1 /* 2 * Copyright (c) 2009, 2014, 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 * Represents the runtime representation of the constant pool that is used by the compiler when 27 * parsing bytecode. Provides methods to look up a constant pool entry without performing 28 * resolution. They are used during compilation. 29 */ 30 public interface ConstantPool { 31 32 /** 33 * Returns the number of entries the constant pool. 34 * 35 * @return number of entries in the constant pool 36 */ 37 int length(); 38 39 /** 40 * Ensures that the type referenced by the specified constant pool entry is loaded and 41 * initialized. This can be used to compile time resolve a type. It works for field, method, or 42 * type constant pool entries. 43 * 44 * @param cpi the index of the constant pool entry that references the type 45 * @param opcode the opcode of the instruction that references the type 46 */ 47 void loadReferencedType(int cpi, int opcode); 48 49 /** 50 * Looks up a reference to a field. If {@code opcode} is non-negative, then resolution checks 51 * specific to the bytecode it denotes are performed if the field is already resolved. Should 52 * any of these checks fail, an unresolved field reference is returned. 53 * 54 * @param cpi the constant pool index 55 * @param opcode the opcode of the instruction for which the lookup is being performed or 56 * {@code -1} 57 * @return a reference to the field at {@code cpi} in this pool 58 * @throws ClassFormatError if the entry at {@code cpi} is not a field 59 */ 60 JavaField lookupField(int cpi, int opcode); 61 62 /** 63 * Looks up a reference to a method. If {@code opcode} is non-negative, then resolution checks 64 * specific to the bytecode it denotes are performed if the method is already resolved. Should 65 * any of these checks fail, an unresolved method reference is returned. 66 * 67 * @param cpi the constant pool index 68 * @param opcode the opcode of the instruction for which the lookup is being performed or 69 * {@code -1} 70 * @return a reference to the method at {@code cpi} in this pool 71 * @throws ClassFormatError if the entry at {@code cpi} is not a method 72 */ 73 JavaMethod lookupMethod(int cpi, int opcode); 74 75 /** 76 * Looks up a reference to a type. If {@code opcode} is non-negative, then resolution checks 77 * specific to the bytecode it denotes are performed if the type is already resolved. Should any 78 * of these checks fail, an unresolved type reference is returned. 79 * 80 * @param cpi the constant pool index 81 * @param opcode the opcode of the instruction for which the lookup is being performed or 82 * {@code -1} 83 * @return a reference to the compiler interface type 84 */ 85 JavaType lookupType(int cpi, int opcode); 86 87 /** 88 * Looks up an Utf8 string. 89 * 90 * @param cpi the constant pool index 91 * @return the Utf8 string at index {@code cpi} in this constant pool 92 */ 93 String lookupUtf8(int cpi); 94 95 /** 96 * Looks up a method signature. 97 * 98 * @param cpi the constant pool index 99 * @return the method signature at index {@code cpi} in this constant pool 100 */ 101 Signature lookupSignature(int cpi); 102 103 /** 104 * Looks up a constant at the specified index. 105 * 106 * @param cpi the constant pool index 107 * @return the {@code Constant} or {@code JavaType} instance representing the constant pool 108 * entry 109 */ 110 Object lookupConstant(int cpi); 111 112 /** 113 * Looks up the appendix at the specified index. 114 * 115 * @param cpi the constant pool index 116 * @param opcode the opcode of the instruction for which the lookup is being performed or 117 * {@code -1} 118 * @return the appendix if it exists and is resolved or {@code null} 119 */ 120 JavaConstant lookupAppendix(int cpi, int opcode); 121 }