codeTable.hpp

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/* Copyright 1994, LongView Technologies L.L.C. $Revision: 1.13 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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#ifdef DELTA_COMPILER

// The code table is used to find nmethods in the zone.
// It is a hash table, where each bucket contains a list of nmethods.

//%note
// Should implement free list like symbolTable (Lars 2/10-95)

const int codeTableSize  = 2048;
const int debugTableSize = 256;

struct codeTableEntry;

struct codeTableLink : public CHeapObj {
  // instance variable
  nmethod*       nm;
  codeTableLink* next;

  // memory operations
  bool verify(int i);
};

struct codeTableEntry : ValueObj {
  // methods are tagged, links are not.
  void* nmethod_or_link;
  bool  is_empty()   { return nmethod_or_link == NULL; }
  bool  is_nmethod() { return (int) nmethod_or_link & 1; }
  void  clear()      { nmethod_or_link = NULL; }

  nmethod* get_nmethod() { 
    return (nmethod*) ((int) nmethod_or_link - 1);
  }
  void set_nmethod(nmethod* nm) {
    assert_oop_aligned(nm);
    nmethod_or_link = (void*) ((int) nm + 1); }

  codeTableLink* get_link() { return (codeTableLink*) nmethod_or_link; }
  void set_link(codeTableLink* l) {
    assert_oop_aligned(l);
    nmethod_or_link = (void*) l;
  }

  // memory operations
  void deallocate();
  
  int length();   // returns the number of nmethod in this bucket.

  bool verify(int i);
};

class codeTable : public PrintableCHeapObj{
 protected:
  int             tableSize;
  codeTableEntry* buckets;

  codeTableEntry* at(int index)       { return &buckets[index]; }
  codeTableEntry* bucketFor(int hash) { return at(hash & (tableSize - 1)); }
  codeTableLink*  new_link(nmethod* nm, codeTableLink* n = NULL);

 public:
  codeTable(int size);
  void clear();
  nmethod* lookup(LookupKey* L);
  bool verify();

  void print();

  void print_stats();

  // Tells whether a nmethod is present
  bool is_present(nmethod* nm);

  // Removes a nmethod from the table
  void remove(nmethod* nm);

 protected:
  // should always add through zone->addToCodeTable()
  void add(nmethod* nm);
  void addIfAbsent(nmethod* nm); // add only if not there yet

  friend class zone;
};

#endif

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