Line data    Source code

       1             : // Copyright 2015 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_HEAP_SCAVENGER_INL_H_
       6             : #define V8_HEAP_SCAVENGER_INL_H_
       7             : 
       8             : #include "src/heap/scavenger.h"
       9             : 
      10             : namespace v8 {
      11             : namespace internal {
      12             : 
      13   180678478 : void Scavenger::ScavengeObject(HeapObject** p, HeapObject* object) {
      14             :   DCHECK(object->GetIsolate()->heap()->InFromSpace(object));
      15             : 
      16             :   // We use the first word (where the map pointer usually is) of a heap
      17             :   // object to record the forwarding pointer.  A forwarding pointer can
      18             :   // point to an old space, the code space, or the to space of the new
      19             :   // generation.
      20             :   MapWord first_word = object->map_word();
      21             : 
      22             :   // If the first word is a forwarding address, the object has already been
      23             :   // copied.
      24   180678478 :   if (first_word.IsForwardingAddress()) {
      25    64035658 :     HeapObject* dest = first_word.ToForwardingAddress();
      26             :     DCHECK(object->GetIsolate()->heap()->InFromSpace(*p));
      27    64035658 :     *p = dest;
      28    64035658 :     return;
      29             :   }
      30             : 
      31             :   object->GetHeap()->UpdateAllocationSite<Heap::kGlobal>(
      32   116642820 :       object, object->GetHeap()->global_pretenuring_feedback_);
      33             : 
      34             :   // AllocationMementos are unrooted and shouldn't survive a scavenge
      35             :   DCHECK(object->map() != object->GetHeap()->allocation_memento_map());
      36             :   // Call the slow part of scavenge object.
      37   116642820 :   return ScavengeObjectSlow(p, object);
      38             : }
      39             : 
      40    80860843 : SlotCallbackResult Scavenger::CheckAndScavengeObject(Heap* heap,
      41             :                                                      Address slot_address) {
      42             :   Object** slot = reinterpret_cast<Object**>(slot_address);
      43    80860843 :   Object* object = *slot;
      44    80860843 :   if (heap->InFromSpace(object)) {
      45             :     HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
      46             :     DCHECK(heap_object->IsHeapObject());
      47             : 
      48    79889024 :     ScavengeObject(reinterpret_cast<HeapObject**>(slot), heap_object);
      49             : 
      50    79889024 :     object = *slot;
      51             :     // If the object was in from space before and is after executing the
      52             :     // callback in to space, the object is still live.
      53             :     // Unfortunately, we do not know about the slot. It could be in a
      54             :     // just freed free space object.
      55    79889024 :     if (heap->InToSpace(object)) {
      56             :       return KEEP_SLOT;
      57             :     }
      58             :   }
      59             :   // Slots can point to "to" space if the slot has been recorded multiple
      60             :   // times in the remembered set. We remove the redundant slot now.
      61             :   return REMOVE_SLOT;
      62             : }
      63             : 
      64             : // static
      65   412217033 : void StaticScavengeVisitor::VisitPointer(Heap* heap, HeapObject* obj,
      66             :                                          Object** p) {
      67   412217033 :   Object* object = *p;
      68   824434066 :   if (!heap->InNewSpace(object)) return;
      69             :   Scavenger::ScavengeObject(reinterpret_cast<HeapObject**>(p),
      70    55845653 :                             reinterpret_cast<HeapObject*>(object));
      71             : }
      72             : 
      73             : }  // namespace internal
      74             : }  // namespace v8
      75             : 
      76             : #endif  // V8_HEAP_SCAVENGER_INL_H_