lithium-gap-resolver-arm.h

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// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_
#define V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_
 
#include "src/v8.h"
 
#include "src/lithium.h"
 
namespace v8 {
namespace internal {
 
class LCodeGen;
class LGapResolver;
 
class LGapResolver FINAL BASE_EMBEDDED {
 public:
  explicit LGapResolver(LCodeGen* owner);
 
  // Resolve a set of parallel moves, emitting assembler instructions.
  void Resolve(LParallelMove* parallel_move);
 
 private:
  // Build the initial list of moves.
  void BuildInitialMoveList(LParallelMove* parallel_move);
 
  // Perform the move at the moves_ index in question (possibly requiring
  // other moves to satisfy dependencies).
  void PerformMove(int index);
 
  // If a cycle is found in the series of moves, save the blocking value to
  // a scratch register.  The cycle must be found by hitting the root of the
  // depth-first search.
  void BreakCycle(int index);
 
  // After a cycle has been resolved, restore the value from the scratch
  // register to its proper destination.
  void RestoreValue();
 
  // Emit a move and remove it from the move graph.
  void EmitMove(int index);
 
  // Verify the move list before performing moves.
  void Verify();
 
  LCodeGen* cgen_;
 
  // List of moves not yet resolved.
  ZoneList<LMoveOperands> moves_;
 
  int root_index_;
  bool in_cycle_;
  LOperand* saved_destination_;
 
  // We use the root register as a scratch in a few places. When that happens,
  // this flag is set to indicate that it needs to be restored.
  bool need_to_restore_root_;
};
 
} }  // namespace v8::internal
 
#endif  // V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_