/*

 * Copyright (c) 1997, 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.

 *

 */

#ifndef SHARE_VM_RUNTIME_SAFEPOINTVERIFIERS_HPP

#define SHARE_VM_RUNTIME_SAFEPOINTVERIFIERS_HPP

#include "memory/allocation.hpp"

#include "runtime/thread.hpp"

// A NoGCVerifier object can be placed in methods where one assumes that

// no garbage collection will occur. The destructor will verify this property

// unless the constructor is called with argument false (not verifygc).

//

// The check will only be done in debug mode and if verifygc true.

class NoGCVerifier: public StackObj {

 friend class PauseNoGCVerifier;

 protected:

  bool _verifygc;

  unsigned int _old_invocations;

 public:

#ifdef ASSERT

  NoGCVerifier(bool verifygc = true);

  ~NoGCVerifier();

#else

  NoGCVerifier(bool verifygc = true) {}

  ~NoGCVerifier() {}

#endif

};

// A PauseNoGCVerifier is used to temporarily pause the behavior

// of a NoGCVerifier object. If we are not in debug mode or if the

// NoGCVerifier object has a _verifygc value of false, then there

// is nothing to do.

class PauseNoGCVerifier: public StackObj {

 private:

  NoGCVerifier * _ngcv;

 public:

#ifdef ASSERT

  PauseNoGCVerifier(NoGCVerifier * ngcv);

  ~PauseNoGCVerifier();

#else

  PauseNoGCVerifier(NoGCVerifier * ngcv) {}

  ~PauseNoGCVerifier() {}

#endif

};

// A NoSafepointVerifier object will throw an assertion failure if

// the current thread passes a possible safepoint while this object is

// instantiated. A safepoint, will either be: an oop allocation, blocking

// on a Mutex or JavaLock, or executing a VM operation.

//

// If StrictSafepointChecks is turned off, it degrades into a NoGCVerifier

//

class NoSafepointVerifier : public NoGCVerifier {

 friend class PauseNoSafepointVerifier;

 private:

  bool _activated;

  Thread *_thread;

 public:

#ifdef ASSERT

  NoSafepointVerifier(bool activated = true, bool verifygc = true ) :

    NoGCVerifier(verifygc),

    _activated(activated) {

    _thread = Thread::current();

    if (_activated) {

      _thread->_allow_allocation_count++;

      _thread->_allow_safepoint_count++;

    }

  }

  ~NoSafepointVerifier() {

    if (_activated) {

      _thread->_allow_allocation_count--;

      _thread->_allow_safepoint_count--;

    }

  }

#else

  NoSafepointVerifier(bool activated = true, bool verifygc = true) : NoGCVerifier(verifygc){}

  ~NoSafepointVerifier() {}

#endif

};

// A PauseNoSafepointVerifier is used to temporarily pause the

// behavior of a NoSafepointVerifier object. If we are not in debug

// mode then there is nothing to do. If the NoSafepointVerifier

// object has an _activated value of false, then there is nothing to

// do for safepoint and allocation checking, but there may still be

// something to do for the underlying NoGCVerifier object.

class PauseNoSafepointVerifier : public PauseNoGCVerifier {

 private:

  NoSafepointVerifier * _nsv;

 public:

#ifdef ASSERT

  PauseNoSafepointVerifier(NoSafepointVerifier * nsv)

    : PauseNoGCVerifier(nsv) {

    _nsv = nsv;

    if (_nsv->_activated) {

      _nsv->_thread->_allow_allocation_count--;

      _nsv->_thread->_allow_safepoint_count--;

    }

  }

  ~PauseNoSafepointVerifier() {

    if (_nsv->_activated) {

      _nsv->_thread->_allow_allocation_count++;

      _nsv->_thread->_allow_safepoint_count++;

    }

  }

#else

  PauseNoSafepointVerifier(NoSafepointVerifier * nsv)

    : PauseNoGCVerifier(nsv) {}

  ~PauseNoSafepointVerifier() {}

#endif

};

// A NoAllocVerifier object can be placed in methods where one assumes that

// no allocation will occur. The destructor will verify this property

// unless the constructor is called with argument false (not activated).

//

// The check will only be done in debug mode and if activated.

// Note: this only makes sense at safepoints (otherwise, other threads may

// allocate concurrently.)

class NoAllocVerifier : public StackObj {

 private:

  bool  _activated;

 public:

#ifdef ASSERT

  NoAllocVerifier(bool activated = true) {

    _activated = activated;

    if (_activated) Thread::current()->_allow_allocation_count++;

  }

  ~NoAllocVerifier() {

    if (_activated) Thread::current()->_allow_allocation_count--;

  }

#else

  NoAllocVerifier(bool activated = true) {}

  ~NoAllocVerifier() {}

#endif

};

#endif // SHARE_VM_RUNTIME_SAFEPOINTVERIFIERS_HPP