/*

 * Copyright (c) 2017, 2019, 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 "classfile/javaClasses.hpp"

#include "gc/shared/oopStorage.inline.hpp"

#include "gc/shared/oopStorageSet.hpp"

#include "logging/log.hpp"

#include "memory/allocation.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "oops/access.inline.hpp"

#include "oops/method.hpp"

#include "oops/oop.inline.hpp"

#include "oops/weakHandle.inline.hpp"

#include "prims/resolvedMethodTable.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/safepointVerifiers.hpp"

#include "runtime/timerTrace.hpp"

#include "utilities/concurrentHashTable.inline.hpp"

#include "utilities/concurrentHashTableTasks.inline.hpp"

#include "utilities/macros.hpp"

// 2^24 is max size

static const size_t END_SIZE = 24;

// If a chain gets to 32 something might be wrong

static const size_t GROW_HINT = 32;

static const size_t ResolvedMethodTableSizeLog = 10;

unsigned int method_hash(const Method* method) {

  unsigned int name_hash = method->name()->identity_hash();

  unsigned int signature_hash = method->signature()->identity_hash();

  return name_hash ^ signature_hash;

}

typedef ConcurrentHashTable<ResolvedMethodTableConfig,

                            mtClass> ResolvedMethodTableHash;

class ResolvedMethodTableConfig : public AllStatic {

 private:

 public:

  typedef WeakHandle<vm_resolved_method_table_data> Value;

  static uintx get_hash(Value const& value, bool* is_dead) {

    oop val_oop = value.peek();

    if (val_oop == NULL) {

      *is_dead = true;

      return 0;

    }

    *is_dead = false;

    Method* method = java_lang_invoke_ResolvedMethodName::vmtarget(val_oop);

    return method_hash(method);

  }

  // We use default allocation/deallocation but counted

  static void* allocate_node(size_t size, Value const& value) {

    ResolvedMethodTable::item_added();

    return AllocateHeap(size, mtClass);

  }

  static void free_node(void* memory, Value const& value) {

    value.release();

    FreeHeap(memory);

    ResolvedMethodTable::item_removed();

  }

};

static ResolvedMethodTableHash* _local_table           = NULL;

static size_t                   _current_size          = (size_t)1 << ResolvedMethodTableSizeLog;

volatile bool            ResolvedMethodTable::_has_work              = false;

volatile size_t          _items_count           = 0;

volatile size_t          _uncleaned_items_count = 0;

void ResolvedMethodTable::create_table() {

  _local_table  = new ResolvedMethodTableHash(ResolvedMethodTableSizeLog, END_SIZE, GROW_HINT);

  log_trace(membername, table)("Start size: " SIZE_FORMAT " (" SIZE_FORMAT ")",

                               _current_size, ResolvedMethodTableSizeLog);

}

size_t ResolvedMethodTable::table_size() {

  return (size_t)1 << _local_table->get_size_log2(Thread::current());

}

class ResolvedMethodTableLookup : StackObj {

 private:

  Thread*       _thread;

  uintx         _hash;

  const Method* _method;

  Handle        _found;

 public:

  ResolvedMethodTableLookup(Thread* thread, uintx hash, const Method* key)

    : _thread(thread), _hash(hash), _method(key) {

  }

  uintx get_hash() const {

    return _hash;

  }

  bool equals(WeakHandle<vm_resolved_method_table_data>* value, bool* is_dead) {

    oop val_oop = value->peek();

    if (val_oop == NULL) {

      // dead oop, mark this hash dead for cleaning

      *is_dead = true;

      return false;

    }

    bool equals = _method == java_lang_invoke_ResolvedMethodName::vmtarget(val_oop);

    if (!equals) {

      return false;

    }

    // Need to resolve weak handle and Handleize through possible safepoint.

    _found = Handle(_thread, value->resolve());

    return true;

  }

};

class ResolvedMethodGet : public StackObj {

  Thread*       _thread;

  const Method* _method;

  Handle        _return;

public:

  ResolvedMethodGet(Thread* thread, const Method* method) : _thread(thread), _method(method) {}

  void operator()(WeakHandle<vm_resolved_method_table_data>* val) {

    oop result = val->resolve();

    assert(result != NULL, "Result should be reachable");

    _return = Handle(_thread, result);

    log_get();

  }

  oop get_res_oop() {

    return _return();

  }

  void log_get() {

    LogTarget(Trace, membername, table) log;

    if (log.is_enabled()) {

      ResourceMark rm;

      log.print("ResolvedMethod entry found for %s",

                _method->name_and_sig_as_C_string());

    }

  }

};

oop ResolvedMethodTable::find_method(const Method* method) {

  Thread* thread = Thread::current();

  ResolvedMethodTableLookup lookup(thread, method_hash(method), method);

  ResolvedMethodGet rmg(thread, method);

  _local_table->get(thread, lookup, rmg);

  return rmg.get_res_oop();

}

static void log_insert(const Method* method) {

  LogTarget(Debug, membername, table) log;

  if (log.is_enabled()) {

    ResourceMark rm;

    log.print("ResolvedMethod entry added for %s",

              method->name_and_sig_as_C_string());

  }

}

oop ResolvedMethodTable::add_method(const Method* method, Handle rmethod_name) {

  Thread* thread = Thread::current();

  ResolvedMethodTableLookup lookup(thread, method_hash(method), method);

  ResolvedMethodGet rmg(thread, method);

  while (true) {

    if (_local_table->get(thread, lookup, rmg)) {

      return rmg.get_res_oop();

    }

    WeakHandle<vm_resolved_method_table_data> wh = WeakHandle<vm_resolved_method_table_data>::create(rmethod_name);

    // The hash table takes ownership of the WeakHandle, even if it's not inserted.

    if (_local_table->insert(thread, lookup, wh)) {

      log_insert(method);

      return wh.resolve();

    }

  }

}

void ResolvedMethodTable::item_added() {

  Atomic::inc(&_items_count);

}

void ResolvedMethodTable::item_removed() {

  Atomic::dec(&_items_count);

  log_trace(membername, table) ("ResolvedMethod entry removed");

}

double ResolvedMethodTable::get_load_factor() {

  return (double)_items_count/_current_size;

}

double ResolvedMethodTable::get_dead_factor() {

  return (double)_uncleaned_items_count/_current_size;

}

static const double PREF_AVG_LIST_LEN = 2.0;

// If we have as many dead items as 50% of the number of bucket

static const double CLEAN_DEAD_HIGH_WATER_MARK = 0.5;

void ResolvedMethodTable::check_concurrent_work() {

  if (_has_work) {

    return;

  }

  double load_factor = get_load_factor();

  double dead_factor = get_dead_factor();

  // We should clean/resize if we have more dead than alive,

  // more items than preferred load factor or

  // more dead items than water mark.

  if ((dead_factor > load_factor) ||

      (load_factor > PREF_AVG_LIST_LEN) ||

      (dead_factor > CLEAN_DEAD_HIGH_WATER_MARK)) {

    log_debug(membername, table)("Concurrent work triggered, live factor: %g dead factor: %g",

                                 load_factor, dead_factor);

    trigger_concurrent_work();

  }

}

void ResolvedMethodTable::trigger_concurrent_work() {

  MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);

  _has_work = true;

  Service_lock->notify_all();

}

void ResolvedMethodTable::do_concurrent_work(JavaThread* jt) {

  _has_work = false;

  double load_factor = get_load_factor();

  log_debug(membername, table)("Concurrent work, live factor: %g", load_factor);

  // We prefer growing, since that also removes dead items

  if (load_factor > PREF_AVG_LIST_LEN && !_local_table->is_max_size_reached()) {

    grow(jt);

  } else {

    clean_dead_entries(jt);

  }

}

void ResolvedMethodTable::grow(JavaThread* jt) {

  ResolvedMethodTableHash::GrowTask gt(_local_table);

  if (!gt.prepare(jt)) {

    return;

  }

  log_trace(membername, table)("Started to grow");

  {

    TraceTime timer("Grow", TRACETIME_LOG(Debug, membername, table, perf));

    while (gt.do_task(jt)) {

      gt.pause(jt);

      {

        ThreadBlockInVM tbivm(jt);

      }

      gt.cont(jt);

    }

  }

  gt.done(jt);

  _current_size = table_size();

  log_info(membername, table)("Grown to size:" SIZE_FORMAT, _current_size);

}

struct ResolvedMethodTableDoDelete : StackObj {

  void operator()(WeakHandle<vm_resolved_method_table_data>* val) {

    /* do nothing */

  }

};

struct ResolvedMethodTableDeleteCheck : StackObj {

  long _count;

  long _item;

  ResolvedMethodTableDeleteCheck() : _count(0), _item(0) {}

  bool operator()(WeakHandle<vm_resolved_method_table_data>* val) {

    ++_item;

    oop tmp = val->peek();

    if (tmp == NULL) {

      ++_count;

      return true;

    } else {

      return false;

    }

  }

};

void ResolvedMethodTable::clean_dead_entries(JavaThread* jt) {

  ResolvedMethodTableHash::BulkDeleteTask bdt(_local_table);

  if (!bdt.prepare(jt)) {

    return;

  }

  ResolvedMethodTableDeleteCheck stdc;

  ResolvedMethodTableDoDelete stdd;

  {

    TraceTime timer("Clean", TRACETIME_LOG(Debug, membername, table, perf));

    while(bdt.do_task(jt, stdc, stdd)) {

      bdt.pause(jt);

      {

        ThreadBlockInVM tbivm(jt);

      }

      bdt.cont(jt);

    }

    bdt.done(jt);

  }

  log_info(membername, table)("Cleaned %ld of %ld", stdc._count, stdc._item);

}

void ResolvedMethodTable::reset_dead_counter() {

  _uncleaned_items_count = 0;

}

void ResolvedMethodTable::inc_dead_counter(size_t ndead) {

  size_t total = Atomic::add(&_uncleaned_items_count, ndead);

  log_trace(membername, table)(

     "Uncleaned items:" SIZE_FORMAT " added: " SIZE_FORMAT " total:" SIZE_FORMAT,

     _uncleaned_items_count, ndead, total);

}

// After the parallel walk this method must be called to trigger

// cleaning. Note it might trigger a resize instead.

void ResolvedMethodTable::finish_dead_counter() {

  check_concurrent_work();

}

#if INCLUDE_JVMTI

class AdjustMethodEntries : public StackObj {

  bool* _trace_name_printed;

public:

  AdjustMethodEntries(bool* trace_name_printed) : _trace_name_printed(trace_name_printed) {};

  bool operator()(WeakHandle<vm_resolved_method_table_data>* entry) {

    oop mem_name = entry->peek();

    if (mem_name == NULL) {

      // Removed

      return true;

    }

    Method* old_method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(mem_name);

    if (old_method->is_old()) {

      Method* new_method = (old_method->is_deleted()) ?

                            Universe::throw_no_such_method_error() :

                            old_method->get_new_method();

      java_lang_invoke_ResolvedMethodName::set_vmtarget(mem_name, new_method);

      ResourceMark rm;

      if (!(*_trace_name_printed)) {

        log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());

         *_trace_name_printed = true;

      }

      log_debug(redefine, class, update, constantpool)

        ("ResolvedMethod method update: %s(%s)",

         new_method->name()->as_C_string(), new_method->signature()->as_C_string());

    }

    return true;

  }

};

// It is called at safepoint only for RedefineClasses

void ResolvedMethodTable::adjust_method_entries(bool * trace_name_printed) {

  assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");

  // For each entry in RMT, change to new method

  AdjustMethodEntries adjust(trace_name_printed);

  _local_table->do_safepoint_scan(adjust);

}

#endif // INCLUDE_JVMTI

// Verification

class VerifyResolvedMethod : StackObj {

 public:

  bool operator()(WeakHandle<vm_resolved_method_table_data>* val) {

    oop obj = val->peek();

    if (obj != NULL) {

      Method* method = (Method*)java_lang_invoke_ResolvedMethodName::vmtarget(obj);

      guarantee(method->is_method(), "Must be");

      guarantee(!method->is_old(), "Must be");

    }

    return true;

  };

};

size_t ResolvedMethodTable::items_count() {

  return _items_count;

}

void ResolvedMethodTable::verify() {

  VerifyResolvedMethod vcs;

  if (!_local_table->try_scan(Thread::current(), vcs)) {

    log_info(membername, table)("verify unavailable at this moment");

  }

}