[heap] don't flush async functions, they may be resumed later

src/heap/objects-visiting-inl.h

 // Copyright 2012 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.
 
 #ifndef V8_OBJECTS_VISITING_INL_H_
 #define V8_OBJECTS_VISITING_INL_H_
 
 #include "src/heap/array-buffer-tracker.h"
 #include "src/heap/objects-visiting.h"
 #include "src/ic/ic-state.h"
@@ skipping 629 matching lines @@
   // Only flush code for functions.
   if (shared_info->code()->kind() != Code::FUNCTION) {
     return false;
   }
 
   // Function must be lazy compilable.
   if (!shared_info->allows_lazy_compilation()) {
     return false;
   }
 
-  // We do not (yet?) flush code for generator functions, because we don't know
-  // if there are still live activations (generator objects) on the heap.
-  if (shared_info->is_generator()) {
+  // We do not (yet?) flush code for generator functions, or async functions,

[Hannes Payer (out of office), 2016/05/20 07:13:52]

How about a list of items enumerating what we don't flush with a reason next to
it?

[caitp (gmail), 2016/05/20 07:55:48]

isn't that what this routine is? thats how it looks to me. Reorganizing it might
be a job for someone else

[Hannes Payer (out of office), 2016/05/20 12:00:41]

Ah, async is based on generators. Then the comments makes sense.

+  // because we don't know if there are still live activations
+  // (generator objects) on the heap.
+  if (shared_info->is_resumable()) {
     return false;
   }
 
   // If this is a full script wrapped in a function we do not flush the code.
   if (shared_info->is_toplevel()) {
     return false;
   }
 
   // The function must not be a builtin.
   if (shared_info->IsBuiltin()) {
@@ skipping 68 matching lines @@
   typedef FlexibleBodyVisitor<StaticVisitor, JSFunction::BodyDescriptorWeakCode,
                               void> JSFunctionWeakCodeBodyVisitor;
   JSFunctionWeakCodeBodyVisitor::Visit(map, object);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_VISITING_INL_H_