I'd like to introduce kSynthetic type of nodes for Heap Profiler.

I will apply it to the nodes that can't be mapped to Heap object or Native object.
As example there are 'Detached DOM Tree' nodes in WebKit. It is very useful to be able to see all such
nodes grouped together. It can be done with help of some post processing but I did this explicitly
on v8 side because it is much faster. At the moment this kind of nodes has kNative type.
I'd like to hide these nodes from the Retainment View but I can filter them only by name.

BUG=none
TEST=HeapSnapshotRetainedObjectInfo

[mnaganov (inactive), 2012-02-06 12:22:59]

Following our VC dicsussion

https://chromiumcodereview.appspot.com/9323064/diff/1/include/v8-profiler.h
File include/v8-profiler.h (right):

https://chromiumcodereview.appspot.com/9323064/diff/1/include/v8-profiler.h#n...
include/v8-profiler.h:259: kArtificial = 9   // Artificial object, usualy used
for grouping
I'd rename this to kVirtual, as virtual is something that can be perceived, but
isn't physically exist.

And I'd remove too specific description and rephrase the comment like this:
"Virtual node, typically used for grouping other nodes together."

"Artificial node, introduced for grouping purposes

https://chromiumcodereview.appspot.com/9323064/diff/1/include/v8-profiler.h#n...
include/v8-profiler.h:259: kArtificial = 9   // Artificial object, usualy used
for grouping
Also, let's convert existing virtual nodes -- the global root, GC root and
subroots into this type. Better to be done as a separate CL.

https://chromiumcodereview.appspot.com/9323064/diff/1/include/v8-profiler.h#n...
include/v8-profiler.h:509: virtual HeapGraphNode::Type GetType() const { return
HeapGraphNode::kNative; }
I'm strongly against adding this method. It's only needed for your
implementation, and creates confusion. Please re-consider your implementation to
avoid it.

[mnaganov (inactive), 2012-02-06 15:37:22]

https://chromiumcodereview.appspot.com/9323064/diff/3001/include/v8-profiler.h
File include/v8-profiler.h (right):

https://chromiumcodereview.appspot.com/9323064/diff/3001/include/v8-profiler....
include/v8-profiler.h:259: kArtificial = 9   // Artificial object, usualy used
for grouping
Agreed offline to renamed this to kSynthetic. And please consider updating the
comment, or explain why do you want to leave it as is.

https://chromiumcodereview.appspot.com/9323064/diff/3001/src/profile-generato...
File src/profile-generator.cc (right):

https://chromiumcodereview.appspot.com/9323064/diff/3001/src/profile-generato...
src/profile-generator.cc:2703: class GenericEntriesAllocator : public
HeapEntriesAllocator {
This sounds more like "the allocator of generic entries", not like "generic
allocator" (perhaps, because it subclasses from HeapEntriesAllocator which is
"allocator of heap entries"). Maybe, rename to NativeEntriesAllocator?

https://chromiumcodereview.appspot.com/9323064/diff/3001/src/profile-generator.h
File src/profile-generator.h (right):

https://chromiumcodereview.appspot.com/9323064/diff/3001/src/profile-generato...
src/profile-generator.h:1078: HeapEntriesAllocator*
artificial_entries_allocator_;
I'm against manual dynamic object allocation unless it's really needed. Perhaps,
you can define the allocator class above and just encapsulate its instances?

[mnaganov (inactive), 2012-02-06 16:59:37]

lgtm