key.hpp

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/* Copyright 1994, 1995 LongView Technologies L.L.C. $Revision: 1.19 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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// LookupKeys are the keys into the code table.  
// There should be at most one compiled method for a given LookupKey.
// A LookupKey can take two forms:
// 1) normal send lookup key (is_normal_type() == true).
//    {receiver klass, selector}
// 2) super  send lookup key (is_super_type()  == true).
//    {receiver klass, method}
// 2) fake lookup key for block methods
//    {receiver klass, block method}

// LookupKeys are allocated in different ways:
//   as embedded objects: the lookupCache has LookupKeys as part of an array element.
//   as dynamically allocated resource objects: used by the optimizing compiler.
//      Use "LookupKey::allocate" for allocating a LookupKey in the resource area.

class LookupKey : ValueObj {
 protected:
  klassOop  _klass;
  oop       _selector_or_method;
 public:
  LookupKey() {
    clear();
  }
  LookupKey(klassOop klass, oop selector_or_method) {
    _klass              = klass;
    _selector_or_method = selector_or_method;
  }
  LookupKey(LookupKey* key) {
    _klass              = key->klass();
    _selector_or_method = key->selector_or_method();
  }

  klassOop klass() const              { return _klass; }
  oop      selector_or_method() const { return _selector_or_method; }

  symbolOop selector() const;

  methodOop method() const {
     assert(selector_or_method()->is_method(), "Wrong lookup type");
     return methodOop(selector_or_method());
  }

  // Lookup type
  bool is_super_type()  const { return selector_or_method()->is_method() && !methodOop(selector_or_method())->is_blockMethod();}
  bool is_normal_type() const { return !selector_or_method()->is_method(); }
  bool is_block_type()  const { return selector_or_method()->is_method() && methodOop(selector_or_method())->is_blockMethod(); }

  bool equal(LookupKey* p) const {
    return klass()              == p->klass() &&
           selector_or_method() == p->selector_or_method();
  }

  void initialize(klassOop klass, oop selector_or_method) {
    _klass              = klass;
    _selector_or_method = selector_or_method;
  }

  void clear() {
    _klass              = NULL;
    _selector_or_method = NULL;
  }

  int hash() const;
  
  void switch_pointers(oop from, oop to);
  void relocate();
  bool verify() const;
  void oops_do(void f(oop*));
  
  // Printing support output format is:
  //   "class::selector" for normal sends and
  //   "class^^selector" for super sends.
  //   "class->selector {bci}+" for block keys
  void  print() const;
  char* print_string() const;
  void  print_on(outputStream* st) const;
  void  print_inlining_database_on(outputStream* st) const;

  // For resource allocation.
  static LookupKey* allocate(klassOop klass, oop selector_or_method);
};

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