/* * Copyright (c) 2002, 2022, 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. *
*/
// // An object for encapsulating the machine/os dependent part of a JavaThread frame state // class JavaThread; class MacroAssembler; class UpcallLinker; class ZeroFrame;
private: // // Whenever _last_Java_sp != NULL other anchor fields MUST be valid! // The stack may not be walkable [check with walkable() ] but the values must be valid. // The profiler apparently depends on this. //
intptr_t* volatile _last_Java_sp;
// Whenever we call from Java to native we can not be assured that the return // address that composes the last_Java_frame will be in an accessible location // so calls from Java to native store that pc (or one good enough to locate // the oopmap) in the frame anchor. Since the frames that call from Java to // native are never deoptimized we never need to patch the pc and so this // is acceptable. volatile address _last_Java_pc;
// tells whether the last Java frame is set // It is important that when last_Java_sp != NULL that the rest of the frame // anchor (including platform specific) all be valid.
bool has_last_Java_frame() const { return _last_Java_sp != NULL; } // This is very dangerous unless sp == NULL // Invalidate the anchor so that has_last_frame is false // and no one should look at the other fields. void zap(void) { _last_Java_sp = NULL; }
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