[generators] Make runtime functions more robust.

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/debug/debug.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(function->shared()->is_resumable());
 
   Handle<FixedArray> operand_stack;
-  if (FLAG_ignition && FLAG_ignition_generators) {
+  if (function->shared()->HasBytecodeArray()) {
+    // New-style generators.
     int size = function->shared()->bytecode_array()->register_count();
     operand_stack = isolate->factory()->NewFixedArray(size);
   } else {
-    DCHECK(!function->shared()->HasBytecodeArray());
+    // Old-style generators.
     operand_stack = handle(isolate->heap()->empty_fixed_array());
   }
 
   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);
@@ skipping 102 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_GeneratorGetSourcePosition) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
 
   if (!generator->is_suspended()) return isolate->heap()->undefined_value();
 
-  if (FLAG_ignition && FLAG_ignition_generators) UNIMPLEMENTED();
+  if (generator->function()->shared()->HasBytecodeArray()) UNIMPLEMENTED();
 
-  DCHECK(!generator->function()->shared()->HasBytecodeArray());
   Handle<Code> code(generator->function()->code(), isolate);
   int offset = generator->continuation();
   CHECK(0 <= offset && offset < code->instruction_size());
   return Smi::FromInt(code->SourcePosition(offset));
 }
 
 }  // namespace internal
 }  // namespace v8