[ESNext] Implement DynamicImportCall

src/runtime/runtime-module.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/counters.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 RUNTIME_FUNCTION(Runtime_DynamicImportCall) {
   HandleScope scope(isolate);
-  DCHECK_EQ(1, args.length());
-  // TODO(gsathya): Implement ImportCall.
-  return isolate->heap()->undefined_value();
+  DCHECK_EQ(2, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, specifier, 1);
+
+  Handle<JSPromise> promise = isolate->factory()->NewJSPromise();
+
+  Handle<String> specifier_str;
+  v8::TryCatch catcher(reinterpret_cast<v8::Isolate*>(isolate));
+  MaybeHandle<String> maybe_specifier = Object::ToString(isolate, specifier);
+  if (!maybe_specifier.ToHandle(&specifier_str)) {
+    DCHECK(catcher.HasCaught());
+    MaybeHandle<Object> reason = v8::Utils::OpenHandle(*catcher.Exception());
+    isolate->OptionalRescheduleException(true);
+
+    Handle<Object> argv[] = {promise, reason.ToHandleChecked(),
+                             isolate->factory()->ToBoolean(false)};
+
+    RETURN_FAILURE_ON_EXCEPTION(
+        isolate, Execution::Call(isolate, isolate->promise_internal_reject(),
+                                 isolate->factory()->undefined_value(),
+                                 arraysize(argv), argv))
+    return *promise;
+  }

[neis, 2017/03/17 10:36:32]

Please add DCHECK(!catcher.HasCaught()) here.

[gsathya, 2017/03/17 21:47:59]

Done.

+

[neis, 2017/03/17 10:36:32]

This comment is about the spec, not your implementation: I find it a little
surprising that ToString(specifier) is considered part of the promise
computation by making it reject the promise rather than just throw.

[gsathya, 2017/03/17 21:47:59]

Yeah, I found this weird too. 

+  Handle<String> source_url = isolate->factory()->empty_string();
+  Handle<Script> script(Script::cast(function->shared()->script()));
+  if (script->name()->IsString()) {
+    source_url = handle(String::cast(script->name()), isolate);
+  }
+

[neis, 2017/03/17 10:36:32]

Do we understand in which situations the name is not a string?

[gsathya, 2017/03/17 21:48:00]

I had this because I thought the D8 shell didn't pass a value for this. But it
seems to pass "(d8)" on double checking. 

Removed the check

+  isolate->RunHostImportModuleDynamicallyCallback(source_url, specifier_str,
+                                                  promise);
+  return *promise;
 }
 
 RUNTIME_FUNCTION(Runtime_GetModuleNamespace) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_SMI_ARG_CHECKED(module_request, 0);
   Handle<Module> module(isolate->context()->module());
   return *Module::GetModuleNamespace(module, module_request);
 }
 
@@ skipping 10 matching lines @@
   DCHECK_EQ(2, args.length());
   CONVERT_SMI_ARG_CHECKED(index, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
   Handle<Module> module(isolate->context()->module());
   Module::StoreVariable(module, index, value);
   return isolate->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8