text: /*
   * Copyright (C) 2013 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. 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 with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #pragma once
  
  #if ENABLE(DFG_JIT)
  
  #include "DFGAbstractHeap.h"
  #include <wtf/HashMap.h>
  #include <wtf/HashSet.h>
  #include <wtf/PrintStream.h>
  
  namespace JSC { namespace DFG {
  
  class Graph;
  struct Node;
  
  // FIXME: If we ever want to compare if two nodes clobber each other, we should
  // have a SmallClobberSet, which just keeps an array of the AbstractHeaps and
  // satisfies overlaps() requests by looping over all of them. This will probably
  // be faster than a full HashMap in a lot of cases. Or, maybe, we could have
  // ClobberSet be smart and use a vector so long as it was small.
  
  class ClobberSet {
  public:
      ClobberSet();
      ~ClobberSet();
      
      bool isEmpty() const { return m_clobbers.isEmpty(); }
      
      void add(AbstractHeap);
      void addAll(const ClobberSet&);
      bool overlaps(AbstractHeap) const;
      void clear();
      
      // Calls useful for debugging the ClobberSet.
      // Do not call for non debugging purpose. Otherwise, you must handle DOMState hierarchy carefully.
      
      HashSet<AbstractHeap> direct() const;
      HashSet<AbstractHeap> super() const;
      
      void dump(PrintStream&) const;
      
  private:
      bool contains(AbstractHeap) const;
  
      HashSet<AbstractHeap> setOf(bool direct) const;
      
      // Maps heap to:
      // true --> it's a direct clobber
      // false --> it's just a supertype of a direct clobber
      HashMap<AbstractHeap, bool> m_clobbers;
  };
  
  class ClobberSetAdd {
  public:
      ClobberSetAdd(ClobberSet& set)
          : m_set(set)
      {
      }
      
      void operator()(AbstractHeap heap) const
      {
          m_set.add(heap);
      }
  private:
      ClobberSet& m_set;
  };
  
  class ClobberSetOverlaps {
  public:
      ClobberSetOverlaps(const ClobberSet& set)
          : m_set(set)
          , m_result(false)
      {
      }
      
      void operator()(AbstractHeap heap) const
      {
          m_result |= m_set.overlaps(heap);
      }
      
      bool result() const { return m_result; }
      
  private:
      const ClobberSet& m_set;
      mutable bool m_result;
  };
  
  void addReads(Graph&, Node*, ClobberSet&);
  void addWrites(Graph&, Node*, ClobberSet&);
  void addReadsAndWrites(Graph&, Node*, ClobberSet& reads, ClobberSet& writes);
  
  bool readsOverlap(Graph&, Node*, ClobberSet&);
  bool writesOverlap(Graph&, Node*, ClobberSet&);
  
  } } // namespace JSC::DFG
  
  #endif // ENABLE(DFG_JIT)
  