[api] Change CreationContext to return a MaybeHandle

The current API returns a Handle<NativeContext> which can be
optionally null and all the users of this API never actually
checked for this null value.

Previously, this wasn't a problem as all the possible JSObjects
that were user visible would return a valid NativeContext but now
there are wasm objects that don't have a valid constructor so don't
have a NativeContext.

Bug: v8:11451, chromium:1166077
Change-Id: I4fd5edf8f1a750e6f0abb931fd41358e5ae4dfcf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2692695
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72769}

include/v8.h

@@ -4222,12 +4222,18 @@ class V8_EXPORT Object : public Value {
   /**
    * Returns the context in which the object was created.
    */
+  V8_DEPRECATE_SOON("Use MaybeLocal<Context> GetCreationContext()")
   Local<Context> CreationContext();
+  MaybeLocal<Context> GetCreationContext();
 
   /** Same as above, but works for Persistents */
-  V8_INLINE static Local<Context> CreationContext(
+  V8_DEPRECATE_SOON(
+      "Use MaybeLocal<Context> GetCreationContext(const "
+      "PersistentBase<Object>& object)")
+  static Local<Context> CreationContext(const PersistentBase<Object>& object);
+  V8_INLINE static MaybeLocal<Context> GetCreationContext(
       const PersistentBase<Object>& object) {
-    return object.val_->CreationContext();
+    return object.val_->GetCreationContext();
   }
 
   /**

src/api/api.cc

@@ -4710,10 +4710,36 @@ Local<v8::Object> v8::Object::Clone() {
   return Utils::ToLocal(result);
 }
 
+namespace {
+Local<v8::Context> CreationContextImpl(i::Handle<i::JSReceiver> self) {
+  i::Handle<i::Context> context;
+  if (self->GetCreationContext().ToHandle(&context)) {
+    return Utils::ToLocal(context);
+  }
+
+  return Local<v8::Context>();
+}
+}  // namespace
+
 Local<v8::Context> v8::Object::CreationContext() {
   auto self = Utils::OpenHandle(this);
-  i::Handle<i::Context> context = self->GetCreationContext();
-  return Utils::ToLocal(context);
+  return CreationContextImpl(self);
+}
+
+Local<v8::Context> v8::Object::CreationContext(
+    const PersistentBase<Object>& object) {
+  auto self = Utils::OpenHandle(object.val_);
+  return CreationContextImpl(self);
+}
+
+MaybeLocal<v8::Context> v8::Object::GetCreationContext() {
+  auto self = Utils::OpenHandle(this);
+  i::Handle<i::Context> context;
+  if (self->GetCreationContext().ToHandle(&context)) {
+    return Utils::ToLocal(context);
+  }
+
+  return MaybeLocal<v8::Context>();
 }
 
 int v8::Object::GetIdentityHash() {

src/builtins/builtins-object.cc

@@ -157,8 +157,9 @@ Object ObjectLookupAccessor(Isolate* isolate, Handle<Object> object,
       case LookupIterator::ACCESSOR: {
         Handle<Object> maybe_pair = it.GetAccessors();
         if (maybe_pair->IsAccessorPair()) {
-          Handle<NativeContext> native_context =
-              it.GetHolder<JSReceiver>()->GetCreationContext();
+          Handle<NativeContext> native_context = it.GetHolder<JSReceiver>()
+                                                     ->GetCreationContext()
+                                                     .ToHandleChecked();
           return *AccessorPair::GetComponent(
               isolate, native_context, Handle<AccessorPair>::cast(maybe_pair),
               component);

src/d8/d8.cc

@@ -1527,7 +1527,12 @@ void Shell::RealmOwner(const v8::FunctionCallbackInfo<v8::Value>& args) {
       i::Handle<i::JSGlobalProxy>::cast(i_object)->IsDetached()) {
     return;
   }
-  int index = data->RealmFind(object->CreationContext());
+  Local<Context> creation_context;
+  if (!object->GetCreationContext().ToLocal(&creation_context)) {
+    Throw(args.GetIsolate(), "object doesn't have creation context");
+    return;
+  }
+  int index = data->RealmFind(creation_context);
   if (index == -1) return;
   args.GetReturnValue().Set(index);
 }

src/debug/debug-interface.cc

@@ -192,12 +192,12 @@ bool GetPrivateMembers(Local<Context> context, Local<Object> value,
   return true;
 }
 
-Local<Context> GetCreationContext(Local<Object> value) {
+MaybeLocal<Context> GetCreationContext(Local<Object> value) {
   i::Handle<i::Object> val = Utils::OpenHandle(*value);
   if (val->IsJSGlobalProxy()) {
-    return Local<Context>();
+    return MaybeLocal<Context>();
   }
-  return value->CreationContext();
+  return value->GetCreationContext();
 }
 
 void ChangeBreakOnException(Isolate* isolate, ExceptionBreakState type) {

src/debug/debug-interface.h

@@ -73,7 +73,7 @@ V8_EXPORT_PRIVATE bool GetPrivateMembers(Local<Context> context,
  * Forwards to v8::Object::CreationContext, but with special handling for
  * JSGlobalProxy objects.
  */
-Local<Context> GetCreationContext(Local<Object> value);
+MaybeLocal<Context> GetCreationContext(Local<Object> value);
 
 enum ExceptionBreakState {
   NoBreakOnException = 0,

src/debug/debug.cc

@@ -1423,8 +1423,9 @@ void Debug::InstallDebugBreakTrampoline() {
             }
             if (recorded.find(accessor_pair) != recorded.end()) continue;
 
-            needs_instantiate.emplace_back(handle(accessor_pair, isolate_),
-                                           object.GetCreationContext());
+            needs_instantiate.emplace_back(
+                handle(accessor_pair, isolate_),
+                object.GetCreationContext().ToHandleChecked());
             recorded.insert(accessor_pair);
           }
         }

src/execution/messages.cc

@@ -304,8 +304,8 @@ MaybeHandle<Object> ErrorUtils::FormatStackTrace(Isolate* isolate,
   Handle<FixedArray> elems = Handle<FixedArray>::cast(raw_stack);
 
   const bool in_recursion = isolate->formatting_stack_trace();
-  if (!in_recursion) {
-    Handle<Context> error_context = error->GetCreationContext();
+  Handle<Context> error_context;
+  if (!in_recursion && error->GetCreationContext().ToHandle(&error_context)) {
     DCHECK(error_context->IsNativeContext());
 
     if (isolate->HasPrepareStackTraceCallback()) {

src/heap/factory.cc

@@ -2574,7 +2574,8 @@ MaybeHandle<JSBoundFunction> Factory::NewJSBoundFunction(
       isolate(), prototype,
       JSReceiver::GetPrototype(isolate(), target_function), JSBoundFunction);
 
-  SaveAndSwitchContext save(isolate(), *target_function->GetCreationContext());
+  SaveAndSwitchContext save(
+      isolate(), *target_function->GetCreationContext().ToHandleChecked());
 
   // Create the [[BoundArguments]] for the result.
   Handle<FixedArray> bound_arguments;

src/inspector/custom-preview.cc

@@ -249,7 +249,11 @@ void generateCustomPreview(int sessionId, const String16& groupName,
                            v8::Local<v8::Object> object,
                            v8::MaybeLocal<v8::Value> maybeConfig, int maxDepth,
                            std::unique_ptr<CustomPreview>* preview) {
-  v8::Local<v8::Context> context = object->CreationContext();
+  v8::Local<v8::Context> context;
+  if (!object->GetCreationContext().ToLocal(&context)) {
+    return;
+  }
+
   v8::Isolate* isolate = context->GetIsolate();
   v8::MicrotasksScope microtasksScope(isolate,
                                       v8::MicrotasksScope::kDoNotRunMicrotasks);

src/inspector/v8-debugger.cc

@@ -43,8 +43,10 @@ class MatchPrototypePredicate : public v8::debug::QueryObjectPredicate {
 
   bool Filter(v8::Local<v8::Object> object) override {
     if (object->IsModuleNamespaceObject()) return false;
-    v8::Local<v8::Context> objectContext =
-        v8::debug::GetCreationContext(object);
+    v8::Local<v8::Context> objectContext;
+    if (!v8::debug::GetCreationContext(object).ToLocal(&objectContext)) {
+      return false;
+    }
     if (objectContext != m_context) return false;
     if (!m_inspector->client()->isInspectableHeapObject(object)) return false;
     // Get prototype chain for current object until first visited prototype.

src/inspector/v8-heap-profiler-agent-impl.cc

@@ -54,9 +54,13 @@ class GlobalObjectNameResolver final
       : m_offset(0), m_strings(10000), m_session(session) {}
 
   const char* GetName(v8::Local<v8::Object> object) override {
+    v8::Local<v8::Context> creationContext;
+    if (!object->GetCreationContext().ToLocal(&creationContext)) {
+      return "";
+    }
     InspectedContext* context = m_session->inspector()->getContext(
         m_session->contextGroupId(),
-        InspectedContext::contextId(object->CreationContext()));
+        InspectedContext::contextId(creationContext));
     if (!context) return "";
     String16 name = context->origin();
     size_t length = name.length();
@@ -286,7 +290,11 @@ Response V8HeapProfilerAgentImpl::getObjectByHeapObjectId(
   if (!m_session->inspector()->client()->isInspectableHeapObject(heapObject))
     return Response::ServerError("Object is not available");
 
-  *result = m_session->wrapObject(heapObject->CreationContext(), heapObject,
+  v8::Local<v8::Context> creationContext;
+  if (!heapObject->GetCreationContext().ToLocal(&creationContext)) {
+    return Response::ServerError("Object is not available");
+  }
+  *result = m_session->wrapObject(creationContext, heapObject,
                                   objectGroup.fromMaybe(""), false);
   if (!*result) return Response::ServerError("Object is not available");
   return Response::Success();

src/objects/js-objects.cc

@@ -534,7 +534,7 @@ Handle<String> JSReceiver::GetConstructorName(Handle<JSReceiver> receiver) {
   return GetConstructorHelper(receiver).second;
 }
 
-Handle<NativeContext> JSReceiver::GetCreationContext() {
+MaybeHandle<NativeContext> JSReceiver::GetCreationContext() {
   JSReceiver receiver = *this;
   // Externals are JSObjects with null as a constructor.
   DCHECK(!receiver.IsExternal(GetIsolate()));
@@ -544,20 +544,19 @@ Handle<NativeContext> JSReceiver::GetCreationContext() {
     function = JSFunction::cast(constructor);
   } else if (constructor.IsFunctionTemplateInfo()) {
     // Remote objects don't have a creation context.
-    return Handle<NativeContext>::null();
+    return MaybeHandle<NativeContext>();
   } else if (receiver.IsJSGeneratorObject()) {
     function = JSGeneratorObject::cast(receiver).function();
-  } else {
-    // Functions have null as a constructor,
-    // but any JSFunction knows its context immediately.
-    CHECK(receiver.IsJSFunction());
+  } else if (receiver.IsJSFunction()) {
     function = JSFunction::cast(receiver);
+  } else {
+    return MaybeHandle<NativeContext>();
   }
 
   return function.has_context()
              ? Handle<NativeContext>(function.context().native_context(),
                                      receiver.GetIsolate())
-             : Handle<NativeContext>::null();
+             : MaybeHandle<NativeContext>();
 }
 
 // static
@@ -1696,7 +1695,7 @@ Maybe<bool> JSReceiver::GetOwnPropertyDescriptor(LookupIterator* it,
     Handle<AccessorPair> accessors =
         Handle<AccessorPair>::cast(it->GetAccessors());
     Handle<NativeContext> native_context =
-        it->GetHolder<JSReceiver>()->GetCreationContext();
+        it->GetHolder<JSReceiver>()->GetCreationContext().ToHandleChecked();
     // 6a. Set D.[[Get]] to the value of X's [[Get]] attribute.
     desc->set_get(AccessorPair::GetComponent(isolate, native_context, accessors,
                                              ACCESSOR_GETTER));

src/objects/js-objects.h

@@ -227,7 +227,7 @@ class JSReceiver : public HeapObject {
   // returned instead.
   static Handle<String> GetConstructorName(Handle<JSReceiver> receiver);
 
-  V8_EXPORT_PRIVATE Handle<NativeContext> GetCreationContext();
+  V8_EXPORT_PRIVATE MaybeHandle<NativeContext> GetCreationContext();
 
   V8_WARN_UNUSED_RESULT static inline Maybe<PropertyAttributes>
   GetPropertyAttributes(Handle<JSReceiver> object, Handle<Name> name);

src/objects/objects.cc

@@ -1490,7 +1490,8 @@ MaybeHandle<Object> Object::GetPropertyWithAccessor(LookupIterator* it) {
   // Regular accessor.
   Handle<Object> getter(accessor_pair->getter(), isolate);
   if (getter->IsFunctionTemplateInfo()) {
-    SaveAndSwitchContext save(isolate, *holder->GetCreationContext());
+    SaveAndSwitchContext save(isolate,
+                              *holder->GetCreationContext().ToHandleChecked());
     return Builtins::InvokeApiFunction(
         isolate, false, Handle<FunctionTemplateInfo>::cast(getter), receiver, 0,
         nullptr, isolate->factory()->undefined_value());
@@ -1595,7 +1596,8 @@ Maybe<bool> Object::SetPropertyWithAccessor(
   // Regular accessor.
   Handle<Object> setter(AccessorPair::cast(*structure).setter(), isolate);
   if (setter->IsFunctionTemplateInfo()) {
-    SaveAndSwitchContext save(isolate, *holder->GetCreationContext());
+    SaveAndSwitchContext save(isolate,
+                              *holder->GetCreationContext().ToHandleChecked());
     Handle<Object> argv[] = {value};
     RETURN_ON_EXCEPTION_VALUE(
         isolate,

test/cctest/heap/test-embedder-tracing.cc

@@ -82,7 +82,9 @@ class TestEmbedderHeapTracer final : public v8::EmbedderHeapTracer {
   void TracePrologue(EmbedderHeapTracer::TraceFlags) final {
     if (prologue_behavior_ == TracePrologueBehavior::kCallV8WriteBarrier) {
       auto local = array_.Get(isolate());
-      local->Set(local->CreationContext(), 0, v8::Object::New(isolate()))
+      local
+          ->Set(local->GetCreationContext().ToLocalChecked(), 0,
+                v8::Object::New(isolate()))
           .Check();
     }
   }

test/cctest/test-api.cc

@@ -19079,49 +19079,49 @@ THREADED_TEST(CreationContext) {
   {
     Local<Context> other_context = Context::New(isolate);
     Context::Scope scope(other_context);
-    CHECK(object1->CreationContext() == context1);
+    CHECK(object1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(object1, 1);
-    CHECK(func1->CreationContext() == context1);
+    CHECK(func1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(func1, 1);
-    CHECK(instance1->CreationContext() == context1);
+    CHECK(instance1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(instance1, 1);
-    CHECK(object2->CreationContext() == context2);
+    CHECK(object2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(object2, 2);
-    CHECK(func2->CreationContext() == context2);
+    CHECK(func2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(func2, 2);
-    CHECK(instance2->CreationContext() == context2);
+    CHECK(instance2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(instance2, 2);
   }
 
   {
     Context::Scope scope(context1);
-    CHECK(object1->CreationContext() == context1);
+    CHECK(object1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(object1, 1);
-    CHECK(func1->CreationContext() == context1);
+    CHECK(func1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(func1, 1);
-    CHECK(instance1->CreationContext() == context1);
+    CHECK(instance1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(instance1, 1);
-    CHECK(object2->CreationContext() == context2);
+    CHECK(object2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(object2, 2);
-    CHECK(func2->CreationContext() == context2);
+    CHECK(func2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(func2, 2);
-    CHECK(instance2->CreationContext() == context2);
+    CHECK(instance2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(instance2, 2);
   }
 
   {
     Context::Scope scope(context2);
-    CHECK(object1->CreationContext() == context1);
+    CHECK(object1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(object1, 1);
-    CHECK(func1->CreationContext() == context1);
+    CHECK(func1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(func1, 1);
-    CHECK(instance1->CreationContext() == context1);
+    CHECK(instance1->GetCreationContext().ToLocalChecked() == context1);
     CheckContextId(instance1, 1);
-    CHECK(object2->CreationContext() == context2);
+    CHECK(object2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(object2, 2);
-    CHECK(func2->CreationContext() == context2);
+    CHECK(func2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(func2, 2);
-    CHECK(instance2->CreationContext() == context2);
+    CHECK(instance2->GetCreationContext().ToLocalChecked() == context2);
     CheckContextId(instance2, 2);
   }
 }
@@ -19140,7 +19140,7 @@ THREADED_TEST(CreationContextOfJsFunction) {
 
   Local<Context> other_context = Context::New(CcTest::isolate());
   Context::Scope scope(other_context);
-  CHECK(function->CreationContext() == context);
+  CHECK(function->GetCreationContext().ToLocalChecked() == context);
   CheckContextId(function, 1);
 }
 
@@ -19171,13 +19171,12 @@ THREADED_TEST(CreationContextOfJsBoundFunction) {
 
   Local<Context> other_context = Context::New(CcTest::isolate());
   Context::Scope scope(other_context);
-  CHECK(bound_function1->CreationContext() == context1);
+  CHECK(bound_function1->GetCreationContext().ToLocalChecked() == context1);
   CheckContextId(bound_function1, 1);
-  CHECK(bound_function2->CreationContext() == context1);
+  CHECK(bound_function2->GetCreationContext().ToLocalChecked() == context1);
   CheckContextId(bound_function2, 1);
 }
 
-
 void HasOwnPropertyIndexedPropertyGetter(
     uint32_t index,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
@@ -24775,7 +24774,7 @@ TEST(ClassPrototypeCreationContext) {
 
   Local<Object> result = Local<Object>::Cast(
       CompileRun("'use strict'; class Example { }; Example.prototype"));
-  CHECK(env.local() == result->CreationContext());
+  CHECK(env.local() == result->GetCreationContext().ToLocalChecked());
 }
 
 
@@ -25554,7 +25553,7 @@ TEST(ObjectTemplatePerContextIntrinsics) {
       object->Get(env.local(), v8_str("values")).ToLocalChecked());
   auto fn = i::Handle<i::JSFunction>::cast(v8::Utils::OpenHandle(*values));
   auto ctx = v8::Utils::OpenHandle(*env.local());
-  CHECK_EQ(*fn->GetCreationContext(), *ctx);
+  CHECK_EQ(*(fn->GetCreationContext().ToHandleChecked()), *ctx);
 
   {
     LocalContext env2;
@@ -25570,7 +25569,7 @@ TEST(ObjectTemplatePerContextIntrinsics) {
         object2->Get(env2.local(), v8_str("values")).ToLocalChecked());
     auto fn2 = i::Handle<i::JSFunction>::cast(v8::Utils::OpenHandle(*values2));
     auto ctx2 = v8::Utils::OpenHandle(*env2.local());
-    CHECK_EQ(*fn2->GetCreationContext(), *ctx2);
+    CHECK_EQ(*(fn2->GetCreationContext().ToHandleChecked()), *ctx2);
   }
 }
 

test/cctest/test-modules.cc

@@ -743,7 +743,7 @@ TEST(ModuleNamespace) {
     Local<Value> ns = module->GetModuleNamespace();
     CHECK_EQ(Module::kInstantiated, module->GetStatus());
     Local<v8::Object> nsobj = ns->ToObject(env.local()).ToLocalChecked();
-    CHECK_EQ(nsobj->CreationContext(), env.local());
+    CHECK_EQ(nsobj->GetCreationContext().ToLocalChecked(), env.local());
 
     // a, b
     CHECK(nsobj->Get(env.local(), v8_str("a")).ToLocalChecked()->IsUndefined());

test/unittests/api/remote-object-unittest.cc

@@ -39,7 +39,7 @@ TEST_F(RemoteObjectTest, CreationContextOfRemoteContext) {
 
   Local<Object> remote_context =
       Context::NewRemoteContext(isolate(), global_template).ToLocalChecked();
-  EXPECT_TRUE(remote_context->CreationContext().IsEmpty());
+  EXPECT_TRUE(remote_context->GetCreationContext().IsEmpty());
 }
 
 TEST_F(RemoteObjectTest, CreationContextOfRemoteObject) {
@@ -51,7 +51,7 @@ TEST_F(RemoteObjectTest, CreationContextOfRemoteObject) {
 
   Local<Object> remote_object =
       constructor_template->NewRemoteInstance().ToLocalChecked();
-  EXPECT_TRUE(remote_object->CreationContext().IsEmpty());
+  EXPECT_TRUE(remote_object->GetCreationContext().IsEmpty());
 }
 
 TEST_F(RemoteObjectTest, RemoteContextInstanceChecks) {

test/unittests/api/v8-object-unittest.cc

@@ -77,8 +77,9 @@ TEST_F(LapContextTest, CurrentContextInLazyAccessorOnPrototype) {
   Local<Object> object =
       interface_for_receiver->NewInstance(receiver_context).ToLocalChecked();
   object->SetPrototype(caller_context, prototype).ToChecked();
-  EXPECT_EQ(receiver_context, object->CreationContext());
-  EXPECT_EQ(prototype_context, prototype->CreationContext());
+  EXPECT_EQ(receiver_context, object->GetCreationContext().ToLocalChecked());
+  EXPECT_EQ(prototype_context,
+            prototype->GetCreationContext().ToLocalChecked());
 
   EXPECT_EQ(0, call_count);
   object->Get(caller_context, property_key).ToLocalChecked();