view src/os/posix/vm/os_posix.hpp @ 15388:769fc3629f59

Add phase FlowSensitiveReductionPhase. It is possible to remove GuardingPiNodes, CheckCastNodes, and FixedGuards during HighTier under certain conditions (control-flow sensitive conditions). The phase added in this commit (FlowSensitiveReductionPhase) does that, and in addition replaces usages with "downcasting" PiNodes when possible thus resulting in more precise object stamps (e.g., non-null). Finally, usages of floating, side-effects free, expressions are also simplified (as per control-flow sensitive conditions). The newly added phase runs only during HighTier and can be deactivated using Graal option FlowSensitiveReduction (it is active by default).
author Miguel Garcia <miguel.m.garcia@oracle.com>
date Fri, 25 Apr 2014 16:50:52 +0200
parents 4ca6dc0799b6
children 89152779163c
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/*
 * Copyright (c) 1999, 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.
 *
 */

#ifndef OS_POSIX_VM_OS_POSIX_HPP
#define OS_POSIX_VM_OS_POSIX_HPP
class Posix {
  friend class os;

protected:
  static void print_distro_info(outputStream* st);
  static void print_rlimit_info(outputStream* st);
  static void print_uname_info(outputStream* st);
  static void print_libversion_info(outputStream* st);
  static void print_load_average(outputStream* st);


};

/*
 * Crash protection for the watcher thread. Wrap the callback
 * with a sigsetjmp and in case of a SIGSEGV/SIGBUS we siglongjmp
 * back.
 * To be able to use this - don't take locks, don't rely on destructors,
 * don't make OS library calls, don't allocate memory, don't print,
 * don't call code that could leave the heap / memory in an inconsistent state,
 * or anything else where we are not in control if we suddenly jump out.
 */
class WatcherThreadCrashProtection : public StackObj {
public:
  WatcherThreadCrashProtection();
  bool call(os::CrashProtectionCallback& cb);

  static void check_crash_protection(int signal, Thread* thread);
private:
  void restore();
  sigjmp_buf _jmpbuf;
};

#endif