Show names for the strong roots in heap snapshot.

src/profile-generator.cc

 // Copyright 2012 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 1718 matching lines @@
         static_cast<intptr_t>(HeapObjectsMap::kFirstAvailableObjectId));
 
 
 V8HeapExplorer::V8HeapExplorer(
     HeapSnapshot* snapshot,
     SnapshottingProgressReportingInterface* progress)
     : heap_(Isolate::Current()->heap()),
       snapshot_(snapshot),
       collection_(snapshot_->collection()),
       progress_(progress),
-      filler_(NULL) {
+      filler_(NULL),
+      gc_subroot_names_(HeapEntriesMap::HeapThingsMatch) {
 }
 
 
 V8HeapExplorer::~V8HeapExplorer() {
 }
 
 
 HeapEntry* V8HeapExplorer::AllocateEntry(
     HeapThing ptr, int children_count, int retainers_count) {
   return AddEntry(
@@ skipping 896 matching lines @@
       HeapGraphEdge::kElement,
       kGcRootsObject, snapshot_->gc_roots(),
       GetNthGcSubrootObject(tag), snapshot_->gc_subroot(tag));
 }
 
 
 void V8HeapExplorer::SetGcSubrootReference(
     VisitorSynchronization::SyncTag tag, bool is_weak, Object* child_obj) {
   HeapEntry* child_entry = GetEntry(child_obj);
   if (child_entry != NULL) {
-    filler_->SetIndexedAutoIndexReference(
-        is_weak ? HeapGraphEdge::kWeak : HeapGraphEdge::kElement,
-        GetNthGcSubrootObject(tag), snapshot_->gc_subroot(tag),
-        child_obj, child_entry);
+    const char* name = GetGcSubrootName(child_obj);
+    if (name != NULL) {
+      filler_->SetNamedReference(
+          HeapGraphEdge::kInternal,
+          GetNthGcSubrootObject(tag), snapshot_->gc_subroot(tag),
+          name,
+          child_obj, child_entry);
+    } else {
+      filler_->SetIndexedAutoIndexReference(
+          is_weak ? HeapGraphEdge::kWeak : HeapGraphEdge::kElement,
+          GetNthGcSubrootObject(tag), snapshot_->gc_subroot(tag),
+          child_obj, child_entry);
+    }
   }
 }
 
 
+const char* V8HeapExplorer::GetGcSubrootName(Object* object) {
+  if (gc_subroot_names_.occupancy() == 0) {
+    HashMap::Entry* entry;
+    Object* obj;
+#define NAME_ENTRY(name) \
+    obj = heap_->name(); \
+    if (obj != NULL) { \
+      entry = gc_subroot_names_.Lookup(obj, HeapEntriesMap::Hash(obj), true); \
+      entry->value = const_cast<char*>(#name); \
+    }
+#define ROOT_NAME(type, name, camel_name) NAME_ENTRY(name)
+    STRONG_ROOT_LIST(ROOT_NAME)
+#undef ROOT_NAME
+#define STRUCT_MAP_NAME(NAME, Name, name) NAME_ENTRY(name##_map)
+    STRUCT_LIST(STRUCT_MAP_NAME)
+#undef STRUCT_MAP_NAME
+#define SYMBOL_NAME(name, str) NAME_ENTRY(name)
+    SYMBOL_LIST(SYMBOL_NAME)
+#undef SYMBOL_NAME
+#undef NAME_ENTRY
+    CHECK(gc_subroot_names_.occupancy() > 0);
+    CHECK(gc_subroot_names_.occupancy() <= Heap::kStrongRootListLength);
+  }
+  HashMap::Entry* entry = gc_subroot_names_.Lookup(
+      object, HeapEntriesMap::Hash(object), false);
+  return entry != NULL ? reinterpret_cast<const char*>(entry->value) : NULL;
+}
+
+
 void V8HeapExplorer::TagObject(Object* obj, const char* tag) {
   if (obj->IsHeapObject() &&
       !obj->IsOddball() &&
       obj != heap_->raw_unchecked_empty_byte_array() &&
       obj != heap_->raw_unchecked_empty_fixed_array() &&
       obj != heap_->raw_unchecked_empty_descriptor_array()) {
     objects_tags_.SetTag(obj, tag);
   }
 }
 
@@ skipping 1225 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