Keep track of array buffers in new space separately

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/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 3088 matching lines @@
   if (object->NeedsToEnsureDoubleAlignment()) {
     allocation = old_space->AllocateRawDoubleAligned(object_size);
   } else {
     allocation = old_space->AllocateRaw(object_size);
   }
 #else
   allocation = old_space->AllocateRaw(object_size);
 #endif
   if (allocation.To(&target)) {
     MigrateObject(target, object, object_size, old_space->identity());
+    if (target->IsJSArrayBuffer()) {
+      heap()->PromoteArrayBuffer(JSArrayBuffer::cast(target));

[Hannes Payer (out of office), 2015/05/08 13:39:29]

Please don't add any JS type specific functionality to this function.

You could iterate over the map after evacuation and see what got promoted.

+    }
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
 
   return false;
 }
 
 
 bool MarkCompactCollector::IsSlotInBlackObject(Page* p, Address slot,
                                                HeapObject** out_object) {
@@ skipping 1286 matching lines @@
 void MarkCompactCollector::SweepSpaces() {
   GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_SWEEP);
   double start_time = 0.0;
   if (FLAG_print_cumulative_gc_stat) {
     start_time = base::OS::TimeCurrentMillis();
   }
 
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
-  heap()->FreeDeadArrayBuffers();
+  // MarkCompact will always also evacuate the new space.
+  heap()->FreeDeadArrayBuffers(true);
+  heap()->FreeDeadArrayBuffers(false);
 
   MoveEvacuationCandidatesToEndOfPagesList();
 
   // Noncompacting collections simply sweep the spaces to clear the mark
   // bits and free the nonlive blocks (for old and map spaces).  We sweep
   // the map space last because freeing non-live maps overwrites them and
   // the other spaces rely on possibly non-live maps to get the sizes for
   // non-live objects.
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
@@ skipping 331 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal