HeapProfiler: very slow ~4min "take snapshot time" for 80MB gmail heap.

test/cctest/test-heap-profiler.cc

 // Copyright 2011 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 386 matching lines @@
   const v8::HeapSnapshot* snapshot =
       heap_profiler->TakeHeapSnapshot(v8_str("strings"));
   CHECK(ValidateSnapshot(snapshot));
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   const v8::HeapGraphNode* parent_string =
       GetProperty(global, v8::HeapGraphEdge::kProperty, "parent_string");
   CHECK_NE(NULL, parent_string);
   const v8::HeapGraphNode* child_string =
       GetProperty(global, v8::HeapGraphEdge::kProperty, "child_string");
   CHECK_NE(NULL, child_string);
+  CHECK_EQ(v8::HeapGraphNode::kSlicedString, child_string->GetType());
   const v8::HeapGraphNode* parent =
       GetProperty(child_string, v8::HeapGraphEdge::kInternal, "parent");
   CHECK_EQ(parent_string, parent);
+  heap_profiler->DeleteAllHeapSnapshots();
 }
 
 
+TEST(HeapSnapshotConsString) {
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::ObjectTemplate> global_template = v8::ObjectTemplate::New();
+  global_template->SetInternalFieldCount(1);
+  LocalContext env(NULL, global_template);
+  v8::Handle<v8::Object> global_proxy = env->Global();
+  v8::Handle<v8::Object> global = global_proxy->GetPrototype().As<v8::Object>();
+  CHECK_EQ(1, global->InternalFieldCount());
+
+  i::Factory* factory = i::Isolate::Current()->factory();
+  i::Handle<i::String> first =
+      factory->NewStringFromAscii(i::CStrVector("0123456789"));
+  i::Handle<i::String> second =
+      factory->NewStringFromAscii(i::CStrVector("0123456789"));
+  i::Handle<i::String> cons_string = factory->NewConsString(first, second);
+
+  global->SetInternalField(0, v8::ToApiHandle<v8::String>(cons_string));
+
+  v8::HeapProfiler* heap_profiler = isolate->GetHeapProfiler();
+  const v8::HeapSnapshot* snapshot =
+      heap_profiler->TakeHeapSnapshot(v8_str("cons_strings"));
+  CHECK(ValidateSnapshot(snapshot));
+  const v8::HeapGraphNode* global_node = GetGlobalObject(snapshot);
+
+  const v8::HeapGraphNode* string_node =
+      GetProperty(global_node, v8::HeapGraphEdge::kInternal, "0");
+  CHECK_NE(NULL, string_node);
+  CHECK_EQ(v8::HeapGraphNode::kConsString, string_node->GetType());
+
+  const v8::HeapGraphNode* first_node =
+      GetProperty(string_node, v8::HeapGraphEdge::kInternal, "first");
+  CHECK_EQ(v8::HeapGraphNode::kString, first_node->GetType());
+
+  const v8::HeapGraphNode* second_node =
+      GetProperty(string_node, v8::HeapGraphEdge::kInternal, "second");
+  CHECK_EQ(v8::HeapGraphNode::kString, second_node->GetType());
+
+  heap_profiler->DeleteAllHeapSnapshots();
+}
+
+
+
 TEST(HeapSnapshotInternalReferences) {
   v8::Isolate* isolate = v8::Isolate::GetCurrent();
   v8::HandleScope scope(isolate);
   v8::Local<v8::ObjectTemplate> global_template = v8::ObjectTemplate::New();
   global_template->SetInternalFieldCount(2);
   LocalContext env(NULL, global_template);
   v8::Handle<v8::Object> global_proxy = env->Global();
   v8::Handle<v8::Object> global = global_proxy->GetPrototype().As<v8::Object>();
   CHECK_EQ(2, global->InternalFieldCount());
   v8::Local<v8::Object> obj = v8::Object::New();
@@ skipping 1530 matching lines @@
       heap_profiler->TakeHeapSnapshot(v8_str("snapshot"));
   CHECK(ValidateSnapshot(snapshot));
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   const v8::HeapGraphNode* foo_func =
       GetProperty(global, v8::HeapGraphEdge::kProperty, "foo");
   CHECK_NE(NULL, foo_func);
   const v8::HeapGraphNode* code =
       GetProperty(foo_func, v8::HeapGraphEdge::kInternal, "code");
   CHECK_NE(NULL, code);
 }