/*

 * Copyright (c) 2014, 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_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP

#include "memory/allocation.hpp"

#include "memory/freeList.hpp"

#include "runtime/globals.hpp"

class CodeBlobClosure;

class G1CodeRootChunk : public CHeapObj<mtGC> {

 private:

  static const int NUM_ENTRIES = 32;

 public:

  G1CodeRootChunk*     _next;

  G1CodeRootChunk*     _prev;

  nmethod** _top;

  nmethod* _data[NUM_ENTRIES];

  nmethod** bottom() const {

    return (nmethod**) &(_data[0]);

  }

  nmethod** end() const {

    return (nmethod**) &(_data[NUM_ENTRIES]);

  }

 public:

  G1CodeRootChunk();

  ~G1CodeRootChunk() {}

  static size_t word_size() { return (size_t)(align_size_up_(sizeof(G1CodeRootChunk), HeapWordSize) / HeapWordSize); }

  // FreeList "interface" methods

  G1CodeRootChunk* next() const         { return _next; }

  G1CodeRootChunk* prev() const         { return _prev; }

  void set_next(G1CodeRootChunk* v)     { _next = v; assert(v != this, "Boom");}

  void set_prev(G1CodeRootChunk* v)     { _prev = v; assert(v != this, "Boom");}

  void clear_next()       { set_next(NULL); }

  void clear_prev()       { set_prev(NULL); }

  size_t size() const { return word_size(); }

  void link_next(G1CodeRootChunk* ptr)  { set_next(ptr); }

  void link_prev(G1CodeRootChunk* ptr)  { set_prev(ptr); }

  void link_after(G1CodeRootChunk* ptr) {

    link_next(ptr);

    if (ptr != NULL) ptr->link_prev((G1CodeRootChunk*)this);

  }

  bool is_free()                 { return true; }

  // New G1CodeRootChunk routines

  void reset();

  bool is_empty() const {

    return _top == bottom();

  }

  bool is_full() const {

    return _top == (nmethod**)end();

  }

  bool contains(nmethod* method) {

    nmethod** cur = bottom();

    while (cur != _top) {

      if (*cur == method) return true;

      cur++;

    }

    return false;

  }

  bool add(nmethod* method) {

    if (is_full()) return false;

    *_top = method;

    _top++;

    return true;

  }

  bool remove(nmethod* method) {

    nmethod** cur = bottom();

    while (cur != _top) {

      if (*cur == method) {

        memmove(cur, cur + 1, (_top - (cur + 1)) * sizeof(nmethod**));

        _top--;

        return true;

      }

      cur++;

    }

    return false;

  }

  void nmethods_do(CodeBlobClosure* blk);

  nmethod* pop() {

    if (is_empty()) {

      return NULL;

    }

    _top--;

    return *_top;

  }

};

// Manages free chunks.

class G1CodeRootChunkManager VALUE_OBJ_CLASS_SPEC {

 private:

  // Global free chunk list management

  FreeList<G1CodeRootChunk> _free_list;

  // Total number of chunks handed out

  size_t _num_chunks_handed_out;

 public:

  G1CodeRootChunkManager();

  G1CodeRootChunk* new_chunk();

  void free_chunk(G1CodeRootChunk* chunk);

  // Free all elements of the given list.

  void free_all_chunks(FreeList<G1CodeRootChunk>* list);

  void initialize();

  void purge_chunks(size_t keep_ratio);

  size_t static_mem_size();

  size_t fl_mem_size();

#ifndef PRODUCT

  size_t num_chunks_handed_out() const;

  size_t num_free_chunks() const;

#endif

};

// Implements storage for a set of code roots.

// All methods that modify the set are not thread-safe except if otherwise noted.

class G1CodeRootSet VALUE_OBJ_CLASS_SPEC {

 private:

  // Global default free chunk manager instance.

  static G1CodeRootChunkManager _default_chunk_manager;

  G1CodeRootChunk* new_chunk() { return _manager->new_chunk(); }

  void free_chunk(G1CodeRootChunk* chunk) { _manager->free_chunk(chunk); }

  // Free all elements of the given list.

  void free_all_chunks(FreeList<G1CodeRootChunk>* list) { _manager->free_all_chunks(list); }

  // Return the chunk that contains the given nmethod, NULL otherwise.

  // Scans the list of chunks backwards, as this method is used to add new

  // entries, which are typically added in bulk for a single nmethod.

  G1CodeRootChunk* find(nmethod* method);

  void free(G1CodeRootChunk* chunk);

  size_t _length;

  FreeList<G1CodeRootChunk> _list;

  G1CodeRootChunkManager* _manager;

 public:

  // If an instance is initialized with a chunk manager of NULL, use the global

  // default one.

  G1CodeRootSet(G1CodeRootChunkManager* manager = NULL);

  ~G1CodeRootSet();

  static void purge_chunks(size_t keep_ratio);

  static size_t static_mem_size();

  static size_t free_chunks_mem_size();

  // Search for the code blob from the recently allocated ones to find duplicates more quickly, as this

  // method is likely to be repeatedly called with the same nmethod.

  void add(nmethod* method);

  void remove(nmethod* method);

  nmethod* pop();

  bool contains(nmethod* method);

  void clear();

  void nmethods_do(CodeBlobClosure* blk) const;

  bool is_empty() { return length() == 0; }

  // Length in elements

  size_t length() const { return _length; }

  // Memory size in bytes taken by this set.

  size_t mem_size();

  static void test() PRODUCT_RETURN;

};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP