENT);
 }
 
 
 // static
 bool JSObject::AllCanWrite(LookupIterator* it) {
   for (; it->IsFound(); it->Next()) {
     if (it->state() == LookupIterator::ACCESSOR) {
       Handle<Object> accessors = it->GetAccessors();
       if (accessors->IsAccessorInfo()) {
         if (AccessorInfo::cast(*accessors)->all_can_write()) return true;
       }
     }
   }
   return false;
 }
 
 
 Maybe<bool> JSObject::SetPropertyWithFailedAccessCheck(
     LookupIterator* it, Handle<Object> value, ShouldThrow should_throw) {
   Handle<JSObject> checked = it->GetHolder<JSObject>();
   if (AllCanWrite(it)) {
     // The supplied language-mode is ignored by SetPropertyWithAccessor.
     return SetPropertyWithAccessor(it, value, SLOPPY, should_throw);
   }
 
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(it->isolate(), Nothing<bool>());
   UNREACHABLE();
+  it->isolate()->Throw(
+      *it->isolate()->factory()->NewTypeError(MessageTemplate::kNoAccess));
   return Nothing<bool>();
 }
 
 
 void JSObject::SetNormalizedProperty(Handle<JSObject> object,
                                      Handle<Name> name,
                                      Handle<Object> value,
                                      PropertyDetails details) {
   DCHECK(!object->HasFastProperties());
   if (!name->IsUniqueName()) {
@@ skipping 3711 matching lines @@
     switch (it->state()) {
       case LookupIterator::JSPROXY:
       case LookupIterator::NOT_FOUND:
       case LookupIterator::TRANSITION:
         UNREACHABLE();
 
       case LookupIterator::ACCESS_CHECK:
         if (!it->HasAccess()) {
           it->isolate()->ReportFailedAccessCheck(it->GetHolder<JSObject>());
           RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(it->isolate(), Object);
-          UNREACHABLE();
+          return value;
         }
         break;
 
       // If there's an interceptor, try to store the property with the
       // interceptor.
       // In case of success, the attributes will have been reset to the default
       // attributes of the interceptor, rather than the incoming attributes.
       //
       // TODO(verwaest): JSProxy afterwards verify the attributes that the
       // JSProxy claims it has, and verifies that they are compatible. If not,
@@ skipping 1008 matching lines @@
   for (; it->IsFound(); it->Next()) {
     switch (it->state()) {
       case LookupIterator::JSPROXY:
       case LookupIterator::NOT_FOUND:
       case LookupIterator::TRANSITION:
         UNREACHABLE();
       case LookupIterator::ACCESS_CHECK:
         if (it->HasAccess()) break;
         isolate->ReportFailedAccessCheck(it->GetHolder<JSObject>());
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-        UNREACHABLE();
+        return it->factory()->false_value();
       case LookupIterator::INTERCEPTOR: {
         MaybeHandle<Object> maybe_result =
             JSObject::DeletePropertyWithInterceptor(it);
         // Delete with interceptor succeeded. Return result.
         if (!maybe_result.is_null()) return maybe_result;
         // An exception was thrown in the interceptor. Propagate.
         if (isolate->has_pending_exception()) return maybe_result;
         break;
       }
       case LookupIterator::INTEGER_INDEXED_EXOTIC:
@@ skipping 940 matching lines @@
 
   if (!object->HasSloppyArgumentsElements() && !object->map()->is_observed()) {
     return PreventExtensionsWithTransition<NONE>(object, should_throw);
   }
 
   if (object->IsAccessCheckNeeded() &&
       !isolate->MayAccess(handle(isolate->context()), object)) {
     isolate->ReportFailedAccessCheck(object);
     RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate, Nothing<bool>());
     UNREACHABLE();
+    RETURN_FAILURE(isolate, should_throw,
+                   NewTypeError(MessageTemplate::kNoAccess));
   }
 
   if (object->IsJSGlobalProxy()) {
     PrototypeIterator iter(isolate, object);
     if (iter.IsAtEnd()) return Just(true);
     DCHECK(PrototypeIterator::GetCurrent(iter)->IsJSGlobalObject());
     return PreventExtensions(PrototypeIterator::GetCurrent<JSObject>(iter),
                              should_throw);
   }
 
@@ skipping 79 matching lines @@
   // Sealing/freezing sloppy arguments should be handled elsewhere.
   DCHECK(!object->HasSloppyArgumentsElements());
   DCHECK(!object->map()->is_observed());
 
   Isolate* isolate = object->GetIsolate();
   if (object->IsAccessCheckNeeded() &&
       !isolate->MayAccess(handle(isolate->context()), object)) {
     isolate->ReportFailedAccessCheck(object);
     RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate, Nothing<bool>());
     UNREACHABLE();
+    RETURN_FAILURE(isolate, should_throw,
+                   NewTypeError(MessageTemplate::kNoAccess));
   }
 
   if (object->IsJSGlobalProxy()) {
     PrototypeIterator iter(isolate, object);
     if (iter.IsAtEnd()) return Just(true);
     DCHECK(PrototypeIterator::GetCurrent(iter)->IsJSGlobalObject());
     return PreventExtensionsWithTransition<attrs>(
         PrototypeIterator::GetCurrent<JSObject>(iter), should_throw);
   }
 
@@ skipping 873 matching lines @@
     }
 
     Handle<JSObject> current = PrototypeIterator::GetCurrent<JSObject>(iter);
 
     // Check access rights if required.
     if (current->IsAccessCheckNeeded() &&
         !isolate->MayAccess(handle(isolate->context()), current)) {
       if (iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN)) {
         isolate->ReportFailedAccessCheck(current);
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, FixedArray);
-        UNREACHABLE();
       }
       break;
     }
 
     JSObject::CollectOwnElementKeys(current, &accumulator,
                                     static_cast<PropertyAttributes>(DONT_ENUM));
 
     // Add the element keys from the interceptor.
     if (current->HasIndexedInterceptor()) {
       Handle<JSObject> result;
@@ skipping 92 matching lines @@
 MaybeHandle<Object> JSObject::DefineAccessor(LookupIterator* it,
                                              Handle<Object> getter,
                                              Handle<Object> setter,
                                              PropertyAttributes attributes) {
   Isolate* isolate = it->isolate();
 
   if (it->state() == LookupIterator::ACCESS_CHECK) {
     if (!it->HasAccess()) {
       isolate->ReportFailedAccessCheck(it->GetHolder<JSObject>());
       RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-      UNREACHABLE();
+      return isolate->factory()->undefined_value();
     }
     it->Next();
   }
 
   Handle<JSObject> object = Handle<JSObject>::cast(it->GetReceiver());
   // Ignore accessors on typed arrays.
   if (it->IsElement() && object->HasFixedTypedArrayElements()) {
     return it->factory()->undefined_value();
   }
 
@@ skipping 44 matching lines @@
 
   // Duplicate ACCESS_CHECK outside of GetPropertyAttributes for the case that
   // the FailedAccessCheckCallbackFunction doesn't throw an exception.
   //
   // TODO(verwaest): Force throw an exception if the callback doesn't, so we can
   // remove reliance on default return values.
   if (it.state() == LookupIterator::ACCESS_CHECK) {
     if (!it.HasAccess()) {
       isolate->ReportFailedAccessCheck(object);
       RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-      UNREACHABLE();
+      return it.factory()->undefined_value();
     }
     it.Next();
   }
 
   // Ignore accessors on typed arrays.
   if (it.IsElement() && object->HasFixedTypedArrayElements()) {
     return it.factory()->undefined_value();
   }
 
   CHECK(GetPropertyAttributes(&it).IsJust());
@@ skipping 26 matching lines @@
     switch (it.state()) {
       case LookupIterator::INTERCEPTOR:
       case LookupIterator::NOT_FOUND:
       case LookupIterator::TRANSITION:
         UNREACHABLE();
 
       case LookupIterator::ACCESS_CHECK:
         if (it.HasAccess()) continue;
         isolate->ReportFailedAccessCheck(it.GetHolder<JSObject>());
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-        UNREACHABLE();
+        return isolate->factory()->undefined_value();
 
       case LookupIterator::JSPROXY:
         return isolate->factory()->undefined_value();
 
       case LookupIterator::INTEGER_INDEXED_EXOTIC:
         return isolate->factory()->undefined_value();
       case LookupIterator::DATA:
         continue;
       case LookupIterator::ACCESSOR: {
         Handle<Object> maybe_pair = it.GetAccessors();
@@ skipping 9831 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8