[modules] Implement namespace imports.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index c7d333f0a534fc194c367304cbd8dafe99706248..76b97b9015b6eb4e8a55dcc2236d7e8a902368f7 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -674,6 +674,9 @@ void BytecodeGenerator::GenerateBytecodeBody() {
   // Visit declarations within the function scope.
   VisitDeclarations(scope()->declarations());
 
+  // Emit initializing assignments for module namespace imports (if any).
+  VisitModuleNamespaceImports();
+
   // Perform a stack-check before the body.
   builder()->StackCheck(info()->literal()->start_position());
 
@@ -873,6 +876,24 @@ void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
   }
 }
 
+void BytecodeGenerator::VisitModuleNamespaceImports() {
+  if (!scope()->is_module_scope()) return;
+
+  RegisterAllocationScope register_scope(this);
+  Register module_request = register_allocator()->NewRegister();
+
+  ModuleDescriptor* descriptor = scope()->AsModuleScope()->module();
+  for (auto entry : descriptor->namespace_imports()) {
+    builder()
+        ->LoadLiteral(Smi::FromInt(entry->module_request))
+        .StoreAccumulatorInRegister(module_request)
+        .CallRuntime(Runtime::kGetModuleNamespace, module_request);
+    Variable* var = scope()->LookupLocal(entry->local_name);
+    DCHECK_NOT_NULL(var);
+    VisitVariableAssignment(var, Token::INIT, FeedbackVectorSlot::Invalid());
+  }
+}
+
 void BytecodeGenerator::VisitDeclarations(
     ZoneList<Declaration*>* declarations) {
   RegisterAllocationScope register_scope(this);