mapConformance.hpp

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/* Copyright 1996 LongView Technologies L.L.C. $Revision: 1.1 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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// Compiler/New Backend/Value Conformance
//
// Used by the new backed to make mappings conform before merging code pieces. 
//
// Usage:
//   MapConformance mp(1);
//   mp.append_mapping(...);
//   mp.generate();
//

// Variable is an abstraction describing a register or stack location
// Format as requested by Robert 9/6/96
// 30 bits signed offset
// 2  bits describes type

#ifdef DELTA_COMPILER

class Variable : ValueObj {
 private:
  int _value;

  enum {
   special_type = 0,
   reg_type     = 1,
   stack_type   = 2
  };

  int type()   const { return _value & 0x3; }
  int offset() const { return _value >> 2;  }
  int value()  const { return _value; }

  static Variable new_variable(int type, int offset) {
    Variable result;
    result._value = (offset << 2) | type;
    return result;
  }

 public:
  Variable() { _value = 0; }

  // Generators
  static Variable new_register(int offset) { return new_variable(reg_type,     offset); }
  static Variable new_stack(int offset)    { return new_variable(stack_type,   offset); }
  static Variable unused()                 { return new_variable(special_type, 0);      }
  static Variable top_of_stack()           { return new_variable(special_type, 1);      }

  // Testing
  bool in_register() const { return type() == reg_type;    }
  bool on_stack()    const { return type() == stack_type;  }

  bool is_unused()       const { return type() == special_type && offset() == 0; }
  bool is_top_of_stack() const { return type() == special_type && offset() == 1; }

  // Accessors
  int register_number() const { return offset(); }
  int stack_offset()    const { return offset(); }
   
  void set_unused() { _value = 0; }

  // Prints the variable.
  void print();

  // Comparison
  friend bool operator == (Variable x, Variable y) { return x.value() == y.value(); }
  friend bool operator != (Variable x, Variable y) { return x.value() != y.value(); }
};


class MappingTask;

class MapConformance : public ResourceObj {
 private:
  Variable                     _free_register;
  GrowableArray<MappingTask*>* mappings;
  Variable*                    used_variables;
  int                          number_of_used_variables;

  bool reduce_noop_task(MappingTask* task);
  void simplify();
  void process_tasks();

  Variable pop_temporary();
  void push_temporary(Variable var);

  void push(Variable src, int n);

  friend class MappingTask;
 public:
  // Constructor
  MapConformance();

  // Appends mapping
  void append_mapping(Variable src_register, Variable src_stack, Variable dst_register, Variable dst_stack);

  // Generates the move operations. free_register is a register that can be used during code generation.
  void generate(Variable free_register1, Variable free_register2);

  // Callback for the generated move operations. Default behavior will print a line per move.
  virtual void move(Variable src, Variable dst);
  virtual void push(Variable src);
  virtual void pop(Variable dst);

  // Print the status of the conformance
  void print();
};

#endif

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