[modules] Implement namespace imports.

src/runtime/runtime-object.cc

 // Copyright 2014 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/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 942 matching lines @@
   bool success;
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, o, key, &success, LookupIterator::OWN);
   if (!success) return isolate->heap()->exception();
   MAYBE_RETURN(
       JSReceiver::CreateDataProperty(&it, value, Object::THROW_ON_ERROR),
       isolate->heap()->exception());
   return *value;
 }
 
+RUNTIME_FUNCTION(Runtime_GetModuleNamespace) {

[adamk, 2016/10/04 18:26:53]

It occurs to me that maybe these runtime functions should be in a new
runtime-modules.cc file (no need to make that change in this CL).

[neis, 2016/10/05 08:18:41]

Yeah I was planning to do that eventually.

+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Smi, module_request, 0);

[adamk, 2016/10/04 18:26:53]

You can use CONVERT_SMI_ARG_CHECKED here to get an int directly.

[neis, 2016/10/05 08:18:42]

Done.

+  Handle<Module> module(isolate->context()->module());

[adamk, 2016/10/04 18:26:53]

Seems a little scary to depend on the current context; do you see us doing this
elsewhere in runtime code?

Still really confusing to me that module() walks the context chain...I guess
I'll send you a CL to change its name everywhere.

Is there any DCHECK we can put here to double-check that this runtime function
was called in the right context?

[neis, 2016/10/05 08:18:42]

I don't understand.  All the module runtime functions do this.

[adamk, 2016/10/05 17:21:54]

Sorry, you're right. Like I said, I need to rename that function so I understand
it better :)

+  return *Module::GetModuleNamespace(module, module_request->value());
+}
+
 RUNTIME_FUNCTION(Runtime_LoadModuleExport) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
   Handle<Module> module(isolate->context()->module());
   return *Module::LoadExport(module, name);
 }
 
 RUNTIME_FUNCTION(Runtime_LoadModuleImport) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
   CONVERT_ARG_HANDLE_CHECKED(Smi, module_request, 1);
   Handle<Module> module(isolate->context()->module());
   return *Module::LoadImport(module, name, module_request->value());
 }
 
 RUNTIME_FUNCTION(Runtime_StoreModuleExport) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(String, name, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
   Handle<Module> module(isolate->context()->module());
   Module::StoreExport(module, name, value);
   return isolate->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8