Java example source code file (unhandledOops.cpp)

This example Java source code file (unhandledOops.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bad_oop_addr, check_unhandled_oops, checkunhandledoops, growablearray, intptr_format, resourceobj\:\:c_heap, unhandledoopentry, unhandledoops\:\:allow_unhandled_oop, unhandledoops\:\:clear_unhandled_oops, unhandledoops\:\:dump_oops, unhandledoops\:\:register_unhandled_oop, unhandledoops\:\:unhandledoops, unhandledoops\:\:unregister_unhandled_oop

The unhandledOops.cpp Java example source code

/*
 * Copyright (c) 2005, 2012, 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 "gc_interface/collectedHeap.hpp"
#include "memory/gcLocker.inline.hpp"
#include "memory/universe.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/thread.hpp"
#include "runtime/unhandledOops.hpp"
#include "utilities/globalDefinitions.hpp"

#ifdef CHECK_UNHANDLED_OOPS
const int free_list_size = 256;


UnhandledOops::UnhandledOops(Thread* thread) {
  _thread = thread;
  _oop_list = new (ResourceObj::C_HEAP, mtInternal)
                    GrowableArray<UnhandledOopEntry>(free_list_size, true);
  _level = 0;
}

UnhandledOops::~UnhandledOops() {
  delete _oop_list;
}


void UnhandledOops::dump_oops(UnhandledOops *list) {
  for (int k = 0; k < list->_oop_list->length(); k++) {
    UnhandledOopEntry entry = list->_oop_list->at(k);
    tty->print(" " INTPTR_FORMAT, entry._oop_ptr);
  }
  tty->cr();
}

// For debugging unhandled oop detector _in the debugger_
// You don't want to turn it on in compiled code here.
static bool unhandled_oop_print=0;

void UnhandledOops::register_unhandled_oop(oop* op, address pc) {
  if (!_thread->is_in_stack((address)op))
    return;

  _level ++;
  if (unhandled_oop_print) {
    for (int i=0; i<_level; i++) tty->print(" ");
    tty->print_cr("r " INTPTR_FORMAT, op);
  }
  UnhandledOopEntry entry(op, pc);
  _oop_list->push(entry);
}


bool match_oop_entry(void *op, UnhandledOopEntry e) {
  return (e.oop_ptr() == op);
}

// Mark unhandled oop as okay for GC - the containing struct has an oops_do and
// for some reason the oop has to be on the stack.
// May not be called for the current thread, as in the case of
// VM_GetOrSetLocal in jvmti.
void UnhandledOops::allow_unhandled_oop(oop* op) {
  assert (CheckUnhandledOops, "should only be called with checking option");

  int i = _oop_list->find_from_end(op, match_oop_entry);
  assert(i!=-1, "safe for gc oop not in unhandled_oop_list");

  UnhandledOopEntry entry = _oop_list->at(i);
  assert(!entry._ok_for_gc, "duplicate entry");
  entry._ok_for_gc = true;
  _oop_list->at_put(i, entry);
}


// Called by the oop destructor to remove unhandled oop from the thread's
// oop list.  All oops given are assumed to be on the list.  If not,
// there's a bug in the unhandled oop detector.
void UnhandledOops::unregister_unhandled_oop(oop* op) {
  if (!_thread->is_in_stack((address)op)) return;

  _level --;
  if (unhandled_oop_print) {
    for (int i=0; i<_level; i++) tty->print(" ");
    tty->print_cr("u "INTPTR_FORMAT, op);
  }

  int i = _oop_list->find_from_end(op, match_oop_entry);
  assert(i!=-1, "oop not in unhandled_oop_list");
  _oop_list->remove_at(i);
}

void UnhandledOops::clear_unhandled_oops() {
  assert (CheckUnhandledOops, "should only be called with checking option");
  if (_thread->is_gc_locked_out()) {
    return;
  }
  for (int k = 0; k < _oop_list->length(); k++) {
    UnhandledOopEntry entry = _oop_list->at(k);
    // If an entry is on the unhandled oop list but isn't on the stack
    // anymore, it must not have gotten unregistered properly and it's a bug
    // in the unhandled oop generator.
    if(!_thread->is_in_stack((address)entry._oop_ptr)) {
      tty->print_cr("oop_ptr is " INTPTR_FORMAT, (address)entry._oop_ptr);
      tty->print_cr("thread is " INTPTR_FORMAT " from pc " INTPTR_FORMAT,
                     (address)_thread, (address)entry._pc);
      assert(false, "heap is corrupted by the unhandled oop detector");
    }
    // Set unhandled oops to a pattern that will crash distinctively
    if (!entry._ok_for_gc) *(intptr_t*)(entry._oop_ptr) = BAD_OOP_ADDR;
  }
}
#endif // CHECK_UNHANDLED_OOPS