/*

 * Copyright (c) 2012, 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.

 *

 */

#include "precompiled.hpp"

#include "code/debugInfoRec.hpp"

#include "code/nmethod.hpp"

#include "code/pcDesc.hpp"

#include "jfr/periodic/sampling/jfrCallTrace.hpp"

#include "oops/method.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/registerMap.hpp"

#include "runtime/thread.inline.hpp"

bool JfrGetCallTrace::find_top_frame(frame& top_frame, Method** method, frame& first_frame) {

  assert(top_frame.cb() != NULL, "invariant");

  RegisterMap map(_thread, false);

  frame candidate = top_frame;

  for (int i = 0; i < MaxJavaStackTraceDepth * 2; ++i) {

    if (candidate.is_entry_frame()) {

      JavaCallWrapper *jcw = candidate.entry_frame_call_wrapper_if_safe(_thread);

      if (jcw == NULL || jcw->is_first_frame()) {

        return false;

      }

    }

    if (candidate.is_interpreted_frame()) {

      JavaThreadState state = _thread->thread_state();

      const bool known_valid = (state == _thread_in_native || state == _thread_in_vm || state == _thread_blocked);

      if (known_valid || candidate.is_interpreted_frame_valid(_thread)) {

        Method* im = candidate.interpreter_frame_method();

        if (known_valid && !im->is_valid_method()) {

          return false;

        }

        *method = im;

        first_frame = candidate;

        return true;

      }

    }

    if (candidate.cb()->is_nmethod()) {

      // first check to make sure that we have a sane stack,

      // the PC is actually inside the code part of the codeBlob,

      // and we are past is_frame_complete_at (stack has been setup)

      if (!candidate.safe_for_sender(_thread)) {

        return false;

      }

      nmethod* nm = (nmethod*)candidate.cb();

      *method = nm->method();

      if (_in_java) {

        PcDesc* pc_desc = nm->pc_desc_near(candidate.pc() + 1);

        if (pc_desc == NULL || pc_desc->scope_decode_offset() == DebugInformationRecorder::serialized_null) {

          return false;

        }

        candidate.set_pc(pc_desc->real_pc(nm));

        assert(nm->pc_desc_at(candidate.pc()) != NULL, "invalid pc");

      }

      first_frame = candidate;

      return true;

    }

    if (!candidate.safe_for_sender(_thread) ||

      candidate.is_stub_frame() ||

      candidate.cb()->frame_size() <= 0) {

      return false;

    }

    candidate = candidate.sender(&map);

    if (candidate.cb() == NULL) {

      return false;

    }

  }

  return false;

}

bool JfrGetCallTrace::get_topframe(void* ucontext, frame& topframe) {

  if (!_thread->pd_get_top_frame_for_profiling(&topframe, ucontext, _in_java)) {

    return false;

  }

  if (topframe.cb() == NULL) {

    return false;

  }

  frame first_java_frame;

  Method* method = NULL;

  if (find_top_frame(topframe, &method, first_java_frame)) {

    if (method == NULL) {

      return false;

    }

    topframe = first_java_frame;

    return true;

  }

  return false;

}