1 /* 2 * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 class BasicLock VALUE_OBJ_CLASS_SPEC { 26 friend class VMStructs; 27 private: 28 volatile markOop _displaced_header; 29 public: 30 markOop displaced_header() const { return _displaced_header; } 31 void set_displaced_header(markOop header) { _displaced_header = header; } 32 33 void print_on(outputStream* st) const; 34 35 // move a basic lock (used during deoptimization 36 void move_to(oop obj, BasicLock* dest); 37 38 static int displaced_header_offset_in_bytes() { return offset_of(BasicLock, _displaced_header); } 39 }; 40 41 // A BasicObjectLock associates a specific Java object with a BasicLock. 42 // It is currently embedded in an interpreter frame. 43 44 // Because some machines have alignment restrictions on the control stack, 45 // the actual space allocated by the interpreter may include padding words 46 // after the end of the BasicObjectLock. Also, in order to guarantee 47 // alignment of the embedded BasicLock objects on such machines, we 48 // put the embedded BasicLock at the beginning of the struct. 49 50 class BasicObjectLock VALUE_OBJ_CLASS_SPEC { 51 friend class VMStructs; 52 private: 53 BasicLock _lock; // the lock, must be double word aligned 54 oop _obj; // object holds the lock; 55 56 public: 57 // Manipulation 58 oop obj() const { return _obj; } 59 void set_obj(oop obj) { _obj = obj; } 60 BasicLock* lock() { return &_lock; } 61 62 // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks 63 // in interpreter activation frames since it includes machine-specific padding. 64 static int size() { return sizeof(BasicObjectLock)/wordSize; } 65 66 // GC support 67 void oops_do(OopClosure* f) { f->do_oop(&_obj); } 68 69 static int obj_offset_in_bytes() { return offset_of(BasicObjectLock, _obj); } 70 static int lock_offset_in_bytes() { return offset_of(BasicObjectLock, _lock); } 71 }; 72