/*

 * Copyright (c) 2003, 2010, 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 "runtime/frame.inline.hpp"

#include "runtime/thread.inline.hpp"

// For Forte Analyzer AsyncGetCallTrace profiling support - thread is

// currently interrupted by SIGPROF

bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,

                                                     void* ucontext,

                                                     bool isInJava) {

  assert(Thread::current() == this, "caller must be current thread");

  assert(this->is_Java_thread(), "must be JavaThread");

  JavaThread* jt = (JavaThread *)this;

  if (!isInJava) {

    // make_walkable flushes register windows and grabs last_Java_pc

    // which can not be done if the ucontext sp matches last_Java_sp

    // stack walking utilities assume last_Java_pc set if marked flushed

    jt->frame_anchor()->make_walkable(jt);

  }

  // If we have a walkable last_Java_frame, then we should use it

  // even if isInJava == true. It should be more reliable than

  // ucontext info.

  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {

    *fr_addr = jt->pd_last_frame();

    return true;

  }

  ucontext_t* uc = (ucontext_t*) ucontext;

  // At this point, we don't have a walkable last_Java_frame, so

  // we try to glean some information out of the ucontext.

  intptr_t* ret_sp;

  ExtendedPC addr =

    os::fetch_frame_from_context(uc, &ret_sp,

                                 NULL /* ret_fp only used on X86 */);

  if (addr.pc() == NULL || ret_sp == NULL) {

    // ucontext wasn't useful

    return false;

  }

  // we were running Java code when SIGPROF came in

  if (isInJava) {

    // If we have a last_Java_sp, then the SIGPROF signal caught us

    // right when we were transitioning from _thread_in_Java to a new

    // JavaThreadState. We use last_Java_sp instead of the sp from

    // the ucontext since it should be more reliable.

    if (jt->has_last_Java_frame()) {

      ret_sp = jt->last_Java_sp();

    }

    // Implied else: we don't have a last_Java_sp so we use what we

    // got from the ucontext.

    frame ret_frame(ret_sp, frame::unpatchable, addr.pc());

    if (!ret_frame.safe_for_sender(jt)) {

      // nothing else to try if the frame isn't good

      return false;

    }

    *fr_addr = ret_frame;

    return true;

  }

  // At this point, we know we weren't running Java code. We might

  // have a last_Java_sp, but we don't have a walkable frame.

  // However, we might still be able to construct something useful

  // if the thread was running native code.

  if (jt->has_last_Java_frame()) {

    assert(!jt->frame_anchor()->walkable(), "case covered above");

    if (jt->thread_state() == _thread_in_native) {

      frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());

      if (!ret_frame.safe_for_sender(jt)) {

        // nothing else to try if the frame isn't good

        return false;

      }

      *fr_addr = ret_frame;

      return true;

    }

  }

  // nothing else to try

  return false;

}

void JavaThread::cache_global_variables() { }