DevTools: Drop kSinTable dependency off the heap profiler ArrayBuffer backing_store test

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 2371 matching lines @@
   const v8::HeapGraphNode* first_view =
       GetProperty(arr1_buffer, v8::HeapGraphEdge::kWeak, "weak_first_view");
   CHECK_NE(NULL, first_view);
   const v8::HeapGraphNode* backing_store =
       GetProperty(arr1_buffer, v8::HeapGraphEdge::kInternal, "backing_store");
   CHECK_NE(NULL, backing_store);
   CHECK_EQ(400, static_cast<int>(backing_store->GetShallowSize()));
 }
 
 
-static int GetRetainersCount(const v8::HeapSnapshot* snapshot,
-                             const v8::HeapGraphNode* node) {
-  int count = 0;
-  for (int i = 0, l = snapshot->GetNodesCount(); i < l; ++i) {
-    const v8::HeapGraphNode* parent = snapshot->GetNode(i);
-    for (int j = 0, l2 = parent->GetChildrenCount(); j < l2; ++j) {
-      if (parent->GetChild(j)->GetToNode() == node) {
-        ++count;
-      }
-    }
-  }
-  return count;
-}
+class ScopedArrayBufferContents {
+ public:
+  explicit ScopedArrayBufferContents(
+      const v8::ArrayBuffer::Contents& contents)
+    : contents_(contents) {}
+  ~ScopedArrayBufferContents() { free(contents_.Data()); }
+  void* Data() const { return contents_.Data(); }
+  size_t ByteLength() const { return contents_.ByteLength(); }
+ private:
+  const v8::ArrayBuffer::Contents contents_;
+};
 
 
 TEST(ArrayBufferSharedBackingStore) {
   LocalContext env;
-  v8::HandleScope scope(env->GetIsolate());
-  v8::HeapProfiler* heap_profiler = env->GetIsolate()->GetHeapProfiler();
-  CompileRun("sin1 = Math.sin(1);");
-  LocalContext env2;
-  CompileRun("sin2 = Math.sin(2);");
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::HeapProfiler* heap_profiler = isolate->GetHeapProfiler();
+
+  v8::Local<v8::ArrayBuffer> ab = v8::ArrayBuffer::New(isolate, 1024);
+  CHECK_EQ(1024, static_cast<int>(ab->ByteLength()));
+  CHECK(!ab->IsExternal());
+  ScopedArrayBufferContents ab_contents(ab->Externalize());
+  CHECK(ab->IsExternal());
+
+  CHECK_EQ(1024, static_cast<int>(ab_contents.ByteLength()));
+  uint8_t* data = static_cast<uint8_t*>(ab_contents.Data());

[Dmitry Lomov (no reviews), 2014/02/18 13:50:43]

Nit: why uint8_t and not void*? Saves you a cast.

[alph, 2014/02/18 15:56:30]

that was a copy-paste. fixed.

+  ASSERT(data != NULL);
+  v8::Local<v8::ArrayBuffer> ab2 =
+      v8::ArrayBuffer::New(isolate, data, ab_contents.ByteLength());
+  CHECK(ab2->IsExternal());
+  env->Global()->Set(v8_str("ab1"), ab);
+  env->Global()->Set(v8_str("ab2"), ab2);
+
+  v8::Handle<v8::Value> result = CompileRun("ab2.byteLength");
+  CHECK_EQ(1024, result->Int32Value());
+
   const v8::HeapSnapshot* snapshot =
       heap_profiler->TakeHeapSnapshot(v8_str("snapshot"));
   CHECK(ValidateSnapshot(snapshot));
-  // The 0th-child is (GC Roots), 1st is the user root.
-  const v8::HeapGraphNode* global =
-      snapshot->GetRoot()->GetChild(1)->GetToNode();
-  const v8::HeapGraphNode* builtins =
-      GetProperty(global, v8::HeapGraphEdge::kInternal, "builtins");
-  CHECK_NE(NULL, builtins);
-  const v8::HeapGraphNode* sin_table =
-      GetProperty(builtins, v8::HeapGraphEdge::kProperty, "kSinTable");
-  CHECK_NE(NULL, sin_table);
-  const v8::HeapGraphNode* buffer =
-      GetProperty(sin_table, v8::HeapGraphEdge::kInternal, "buffer");
-  CHECK_NE(NULL, buffer);
-  const v8::HeapGraphNode* backing_store =
-      GetProperty(buffer, v8::HeapGraphEdge::kInternal, "backing_store");
-  CHECK_NE(NULL, backing_store);
-  int retainers = GetRetainersCount(snapshot, backing_store);

[Dmitry Lomov (no reviews), 2014/02/18 13:50:43]

Looks like coverage for GetRetainersCount is gone?

[alph, 2014/02/18 15:56:30]

Thought it's redundant. Added back.

-  CHECK_EQ(2, retainers);
+  const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
+  const v8::HeapGraphNode* ab1_node =
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "ab1");
+  CHECK_NE(NULL, ab1_node);
+  const v8::HeapGraphNode* ab1_data =
+      GetProperty(ab1_node, v8::HeapGraphEdge::kInternal, "backing_store");
+  CHECK_NE(NULL, ab1_data);
+  const v8::HeapGraphNode* ab2_node =
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "ab2");
+  CHECK_NE(NULL, ab2_node);
+  const v8::HeapGraphNode* ab2_data =
+      GetProperty(ab2_node, v8::HeapGraphEdge::kInternal, "backing_store");
+  CHECK_NE(NULL, ab2_data);
+  CHECK_EQ(ab1_data, ab2_data);
 }
 
 
 TEST(BoxObject) {
   v8::Isolate* isolate = CcTest::isolate();
   v8::HandleScope scope(isolate);
   LocalContext env;
   v8::Handle<v8::Object> global_proxy = env->Global();
   v8::Handle<v8::Object> global = global_proxy->GetPrototype().As<v8::Object>();
 
@@ skipping 10 matching lines @@
   const v8::HeapGraphNode* global_node = GetGlobalObject(snapshot);
   const v8::HeapGraphNode* box_node =
       GetProperty(global_node, v8::HeapGraphEdge::kElement, "0");
   CHECK_NE(NULL, box_node);
   v8::String::Utf8Value box_node_name(box_node->GetName());
   CHECK_EQ("system / Box", *box_node_name);
   const v8::HeapGraphNode* box_value =
       GetProperty(box_node, v8::HeapGraphEdge::kInternal, "value");
   CHECK_NE(NULL, box_value);
 }