Add flag to trace object groups

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 810 matching lines @@
   TRACE_EVENT0("v8", "V8.GCIncrementalMarkingFinalize");
 
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
       CallGCPrologueCallbacks(kGCTypeIncrementalMarking, kNoGCCallbackFlags);
+      if (FLAG_trace_object_groups) {

[ulan, 2016/03/09 14:37:49]

Let's move it in CallGCPrologueCallbacks and we need to check for GC type so
that we don't print groups for Scavenge GCs.

[Marcel Hlopko, 2016/03/09 17:20:23]

Done.

+        isolate_->global_handles()->PrintObjectGroups();
+      }
     }
   }
   incremental_marking()->FinalizeIncrementally();
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
@@ skipping 437 matching lines @@
       collector == MARK_COMPACTOR ? kGCTypeMarkSweepCompact : kGCTypeScavenge;
 
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
       CallGCPrologueCallbacks(gc_type, kNoGCCallbackFlags);
+      if (FLAG_trace_object_groups) {

[ulan, 2016/03/09 14:37:49]

See comment above.

[Marcel Hlopko, 2016/03/09 17:20:23]

Done.

+        isolate_->global_handles()->PrintObjectGroups();
+      }
     }
   }
 
   EnsureFromSpaceIsCommitted();
 
   int start_new_space_size = Heap::new_space()->SizeAsInt();
 
   if (IsHighSurvivalRate()) {
     // We speed up the incremental marker if it is running so that it
     // does not fall behind the rate of promotion, which would cause a
@@ skipping 5045 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8