Reland "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 3023 matching lines @@
                                             int object_size) {
   DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
 
   OldSpace* old_space = heap()->old_space();
 
   HeapObject* target;
   AllocationAlignment alignment = object->RequiredAlignment();
   AllocationResult allocation = old_space->AllocateRaw(object_size, alignment);
   if (allocation.To(&target)) {
     MigrateObject(target, object, object_size, old_space->identity());
+    // If we end up needing more special cases, we should factor this out.
+    if (V8_UNLIKELY(target->IsJSArrayBuffer())) {
+      heap()->PromoteArrayBuffer(target);
+    }
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
 
   return false;
 }
 
 
 bool MarkCompactCollector::IsSlotInBlackObject(Page* p, Address slot,
                                                HeapObject** out_object) {
@@ skipping 1306 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();
 
   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(),
                                 GCTracer::Scope::MC_SWEEP_OLDSPACE);
     { SweepSpace(heap()->old_space(), CONCURRENT_SWEEPING); }
     sweeping_in_progress_ = true;
     if (heap()->concurrent_sweeping_enabled()) {
       StartSweeperThreads();
     }
   }
   RemoveDeadInvalidatedCode();
 
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_CODE);
     SweepSpace(heap()->code_space(), SEQUENTIAL_SWEEPING);
   }
 
   EvacuateNewSpaceAndCandidates();
 
+  heap()->FreeDeadArrayBuffers(false);
+
   // ClearNonLiveReferences depends on precise sweeping of map space to
   // detect whether unmarked map became dead in this collection or in one
   // of the previous ones.
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_MAP);
     SweepSpace(heap()->map_space(), SEQUENTIAL_SWEEPING);
   }
 
   // Deallocate unmarked objects and clear marked bits for marked objects.
@@ skipping 315 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }  // namespace internal
 }  // namespace v8