Force mark sweep if size of map space is to big to allow forward pointers enc...

src/spaces.h

 // Copyright 2006-2008 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 975 matching lines @@
   virtual HeapObject* AllocateInNextPage(Page* current_page,
                                          int size_in_bytes) = 0;
 
   // Slow path of AllocateRaw.  This function is space-dependent.
   virtual HeapObject* SlowAllocateRaw(int size_in_bytes) = 0;
 
   // Slow path of MCAllocateRaw.
   HeapObject* SlowMCAllocateRaw(int size_in_bytes);
 
 #ifdef DEBUG
+  // Returns the number of total pages in this space.
+  int CountTotalPages();
+
   void DoPrintRSet(const char* space_name);
 #endif
  private:
   // Returns the page of the allocation pointer.
   Page* AllocationTopPage() { return TopPageOf(allocation_info_); }
 
   // Returns a pointer to the page of the relocation pointer.
   Page* MCRelocationTopPage() { return TopPageOf(mc_forwarding_info_); }
 
-#ifdef DEBUG
-  // Returns the number of total pages in this space.
-  int CountTotalPages();
-#endif
-
   friend class PageIterator;
 };
 
 
 #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
 class NumberAndSizeInfo BASE_EMBEDDED {
  public:
   NumberAndSizeInfo() : number_(0), bytes_(0) {}
 
   int number() const { return number_; }
@@ skipping 713 matching lines @@
 
   // Prepares for a mark-compact GC.
   virtual void PrepareForMarkCompact(bool will_compact);
 
   // Given an index, returns the page address.
   Address PageAddress(int page_index) { return page_addresses_[page_index]; }
 
   // Constants.
   static const int kMaxMapPageIndex = (1 << MapWord::kMapPageIndexBits) - 1;
 
+  // Are map pointers encodable into map word?
+  bool MapPointersEncodable() {
+    if (!FLAG_use_big_map_space) {
+      ASSERT(CountTotalPages() <= kMaxMapPageIndex);
+      return true;
+    }
+    int n_of_pages = Capacity() / Page::kObjectAreaSize;
+    ASSERT(n_of_pages == CountTotalPages());
+    return n_of_pages <= kMaxMapPageIndex;
+  }
+
  protected:
 #ifdef DEBUG
   virtual void VerifyObject(HeapObject* obj);
 #endif
 
  private:
   // An array of page start address in a map space.
   Address page_addresses_[kMaxMapPageIndex + 1];
 
  public:
@@ skipping 193 matching lines @@
 
  private:
   LargeObjectChunk* current_;
   HeapObjectCallback size_func_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_