Fix inobject slack tracking for both subclassing and non-subclassing cases.

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 6143 matching lines @@
       Builtins::kCompileOptimizedConcurrent);
 }
 
 
 bool JSFunction::IsInOptimizationQueue() {
   return code() == GetIsolate()->builtins()->builtin(
       Builtins::kInOptimizationQueue);
 }
 
 
-bool JSFunction::IsInobjectSlackTrackingInProgress() {
-  return has_initial_map() &&
-         initial_map()->counter() >= Map::kSlackTrackingCounterEnd;
+void JSFunction::CompleteInobjectSlackTrackingIfActive() {
+  if (has_initial_map() && initial_map()->IsInobjectSlackTrackingInProgress()) {
+    initial_map()->CompleteInobjectSlackTracking();
+  }
 }
 
 
+bool Map::IsInobjectSlackTrackingInProgress() {
+  return counter() >= Map::kSlackTrackingCounterEnd;
+}
+
+
+void Map::InobjectSlackTrackingStep() {
+  if (!IsInobjectSlackTrackingInProgress()) return;
+  int counter = this->counter();
+  set_counter(counter - 1);
+  if (counter == kSlackTrackingCounterEnd) {
+    CompleteInobjectSlackTracking();
+  }
+}
+
+
 Code* JSFunction::code() {
   return Code::cast(
       Code::GetObjectFromEntryAddress(FIELD_ADDR(this, kCodeEntryOffset)));
 }
 
 
 void JSFunction::set_code(Code* value) {
   DCHECK(!GetHeap()->InNewSpace(value));
   Address entry = value->entry();
   WRITE_INTPTR_FIELD(this, kCodeEntryOffset, reinterpret_cast<intptr_t>(entry));
@@ skipping 1676 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_