Move RootIndexMap out of serializer file.

src/address-map.cc

Index: src/address-map.cc
diff --git a/src/address-map.cc b/src/address-map.cc
new file mode 100644
index 0000000000000000000000000000000000000000..681661af2978bbdcc78754a2f9e5a82e1dc9f46d
--- /dev/null
+++ b/src/address-map.cc
@@ -0,0 +1,38 @@
+// Copyright 2015 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/address-map.h"
+#include "src/heap/heap.h"
+#include "src/isolate.h"
+#include "src/objects-inl.h"
+
+namespace v8 {
+namespace internal {
+
+RootIndexMap::RootIndexMap(Isolate* isolate) {
+  map_ = isolate->root_index_map();
+  if (map_ != NULL) return;
+  map_ = new HashMap(HashMap::PointersMatch);
+  for (uint32_t i = 0; i < Heap::kStrongRootListLength; i++) {
+    Heap::RootListIndex root_index = static_cast<Heap::RootListIndex>(i);
+    Object* root = isolate->heap()->root(root_index);
+    // Omit root entries that can be written after initialization. They must
+    // not be referenced through the root list in the snapshot.
+    if (root->IsHeapObject() &&
+        isolate->heap()->RootCanBeTreatedAsConstant(root_index)) {
+      HeapObject* heap_object = HeapObject::cast(root);
+      HashMap::Entry* entry = LookupEntry(map_, heap_object, false);
+      if (entry != NULL) {
+        // Some are initialized to a previous value in the root list.
+        DCHECK_LT(GetValue(entry), i);
+      } else {
+        SetValue(LookupEntry(map_, heap_object, true), i);
+      }
+    }
+  }
+  isolate->set_root_index_map(map_);
+}
+
+}  // namespace internal
+}  // namespace v8