/*

 * 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 "code/icBuffer.hpp"

#include "gc/shared/barrierSet.hpp"

#include "gc/shared/barrierSetNMethod.hpp"

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

#include "gc/z/zGlobals.hpp"

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

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

#include "gc/z/zNMethodTable.hpp"

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

#include "gc/z/zTask.hpp"

#include "gc/z/zWorkers.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/atomic.hpp"

#include "runtime/orderAccess.hpp"

#include "utilities/debug.hpp"

class ZNMethodDataImmediateOops {

private:

  const size_t _nimmediate_oops;

  static size_t header_size();

  ZNMethodDataImmediateOops(const GrowableArray<oop*>& immediate_oops);

public:

  static ZNMethodDataImmediateOops* create(const GrowableArray<oop*>& immediate_oops);

  static void destroy(ZNMethodDataImmediateOops* data_immediate_oops);

  size_t immediate_oops_count() const;

  oop** immediate_oops_begin() const;

  oop** immediate_oops_end() const;

};

size_t ZNMethodDataImmediateOops::header_size() {

  const size_t size = sizeof(ZNMethodDataImmediateOops);

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

  return size;

}

ZNMethodDataImmediateOops* ZNMethodDataImmediateOops::create(const GrowableArray<oop*>& immediate_oops) {

  // Allocate memory for the ZNMethodDataImmediateOops object

  // plus the immediate oop* array that follows right after.

  const size_t size = ZNMethodDataImmediateOops::header_size() + (sizeof(oop*) * immediate_oops.length());

  void* const data_immediate_oops = NEW_C_HEAP_ARRAY(uint8_t, size, mtGC);

  return ::new (data_immediate_oops) ZNMethodDataImmediateOops(immediate_oops);

}

void ZNMethodDataImmediateOops::destroy(ZNMethodDataImmediateOops* data_immediate_oops) {

  ZNMethodTable::safe_delete(data_immediate_oops);

}

ZNMethodDataImmediateOops::ZNMethodDataImmediateOops(const GrowableArray<oop*>& immediate_oops) :

    _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);

  }

}

size_t ZNMethodDataImmediateOops::immediate_oops_count() const {

  return _nimmediate_oops;

}

oop** ZNMethodDataImmediateOops::immediate_oops_begin() const {

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

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

}

oop** ZNMethodDataImmediateOops::immediate_oops_end() const {

  return immediate_oops_begin() + immediate_oops_count();

}

class ZNMethodData {

private:

  ZReentrantLock                      _lock;

  ZNMethodDataImmediateOops* volatile _immediate_oops;

  ZNMethodData(nmethod* nm);

public:

  static ZNMethodData* create(nmethod* nm);

  static void destroy(ZNMethodData* data);

  ZReentrantLock* lock();

  ZNMethodDataImmediateOops* immediate_oops() const;

  ZNMethodDataImmediateOops* swap_immediate_oops(const GrowableArray<oop*>& immediate_oops);

};

ZNMethodData* ZNMethodData::create(nmethod* nm) {

  void* const method = NEW_C_HEAP_ARRAY(uint8_t, sizeof(ZNMethodData), mtGC);

  return ::new (method) ZNMethodData(nm);

}

void ZNMethodData::destroy(ZNMethodData* data) {

  ZNMethodDataImmediateOops::destroy(data->immediate_oops());

  ZNMethodTable::safe_delete(data);

}

ZNMethodData::ZNMethodData(nmethod* nm) :

    _lock(),

    _immediate_oops(NULL) {}

ZReentrantLock* ZNMethodData::lock() {

  return &_lock;

}

ZNMethodDataImmediateOops* ZNMethodData::immediate_oops() const {

  return OrderAccess::load_acquire(&_immediate_oops);

}

ZNMethodDataImmediateOops* ZNMethodData::swap_immediate_oops(const GrowableArray<oop*>& immediate_oops) {

  ZNMethodDataImmediateOops* const data_immediate_oops =

    immediate_oops.is_empty() ? NULL : ZNMethodDataImmediateOops::create(immediate_oops);

  return Atomic::xchg(data_immediate_oops, &_immediate_oops);

}

static ZNMethodData* gc_data(const nmethod* nm) {

  return nm->gc_data<ZNMethodData>();

}

static void set_gc_data(nmethod* nm, ZNMethodData* data) {

  return nm->set_gc_data<ZNMethodData>(data);

}

ZNMethodTableEntry* ZNMethodTable::_table = NULL;

size_t ZNMethodTable::_size = 0;

ZLock ZNMethodTable::_iter_lock;

ZNMethodTableEntry* ZNMethodTable::_iter_table = NULL;

size_t ZNMethodTable::_iter_table_size = 0;

ZArray<void*> ZNMethodTable::_iter_deferred_deletes;

size_t ZNMethodTable::_nregistered = 0;

size_t ZNMethodTable::_nunregistered = 0;

volatile size_t ZNMethodTable::_claimed = 0;

void ZNMethodTable::safe_delete(void* data) {

  if (data == NULL) {

    return;

  }

  ZLocker<ZLock> locker(&_iter_lock);

  if (_iter_table != NULL) {

    // Iteration in progress, defer delete

    _iter_deferred_deletes.add(data);

  } else {

    // Iteration not in progress, delete now

    FREE_C_HEAP_ARRAY(uint8_t, data);

  }

}

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());

    }

  }

  // Attach GC data to nmethod

  ZNMethodData* data = gc_data(nm);

  if (data == NULL) {

    data = ZNMethodData::create(nm);

    set_gc_data(nm, data);

  }

  // Attach immediate oops in GC data

  ZNMethodDataImmediateOops* const old_data_immediate_oops = data->swap_immediate_oops(immediate_oops);

  ZNMethodDataImmediateOops::destroy(old_data_immediate_oops);

  // Create entry

  return ZNMethodTableEntry(nm, non_immediate_oops, !immediate_oops.is_empty());

}

ZReentrantLock* ZNMethodTable::lock_for_nmethod(nmethod* nm) {

  ZNMethodData* const data = gc_data(nm);

  if (data == NULL) {

    return NULL;

  }

  return data->lock();

}

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) {

  const nmethod* const nm = entry.method();

  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;

    }

    if (table_entry.registered() && table_entry.method() == nm) {

      // Replace existing entry

      table[index] = entry;

      return false;

    }

    index = next_index(index, size);

  }

}

void ZNMethodTable::unregister_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) {

  if (size == 0) {

    // Table is empty

    return;

  }

  size_t index = first_index(nm, size);

  for (;;) {

    const ZNMethodTableEntry table_entry = table[index];

    assert(table_entry.registered() || table_entry.unregistered(), "Entry not found");

    if (table_entry.registered() && table_entry.method() == nm) {

      // Remove entry

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

      // Destroy GC data

      ZNMethodData::destroy(gc_data(nm));

      set_gc_data(nm, NULL);

      return;

    }

    index = next_index(index, size);

  }

}

void ZNMethodTable::rebuild(size_t new_size) {

  ZLocker<ZLock> locker(&_iter_lock);

  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);

    }

  }

  if (_iter_table != _table) {

    // Delete old table

    delete [] _table;

  }

  // 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,

            entry.immediate_oops() ? gc_data(nm)->immediate_oops()->immediate_oops_count() : 0,

            entry.non_immediate_oops() ? "Yes" : "No");

  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

    const ZNMethodDataImmediateOops* const nmi = gc_data(nm)->immediate_oops();

    if (nmi != NULL) {

      oop** const begin = nmi->immediate_oops_begin();

      oop** const end = nmi->immediate_oops_end();

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

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

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

      }

    }

  }

}

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) {

  assert(CodeCache_lock->owned_by_self(), "Lock must be held");

  ResourceMark rm;

  // Grow/Shrink/Prune table if needed

  rebuild_if_needed();

  // 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++;

  }

  // Disarm nmethod entry barrier

  disarm_nmethod(nm);

}

  while (_iter_table != NULL) {

  }

}

void ZNMethodTable::unregister_nmethod(nmethod* nm) {

  assert(CodeCache_lock->owned_by_self(), "Lock must be held");

  log_unregister(nm);

  // Remove entry

  unregister_entry(_table, _size, nm);

  _nunregistered++;

  _nregistered--;

}

void ZNMethodTable::disarm_nmethod(nmethod* nm) {

  BarrierSetNMethod* const bs = BarrierSet::barrier_set()->barrier_set_nmethod();

  if (bs != NULL) {

    bs->disarm(nm);

  }

}

void ZNMethodTable::nmethod_entries_do_begin() {

  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

  ZLocker<ZLock> locker(&_iter_lock);

  // Prepare iteration

  _iter_table = _table;

  _iter_table_size = _size;

  _claimed = 0;

  assert(_iter_deferred_deletes.is_empty(), "Should be emtpy");

}

void ZNMethodTable::nmethod_entries_do_end() {

  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

  ZLocker<ZLock> locker(&_iter_lock);

  // Finish iteration

  if (_iter_table != _table) {

    delete [] _iter_table;

  }

  _iter_table = NULL;

  assert(_claimed >= _iter_table_size, "Failed to claim all table entries");

  // Process deferred deletes

  ZArrayIterator<void*> iter(&_iter_deferred_deletes);

  for (void* data; iter.next(&data);) {

    FREE_C_HEAP_ARRAY(uint8_t, data);

  }

  _iter_deferred_deletes.clear();

}