Merge SetObjectNames extra pass into the main pass.

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 1657 matching lines @@
     SharedFunctionInfo* shared = func->shared();
     const char* name = shared->bound() ? "native_bind" :
         collection_->names()->GetName(String::cast(shared->name()));
     return AddEntry(object, HeapEntry::kClosure, name);
   } else if (object->IsJSRegExp()) {
     JSRegExp* re = JSRegExp::cast(object);
     return AddEntry(object,
                     HeapEntry::kRegExp,
                     collection_->names()->GetName(re->Pattern()));
   } else if (object->IsJSObject()) {
-    return AddEntry(object, HeapEntry::kObject, "");
+    const char* name = collection_->names()->GetName(
+        GetConstructorName(JSObject::cast(object)));
+    if (object->IsJSGlobalObject()) {
+      const char* tag = objects_tags_.GetTag(object);

[yurys, 2012/05/10 12:13:52]

How can we be sure that the object has already been tagged at this point?

[mnaganov (inactive), 2012/05/10 12:15:56]

Global objects tagging is always done before snapshot taking, because it can
modify the heap state. Perhaps, add a comment about this?

[yurys, 2012/05/10 12:23:31]

I think a comment would be helpful here. Also what about non-global objects, do
we care about their tags?

[alexeif, 2012/05/10 13:40:24]

Yep, looks like non-global objects, i.e. arrays those names are setup near line
1713 may miss their tags. This happens if the array is processed before its
retainer. It needs to be fixed. Btw it is not related to this patch, which is
about setting JSGlobalObject tags only.

+      if (tag != NULL) {
+        name = collection_->names()->GetFormatted("%s / %s", name, tag);
+      }
+    }
+    return AddEntry(object, HeapEntry::kObject, name);
   } else if (object->IsString()) {
     return AddEntry(object,
                     HeapEntry::kString,
                     collection_->names()->GetName(String::cast(object)));
   } else if (object->IsCode()) {
     return AddEntry(object, HeapEntry::kCode, "");
   } else if (object->IsSharedFunctionInfo()) {
     String* name = String::cast(SharedFunctionInfo::cast(object)->name());
     return AddEntry(object,
                     HeapEntry::kCode,
@@ skipping 700 matching lines @@
   RootsReferencesExtractor extractor;
   heap_->IterateRoots(&extractor, VISIT_ONLY_STRONG);
   extractor.SetCollectingAllReferences();
   heap_->IterateRoots(&extractor, VISIT_ALL);
   extractor.FillReferences(this);
   filler_ = NULL;
   return progress_->ProgressReport(true);
 }
 
 
-bool V8HeapExplorer::IterateAndSetObjectNames(SnapshotFillerInterface* filler) {
-  HeapIterator iterator(HeapIterator::kFilterUnreachable);
-  filler_ = filler;
-  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
-    SetObjectName(obj);
-  }
-  return true;
-}
-
-
-void V8HeapExplorer::SetObjectName(HeapObject* object) {
-  if (!object->IsJSObject() || object->IsJSRegExp() || object->IsJSFunction()) {
-    return;
-  }
-  const char* name = collection_->names()->GetName(
-      GetConstructorName(JSObject::cast(object)));
-  if (object->IsJSGlobalObject()) {
-    const char* tag = objects_tags_.GetTag(object);
-    if (tag != NULL) {
-      name = collection_->names()->GetFormatted("%s / %s", name, tag);
-    }
-  }
-  GetEntry(object)->set_name(name);
-}
-
-
 bool V8HeapExplorer::IsEssentialObject(Object* object) {
   // We have to use raw_unchecked_* versions because checked versions
   // would fail during iteration over object properties.
   return object->IsHeapObject()
       && !object->IsOddball()
       && object != heap_->raw_unchecked_empty_byte_array()
       && object != heap_->raw_unchecked_empty_fixed_array()
       && object != heap_->raw_unchecked_empty_descriptor_array()
       && object != heap_->raw_unchecked_fixed_array_map()
       && object != heap_->raw_unchecked_global_property_cell_map()
@@ skipping 660 matching lines @@
   // stable. It should follow TagGlobalObjects as that can allocate.
   AssertNoAllocation no_alloc;
 
 #ifdef DEBUG
   debug_heap->Verify();
 #endif
 
   SetProgressTotal(1);  // 1 pass.
 
 #ifdef DEBUG
   debug_heap->Verify();

[yurys, 2012/05/10 12:13:52]

We can remove this second verification.

 #endif
 
   if (!FillReferences()) return false;
 
   snapshot_->FillChildrenAndRetainers();
   snapshot_->RememberLastJSObjectId();
 
   if (!SetEntriesDominators()) return false;
   if (!CalculateRetainedSizes()) return false;
 
@@ skipping 26 matching lines @@
   progress_total_ = iterations_count * (
       v8_heap_explorer_.EstimateObjectsCount(&iterator) +
       dom_explorer_.EstimateObjectsCount());
   progress_counter_ = 0;
 }
 
 
 bool HeapSnapshotGenerator::FillReferences() {
   SnapshotFiller filler(snapshot_, &entries_);
   v8_heap_explorer_.AddRootEntries(&filler);
-  // IterateAndExtractReferences cannot set object names because
-  // it makes call to JSObject::LocalLookupRealNamedProperty which
-  // in turn may relocate objects in property maps thus changing the heap
-  // layout and affecting retainer counts. This is not acceptable because
-  // number of retainers must not change between count and fill passes.
-  // To avoid this there's a separate postpass that set object names.
   return v8_heap_explorer_.IterateAndExtractReferences(&filler)
-      && dom_explorer_.IterateAndExtractReferences(&filler)
-      && v8_heap_explorer_.IterateAndSetObjectNames(&filler);
+      && dom_explorer_.IterateAndExtractReferences(&filler);
 }
 
 
 bool HeapSnapshotGenerator::IsUserGlobalReference(const HeapGraphEdge* edge) {
   ASSERT(edge->from() == snapshot_->root());
   return edge->type() == HeapGraphEdge::kShortcut;
 }
 
 
 void HeapSnapshotGenerator::MarkUserReachableObjects() {
@@ skipping 607 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