Don't record slots of objects that may contain raw values.

src/objects-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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 1455 matching lines @@
 Address HeapObject::address() {
   return reinterpret_cast<Address>(this) - kHeapObjectTag;
 }
 
 
 int HeapObject::Size() {
   return SizeFromMap(map());
 }
 
 
-bool HeapObject::MayContainNewSpacePointers() {
+bool HeapObject::MayContainRawValues() {
   InstanceType type = map()->instance_type();
   if (type <= LAST_NAME_TYPE) {
     if (type == SYMBOL_TYPE) {
-      return true;
+      return false;
     }
     DCHECK(type < FIRST_NONSTRING_TYPE);
     // There are four string representations: sequential strings, external
     // strings, cons strings, and sliced strings.
     // Only the latter two contain non-map-word pointers to heap objects.

[Michael Starzinger, 2014/09/09 10:00:08]

nit: s/the latter two contain non-map-word pointers to heap objects/the former
two contain raw values and no heap pointers (besides the map-word)/

[Hannes Payer (out of office), 2014/09/09 10:05:16]

Done.

-    return ((type & kIsIndirectStringMask) == kIsIndirectStringTag);
+    return ((type & kIsIndirectStringMask) != kIsIndirectStringTag);
   }
   // The ConstantPoolArray contains heap pointers, but not new space pointers.

[Michael Starzinger, 2014/09/09 10:00:08]

nit: s/but not new space pointers/but also raw values/

[Hannes Payer (out of office), 2014/09/09 10:05:16]

Done.

-  if (type == CONSTANT_POOL_ARRAY_TYPE) return false;
-  return (type > LAST_DATA_TYPE);
+  if (type == CONSTANT_POOL_ARRAY_TYPE) return true;
+  return (type <= LAST_DATA_TYPE);
 }
 
 
 void HeapObject::IteratePointers(ObjectVisitor* v, int start, int end) {
   v->VisitPointers(reinterpret_cast<Object**>(FIELD_ADDR(this, start)),
                    reinterpret_cast<Object**>(FIELD_ADDR(this, end)));
 }
 
 
 void HeapObject::IteratePointer(ObjectVisitor* v, int offset) {
@@ skipping 5746 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_