/*

 * Copyright (c) 1997, 2017, 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

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 */

#include "precompiled.hpp"

#include "interpreter/invocationCounter.hpp"

#include "runtime/frame.hpp"

#include "runtime/handles.inline.hpp"

// Implementation of InvocationCounter

void InvocationCounter::init() {

  _counter = 0;  // reset all the bits, including the sticky carry

  reset();

}

void InvocationCounter::reset() {

  // Only reset the state and don't make the method look like it's never

  // been executed

  set_state(wait_for_compile);

}

void InvocationCounter::set_carry() {

  set_carry_flag();

  // The carry bit now indicates that this counter had achieved a very

  // large value.  Now reduce the value, so that the method can be

  // executed many more times before re-entering the VM.

  int old_count = count();

  int new_count = MIN2(old_count, (int) (CompileThreshold / 2));

  // prevent from going to zero, to distinguish from never-executed methods

  if (new_count == 0)  new_count = 1;

  if (old_count != new_count)  set(state(), new_count);

}

void InvocationCounter::set_state(State state) {

  assert(0 <= state && state < number_of_states, "illegal state");

  int init = _init[state];

  // prevent from going to zero, to distinguish from never-executed methods

  if (init == 0 && count() > 0)  init = 1;

  int carry = (_counter & carry_mask);    // the carry bit is sticky

  _counter = (init << number_of_noncount_bits) | carry | state;

}

void InvocationCounter::print() {

  tty->print_cr("invocation count: up = %d, limit = %d, carry = %s, state = %s",

                                   count(), limit(),

                                   carry() ? "true" : "false",

                                   state_as_string(state()));

}

void InvocationCounter::print_short() {

  tty->print(" [%d%s;%s]", count(), carry()?"+carry":"", state_as_short_string(state()));

}

// Initialization

int                       InvocationCounter::_init  [InvocationCounter::number_of_states];

InvocationCounter::Action InvocationCounter::_action[InvocationCounter::number_of_states];

int                       InvocationCounter::InterpreterInvocationLimit;

int                       InvocationCounter::InterpreterBackwardBranchLimit;

int                       InvocationCounter::InterpreterProfileLimit;

const char* InvocationCounter::state_as_string(State state) {

  switch (state) {

    case wait_for_nothing            : return "wait_for_nothing";

    case wait_for_compile            : return "wait_for_compile";

    default:

      ShouldNotReachHere();

      return NULL;

  }

}

const char* InvocationCounter::state_as_short_string(State state) {

  switch (state) {

    case wait_for_nothing            : return "not comp.";

    case wait_for_compile            : return "compileable";

    default:

      ShouldNotReachHere();

      return NULL;

  }

}

  // dummy action for inactive invocation counters

  MethodCounters* mcs = method->method_counters();

  assert(mcs != NULL, "");

  mcs->invocation_counter()->set_carry();

  mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);

  return NULL;

}

  // decay invocation counters so compilation gets delayed

  MethodCounters* mcs = method->method_counters();

  assert(mcs != NULL, "");

  mcs->invocation_counter()->decay();

  return NULL;

}

void InvocationCounter::def(State state, int init, Action action) {

  assert(0 <= state && state < number_of_states, "illegal state");

  assert(0 <= init  && init  < count_limit, "initial value out of range");

  _init  [state] = init;

  _action[state] = action;

}

  ShouldNotReachHere();

  return NULL;

}

void InvocationCounter::reinitialize(bool delay_overflow) {

  // define states

  guarantee((int)number_of_states <= (int)state_limit, "adjust number_of_state_bits");

  def(wait_for_nothing, 0, do_nothing);

  if (delay_overflow) {

    def(wait_for_compile, 0, do_decay);

  } else {

    def(wait_for_compile, 0, dummy_invocation_counter_overflow);

  }

  InterpreterInvocationLimit = CompileThreshold << number_of_noncount_bits;

  InterpreterProfileLimit = ((CompileThreshold * InterpreterProfilePercentage) / 100)<< number_of_noncount_bits;

  // When methodData is collected, the backward branch limit is compared against a

  // methodData counter, rather than an InvocationCounter.  In the former case, we

  // don't need the shift by number_of_noncount_bits, but we do need to adjust

  // the factor by which we scale the threshold.

  if (ProfileInterpreter) {

    InterpreterBackwardBranchLimit = (CompileThreshold * (OnStackReplacePercentage - InterpreterProfilePercentage)) / 100;

  } else {

    InterpreterBackwardBranchLimit = ((CompileThreshold * OnStackReplacePercentage) / 100) << number_of_noncount_bits;

  }

  assert(0 <= InterpreterBackwardBranchLimit,

         "OSR threshold should be non-negative");

  assert(0 <= InterpreterProfileLimit &&

         InterpreterProfileLimit <= InterpreterInvocationLimit,

         "profile threshold should be less than the compilation threshold "

         "and non-negative");

}

void invocationCounter_init() {

  InvocationCounter::reinitialize(DelayCompilationDuringStartup);

}