/*

 * 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 "runtime/frame.inline.hpp"

#include "runtime/vframe.hpp"

inline vframeStreamCommon::vframeStreamCommon(JavaThread* thread) : _reg_map(thread, false) {

  _thread = thread;

}

inline intptr_t* vframeStreamCommon::frame_id() const        { return _frame.id(); }

inline bool vframeStreamCommon::is_interpreted_frame() const { return _frame.is_interpreted_frame(); }

inline bool vframeStreamCommon::is_entry_frame() const       { return _frame.is_entry_frame(); }

inline void vframeStreamCommon::next() {

  // handle frames with inlining

  if (_mode == compiled_mode    && fill_in_compiled_inlined_sender()) return;

  // handle general case

  do {

    _prev_frame = _frame;

    _frame = _frame.sender(&_reg_map);

  } while (!fill_from_frame());

}

inline vframeStream::vframeStream(JavaThread* thread, bool stop_at_java_call_stub)

  : vframeStreamCommon(thread) {

  _stop_at_java_call_stub = stop_at_java_call_stub;

  if (!thread->has_last_Java_frame()) {

    _mode = at_end_mode;

    return;

  }

  _frame = _thread->last_frame();

  while (!fill_from_frame()) {

    _prev_frame = _frame;

    _frame = _frame.sender(&_reg_map);

  }

}

inline bool vframeStreamCommon::fill_in_compiled_inlined_sender() {

  if (_sender_decode_offset == DebugInformationRecorder::serialized_null) {

    return false;

  }

  fill_from_compiled_frame(_sender_decode_offset);

  ++_vframe_id;

  return true;

}

inline void vframeStreamCommon::fill_from_compiled_frame(int decode_offset) {

  _mode = compiled_mode;

  _decode_offset = decode_offset;

  // Range check to detect ridiculous offsets.

  if (decode_offset == DebugInformationRecorder::serialized_null ||

      decode_offset < 0 ||

      decode_offset >= nm()->scopes_data_size()) {

    // 6379830 AsyncGetCallTrace sometimes feeds us wild frames.

    // If we read nmethod::scopes_data at serialized_null (== 0)

    // or if read some at other invalid offset, invalid values will be decoded.

    // Based on these values, invalid heap locations could be referenced

    // that could lead to crashes in product mode.

    // Therefore, do not use the decode offset if invalid, but fill the frame

    // as it were a native compiled frame (no Java-level assumptions).

#ifdef ASSERT

    if (WizardMode) {

      ttyLocker ttyl;

      tty->print_cr("Error in fill_from_frame: pc_desc for "

                    INTPTR_FORMAT " not found or invalid at %d",

                    p2i(_frame.pc()), decode_offset);

      nm()->print();

      nm()->method()->print_codes();

      nm()->print_code();

      nm()->print_pcs();

    }

    found_bad_method_frame();

#endif

    // Provide a cheap fallback in product mode.  (See comment above.)

    fill_from_compiled_native_frame();

    return;

  }

  // Decode first part of scopeDesc

  DebugInfoReadStream buffer(nm(), decode_offset);

  _sender_decode_offset = buffer.read_int();

  _method               = buffer.read_method();

  _bci                  = buffer.read_bci();

  assert(_method->is_method(), "checking type of decoded method");

}

// The native frames are handled specially. We do not rely on ScopeDesc info

// since the pc might not be exact due to the _last_native_pc trick.

inline void vframeStreamCommon::fill_from_compiled_native_frame() {

  _mode = compiled_mode;

  _sender_decode_offset = DebugInformationRecorder::serialized_null;

  _decode_offset = DebugInformationRecorder::serialized_null;

  _vframe_id = 0;

  _method = nm()->method();

  _bci = 0;

}

inline bool vframeStreamCommon::fill_from_frame() {

  // Interpreted frame

  if (_frame.is_interpreted_frame()) {

    fill_from_interpreter_frame();

    return true;

  }

  // Compiled frame

  if (cb() != NULL && cb()->is_compiled()) {

    if (nm()->is_native_method()) {

      // Do not rely on scopeDesc since the pc might be unprecise due to the _last_native_pc trick.

      fill_from_compiled_native_frame();

    } else {

      PcDesc* pc_desc = nm()->pc_desc_at(_frame.pc());

      int decode_offset;

      if (pc_desc == NULL) {

        // Should not happen, but let fill_from_compiled_frame handle it.

        // If we are trying to walk the stack of a thread that is not

        // at a safepoint (like AsyncGetCallTrace would do) then this is an

        // acceptable result. [ This is assuming that safe_for_sender

        // is so bullet proof that we can trust the frames it produced. ]

        //

        // So if we see that the thread is not safepoint safe

        // then simply produce the method and a bci of zero

        // and skip the possibility of decoding any inlining that

        // may be present. That is far better than simply stopping (or

        // asserting. If however the thread is safepoint safe this

        // is the sign of a compiler bug  and we'll let

        // fill_from_compiled_frame handle it.

        JavaThreadState state = _thread->thread_state();

        // in_Java should be good enough to test safepoint safety

        // if state were say in_Java_trans then we'd expect that

        // the pc would have already been slightly adjusted to

        // one that would produce a pcDesc since the trans state

        // would be one that might in fact anticipate a safepoint

        if (state == _thread_in_Java ) {

          // This will get a method a zero bci and no inlining.

          // Might be nice to have a unique bci to signify this

          // particular case but for now zero will do.

          fill_from_compiled_native_frame();

          // There is something to be said for setting the mode to

          // at_end_mode to prevent trying to walk further up the

          // stack. There is evidence that if we walk any further

          // that we could produce a bad stack chain. However until

          // we see evidence that allowing this causes us to find

          // frames bad enough to cause segv's or assertion failures

          // we don't do it as while we may get a bad call chain the

          // probability is much higher (several magnitudes) that we

          // get good data.

          return true;

        }

        decode_offset = DebugInformationRecorder::serialized_null;

      } else {

        decode_offset = pc_desc->scope_decode_offset();

      }

      fill_from_compiled_frame(decode_offset);

      _vframe_id = 0;

    }

    return true;

  }

  // End of stack?

  if (_frame.is_first_frame() || (_stop_at_java_call_stub && _frame.is_entry_frame())) {

    _mode = at_end_mode;

    return true;

  }

  return false;

}

inline void vframeStreamCommon::fill_from_interpreter_frame() {

  Method* method = _frame.interpreter_frame_method();

  address   bcp    = _frame.interpreter_frame_bcp();

  int       bci    = method->validate_bci_from_bcp(bcp);

  // 6379830 AsyncGetCallTrace sometimes feeds us wild frames.

  // AsyncGetCallTrace interrupts the VM asynchronously. As a result

  // it is possible to access an interpreter frame for which

  // no Java-level information is yet available (e.g., becasue

  // the frame was being created when the VM interrupted it).

  // In this scenario, pretend that the interpreter is at the point

  // of entering the method.

  if (bci < 0) {

    DEBUG_ONLY(found_bad_method_frame();)

    bci = 0;

  }

  _mode   = interpreted_mode;

  _method = method;

  _bci    = bci;

}