/*

 * Copyright (c) 2003, 2015, 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 "jvmtifiles/jvmtiEnv.hpp"

#include "memory/resourceArea.hpp"

#include "prims/jvmtiEventController.inline.hpp"

#include "prims/jvmtiImpl.hpp"

#include "prims/jvmtiThreadState.inline.hpp"

#include "runtime/vframe.hpp"

// marker for when the stack depth has been reset and is now unknown.

// any negative number would work but small ones might obscure an

// underrun error.

static const int UNKNOWN_STACK_DEPTH = -99;

///////////////////////////////////////////////////////////////

//

// class JvmtiThreadState

//

// Instances of JvmtiThreadState hang off of each thread.

// Thread local storage for JVMTI.

//

JvmtiThreadState *JvmtiThreadState::_head = NULL;

JvmtiThreadState::JvmtiThreadState(JavaThread* thread)

  : _thread_event_enable() {

  assert(JvmtiThreadState_lock->is_locked(), "sanity check");

  _thread               = thread;

  _exception_state      = ES_CLEARED;

  _debuggable           = true;

  _hide_single_stepping = false;

  _hide_level           = 0;

  _pending_step_for_popframe = false;

  _class_being_redefined = NULL;

  _class_load_kind = jvmti_class_load_kind_load;

  _head_env_thread_state = NULL;

  _dynamic_code_event_collector = NULL;

  _vm_object_alloc_event_collector = NULL;

  _the_class_for_redefinition_verification = NULL;

  _scratch_class_for_redefinition_verification = NULL;

  _cur_stack_depth = UNKNOWN_STACK_DEPTH;

  // JVMTI ForceEarlyReturn support

  _pending_step_for_earlyret = false;

  _earlyret_state = earlyret_inactive;

  _earlyret_tos = ilgl;

  _earlyret_value.j = 0L;

  _earlyret_oop = NULL;

  // add all the JvmtiEnvThreadState to the new JvmtiThreadState

  {

    JvmtiEnvIterator it;

    for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {

      if (env->is_valid()) {

        add_env(env);

      }

    }

  }

  // link us into the list

  {

    // The thread state list manipulation code must not have safepoints.

    // See periodic_clean_up().

    debug_only(NoSafepointVerifier nosafepoint;)

    _prev = NULL;

    _next = _head;

    if (_head != NULL) {

      _head->_prev = this;

    }

    _head = this;

  }

  // set this as the state for the thread

  thread->set_jvmti_thread_state(this);

}

JvmtiThreadState::~JvmtiThreadState()   {

  assert(JvmtiThreadState_lock->is_locked(), "sanity check");

  // clear this as the state for the thread

  get_thread()->set_jvmti_thread_state(NULL);

  // zap our env thread states

  {

    JvmtiEnvBase::entering_dying_thread_env_iteration();

    JvmtiEnvThreadStateIterator it(this);

    for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ) {

      JvmtiEnvThreadState* zap = ets;

      ets = it.next(ets);

      delete zap;

    }

    JvmtiEnvBase::leaving_dying_thread_env_iteration();

  }

  // remove us from the list

  {

    // The thread state list manipulation code must not have safepoints.

    // See periodic_clean_up().

    debug_only(NoSafepointVerifier nosafepoint;)

    if (_prev == NULL) {

      assert(_head == this, "sanity check");

      _head = _next;

    } else {

      assert(_head != this, "sanity check");

      _prev->_next = _next;

    }

    if (_next != NULL) {

      _next->_prev = _prev;

    }

    _next = NULL;

    _prev = NULL;

  }

}

void

JvmtiThreadState::periodic_clean_up() {

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

  // This iteration is initialized with "_head" instead of "JvmtiThreadState::first()"

  // because the latter requires the JvmtiThreadState_lock.

  // This iteration is safe at a safepoint as well, see the NoSafepointVerifier

  // asserts at all list manipulation sites.

  for (JvmtiThreadState *state = _head; state != NULL; state = state->next()) {

    // For each environment thread state corresponding to an invalid environment

    // unlink it from the list and deallocate it.

    JvmtiEnvThreadStateIterator it(state);

    JvmtiEnvThreadState* previous_ets = NULL;

    JvmtiEnvThreadState* ets = it.first();

    while (ets != NULL) {

      if (ets->get_env()->is_valid()) {

        previous_ets = ets;

        ets = it.next(ets);

      } else {

        // This one isn't valid, remove it from the list and deallocate it

        JvmtiEnvThreadState* defunct_ets = ets;

        ets = ets->next();

        if (previous_ets == NULL) {

          assert(state->head_env_thread_state() == defunct_ets, "sanity check");

          state->set_head_env_thread_state(ets);

        } else {

          previous_ets->set_next(ets);

        }

        delete defunct_ets;

      }

    }

  }

}

void JvmtiThreadState::add_env(JvmtiEnvBase *env) {

  assert(JvmtiThreadState_lock->is_locked(), "sanity check");

  JvmtiEnvThreadState *new_ets = new JvmtiEnvThreadState(_thread, env);

  // add this environment thread state to the end of the list (order is important)

  {

    // list deallocation (which occurs at a safepoint) cannot occur simultaneously

    debug_only(NoSafepointVerifier nosafepoint;)

    JvmtiEnvThreadStateIterator it(this);

    JvmtiEnvThreadState* previous_ets = NULL;

    for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {

      previous_ets = ets;

    }

    if (previous_ets == NULL) {

      set_head_env_thread_state(new_ets);

    } else {

      previous_ets->set_next(new_ets);

    }

  }

}

void JvmtiThreadState::enter_interp_only_mode() {

  assert(_thread->get_interp_only_mode() == 0, "entering interp only when mode not zero");

  _thread->increment_interp_only_mode();

}

void JvmtiThreadState::leave_interp_only_mode() {

  assert(_thread->get_interp_only_mode() == 1, "leaving interp only when mode not one");

  _thread->decrement_interp_only_mode();

}

// Helper routine used in several places

int JvmtiThreadState::count_frames() {

  guarantee(SafepointSynchronize::is_at_safepoint() ||

    (JavaThread *)Thread::current() == get_thread(),

    "must be current thread or at safepoint");

  if (!get_thread()->has_last_Java_frame()) return 0;  // no Java frames

  ResourceMark rm;

  RegisterMap reg_map(get_thread());

  javaVFrame *jvf = get_thread()->last_java_vframe(&reg_map);

  int n = 0;

  while (jvf != NULL) {

    Method* method = jvf->method();

    jvf = jvf->java_sender();

    n++;

  }

  return n;

}

void JvmtiThreadState::invalidate_cur_stack_depth() {

  guarantee(SafepointSynchronize::is_at_safepoint() ||

    (JavaThread *)Thread::current() == get_thread(),

    "must be current thread or at safepoint");

  _cur_stack_depth = UNKNOWN_STACK_DEPTH;

}

void JvmtiThreadState::incr_cur_stack_depth() {

  guarantee(JavaThread::current() == get_thread(), "must be current thread");

  if (!is_interp_only_mode()) {

    _cur_stack_depth = UNKNOWN_STACK_DEPTH;

  }

  if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {

    ++_cur_stack_depth;

  }

}

void JvmtiThreadState::decr_cur_stack_depth() {

  guarantee(JavaThread::current() == get_thread(), "must be current thread");

  if (!is_interp_only_mode()) {

    _cur_stack_depth = UNKNOWN_STACK_DEPTH;

  }

  if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {

    --_cur_stack_depth;

    assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch");

  }

}

int JvmtiThreadState::cur_stack_depth() {

  guarantee(SafepointSynchronize::is_at_safepoint() ||

    (JavaThread *)Thread::current() == get_thread(),

    "must be current thread or at safepoint");

  if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) {

    _cur_stack_depth = count_frames();

  } else {

    // heavy weight assert

    assert(_cur_stack_depth == count_frames(),

           "cur_stack_depth out of sync");

  }

  return _cur_stack_depth;

}

bool JvmtiThreadState::may_be_walked() {

  return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread()));

}

void JvmtiThreadState::process_pending_step_for_popframe() {

  // We are single stepping as the last part of the PopFrame() dance

  // so we have some house keeping to do.

  JavaThread *thr = get_thread();

  if (thr->popframe_condition() != JavaThread::popframe_inactive) {

    // If the popframe_condition field is not popframe_inactive, then

    // we missed all of the popframe_field cleanup points:

    //

    // - unpack_frames() was not called (nothing to deopt)

    // - remove_activation_preserving_args_entry() was not called

    //   (did not get suspended in a call_vm() family call and did

    //   not complete a call_vm() family call on the way here)

    thr->clear_popframe_condition();

  }

  // clearing the flag indicates we are done with the PopFrame() dance

  clr_pending_step_for_popframe();

  // If exception was thrown in this frame, need to reset jvmti thread state.

  // Single stepping may not get enabled correctly by the agent since

  // exception state is passed in MethodExit event which may be sent at some

  // time in the future. JDWP agent ignores MethodExit events if caused by

  // an exception.

  //

  if (is_exception_detected()) {

    clear_exception_state();

  }

  // If step is pending for popframe then it may not be

  // a repeat step. The new_bci and method_id is same as current_bci

  // and current method_id after pop and step for recursive calls.

  // Force the step by clearing the last location.

  JvmtiEnvThreadStateIterator it(this);

  for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {

    ets->clear_current_location();

  }

}

// Class:     JvmtiThreadState

// Function:  update_for_pop_top_frame

// Description:

//   This function removes any frame pop notification request for

//   the top frame and invalidates both the current stack depth and

//   all cached frameIDs.

//

// Called by: PopFrame

//

void JvmtiThreadState::update_for_pop_top_frame() {

  if (is_interp_only_mode()) {

    // remove any frame pop notification request for the top frame

    // in any environment

    int popframe_number = cur_stack_depth();

    {

      JvmtiEnvThreadStateIterator it(this);

      for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {

        if (ets->is_frame_pop(popframe_number)) {

          ets->clear_frame_pop(popframe_number);

        }

      }

    }

    // force stack depth to be recalculated

    invalidate_cur_stack_depth();

  } else {

    assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set");

  }

}

void JvmtiThreadState::process_pending_step_for_earlyret() {

  // We are single stepping as the last part of the ForceEarlyReturn

  // dance so we have some house keeping to do.

  if (is_earlyret_pending()) {

    // If the earlyret_state field is not earlyret_inactive, then

    // we missed all of the earlyret_field cleanup points:

    //

    // - remove_activation() was not called

    //   (did not get suspended in a call_vm() family call and did

    //   not complete a call_vm() family call on the way here)

    //

    // One legitimate way for us to miss all the cleanup points is

    // if we got here right after handling a compiled return. If that

    // is the case, then we consider our return from compiled code to

    // complete the ForceEarlyReturn request and we clear the condition.

    clr_earlyret_pending();

    set_earlyret_oop(NULL);

    clr_earlyret_value();

  }

  // clearing the flag indicates we are done with

  // the ForceEarlyReturn() dance

  clr_pending_step_for_earlyret();

  // If exception was thrown in this frame, need to reset jvmti thread state.

  // Single stepping may not get enabled correctly by the agent since

  // exception state is passed in MethodExit event which may be sent at some

  // time in the future. JDWP agent ignores MethodExit events if caused by

  // an exception.

  //

  if (is_exception_detected()) {

    clear_exception_state();

  }

  // If step is pending for earlyret then it may not be a repeat step.

  // The new_bci and method_id is same as current_bci and current

  // method_id after earlyret and step for recursive calls.

  // Force the step by clearing the last location.

  JvmtiEnvThreadStateIterator it(this);

  for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {

    ets->clear_current_location();

  }

}

void JvmtiThreadState::oops_do(OopClosure* f) {

  f->do_oop((oop*) &_earlyret_oop);

}