/*

 * Copyright (c) 2017, 2018, 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.

 */

#include "precompiled.hpp"

#include "code/relocInfo.hpp"

#include "code/nmethod.hpp"

#include "gc/z/zGlobals.hpp"

#include "gc/z/zHash.inline.hpp"

#include "gc/z/zNMethodTable.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/atomic.hpp"

#include "utilities/debug.hpp"

private:

  static size_t header_size();

public:

  size_t immediate_oops_count() const;

  oop** immediate_oops_begin() const;

  oop** immediate_oops_end() const;

};

  assert(is_aligned(size, sizeof(oop*)), "Header misaligned");

  return size;

}

    _nimmediate_oops(immediate_oops.length()) {

  // Save all immediate oops

  for (size_t i = 0; i < _nimmediate_oops; i++) {

    immediate_oops_begin()[i] = immediate_oops.at(i);

  }

}

  return _nimmediate_oops;

}

  // The immediate oop* array starts immediately after this object

  return (oop**)((uintptr_t)this + header_size());

}

  return immediate_oops_begin() + immediate_oops_count();

}

ZNMethodTableEntry* ZNMethodTable::_table = NULL;

size_t ZNMethodTable::_size = 0;

size_t ZNMethodTable::_nregistered = 0;

size_t ZNMethodTable::_nunregistered = 0;

volatile size_t ZNMethodTable::_claimed = 0;

ZNMethodTableEntry ZNMethodTable::create_entry(nmethod* nm) {

  GrowableArray<oop*> immediate_oops;

  bool non_immediate_oops = false;

  // Find all oops relocations

  RelocIterator iter(nm);

  while (iter.next()) {

    if (iter.type() != relocInfo::oop_type) {

      // Not an oop

      continue;

    }

    oop_Relocation* r = iter.oop_reloc();

    if (!r->oop_is_immediate()) {

      // Non-immediate oop found

      non_immediate_oops = true;

      continue;

    }

    if (r->oop_value() != NULL) {

      // Non-NULL immediate oop found. NULL oops can safely be

      // ignored since the method will be re-registered if they

      // are later patched to be non-NULL.

      immediate_oops.push(r->oop_addr());

    }

  }

  }

}

  }

}

size_t ZNMethodTable::first_index(const nmethod* nm, size_t size) {

  assert(is_power_of_2(size), "Invalid size");

  const size_t mask = size - 1;

  const size_t hash = ZHash::address_to_uint32((uintptr_t)nm);

  return hash & mask;

}

size_t ZNMethodTable::next_index(size_t prev_index, size_t size) {

  assert(is_power_of_2(size), "Invalid size");

  const size_t mask = size - 1;

  return (prev_index + 1) & mask;

}

bool ZNMethodTable::register_entry(ZNMethodTableEntry* table, size_t size, ZNMethodTableEntry entry) {

  size_t index = first_index(nm, size);

  for (;;) {

    const ZNMethodTableEntry table_entry = table[index];

    if (!table_entry.registered() && !table_entry.unregistered()) {

      // Insert new entry

      table[index] = entry;

      return true;

    }

      // Replace existing entry

      table[index] = entry;

      return false;

    }

    index = next_index(index, size);

  }

}

  if (size == 0) {

    // Table is empty

    return false;

  }

  size_t index = first_index(nm, size);

  for (;;) {

    const ZNMethodTableEntry table_entry = table[index];

    if (!table_entry.registered() && !table_entry.unregistered()) {

      // Entry not found

      return false;

    }

      // Remove entry

      table[index] = ZNMethodTableEntry(true /* unregistered */);

      return true;

    }

    index = next_index(index, size);

  }

}

void ZNMethodTable::rebuild(size_t new_size) {

  assert(is_power_of_2(new_size), "Invalid size");

  log_debug(gc, nmethod)("Rebuilding NMethod Table: "

                         SIZE_FORMAT "->" SIZE_FORMAT " entries, "

                         SIZE_FORMAT "(%.0lf%%->%.0lf%%) registered, "

                         SIZE_FORMAT "(%.0lf%%->%.0lf%%) unregistered",

                         _size, new_size,

                         _nregistered, percent_of(_nregistered, _size), percent_of(_nregistered, new_size),

                         _nunregistered, percent_of(_nunregistered, _size), 0.0);

  // Allocate new table

  ZNMethodTableEntry* const new_table = new ZNMethodTableEntry[new_size];

  // Transfer all registered entries

  for (size_t i = 0; i < _size; i++) {

    const ZNMethodTableEntry entry = _table[i];

    if (entry.registered()) {

      register_entry(new_table, new_size, entry);

    }

  }

  // Install new table

  _table = new_table;

  _size = new_size;

  _nunregistered = 0;

}

void ZNMethodTable::rebuild_if_needed() {

  // The hash table uses linear probing. To avoid wasting memory while

  // at the same time maintaining good hash collision behavior we want

  // to keep the table occupancy between 30% and 70%. The table always

  // grows/shrinks by doubling/halving its size. Pruning of unregistered

  // entries is done by rebuilding the table with or without resizing it.

  const size_t min_size = 1024;

  const size_t shrink_threshold = _size * 0.30;

  const size_t prune_threshold = _size * 0.65;

  const size_t grow_threshold = _size * 0.70;

  if (_size == 0) {

    // Initialize table

    rebuild(min_size);

  } else if (_nregistered < shrink_threshold && _size > min_size) {

    // Shrink table

    rebuild(_size / 2);

  } else if (_nregistered + _nunregistered > grow_threshold) {

    // Prune or grow table

    if (_nregistered < prune_threshold) {

      // Prune table

      rebuild(_size);

    } else {

      // Grow table

      rebuild(_size * 2);

    }

  }

}

void ZNMethodTable::log_register(const nmethod* nm, ZNMethodTableEntry entry) {

  LogTarget(Trace, gc, nmethod) log;

  if (!log.is_enabled()) {

    return;

  }

  log.print("Register NMethod: %s.%s (" PTR_FORMAT "), "

            "Compiler: %s, Oops: %d, ImmediateOops: " SIZE_FORMAT ", NonImmediateOops: %s",

            nm->method()->method_holder()->external_name(),

            nm->method()->name()->as_C_string(),

            p2i(nm),

            nm->compiler_name(),

            nm->oops_count() - 1,

  LogTarget(Trace, gc, nmethod, oops) log_oops;

  if (!log_oops.is_enabled()) {

    return;

  }

  // Print nmethod oops table

  oop* const begin = nm->oops_begin();

  oop* const end = nm->oops_end();

  for (oop* p = begin; p < end; p++) {

    log_oops.print("           Oop[" SIZE_FORMAT "] " PTR_FORMAT " (%s)",

                   (p - begin), p2i(*p), (*p)->klass()->external_name());

  }

  if (entry.immediate_oops()) {

    // Print nmethod immediate oops

    }

  }

}

void ZNMethodTable::log_unregister(const nmethod* nm) {

  LogTarget(Debug, gc, nmethod) log;

  if (!log.is_enabled()) {

    return;

  }

  log.print("Unregister NMethod: %s.%s (" PTR_FORMAT ")",

            nm->method()->method_holder()->external_name(),

            nm->method()->name()->as_C_string(),

            p2i(nm));

}

size_t ZNMethodTable::registered_nmethods() {

  return _nregistered;

}

size_t ZNMethodTable::unregistered_nmethods() {

  return _nunregistered;

}

void ZNMethodTable::register_nmethod(nmethod* nm) {

  ResourceMark rm;

  // Create entry

  const ZNMethodTableEntry entry = create_entry(nm);

  log_register(nm, entry);

  // Insert new entry

  if (register_entry(_table, _size, entry)) {

    // New entry registered. When register_entry() instead returns

    // false the nmethod was already in the table so we do not want

    // to increase number of registered entries in that case.

    _nregistered++;

  }

}

void ZNMethodTable::unregister_nmethod(nmethod* nm) {

  ResourceMark rm;

  log_unregister(nm);

  // Remove entry

  if (unregister_entry(_table, _size, nm)) {

    // Entry was unregistered. When unregister_entry() instead returns

    // false the nmethod was not in the table (because it didn't have

    // any oops) so we do not want to decrease the number of registered

    // entries in that case.

    _nregistered--;

    _nunregistered++;

  }

}

  _claimed = 0;

}