Ensure Isolate::GetEnteredOrMicrotaskContext returns a NativeContext

Unlike other v8::Context getter on v8::Isolate, the v8::Context returned
by GetEnteredOrMicrotaskContext may be non-NativeContext. However,
Blink implicitly assumes all v8::Context is backed by NativeContexts.

This CL updates GetEnteredOrMicrotaskContext() to check the resulting
Context is NativeContext, and updates callers of EnterMicrotaskContext
to use NativeContext.

Change-Id: Ifae528f4ce8feb067f4ad1a43330dc55f4a8ed79
Reviewed-on: https://chromium-review.googlesource.com/c/1301653Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57259}

src/api.cc

@@ -8011,6 +8011,7 @@ v8::Local<v8::Context> Isolate::GetEnteredOrMicrotaskContext() {
     last = isolate->handle_scope_implementer()->LastEnteredContext();
   }
   if (last.is_null()) return Local<Context>();
+  DCHECK(last->IsNativeContext());
   return Utils::ToLocal(i::Handle<i::Context>::cast(last));
 }
 

src/builtins/builtins-internal-gen.cc

@@ -761,13 +761,15 @@ void InternalBuiltinsAssembler::SetCurrentContext(TNode<Context> context) {
 }
 
 void InternalBuiltinsAssembler::EnterMicrotaskContext(
-    TNode<Context> microtask_context) {
+    TNode<Context> native_context) {
+  CSA_ASSERT(this, IsNativeContext(native_context));
+
   auto ref = ExternalReference::handle_scope_implementer_address(isolate());
   Node* const hsi = Load(MachineType::Pointer(), ExternalConstant(ref));
   StoreNoWriteBarrier(
       MachineType::PointerRepresentation(), hsi,
       IntPtrConstant(HandleScopeImplementerOffsets::kMicrotaskContext),
-      BitcastTaggedToWord(microtask_context));
+      BitcastTaggedToWord(native_context));
 
   // Load mirrored std::vector length from
   // HandleScopeImplementer::entered_contexts_count_
@@ -971,7 +973,7 @@ TF_BUILTIN(RunMicrotasks, InternalBuiltinsAssembler) {
         TNode<Context> native_context = LoadNativeContext(microtask_context);
 
         CSA_ASSERT(this, IsNativeContext(native_context));
-        EnterMicrotaskContext(microtask_context);
+        EnterMicrotaskContext(native_context);
         SetCurrentContext(native_context);
 
         TNode<JSReceiver> callable = LoadObjectField<JSReceiver>(
@@ -1016,7 +1018,7 @@ TF_BUILTIN(RunMicrotasks, InternalBuiltinsAssembler) {
             microtask, PromiseResolveThenableJobTask::kContextOffset);
         TNode<Context> native_context = LoadNativeContext(microtask_context);
         CSA_ASSERT(this, IsNativeContext(native_context));
-        EnterMicrotaskContext(microtask_context);
+        EnterMicrotaskContext(native_context);
         SetCurrentContext(native_context);
 
         Node* const promise_to_resolve = LoadObjectField(
@@ -1042,7 +1044,7 @@ TF_BUILTIN(RunMicrotasks, InternalBuiltinsAssembler) {
             microtask, PromiseReactionJobTask::kContextOffset);
         TNode<Context> native_context = LoadNativeContext(microtask_context);
         CSA_ASSERT(this, IsNativeContext(native_context));
-        EnterMicrotaskContext(microtask_context);
+        EnterMicrotaskContext(native_context);
         SetCurrentContext(native_context);
 
         Node* const argument =
@@ -1077,7 +1079,7 @@ TF_BUILTIN(RunMicrotasks, InternalBuiltinsAssembler) {
             microtask, PromiseReactionJobTask::kContextOffset);
         TNode<Context> native_context = LoadNativeContext(microtask_context);
         CSA_ASSERT(this, IsNativeContext(native_context));
-        EnterMicrotaskContext(microtask_context);
+        EnterMicrotaskContext(native_context);
         SetCurrentContext(native_context);
 
         Node* const argument =

test/cctest/test-api.cc

@@ -28929,3 +28929,34 @@ TEST(TestGetEmbeddedCodeRange) {
     CHECK_EQ(0, builtins_range.length_in_bytes);
   }
 }
+
+TEST(MicrotaskContextShouldBeNativeContext) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+
+  auto callback = [](const v8::FunctionCallbackInfo<v8::Value>& info) {
+    v8::Isolate* isolate = info.GetIsolate();
+    v8::HandleScope scope(isolate);
+    i::Handle<i::Context> context =
+        v8::Utils::OpenHandle(*isolate->GetEnteredOrMicrotaskContext());
+
+    CHECK(context->IsNativeContext());
+    info.GetReturnValue().SetUndefined();
+  };
+
+  Local<v8::FunctionTemplate> desc = v8::FunctionTemplate::New(isolate);
+  desc->InstanceTemplate()->SetCallAsFunctionHandler(callback);
+  Local<v8::Object> obj = desc->GetFunction(env.local())
+                              .ToLocalChecked()
+                              ->NewInstance(env.local())
+                              .ToLocalChecked();
+
+  CHECK(env->Global()->Set(env.local(), v8_str("callback"), obj).FromJust());
+  CompileRun(
+      "with({}){(async ()=>{"
+      "  await 42;"
+      "})().then(callback);}");
+
+  isolate->RunMicrotasks();
+}