Heap snapshot: Update user roots definition.

src/heap-snapshot-generator.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 943 matching lines @@
 };
 
 
 void V8HeapExplorer::ExtractReferences(HeapObject* obj) {
   HeapEntry* heap_entry = GetEntry(obj);
   if (heap_entry == NULL) return;  // No interest in this object.
   int entry = heap_entry->index();
 
   bool extract_indexed_refs = true;
   if (obj->IsJSGlobalProxy()) {
-    ExtractJSGlobalProxyReferences(JSGlobalProxy::cast(obj));
+    ExtractJSGlobalProxyReferences(entry, JSGlobalProxy::cast(obj));
   } else if (obj->IsJSObject()) {
     ExtractJSObjectReferences(entry, JSObject::cast(obj));
   } else if (obj->IsString()) {
     ExtractStringReferences(entry, String::cast(obj));
   } else if (obj->IsContext()) {
     ExtractContextReferences(entry, Context::cast(obj));
   } else if (obj->IsMap()) {
     ExtractMapReferences(entry, Map::cast(obj));
   } else if (obj->IsSharedFunctionInfo()) {
     ExtractSharedFunctionInfoReferences(entry, SharedFunctionInfo::cast(obj));
@@ skipping 14 matching lines @@
     extract_indexed_refs = false;
   }
   if (extract_indexed_refs) {
     SetInternalReference(obj, entry, "map", obj->map(), HeapObject::kMapOffset);
     IndexedReferencesExtractor refs_extractor(this, obj, entry);
     obj->Iterate(&refs_extractor);
   }
 }
 
 
-void V8HeapExplorer::ExtractJSGlobalProxyReferences(JSGlobalProxy* proxy) {
-  // We need to reference JS global objects from snapshot's root.
-  // We use JSGlobalProxy because this is what embedder (e.g. browser)
-  // uses for the global object.
-  Object* object = proxy->map()->prototype();
-  bool is_debug_object = false;
-#ifdef ENABLE_DEBUGGER_SUPPORT
-  is_debug_object = object->IsGlobalObject() &&
-      Isolate::Current()->debug()->IsDebugGlobal(GlobalObject::cast(object));
-#endif
-  if (!is_debug_object) {
-    SetUserGlobalReference(object);
-  }
+void V8HeapExplorer::ExtractJSGlobalProxyReferences(
+    int entry, JSGlobalProxy* proxy) {
+  SetInternalReference(proxy, entry,
+                       "native_context", proxy->native_context(),
+                       JSGlobalProxy::kNativeContextOffset);
 }
 
 
 void V8HeapExplorer::ExtractJSObjectReferences(
     int entry, JSObject* js_obj) {
   HeapObject* obj = js_obj;
   ExtractClosureReferences(js_obj, entry);
   ExtractPropertyReferences(js_obj, entry);
   ExtractElementReferences(js_obj, entry);
   ExtractInternalReferences(js_obj, entry);
@@ skipping 749 matching lines @@
           HeapGraphEdge::kInternal,
           snapshot_->gc_subroot(tag)->index(),
           name,
           child_entry);
     } else {
       filler_->SetIndexedAutoIndexReference(
           is_weak ? HeapGraphEdge::kWeak : HeapGraphEdge::kElement,
           snapshot_->gc_subroot(tag)->index(),
           child_entry);
     }
+
+    // Add a shortcut to JS global object reference at snapshot root.
+    if (child_obj->IsNativeContext()) {
+      Context* context = Context::cast(child_obj);
+      GlobalObject* global = context->global_object();
+      if (global->IsJSGlobalObject()) {
+        bool is_debug_object = false;
+#ifdef ENABLE_DEBUGGER_SUPPORT
+        is_debug_object = heap_->isolate()->debug()->IsDebugGlobal(global);
+#endif
+        if (!is_debug_object && !user_roots_.Contains(global)) {
+          user_roots_.Insert(global);
+          SetUserGlobalReference(global);
+        }
+      }
+    }
   }
 }
 
 
 const char* V8HeapExplorer::GetStrongGcSubrootName(Object* object) {
   if (strong_gc_subroot_names_.is_empty()) {
 #define NAME_ENTRY(name) strong_gc_subroot_names_.SetTag(heap_->name(), #name);
 #define ROOT_NAME(type, name, camel_name) NAME_ENTRY(name)
     STRONG_ROOT_LIST(ROOT_NAME)
 #undef ROOT_NAME
@@ skipping 895 matching lines @@
 
 
 void HeapSnapshotJSONSerializer::SortHashMap(
     HashMap* map, List<HashMap::Entry*>* sorted_entries) {
   for (HashMap::Entry* p = map->Start(); p != NULL; p = map->Next(p))
     sorted_entries->Add(p);
   sorted_entries->Sort(SortUsingEntryValue);
 }
 
 } }  // namespace v8::internal