stackChunk.hpp

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/* Copyright 1994, 1995, 1996 LongView Technologies L.L.C. $Revision: 1.6 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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// The StackChunkBuilder helps generate the canonical form
// of vframes.
// Used for: 
//  - stack deoptimization.
//  - save stacks in heap.

class StackChunkBuilder: public ResourceObj {
 private:
  // These numbers makes it possible to compute the
  // size of the corresponding deoptimized interpreter stack.
  int number_of_vframes;    // Number of vframes collected
  int number_of_locals;     // Sum of all temporaries and expressions in colleced vframes
  static int* frame_pointer;// Frame pointer of the resulting frame

  static int header_size() { return 2; }
  static bool _is_deoptimizing;

  GrowableArray<oop>* array;
 public:
  // Constructor
  StackChunkBuilder(int* fp, int size = 100);
  ~StackChunkBuilder();

  // Adds a frame
  void append(deltaVFrame* f);

  // Returns the packed frames as an object array.
  objArrayOop as_objArray();

  // Constants for the resulting object array
  enum {
    number_of_vframes_index = 1,
    number_of_locals_index  = 2,
    first_frame_index       = 3
  };

  static void begin_deoptimization();
  static void end_deoptimization();

  static bool is_deoptimizing() { return _is_deoptimizing; }

  // The context cache
  static void       context_at_put(const compiledVFrame* frame, contextOop con);
  static contextOop context_at(const compiledVFrame* frame);
};

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