001 /* 002 * This file is part of the Jikes RVM project (http://jikesrvm.org). 003 * 004 * This file is licensed to You under the Eclipse Public License (EPL); 005 * You may not use this file except in compliance with the License. You 006 * may obtain a copy of the License at 007 * 008 * http://www.opensource.org/licenses/eclipse-1.0.php 009 * 010 * See the COPYRIGHT.txt file distributed with this work for information 011 * regarding copyright ownership. 012 */ 013 package org.jikesrvm.mm.mminterface; 014 015 import org.jikesrvm.SizeConstants; 016 017 /** 018 * This class merely exposes the MMTk constants into the Jikes RVM 019 * package space so that they can be accessed by the VM in an 020 * MM-neutral way. It is separate from MemoryManager to break 021 * cyclic class-loading dependencies. 022 */ 023 public class MemoryManagerConstants implements SizeConstants { 024 /** {@code true} if the selected plan needs support for linearly scanning the heap */ 025 public static final boolean NEEDS_LINEAR_SCAN = Selected.Constraints.get().needsLinearScan(); 026 /** Number of bits in the GC header required by the selected plan */ 027 public static final int GC_HEADER_BITS = Selected.Constraints.get().gcHeaderBits(); 028 /** Number of additional bytes required in the header by the selected plan */ 029 public static final int GC_HEADER_BYTES = Selected.Constraints.get().gcHeaderWords() << LOG_BYTES_IN_WORD; 030 /** {@code true} if the selected plan requires concurrent worker threads */ 031 public static final boolean NEEDS_CONCURRENT_WORKERS = Selected.Constraints.get().needsConcurrentWorkers(); 032 /** {@code true} if the selected plan needs support for generating a GC trace */ 033 public static final boolean GENERATE_GC_TRACE = Selected.Constraints.get().generateGCTrace(); 034 /** {@code true} if the selected plan may move objects */ 035 public static final boolean MOVES_OBJECTS = Selected.Constraints.get().movesObjects(); 036 /** {@code true} if the selected plan moves TIB objects */ 037 public static final boolean MOVES_TIBS = false; 038 /** {@code true} if the selected plan moves code */ 039 public static final boolean MOVES_CODE = false; 040 } 041