/*

 * Copyright (c) 1997, 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/symbolTable.hpp"

#include "classfile/vmSymbols.hpp"

#include "code/codeCache.hpp"

#include "compiler/compileBroker.hpp"

#include "gc/shared/isGCActiveMark.hpp"

#include "logging/log.hpp"

#include "logging/logStream.hpp"

#include "memory/heapInspection.hpp"

#include "memory/resourceArea.hpp"

#include "oops/symbol.hpp"

#include "runtime/arguments.hpp"

#include "runtime/deoptimization.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/sweeper.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/threadSMR.inline.hpp"

#include "runtime/vmOperations.hpp"

#include "services/threadService.hpp"

#define VM_OP_NAME_INITIALIZE(name) #name,

const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \

  { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };

void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {

  _calling_thread = thread;

  assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");

  _priority = priority;

}

void VM_Operation::evaluate() {

  ResourceMark rm;

  LogTarget(Debug, vmoperation) lt;

  if (lt.is_enabled()) {

    LogStream ls(lt);

    ls.print("begin ");

    print_on_error(&ls);

    ls.cr();

  }

  doit();

  if (lt.is_enabled()) {

    LogStream ls(lt);

    ls.print("end ");

    print_on_error(&ls);

    ls.cr();

  }

}

const char* VM_Operation::mode_to_string(Mode mode) {

  switch(mode) {

    case _safepoint      : return "safepoint";

    case _no_safepoint   : return "no safepoint";

    case _concurrent     : return "concurrent";

    case _async_safepoint: return "async safepoint";

    default              : return "unknown";

  }

}

// Called by fatal error handler.

void VM_Operation::print_on_error(outputStream* st) const {

  st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));

  st->print("%s", name());

  const char* mode = mode_to_string(evaluation_mode());

  st->print(", mode: %s", mode);

  if (calling_thread()) {

    st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));

  }

}

void VM_ThreadStop::doit() {

  assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");

  ThreadsListHandle tlh;

  JavaThread* target = java_lang_Thread::thread(target_thread());

  // Note that this now allows multiple ThreadDeath exceptions to be

  // thrown at a thread.

  if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) {

    // The target thread has run and has not exited yet.

    target->send_thread_stop(throwable());

  }

}

void VM_ClearICs::doit() {

  if (_preserve_static_stubs) {

    CodeCache::cleanup_inline_caches();

  } else {

    CodeCache::clear_inline_caches();

  }

}

void VM_Deoptimize::doit() {

  // We do not want any GCs to happen while we are in the middle of this VM operation

  ResourceMark rm;

  DeoptimizationMarker dm;

  // Deoptimize all activations depending on marked nmethods

  Deoptimization::deoptimize_dependents();

  // Make the dependent methods not entrant

  CodeCache::make_marked_nmethods_not_entrant();

}

void VM_MarkActiveNMethods::doit() {

  NMethodSweeper::mark_active_nmethods();

}

VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {

  _thread = thread;

  _id     = id;

  _reason = reason;

}

void VM_DeoptimizeFrame::doit() {

  assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");

  Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);

}

#ifndef PRODUCT

void VM_DeoptimizeAll::doit() {

  DeoptimizationMarker dm;

  JavaThreadIteratorWithHandle jtiwh;

  // deoptimize all java threads in the system

  if (DeoptimizeALot) {

    for (; JavaThread *thread = jtiwh.next(); ) {

      if (thread->has_last_Java_frame()) {

        thread->deoptimize();

      }

    }

  } else if (DeoptimizeRandom) {

    // Deoptimize some selected threads and frames

    int tnum = os::random() & 0x3;

    int fnum =  os::random() & 0x3;

    int tcount = 0;

    for (; JavaThread *thread = jtiwh.next(); ) {

      if (thread->has_last_Java_frame()) {

        if (tcount++ == tnum)  {

        tcount = 0;

          int fcount = 0;

          // Deoptimize some selected frames.

          // Biased llocking wants a updated register map

          for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {

            if (fst.current()->can_be_deoptimized()) {

              if (fcount++ == fnum) {

                fcount = 0;

                Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());

              }

            }

          }

        }

      }

    }

  }

}

void VM_ZombieAll::doit() {

  JavaThread *thread = (JavaThread *)calling_thread();

  assert(thread->is_Java_thread(), "must be a Java thread");

  thread->make_zombies();

}

#endif // !PRODUCT

void VM_Verify::doit() {

  Universe::heap()->prepare_for_verify();

  Universe::verify();

}

bool VM_PrintThreads::doit_prologue() {

  // Get Heap_lock if concurrent locks will be dumped

  if (_print_concurrent_locks) {

    Heap_lock->lock();

  }

  return true;

}

void VM_PrintThreads::doit() {

  Threads::print_on(_out, true, false, _print_concurrent_locks, _print_extended_info);

}

void VM_PrintThreads::doit_epilogue() {

  if (_print_concurrent_locks) {

    // Release Heap_lock

    Heap_lock->unlock();

  }

}

void VM_PrintJNI::doit() {

  JNIHandles::print_on(_out);

}

void VM_PrintMetadata::doit() {

  MetaspaceUtils::print_report(_out, _scale, _flags);

}

VM_FindDeadlocks::~VM_FindDeadlocks() {

  if (_deadlocks != NULL) {

    DeadlockCycle* cycle = _deadlocks;

    while (cycle != NULL) {

      DeadlockCycle* d = cycle;

      cycle = cycle->next();

      delete d;

    }

  }

}

void VM_FindDeadlocks::doit() {

  // Update the hazard ptr in the originating thread to the current

  // list of threads. This VM operation needs the current list of

  // threads for proper deadlock detection and those are the

  // JavaThreads we need to be protected when we return info to the

  // originating thread.

  _setter.set();

  _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);

  if (_out != NULL) {

    int num_deadlocks = 0;

    for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {

      num_deadlocks++;

      cycle->print_on_with(_setter.list(), _out);

    }

    if (num_deadlocks == 1) {

      _out->print_cr("\nFound 1 deadlock.\n");

      _out->flush();

    } else if (num_deadlocks > 1) {

      _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);

      _out->flush();

    }

  }

}

VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,

                             int max_depth,

                             bool with_locked_monitors,

                             bool with_locked_synchronizers) {

  _result = result;

  _num_threads = 0; // 0 indicates all threads

  _threads = NULL;

  _result = result;

  _max_depth = max_depth;

  _with_locked_monitors = with_locked_monitors;

  _with_locked_synchronizers = with_locked_synchronizers;

}

VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,

                             GrowableArray<instanceHandle>* threads,

                             int num_threads,

                             int max_depth,

                             bool with_locked_monitors,

                             bool with_locked_synchronizers) {

  _result = result;

  _num_threads = num_threads;

  _threads = threads;

  _result = result;

  _max_depth = max_depth;

  _with_locked_monitors = with_locked_monitors;

  _with_locked_synchronizers = with_locked_synchronizers;

}

bool VM_ThreadDump::doit_prologue() {

  if (_with_locked_synchronizers) {

    // Acquire Heap_lock to dump concurrent locks

    Heap_lock->lock();

  }

  return true;

}

void VM_ThreadDump::doit_epilogue() {

  if (_with_locked_synchronizers) {

    // Release Heap_lock

    Heap_lock->unlock();

  }

}

void VM_ThreadDump::doit() {

  ResourceMark rm;

  // Set the hazard ptr in the originating thread to protect the

  // current list of threads. This VM operation needs the current list

  // of threads for a proper dump and those are the JavaThreads we need

  // to be protected when we return info to the originating thread.

  _result->set_t_list();

  ConcurrentLocksDump concurrent_locks(true);

  if (_with_locked_synchronizers) {

    concurrent_locks.dump_at_safepoint();

  }

  if (_num_threads == 0) {

    // Snapshot all live threads

    for (uint i = 0; i < _result->t_list()->length(); i++) {

      JavaThread* jt = _result->t_list()->thread_at(i);

      if (jt->is_exiting() ||

          jt->is_hidden_from_external_view())  {

        // skip terminating threads and hidden threads

        continue;

      }

      ThreadConcurrentLocks* tcl = NULL;

      if (_with_locked_synchronizers) {

        tcl = concurrent_locks.thread_concurrent_locks(jt);

      }

      snapshot_thread(jt, tcl);

    }

  } else {

    // Snapshot threads in the given _threads array

    // A dummy snapshot is created if a thread doesn't exist

    for (int i = 0; i < _num_threads; i++) {

      instanceHandle th = _threads->at(i);

      if (th() == NULL) {

        // skip if the thread doesn't exist

        // Add a dummy snapshot

        _result->add_thread_snapshot();

        continue;

      }

      // Dump thread stack only if the thread is alive and not exiting

      // and not VM internal thread.

      JavaThread* jt = java_lang_Thread::thread(th());

      if (jt != NULL && !_result->t_list()->includes(jt)) {

        // _threads[i] doesn't refer to a valid JavaThread; this check

        // is primarily for JVM_DumpThreads() which doesn't have a good

        // way to validate the _threads array.

        jt = NULL;

      }

      if (jt == NULL || /* thread not alive */

          jt->is_exiting() ||

          jt->is_hidden_from_external_view())  {

        // add a NULL snapshot if skipped

        _result->add_thread_snapshot();

        continue;

      }

      ThreadConcurrentLocks* tcl = NULL;

      if (_with_locked_synchronizers) {

        tcl = concurrent_locks.thread_concurrent_locks(jt);

      }

      snapshot_thread(jt, tcl);

    }

  }

}

void VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {

  ThreadSnapshot* snapshot = _result->add_thread_snapshot(java_thread);

  snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);

  snapshot->set_concurrent_locks(tcl);

}

volatile bool VM_Exit::_vm_exited = false;

Thread * volatile VM_Exit::_shutdown_thread = NULL;

int VM_Exit::set_vm_exited() {

  Thread * thr_cur = Thread::current();

  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");

  int num_active = 0;

  _shutdown_thread = thr_cur;

  _vm_exited = true;                                // global flag

  for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {

    if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {

      ++num_active;

      thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag

    }

  }

  return num_active;

}

int VM_Exit::wait_for_threads_in_native_to_block() {

  // VM exits at safepoint. This function must be called at the final safepoint

  // to wait for threads in _thread_in_native state to be quiescent.

  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");

  Thread * thr_cur = Thread::current();

  Monitor timer(Mutex::leaf, "VM_Exit timer", true,

                Monitor::_safepoint_check_never);

  // Compiler threads need longer wait because they can access VM data directly

  // while in native. If they are active and some structures being used are

  // deleted by the shutdown sequence, they will crash. On the other hand, user

  // threads must go through native=>Java/VM transitions first to access VM

  // data, and they will be stopped during state transition. In theory, we

  // don't have to wait for user threads to be quiescent, but it's always

  // better to terminate VM when current thread is the only active thread, so

  // wait for user threads too. Numbers are in 10 milliseconds.

  int max_wait_user_thread = 30;                  // at least 300 milliseconds

  int max_wait_compiler_thread = 1000;            // at least 10 seconds

  int max_wait = max_wait_compiler_thread;

  int attempts = 0;

  JavaThreadIteratorWithHandle jtiwh;

  while (true) {

    int num_active = 0;

    int num_active_compiler_thread = 0;

    jtiwh.rewind();

    for (; JavaThread *thr = jtiwh.next(); ) {

      if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {

        num_active++;

        if (thr->is_Compiler_thread()) {

#if INCLUDE_JVMCI

          CompilerThread* ct = (CompilerThread*) thr;

          if (ct->compiler() == NULL || !ct->compiler()->is_jvmci() || !UseJVMCINativeLibrary) {

            num_active_compiler_thread++;

          } else {

            // When using a compiler in a JVMCI shared library, it's possible

            // for one compiler thread to grab a lock in the shared library,

            // enter HotSpot and go to sleep on the shutdown safepoint. Another

            // JVMCI shared library compiler thread can then attempt to grab the

            // lock and thus never make progress.

          }

#else

          num_active_compiler_thread++;

#endif

        }

      }

    }

    if (num_active == 0) {

       return 0;

    } else if (attempts > max_wait) {

       return num_active;

    } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {

       return num_active;

    }

    attempts++;

    MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);

    ml.wait(10);

  }

}

void VM_Exit::doit() {

  CompileBroker::set_should_block();

  // Wait for a short period for threads in native to block. Any thread

  // still executing native code after the wait will be stopped at

  // native==>Java/VM barriers.

  // Among 16276 JCK tests, 94% of them come here without any threads still

  // running in native; the other 6% are quiescent within 250ms (Ultra 80).

  wait_for_threads_in_native_to_block();

  set_vm_exited();

  // cleanup globals resources before exiting. exit_globals() currently

  // cleans up outputStream resources and PerfMemory resources.

  exit_globals();

  // Check for exit hook

  exit_hook_t exit_hook = Arguments::exit_hook();

  if (exit_hook != NULL) {

    // exit hook should exit.

    exit_hook(_exit_code);

    // ... but if it didn't, we must do it here