[heap] User safer root set accessor when possible.

src/objects-debug.cc

 // 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.
 
 #include "src/objects.h"
 
 #include "src/bootstrapper.h"
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/macro-assembler.h"
@@ skipping 1218 matching lines @@
   if (obj->IsCell()) {
     return CanLeak(Cell::cast(obj)->value(), heap, skip_weak_cell);
   }
   if (obj->IsPropertyCell()) {
     return CanLeak(PropertyCell::cast(obj)->value(), heap, skip_weak_cell);
   }
   if (obj->IsContext()) return true;
   if (obj->IsMap()) {
     Map* map = Map::cast(obj);
     for (int i = 0; i < Heap::kStrongRootListLength; i++) {
-      if (map == heap->roots_array_start()[i]) return false;
+      Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(i);
+      if (map == heap->root(root_index)) return false;
     }
     return true;
   }
   return CanLeak(HeapObject::cast(obj)->map(), heap, skip_weak_cell);
 }
 
 
 void Code::VerifyEmbeddedObjects(VerifyMode mode) {
   if (kind() == OPTIMIZED_FUNCTION) return;
   Heap* heap = GetIsolate()->heap();
@@ skipping 62 matching lines @@
 
   // Both are done at the same time.
   CHECK_EQ(new_it.done(), old_it.done());
 }
 
 
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8