Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/sources/formale Sprachen/Java/Openjdk/src/hotspot/share/code/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 7 kB

Quelle oopRecorder.hpp Sprache: C

/*
* Copyright (c) 1998, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#ifndef SHARE_CODE_OOPRECORDER_HPP
#define SHARE_CODE_OOPRECORDER_HPP

#include "runtime/handles.hpp"
#include "utilities/growableArray.hpp"

// Recording and retrieval of either oop relocations or metadata in compiled code.

class CodeBlob;

template <class T> class ValueRecorder : public StackObj {
public:
  // A two-way mapping from positive indexes to oop handles.
  // The zero index is reserved for a constant (shareable) null.
  // Indexes may not be negative.

  // Use the given arena to manage storage, if not NULL.
  // By default, uses the current ResourceArea.
  ValueRecorder(Arena* arena = NULL);

  // Generate a new index on which nmethod::oop_addr_at will work.
  // allocate_index and find_index never return the same index,
  // and allocate_index never returns the same index twice.
  // In fact, two successive calls to allocate_index return successive ints.
  int allocate_index(T h) {
    return add_handle(h, false);
  }

  // For a given jobject or Metadata*, this will return the same index
  // repeatedly. The index can later be given to nmethod::oop_at or
  // metadata_at to retrieve the oop.
  // However, the oop must not be changed via nmethod::oop_addr_at.
  int find_index(T h) {
    int index = maybe_find_index(h);
    if (index < 0) {  // previously unallocated
      index = add_handle(h, true);
    }
    return index;
  }

  // returns the size of the generated oop/metadata table, for sizing the
  // CodeBlob. Must be called after all oops are allocated!
  int size();

  // Retrieve the value at a given index.
  T at(int index);

  int count() {
    if (_handles == NULL) return 0;
    // there is always a NULL virtually present as first object
    return _handles->length() + first_index;
  }

  // Helper function; returns false for NULL or Universe::non_oop_word().
  inline bool is_real(T h);

  // copy the generated table to nmethod
  void copy_values_to(nmethod* nm);

  bool is_unused() { return _handles == NULL && !_complete; }
#ifdef ASSERT
  bool is_complete() { return _complete; }
#endif

private:
  // variant of find_index which does not allocate if not found (yields -1)
  int maybe_find_index(T h);

  // leaky hash table of handle => index, to help detect duplicate insertion
  template <class X> class IndexCache : public ArenaObj {
    // This class is only used by the ValueRecorder class.
    friend class ValueRecorder;
    enum {
      _log_cache_size = 9,
      _cache_size = (1<<_log_cache_size),
      // Index entries are ints.  The LSBit is a collision indicator.
      _collision_bit_shift = 0,
      _collision_bit = 1,
      _index_shift = _collision_bit_shift+1
    };
    int _cache[_cache_size];
    static juint cache_index(X handle) {
      juint ci = (int) (intptr_t) handle;
      ci ^= ci >> (BitsPerByte*2);
      ci += ci >> (BitsPerByte*1);
      return ci & (_cache_size-1);
    }
    int* cache_location(X handle) {
      return &_cache[ cache_index(handle) ];
    }
    static bool cache_location_collision(int* cloc) {
      return ((*cloc) & _collision_bit) != 0;
    }
    static int cache_location_index(int* cloc) {
      return (*cloc) >> _index_shift;
    }
    static void set_cache_location_index(int* cloc, int index) {
      int cval0 = (*cloc);
      int cval1 = (index << _index_shift);
      if (cval0 != 0 && cval1 != cval0)  cval1 += _collision_bit;
      (*cloc) = cval1;
    }
    IndexCache();
  };

  void maybe_initialize();
  int add_handle(T h, bool make_findable);

  enum { null_index = 0, first_index = 1, index_cache_threshold = 20 };

  GrowableArray<T>*        _handles;  // ordered list (first is always NULL)
  GrowableArray<int>*       _no_finds; // all unfindable indexes; usually empty
  IndexCache<T>*           _indexes;  // map: handle -> its probable index
  Arena*                    _arena;
  bool                      _complete;

#ifdef ASSERT
  static int _find_index_calls, _hit_indexes, _missed_indexes;
#endif
};

class OopRecorder;

class ObjectLookup : public ResourceObj {
private:
  class ObjectEntry {
   private:
    jobject _value;
    int     _index;

   public:
    ObjectEntry(jobject value, int index) : _value(value), _index(index) {}
    ObjectEntry() : _value(NULL), _index(0) {}
    oop oop_value() const;
    int index() { return _index; }
  };

  GrowableArray<ObjectEntry> _values;
  unsigned int _gc_count;

  // Utility sort functions
  static int sort_by_address(oop a, oop b);
  static int sort_by_address(ObjectEntry* a, ObjectEntry* b);
  static int sort_oop_by_address(oop const& a, ObjectEntry const& b);

public:
  ObjectLookup();

  // Resort list if a GC has occurred since the last sort
  void maybe_resort();
  int find_index(jobject object, OopRecorder* oop_recorder);
};

class OopRecorder : public ResourceObj {
private:
  ValueRecorder<jobject>      _oops;
  ValueRecorder<Metadata*>    _metadata;
  ObjectLookup*               _object_lookup;
public:
  OopRecorder(Arena* arena = NULL, bool deduplicate = false);

  int allocate_oop_index(jobject h) {
    return _oops.allocate_index(h);
  }
  virtual int find_index(jobject h) {
    return _object_lookup != NULL ? _object_lookup->find_index(h, this) : _oops.find_index(h);
  }
  jobject oop_at(int index) {
    return _oops.at(index);
  }
  int oop_size() {
    return _oops.size();
  }
  int oop_count() {
    return _oops.count();
  }
  inline bool is_real(jobject h);

  int allocate_metadata_index(Metadata* oop) {
    return _metadata.allocate_index(oop);
  }
  virtual int find_index(Metadata* h) {
    return _metadata.find_index(h);
  }
  Metadata* metadata_at(int index) {
    return _metadata.at(index);
  }
  int metadata_size() {
    return _metadata.size();
  }
  int metadata_count() {
    return _metadata.count();
  }
  inline bool is_real(Metadata* h);

  bool is_unused() {
    return _oops.is_unused() && _metadata.is_unused();
  }

  void freeze() {
    _oops.size();
    _metadata.size();
  }

  void copy_values_to(nmethod* nm) {
    if (!_oops.is_unused()) {
      _oops.copy_values_to(nm);
    }
    if (!_metadata.is_unused()) {
      _metadata.copy_values_to(nm);
    }
  }

#ifdef ASSERT
  bool is_complete() {
    assert(_oops.is_complete() == _metadata.is_complete(), "must agree");
    return _oops.is_complete();
  }
#endif
};

#endif // SHARE_CODE_OOPRECORDER_HPP

quality100%

¤ Dauer der Verarbeitung: 0.25 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.