Heap profiler should report implicit references

src/profile-generator.cc

Index: src/profile-generator.cc
===================================================================
--- src/profile-generator.cc	(revision 10596)
+++ src/profile-generator.cc	(working copy)
@@ -2782,6 +2782,27 @@
   embedder_queried_ = true;
 }
 
+void NativeObjectsExplorer::FillImplicitReferences() {
+  Isolate* isolate = Isolate::Current();
+  List<ImplicitRefGroup*>* groups =
+      isolate->global_handles()->implicit_ref_groups();
+  for (int i = 0; i < groups->length(); ++i) {
+    ImplicitRefGroup* group = groups->at(i);
+    HeapObject* parent = *group->parent_;
+    HeapEntry* parent_entry = filler_->FindOrAddEntry(parent, this);
+    ASSERT(parent_entry != NULL);
+    Object*** children = group->children_;
+    for (size_t j = 0; j < group->length_; ++j) {
+      Object* child = *children[j];
+      HeapEntry* child_entry = filler_->FindOrAddEntry(child, this);
+      filler_->SetNamedReference(
+          HeapGraphEdge::kInternal,
+          parent, parent_entry,
+          "native",

[mnaganov (inactive), 2012/02/03 13:57:19]

Does this look descriptive enough? If implicit refs are only for event handlers,
perhaps we can call this more specific?

[yurys, 2012/02/03 14:09:26]

For now it seems good enough. We cannot assume that all implicit references on
all embedders will always be for event handlers only even if it is so in
Chromium at the moment. We would like to extend information about such
references with e.g. event names and probably something else but for now just
having a strong reference reflected in the heap snapshot is enough.

+          child, child_entry);
+    }
+  }
+}
 
 List<HeapObject*>* NativeObjectsExplorer::GetListMaybeDisposeInfo(
     v8::RetainedObjectInfo* info) {
@@ -2798,9 +2819,13 @@
 
 bool NativeObjectsExplorer::IterateAndExtractReferences(
     SnapshotFillerInterface* filler) {
-  if (EstimateObjectsCount() <= 0) return true;
   filler_ = filler;
   FillRetainedObjects();
+  FillImplicitReferences();
+  if (EstimateObjectsCount() <= 0) {

[mnaganov (inactive), 2012/02/03 13:57:19]

Let's rewrite this as follows to avoid cleanup code duplication:

if (EstimateObjectsCount() > 0) {
  for(...) {
  }
  SetRootNative...
}
filler_ = NULL;
return true;

[yurys, 2012/02/03 14:09:26]

Done.

+    filler_ = NULL;
+    return true;
+  }
   for (HashMap::Entry* p = objects_by_info_.Start();
        p != NULL;
        p = objects_by_info_.Next(p)) {