Speed up debug mode GC.

src/mark-compact.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 47 matching lines @@
 MarkCompactCollector::MarkCompactCollector() :  // NOLINT
 #ifdef DEBUG
       state_(IDLE),
 #endif
       sweep_precisely_(false),
       compacting_(false),
       was_marked_incrementally_(false),
       collect_maps_(FLAG_collect_maps),
       tracer_(NULL),
       migration_slots_buffer_(NULL),
-#ifdef DEBUG
-      live_young_objects_size_(0),
-      live_old_pointer_objects_size_(0),
-      live_old_data_objects_size_(0),
-      live_code_objects_size_(0),
-      live_map_objects_size_(0),
-      live_cell_objects_size_(0),
-      live_lo_objects_size_(0),
-      live_bytes_(0),
-#endif
       heap_(NULL),
       code_flusher_(NULL),
       encountered_weak_maps_(NULL) { }
 
 
 #ifdef DEBUG
 class VerifyMarkingVisitor: public ObjectVisitor {
  public:
   void VisitPointers(Object** start, Object** end) {
     for (Object** current = start; current < end; current++) {
@@ skipping 428 matching lines @@
   }
 
   PagedSpaces spaces;
   for (PagedSpace* space = spaces.next();
        space != NULL;
        space = spaces.next()) {
     space->PrepareForMarkCompact();
   }
 
 #ifdef DEBUG
-  if (!was_marked_incrementally_) {
+  if (!was_marked_incrementally_ && FLAG_verify_heap) {
     VerifyMarkbitsAreClean();
   }
 #endif
-
-#ifdef DEBUG
-  live_bytes_ = 0;
-  live_young_objects_size_ = 0;
-  live_old_pointer_objects_size_ = 0;
-  live_old_data_objects_size_ = 0;
-  live_code_objects_size_ = 0;
-  live_map_objects_size_ = 0;
-  live_cell_objects_size_ = 0;
-  live_lo_objects_size_ = 0;
-#endif
 }
 
 
 void MarkCompactCollector::Finish() {
 #ifdef DEBUG
   ASSERT(state_ == SWEEP_SPACES || state_ == RELOCATE_OBJECTS);
   state_ = IDLE;
 #endif
   // The stub cache is not traversed during GC; clear the cache to
   // force lazy re-initialization of it. This must be done after the
@@ skipping 1618 matching lines @@
         }
       }
     }
     // Move to next element in the list.
     raw_context = context->get(Context::NEXT_CONTEXT_LINK);
   }
   ProcessMarkingDeque();
 }
 
 
-#ifdef DEBUG
-void MarkCompactCollector::UpdateLiveObjectCount(HeapObject* obj) {
-  live_bytes_ += obj->Size();
-  if (heap()->new_space()->Contains(obj)) {
-    live_young_objects_size_ += obj->Size();
-  } else if (heap()->map_space()->Contains(obj)) {
-    ASSERT(obj->IsMap());
-    live_map_objects_size_ += obj->Size();
-  } else if (heap()->cell_space()->Contains(obj)) {
-    ASSERT(obj->IsJSGlobalPropertyCell());
-    live_cell_objects_size_ += obj->Size();
-  } else if (heap()->old_pointer_space()->Contains(obj)) {
-    live_old_pointer_objects_size_ += obj->Size();
-  } else if (heap()->old_data_space()->Contains(obj)) {
-    live_old_data_objects_size_ += obj->Size();
-  } else if (heap()->code_space()->Contains(obj)) {
-    live_code_objects_size_ += obj->Size();
-  } else if (heap()->lo_space()->Contains(obj)) {
-    live_lo_objects_size_ += obj->Size();
-  } else {
-    UNREACHABLE();
-  }
-}
-#endif  // DEBUG
-
-
 void MarkCompactCollector::ReattachInitialMaps() {
   HeapObjectIterator map_iterator(heap()->map_space());
   for (HeapObject* obj = map_iterator.Next();
        obj != NULL;
        obj = map_iterator.Next()) {
     if (obj->IsFreeSpace()) continue;
     Map* map = Map::cast(obj);
 
     STATIC_ASSERT(LAST_TYPE == LAST_JS_RECEIVER_TYPE);
     if (map->instance_type() < FIRST_JS_RECEIVER_TYPE) continue;
@@ skipping 1427 matching lines @@
 
   { GCTracer::Scope gc_scope(tracer_, GCTracer::Scope::MC_SWEEP_NEWSPACE);
     EvacuateNewSpaceAndCandidates();
   }
 
   // ClearNonLiveTransitions depends on precise sweeping of map space to
   // detect whether unmarked map became dead in this collection or in one
   // of the previous ones.
   SweepSpace(heap()->map_space(), PRECISE);
 
-  ASSERT(live_map_objects_size_ <= heap()->map_space()->Size());
-
   // Deallocate unmarked objects and clear marked bits for marked objects.
   heap_->lo_space()->FreeUnmarkedObjects();
 }
 
 
 void MarkCompactCollector::EnableCodeFlushing(bool enable) {
   if (enable) {
     if (code_flusher_ != NULL) return;
     code_flusher_ = new CodeFlusher(heap()->isolate());
   } else {
@@ skipping 159 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal