text: /*
   * Copyright (C) 2013-2015 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. 
   */
  
  #include "config.h"
  #include "DFGBasicBlock.h"
  
  #if ENABLE(DFG_JIT)
  
  #include "JSCJSValueInlines.h"
  
  namespace JSC { namespace DFG {
  
  DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(BasicBlock);
  
  BasicBlock::BasicBlock(BytecodeIndex bytecodeBegin, unsigned numArguments, unsigned numLocals, unsigned numTmps, float executionCount)
      : bytecodeBegin(bytecodeBegin)
      , index(NoBlock)
      , cfaStructureClobberStateAtHead(StructuresAreWatched)
      , cfaStructureClobberStateAtTail(StructuresAreWatched)
      , cfaBranchDirection(InvalidBranchDirection)
      , cfaHasVisited(false)
      , cfaShouldRevisit(false)
      , cfaDidFinish(true)
      , intersectionOfCFAHasVisited(true)
      , isOSRTarget(false)
      , isCatchEntrypoint(false)
  #if ASSERT_ENABLED
      , isLinked(false)
  #endif
      , isReachable(false)
      , variablesAtHead(numArguments, numLocals, numTmps)
      , variablesAtTail(numArguments, numLocals, numTmps)
      , valuesAtHead(numArguments, numLocals, numTmps)
      , valuesAtTail(numArguments, numLocals, numTmps)
      , intersectionOfPastValuesAtHead(numArguments, numLocals, numTmps, AbstractValue::fullTop())
      , executionCount(executionCount)
  {
  }
  
  BasicBlock::~BasicBlock()
  {
  }
  
  void BasicBlock::ensureLocals(unsigned newNumLocals)
  {
      variablesAtHead.ensureLocals(newNumLocals);
      variablesAtTail.ensureLocals(newNumLocals);
      valuesAtHead.ensureLocals(newNumLocals);
      valuesAtTail.ensureLocals(newNumLocals);
      intersectionOfPastValuesAtHead.ensureLocals(newNumLocals, AbstractValue::fullTop());
  }
  
  void BasicBlock::ensureTmps(unsigned newNumTmps)
  {
      variablesAtHead.ensureTmps(newNumTmps);
      variablesAtTail.ensureTmps(newNumTmps);
      valuesAtHead.ensureTmps(newNumTmps);
      valuesAtTail.ensureTmps(newNumTmps);
      intersectionOfPastValuesAtHead.ensureTmps(newNumTmps, AbstractValue::fullTop());
  }
  
  void BasicBlock::replaceTerminal(Graph& graph, Node* node)
  {
      NodeAndIndex result = findTerminal();
      if (!result)
          append(node);
      else {
          m_nodes.insert(result.index + 1, node);
          result.node->remove(graph);
      }
      
      ASSERT(terminal());
  }
  
  bool BasicBlock::isInPhis(Node* node) const
  {
      for (size_t i = 0; i < phis.size(); ++i) {
          if (phis[i] == node)
              return true;
      }
      return false;
  }
  
  bool BasicBlock::isInBlock(Node* myNode) const
  {
      for (size_t i = 0; i < numNodes(); ++i) {
          if (node(i) == myNode)
              return true;
      }
      return false;
  }
  
  void BasicBlock::removePredecessor(BasicBlock* block)
  {
      for (unsigned i = 0; i < predecessors.size(); ++i) {
          if (predecessors[i] != block)
              continue;
          predecessors[i] = predecessors.last();
          predecessors.removeLast();
          return;
      }
      RELEASE_ASSERT_NOT_REACHED();
  }
  
  void BasicBlock::replacePredecessor(BasicBlock* from, BasicBlock* to)
  {
      for (unsigned i = predecessors.size(); i--;) {
          if (predecessors[i] != from)
              continue;
          predecessors[i] = to;
          return;
      }
      RELEASE_ASSERT_NOT_REACHED();
  }
  
  void BasicBlock::dump(PrintStream& out) const
  {
      out.print("#", index);
  }
  
  BasicBlock::SSAData::SSAData(BasicBlock* block)
  {
      availabilityAtHead.m_locals = Operands<Availability>(OperandsLike, block->variablesAtHead);
      availabilityAtTail.m_locals = Operands<Availability>(OperandsLike, block->variablesAtHead);
  }
  
  BasicBlock::SSAData::~SSAData() { }
  
  } } // namespace JSC::DFG
  
  #endif // ENABLE(DFG_JIT)
  
  