Use EmbedderHeapTracer instead of object grouping when trace_embedder_heap flag is set

src/heap/mark-compact.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/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 1943 matching lines @@
 // pointers.  After: the marking stack is empty and there are no overflowed
 // objects in the heap.
 void MarkCompactCollector::ProcessMarkingDeque() {
   EmptyMarkingDeque();
   while (marking_deque_.overflowed()) {
     RefillMarkingDeque();
     EmptyMarkingDeque();
   }
 }
 
-
 // Mark all objects reachable (transitively) from objects on the marking
 // stack including references only considered in the atomic marking pause.
 void MarkCompactCollector::ProcessEphemeralMarking(
     ObjectVisitor* visitor, bool only_process_harmony_weak_collections) {
   bool work_to_do = true;
   DCHECK(marking_deque_.IsEmpty() && !marking_deque_.overflowed());
   while (work_to_do) {
-    if (!only_process_harmony_weak_collections) {
+    if (heap()->UsingEmbedderHeapTracer()) {
+      heap()->embedder_heap_tracer()->TraceWrappableFrom(
+          reinterpret_cast<v8::Isolate*>(isolate()), wrappers_to_trace_);
+      wrappers_to_trace_.clear();
+    } else if (!only_process_harmony_weak_collections) {
       isolate()->global_handles()->IterateObjectGroups(
           visitor, &IsUnmarkedHeapObjectWithHeap);
       MarkImplicitRefGroups(&MarkCompactMarkingVisitor::MarkObject);
     }
     ProcessWeakCollections();
     work_to_do = !marking_deque_.IsEmpty();
     ProcessMarkingDeque();
   }
 }
 
-
 void MarkCompactCollector::ProcessTopOptimizedFrame(ObjectVisitor* visitor) {
   for (StackFrameIterator it(isolate(), isolate()->thread_local_top());
        !it.done(); it.Advance()) {
     if (it.frame()->type() == StackFrame::JAVA_SCRIPT) {
       return;
     }
     if (it.frame()->type() == StackFrame::OPTIMIZED) {
       Code* code = it.frame()->LookupCode();
       if (!code->CanDeoptAt(it.frame()->pc())) {
         Code::BodyDescriptor::IterateBody(code, visitor);
@@ skipping 134 matching lines @@
 
   {
     TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WEAK_CLOSURE);
 
     // The objects reachable from the roots are marked, yet unreachable
     // objects are unmarked.  Mark objects reachable due to host
     // application specific logic or through Harmony weak maps.
     {
       TRACE_GC(heap()->tracer(),
                GCTracer::Scope::MC_MARK_WEAK_CLOSURE_EPHEMERAL);
+      if (heap()->UsingEmbedderHeapTracer()) {

[Hannes Payer (out of office), 2016/04/07 20:38:31]

This piece of code and the code below need separate timer scopes.

[Marcel Hlopko, 2016/04/08 08:08:10]

Let's not make this method more complicated than it already is. We can do it
later if we'll need more precise numbers than what we have now.

+        heap()->embedder_heap_tracer()->TraceRoots(
+            reinterpret_cast<v8::Isolate*>(isolate()));
+      }
       ProcessEphemeralMarking(&root_visitor, false);
       ProcessMarkingDeque();
     }
 
     // The objects reachable from the roots, weak maps or object groups
     // are marked. Objects pointed to only by weak global handles cannot be
     // immediately reclaimed. Instead, we have to mark them as pending and mark
     // objects reachable from them.
     //
     // First we identify nonlive weak handles and mark them as pending
@@ skipping 16 matching lines @@
 
     // Repeat Harmony weak maps marking to mark unmarked objects reachable from
     // the weak roots we just marked as pending destruction.
     //
     // We only process harmony collections, as all object groups have been fully
     // processed and no weakly reachable node can discover new objects groups.
     {
       TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WEAK_CLOSURE_HARMONY);
       ProcessEphemeralMarking(&root_visitor, true);
       ProcessMarkingDeque();
+      if (heap()->UsingEmbedderHeapTracer()) {
+        heap()->embedder_heap_tracer()->ClearTracingMarks(
+            reinterpret_cast<v8::Isolate*>(isolate()));
+      }
     }
   }
 
   if (FLAG_print_cumulative_gc_stat) {
     heap_->tracer()->AddMarkingTime(heap_->MonotonicallyIncreasingTimeInMs() -
                                     start_time);
   }
   if (FLAG_track_gc_object_stats) {
     if (FLAG_trace_gc_object_stats) {
       heap()->object_stats_->TraceObjectStats();
@@ skipping 1622 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8