[runtime] Ensure {JSGeneratorObject} is created for bytecode.

src/runtime/runtime-generator.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/factory.h"
 #include "src/frames-inl.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 RUNTIME_FUNCTION(Runtime_CreateJSGeneratorObject) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 1);
   CHECK(IsResumableFunction(function->shared()->kind()));
 
-  Handle<FixedArray> operand_stack;
-  if (function->shared()->HasBytecodeArray()) {
-    // New-style generators.
-    DCHECK(!function->shared()->HasBaselineCode());
-    int size = function->shared()->bytecode_array()->register_count();
-    operand_stack = isolate->factory()->NewFixedArray(size);
-  } else {
-    // Old-style generators.
-    DCHECK(function->shared()->HasBaselineCode());
-    operand_stack = isolate->factory()->empty_fixed_array();
-  }
+  // Underlying function needs to have bytecode available.
+  DCHECK(function->shared()->HasBytecodeArray());
+  DCHECK(!function->shared()->HasBaselineCode());
+  int size = function->shared()->bytecode_array()->register_count();
+  Handle<FixedArray> operand_stack = isolate->factory()->NewFixedArray(size);
 
   Handle<JSGeneratorObject> generator =
       isolate->factory()->NewJSGeneratorObject(function);
   generator->set_function(*function);
   generator->set_context(isolate->context());
   generator->set_receiver(*receiver);
   generator->set_operand_stack(*operand_stack);
   generator->set_continuation(JSGeneratorObject::kGeneratorExecuting);
   return *generator;
 }
@@ skipping 52 matching lines @@
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
 
   if (!generator->is_suspended()) return isolate->heap()->undefined_value();
   return Smi::FromInt(generator->source_position());
 }
 
 }  // namespace internal
 }  // namespace v8