1 /*
   2  * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 // An ImmutableSpace is a viewport into a contiguous range
  26 // (or subrange) of previously allocated objects.
  27 
  28 // Invariant: bottom() and end() are on page_size boundaries and
  29 // bottom() <= end()
  30 
  31 class ImmutableSpace: public CHeapObj {
  32   friend class VMStructs;
  33  protected:
  34   HeapWord* _bottom;
  35   HeapWord* _end;
  36 
  37  public:
  38   ImmutableSpace()                   { _bottom = NULL; _end = NULL;  }
  39   HeapWord* bottom() const           { return _bottom;               }
  40   HeapWord* end() const              { return _end;                  }
  41 
  42   MemRegion region() const { return MemRegion(bottom(), end()); }
  43 
  44   // Initialization
  45   void initialize(MemRegion mr);
  46 
  47   bool contains(const void* p) const { return _bottom <= p && p < _end; }
  48 
  49   // Size computations.  Sizes are in bytes.
  50   size_t capacity_in_bytes() const            { return capacity_in_words() * HeapWordSize; }
  51 
  52   // Size computations.  Sizes are in heapwords.
  53   size_t capacity_in_words() const                { return pointer_delta(end(), bottom()); }
  54   virtual size_t capacity_in_words(Thread*) const { return capacity_in_words(); }
  55 
  56   // Iteration.
  57   virtual void oop_iterate(OopClosure* cl);
  58   virtual void object_iterate(ObjectClosure* cl);
  59 
  60   // Debugging
  61   virtual void print() const            PRODUCT_RETURN;
  62   virtual void print_short() const      PRODUCT_RETURN;
  63   virtual void verify(bool allow_dirty);
  64 };