text: /*
   * Copyright (C) 2017 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(B3_JIT)
  
  #include "PureNaN.h"
  #include <climits>
  #include <wtf/BubbleSort.h>
  #include <wtf/Insertion.h>
  #include <wtf/Vector.h>
  
  namespace JSC { namespace B3 {
  
  class InsertionSet;
  
  template<typename BasicBlock>
  class GenericBlockInsertionSet {
  public:
      typedef WTF::Insertion<std::unique_ptr<BasicBlock>> BlockInsertion;
      
      GenericBlockInsertionSet(Vector<std::unique_ptr<BasicBlock>>& blocks)
          : m_blocks(blocks)
      {
      }
      
      void insert(BlockInsertion&& insertion)
      {
          m_insertions.append(WTFMove(insertion));
      }
  
      // Insert a new block at a given index.
      BasicBlock* insert(unsigned index, double frequency = PNaN)
      {
          std::unique_ptr<BasicBlock> block(new BasicBlock(BasicBlock::uninsertedIndex, frequency));
          BasicBlock* result = block.get();
          insert(BlockInsertion(index, WTFMove(block)));
          return result;
      }
  
      // Inserts a new block before the given block. Usually you will not pass the frequency
      // argument. Passing PNaN causes us to just use the frequency of the 'before' block. That's
      // usually what you want.
      BasicBlock* insertBefore(BasicBlock* before, double frequency = PNaN)
      {
          return insert(before->index(), frequency == frequency ? frequency : before->frequency());
      }
  
      // Inserts a new block after the given block.
      BasicBlock* insertAfter(BasicBlock* after, double frequency = PNaN)
      {
          return insert(after->index() + 1, frequency == frequency ? frequency : after->frequency());
      }
  
      bool execute()
      {
          if (m_insertions.isEmpty())
              return false;
          
          // We allow insertions to be given to us in any order. So, we need to sort them before
          // running WTF::executeInsertions. We strongly prefer a stable sort and we want it to be
          // fast, so we use bubble sort.
          bubbleSort(m_insertions.begin(), m_insertions.end());
          
          executeInsertions(m_blocks, m_insertions);
          
          // Prune out empty entries. This isn't strictly necessary but it's
          // healthy to keep the block list from growing.
          m_blocks.removeAllMatching(
              [&] (std::unique_ptr<BasicBlock>& blockPtr) -> bool {
                  return !blockPtr;
              });
          
          // Make sure that the blocks know their new indices.
          for (unsigned i = 0; i < m_blocks.size(); ++i)
              m_blocks[i]->m_index = i;
          
          return true;
      }
  
  private:
      Vector<std::unique_ptr<BasicBlock>>& m_blocks;
      Vector<BlockInsertion, 8> m_insertions;
  };
  
  } } // namespace JSC::B3
  
  #endif // ENABLE(B3_JIT)
  