1 /* 2 * Copyright (c) 2012, 2015, 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 package jdk.vm.ci.meta; 24 25 /** 26 * Provides memory access operations for the target VM. 27 */ 28 public interface MemoryAccessProvider { 29 30 /** 31 * Reads a value of this kind using a base address and a displacement. No bounds checking or 32 * type checking is performed. Returns {@code null} if the value is not available at this point. 33 * 34 * @param base the base address from which the value is read. 35 * @param displacement the displacement within the object in bytes 36 * @return the read value encapsulated in a {@link JavaConstant} object, or {@code null} if the 37 * value cannot be read. 38 * @throws IllegalArgumentException if {@code kind} is {@code null}, {@link JavaKind#Void} or 39 * not {@linkplain JavaKind#isPrimitive() primitive} kind 40 */ 41 JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant base, long displacement) throws IllegalArgumentException; 42 43 /** 44 * Reads a primitive value using a base address and a displacement. 45 * 46 * @param kind the {@link JavaKind} of the returned {@link JavaConstant} object 47 * @param base the base address from which the value is read 48 * @param displacement the displacement within the object in bytes 49 * @param bits the number of bits to read from memory 50 * @return the read value encapsulated in a {@link JavaConstant} object of {@link JavaKind} kind 51 * @throws IllegalArgumentException if {@code kind} is {@link JavaKind#Void} or not 52 * {@linkplain JavaKind#isPrimitive() primitive} kind or {@code bits} is not 8, 16, 53 * 32 or 64 54 */ 55 JavaConstant readPrimitiveConstant(JavaKind kind, Constant base, long displacement, int bits) throws IllegalArgumentException; 56 57 /** 58 * Reads a Java {@link Object} value using a base address and a displacement. 59 * 60 * @param base the base address from which the value is read 61 * @param displacement the displacement within the object in bytes 62 * @return the read value encapsulated in a {@link Constant} object 63 */ 64 JavaConstant readObjectConstant(Constant base, long displacement); 65 }